＜抄録＞　河川・海岸分野の今後の発展に資することが期待される異分野技術について述べた。防災のための管理および利用の観点からは気象予測に関わる技術、減災のための危機管理の観点からは、ソーシャル物理学の知見、施設管理の観点からは、計測・監視技術への期待が大きいことを示した。これら技術を適切に取り入れることで、よりよい河川・海岸管理を行う必要がある。
In this report, we address interdisciplinary technologies expected to contribute to progress in river and coastal management. Disaster management can benefit from technologies developed for meteorological forecasting; crisis management to reduce disaster risks from social physics; and facility management from technologies for measurement and monitoring. Technologies developed in different fields of science and technology are necessary for the improvement of river and coastal management.

＜抄録＞　道路橋メンテナンスにおける点検・診断作業の省力化や診断レベルの維持を目的に、点検、診断、データ基盤構築におけるAIの活用について、業務支援につながる開発要求事項を踏まえ、開発の方向性を考察し、平成30年9月に土木研究所で着手した「AIを活用した道路橋メンテ ナンスの効率化に関する共同研究」の内容を報告する。
Artificial intelligence (AI) is expected to contribute to road-bridge maintenance by helping perform high-quality inspection and diagnosis more efficiently. To increase the use of AI in inspection, diagnosis, and database development, the Public Works Research Institute of Japan started joint research in September 2018 on the application of AI for more efficient road-bridge maintenance after setting the development direction based on users' needs for AI assistance. This report presents the latest results of the joint research.

＜抄録＞　老朽化の進む膨大な社会インフラに対し、効率的に維持管理を行うための技術革新が期待されている。土木研究所iMaRRCでは、これら解決する一つの方法として先端機能材料を利用して構造物の点検を簡易化する技術の開発を行っている。生体模倣、光化学、光干渉・幾何の分 野と共同開発している3つの研究の概要について報告する。
Technological innovation is keenly anticipated to efficiently maintain a significant amount of social infrastructure that is increasingly aging. To address this challenge, the Innovative Materials and Resources Research Center (iMaRRC), a research center of the Public Works Research Institute of Japan, has been developing technologies that help simplify structural inspection using advanced functional materials. This report outlines three interdisciplinary projects that are currently underway using the knowledge of biomimetics, photochemistry, optical interference, and geometrical optics.

＜抄録＞　第4次産業革命技術とも呼ばれているIoT、ビッグデータ、AI、ロボットの先端技術が公共土木分野の技術研究開発を支える手段や現場の実務を支える手段としてどのような活用が期待できるのか、また、社会実装する技術として更には公共調達で扱う対象とする上でどのような課題が見えているのか簡潔に整理し論じたものである。
IoT, big data, AI, and robots are commonly addressed as technologies that will bring the fourth industrial revolution to society. This report explores the possibilities of these advanced technologies as a means to support technological research and development, as well as actual project operations, in civil engineering. The report also concisely organizes and discusses issues related to the advanced technologies when they are implemented in various parts of society and when they are publicly procured.

＜抄録＞　各種ロボット技術について、技術特性や配備状況等の関連情報を一元化した、インフラ用ロボット情報一元化システムの概要とそのコミュ ニティの活動状況、平成30年度の技術公募の概要を紹介し、異分野連携におけるニーズとシーズのマッチングに併せて、多様な技術者の参画を図ることが重要であることを述べる。
In this report, we first outline a “one-stop” robot information system, which provides users with a wide range of information on construction robots, including their technological features and availability. How general users have been using the system is also explained briefly. Outlining the 2018 program calling for proposals of new technologies, we also highlight the importance of involving engineers of different expertise in a project by matching needs and seeds in different fields of engineering and science.

＜抄録＞　近年のICT等の技術革新が急速に進展する中で、ICTやETC2.0プローブデータ等を最大限活用して道路の既存ストックを有効活用する取り組みを推進しており、道路交通分野において情報通信、自動車、電気、地図などの分野と連携・協同して取り組んでいるビッグデータを活用 した道路交通マネジメントと自動運転を中心に、取り組みの概要と今後の展望について述べる。
As technology, such as ICT, has been fast evolving in recent years, we have been exploring various ways to utilize the capacity of existing road network efficiently by maximizing the use of ICT and ETC2.0 probe data. In this report, we provide an overview of our ongoing efforts and prospect mainly about big data-driven road traffic management and self-driving technology, while explaining how we collaborate with experts in different fields related to road traffic management, such as information and communication, motor vehicles, electricity, and mapping technology.

＜抄録＞　水中に浮遊する生物の組織片から生物の遺伝情報をとりだす“環境DNAを使った生物調査”は、生態学や分子系統学といった理学分野において開発・急速に広まっている。生物を直接捕えることなく周辺の生物種や存在量の情報を得る本技術を河川管理の現場に取り入れることに より、調査負担の軽減や高度化を図ることが期待される。既に希少種の調査などでは良好な成果が得られつつある1)一方で、未解明な部分も多いことから、土木研究所では異分野の専門家たちと連携しながら精査を行っている。本報文では実務における効果的な活用方法と実用化にあたっての留意点を述べる。
Biological investigations using environmental DNA, which collect genetic information of living organisms from tissue fragments floating in environmental water, have been developed and rapidly spreading in the field of science such as ecology and molecular phylogeny. Since this innovative approach can help acquire information on biological species and abundance in a specific environment without capturing creatures, it is expected to improve the efficiency and quality of investigations in river management. The approach has already been evaluated positively in investigations on rare species. However, further study is necessary to understand the approach better, and the Public Works Research Institute of Japan has been vigorously working on the matter with support from experts in different areas of science and technology. This report presents several applications of the new approach we have found practical and key considerations for actual use.

＜抄録＞　平成25年の道路法改正等を受け点検要領が策定され、道路管理者はトンネル等の道路構造物について5年に1度、近接目視を基本とした定期点検を行うこととなった。本稿は、シェッド及び大型カルバートについて平成26～28年度の定期点検結果より、構造物の構造特性や設置環境特性から変状の発生傾向を整理したものである。
Following the 2014 revision of the Road Law, the road inspection procedures were also revised, requiring road managers to conduct periodic close visual inspections once in every five years for road structures such as tunnels. This report summarizes deformation trends of sheds and culverts according to the characteristics of structures and building-site environments, based on the analysis of the periodic inspection data collected in 2015, 2016 and 2017.

＜抄録＞　本稿では、都市間高速道路の加速車線において、車両の合流速度及び合流位置等による合流挙動実態を把握して、合流挙動実態に基づく合流挙動に影響を及ぼす要因について分析を行い、現行の加速車線長算定手法について考察を行った。
In this study, we investigated the condition of merging behavior in terms of merging speed and merging position in an inter-urban expressway acceleration lane and identified factors considered to affect the merging behavior, based on the investigation results. Then, we examined the current method used to calculate acceleration lane length in consideration of the factors identified.

＜抄録＞　本稿は、単路部での横断歩行者事故の対策推進に向けた基礎的な検討として、歩行者横断中の交通事故及びその集中箇所の特徴分析を行った。その結果、2車線の道路で多く発生していること、集中箇所が存在することとその特徴などを明らかにした。
To reduce traffic accidents that victimize pedestrians crossing the basic road section, we analyzed the characteristics of such traffic accidents and those of locations prone to the accidents in question. The analysis found that they occur more often in specific locations and when a pedestrian is crossing a two-lane roadway. The characteristics of the accident-prone locations were also revealed through the analysis.

＜抄録＞　CAESARでは鋼橋の設計の合理化に向けて、高力ボルト及びケーブル部材を対象とした研究を行っている。その結果、高力ボルト摩擦接合継手の多列配置におけるすべり耐力の低減係数、橋の種類や構造形式によらないケーブル部材の部分係数の規定化につながる成果を得た。
The Center for Advanced Engineering Structural Assessment and Research has been studying the rationalization of steel bridge design, focusing on high-strength bolts and cables. The results have been promising for standardizing the reduction coefficient of slip resistance to be used for arranging multiple high-strength bolted friction-type joints, as well as for standardizing load and resistance factors for cables applicable regardless of bridge types or structures.

＜抄録＞　北海道におけるRC床版では、近年、凍害とASRが複合的に進行した床版が顕在化しつつある。本稿では、凍害とASRによる複合劣化が進行した床版の健全度評価手法の確立に向けた一検討として、実橋撤去床版の静的載荷試験に基づくたわみ計測およびたわみ評価方法の検討を実施した結果について報告する。
In recent years, frost damage-ASR combined deterioration has been increasingly apparent in RC slabs used in Hokkaido, Japan. To take effective measures for this problem, we have been exploring approaches to the integrity evaluation of RC slabs that show signs of deterioration due to frost damage and ASR. In this report, we present the results of static loading tests conducted to evaluate the deflection of RC slabs removed from actual bridges.

＜抄録＞　土木研究所構造物メンテナンス研究センターでは、液状化地盤における橋梁基礎の耐震性能評価技術および耐震対策技術の開発に取り組んでいる。本報では特に、液状化地盤における橋台基礎の耐震性能照査法の課題を示すとともに、課題解決の上で重要なポイントとなる基礎への作用土圧について、分析を行った結果を報告する。
The Center for Advanced Engineering Structural Assessment and Research has been working on the development of technologies for seismic performance evaluation and seismic damage control for abutment foundations built on the liquefiable ground. In this report, we first address issues of a seismic performance inspection method currently in use for abutment foundations on the liquefiable ground. We also present the results of an analysis performed on earth pressure acting on the foundation, which is a crucial factor for finding solutions to the issues addressed.

＜抄録＞　本稿では、RC巻立て補強された橋脚を対象に限界状態の評価方法について検討を行った。その結果、損傷の進展メカニズムに基づき限界状態を評価する方法を示し、既往の方法と比較して精度よく推定できることを確認した。
In this research, we studied a new method to evaluate the limit states of bridge columns retrofitted by RC Jacketing. We developed the method based on a damage mechanism. The test results confirmed that our method can evaluate the limit states better than the current method.

＜抄録＞　熊本地震において損傷が生じた鋼I桁橋の主桁支点部に着目し、塑性化挙動において鉛直耐荷力が急激に低下せず、橋の機能回復が容易に行える損傷形態に誘導するなどのダメージコントロールの実現性について基礎的な解析的検討を行った結果を報告する。
In the Kumamoto Earthquake, bridges suffered considerable damage in steel I-girder ends. To avert such damage in future seismic events, we have been studying damage control measures that prevent sharp reduction of vertical loading capacity in the plasticizing behavior and only allow damage that requires simple repair in restoring the function of the bridge. This report presents the results of a preliminary analysis to assess the feasibility of the damage control measures.

＜抄録＞　沖縄県は、「国立研究開発法人土木研究所」及び「一般財団法人沖縄県建設技術センター」と塩害環境下でコンクリート橋を100年供用するための維持管理手法や技術基準の確立を目指した協力協定を締結しており、調査データを共有・活用している。協力協定の取り組みについて紹介する。
Okinawa Prefecture of Japan has signed a cooperation agreement with the Public Works Research Institute and the Okinawa Prefectural Center of Constructional Technology, aiming at the establishment of maintenance methods and technological standards to ensure the 100-year durability of concrete bridges in a salt-damage environment. Under the agreement, the three entities have been sharing data and information that are useful to achieve the goal. This report describes their efforts that have been made in this cooperative framework.

＜抄録＞　平成25年の道路法改正を受け、道路管理者は全ての橋梁について5年に1回の定期点検を実施しており、本稿では、定期点検で確認されたＲＣ床版の損傷事例や、これまでに実施したＲＣ床版の補修事例と課題について述べる。
In compliance with the Road Law revised in 2013, road management offices in Japan inspect all bridges in their area every five years. In this report, we present several cases of damage found in the periodical inspections of RC bridge slabs. We also explain how the repair was done as well as some issues related to the repair work.

＜抄録＞　公共用水域の衛生学的安全性を担保ため、水系感染リスクを低減させるため下水処理場における的確な消毒レベルを設定する必要がある。 現状では不活化効果の評価手法が確立されていないノロウイルスにおいて、F特異RNAファージを用いることで不活化効果を推定できる可能 性が示唆された。
To ensure the hygienic safety of public water bodies, it is crucial to set a disinfection level to reduce water-borne infection risks at sewage treatment facilities appropriately. Focusing on norovirus, for which no measures have been established to evaluate the virus’s inactivation, our study suggests that it may be possible to evaluate its inactivation by introducing F-specific RNA bacteriophage genotypes.

＜抄録＞　本報では、アスファルト舗装の劣化診断の簡便化と省力化を目指し、赤外分光分析を利用したアスファルト混合物の劣化評価手法について紹介する。また、本手法を利用して、アスファルト舗装内部の劣化度合いについて検証したので報告する。
We have been developing a simpler, more efficient method to evaluate the aging status of asphalt pavement. In this report, we introduce a new method using Fourier-transform infrared spectroscopy to evaluate asphalt mixture for deterioration. We also report the results of an inspection in which this method was used to estimate the inner degradation of asphalt pavement.

＜抄録＞　消化汚泥の脱水ろ液には高濃度のアンモニアが含まれているが、一般的には資源として有効利用されていない。本研究では、既存のアンモ ニア回収技術を脱水ろ液に適用した場合の回収濃度・回収率の分析、下水道統計に基づく回収可能量の推定及び脱硝剤としての有効利用の可能性検討を行ったため、その成果を報告する。
Although high concentrations of ammonia is contained in dehydration filtrate from digested sludge, this potentially useful gas has not been effectively used in general. In this study, we analyzed the recovery concentration and rate of ammonia that was collected by applying conventional ammonia recovery technology to dehydration filtrate. We also evaluated the recoverable volume of ammonia based on sewage statistics and studied the possibility of using recovered ammonia as a denitrifying agent. The results are presented in this report.

＜抄録＞　平成29年道路橋示方書において、耐荷性能が位置づけられ、限界状態設計法、部分係数法が導入された。そこで、せん断力を受ける橋梁用積層ゴム支承についての限界状態を把握し、設定方法を提案するために水平加振実験に基づく検討を行った。
In The Specifications for Highway Bridges revised in July 2017, the new concepts of the load and resistance factor design and the limit state design were introduced to check the load carrying capacity of highway bridges. Therefore, we conducted horizontal loading tests to propose an approach to appropriately assess and set the limit state of bridge laminated rubber bearing, which receives shear force.

＜抄録＞　国土交通省では、ＩＣＴ活用のため、アスファルト舗装工事の出来形管理へ新たに「面管理」を導入の上、各種基準類を整備したが、実際にＩＣＴを活用した工事現場において基準類の適用性検証を行い、検証結果を踏まえた課題を整理するとともに、課題を踏まえた改善を行っ た。
The Ministry of Land, Infrastructure, Transport and Tourism of Japan has introduced the new concept of “area as-built management” to promote as-built management in ICT-based road paving work and prepared criteria necessary for the implementation of road pavement. In this study, we tested the criteria at an ICT-driven work site to assess their applicability. The test results were used to sort out issues, and the improvement of ICT-based paving work was carried out in reference to the issues identified.

＜抄録＞　本文では、斜面上に設置された道路橋基礎に対してすべり力が作用した場合の、斜面崩壊等の条件や基礎の構造の違いが基礎の安定性に及ぼす影響や斜面崩壊等のメカニズムを把握することを目的として実施した遠心模型実験の結果を報告する。
In this study, we conducted centrifuge model tests for the following purposes: to characterize the conditions and mechanisms of slope failure and other types of ground movements and to assess the effect of different ground movements on the stability of road bridge foundations when sliding force acts on bridge foundations built on a slope. The results are presented in this report.

＜抄録＞　伝統工法に係る人材・材料・資金等の確保が困難な状況を踏まえ、伝統工法の保全・活用に携わる有識者に対するヒアリングや全国各地における取組事例の調査を通じて、伝統工法に係る各種資源を確保し、伝統工法の保全・活用を通じた持続的な地域づくりを進める上での基本的な考え方や具体的なアイデア・ノウハウを整理した。
Since our previous study revealed that it has become difficult to supply human, material, financial and other resources necessary for traditional construction methods in Japan, we have conducted interviews with experts in this field and case studies of conservation and utilization of traditional construction methods in different regions. As a result, we suggested basic principles and practical ideas of conservation and utilization of traditional construction methods for sustainable community development.

＜抄録＞　近年、南海トラフ巨大地震等の大規模地震の切迫性や気候変動に伴う水害リスクの増大を踏まえ、都市の防災性向上が求められている。本稿では、防災公園等の都市公園のみならず、道路・河川・学校等の公共緑地や樹林地・農地等の民有緑地を含めた防災系統緑地全体の充実に向けた緑の基本計画の策定手法について紹介する。
As the risks of mega-earthquakes and extreme weather disasters associated with climate change increase, municipal governments in Japan are faced with the urgent need for implementing disaster risk reduction systematically by making effective use of urban green infrastructure. This report presents a methodology for developing green master plans for disaster risk reduction.

＜抄録＞　冬期道路交通の確保における効果的な除雪手法や体制の検討のため、国土交通省が作成した費用便益分析マニュアルの考え方を援用して道路除雪の効果を経済的に評価することを試みた。試算の結果、早期の通行止め及び集中除雪による早期の交通回復により、交通障害時間及び経済損失の大幅な軽減が期待される可能性を示した。
In order to introduce more effective snow removal methods and systems, we evaluated the effects of the snow removal using the procedures described in the cost-benefit analysis manual compiled by the Ministry of Land, Infrastructure, Transport and Tourism of Japan. The analysis indicated that the restoration of the normal road traffic would take less time than otherwise if early road closures and targeted snow removal are executed and that a significant reduction would be expected in traffic disruption time and economic loss.

＜抄録＞　東日本大震災で未曾有の被害を受けた海岸堤防は、「粘り強い構造の堤防」で整備した。その中でも仙台市の井土浦地区では、優れた自然環境の回復に配慮してCSG海岸堤防を実施したので、その設計・施工事例について報告するものである。
Resilient coastal levees have been introduced for rebuilding the coastal levees that were damaged unprecedentedly when the Great East Japan Earthquake occurred. In this project, cemented sand and gravel (CSG) was used to build levees in the coastal sections of Idoura, Sendai, in the hope of the robust recovery of the natural environment. In this report, we explain a case of the design and construction of the CSG levees.

＜抄録＞　平成23年の台風12号により、紀伊半島では一部地域で雨量が2,000ミリを超えるなど記録的な豪雨に見舞われ、甚大な被害が発生し、発災直後から緊急対策工事を実施してきた。本稿ではこれらの対策のうち、これまでに対策事例が少なかった河道閉塞箇所（天然ダム）における対策工事について、これまでの取組について紹介する。
Heavy rainfall by Typhoon No.12 in 2011 caused serious damage in the Kii Peninsula of Wakayama, Japan. The rainfall recorded more than 2,000 mm in some parts of the peninsula. We constructed emergency sabo structures soon after the disaster to prevent landslide dams from causing further damage. Few countermeasures have so far been implemented to prevent possible damage due to landslide dams. In this report, we describe how we constructed the sabo structures after the September 2011 flood in the Kii Penninsula.

＜抄録＞　道路舗装の効率的な構造評価手法の確立が求められる中、土木研究所では移動しながら舗装のたわみを測定する装置であるMWD(Moving Wheel Deflectometer)の開発を進めてきた。本報では、これまでのMWDの開発成果及び試作機を用いた実道での検証などこれまでの開発の取り組みについて報告する。
The establishment of an efficient structural assessment method for road pavement has been placed high in the priority list. The Public Works Research Institute of Japan has been working on the development of a Moving Wheel Deflectometer (MWD), which is capable of measuring deflection levels of road pavement while moving. In this report, we explain the MWD that we have developed and the results of experiments conducted using a test model on an actual road.

＜抄録＞　「舗装点検要領」において、コンクリート舗装の破壊メカニズムの観点から目地部管理の重要性が指摘されている。土木研究所では、コンクリート舗装の目地部における健全性診断手法の構築に取り組んでおり、本稿では、目地部の点検・診断における課題と課題解決に向けた近年の取り組みを紹介する。
The guidelines for pavement inspection, published in October 2016, points out the importance of managing pavement joints from the viewpoint of the destruction mechanism of concrete pavement. In response, the Public Works Research Institute has been developing a soundness evaluation method for concrete pavement joints. In this report, we address issues related to the inspection and soundness evaluation of pavement joints and explain our recent efforts to solve these issues.

＜抄録＞　平成25年の道路法改正等を受け道路トンネル等の道路構造物について5年に1度、近接目視を基本とした定期点検を行うこととなった。本報文は、既設道路トンネルの現状と定期点検結果の概要及び国管理の道路トンネル定期点検結果の分析結果を示したうえで、全道路トンネルに対する定期点検要領の見直しの動向について報告するものである。
In 2013, the Road Act and related regulations were revised in Japan, requiring close visual inspection of road structures such as tunnels every five years. In this report, we present the current status of existing road tunnels, the summary of results of its periodic inspections and the results of analyses performed on nationally-managed road tunnels, as well as explain the prospect of revising the guidelines for road tunnel periodic inspection.

＜抄録＞　本稿では、NATMにより建設された道路トンネルにおいて、覆工コンクリート表面の点検記録から、材質劣化に起因するひび割れやうきの発生時期・部位・規模の傾向や、ひび割れとうきの相互の関連性等の分析結果について報告する。
We have been studying the deterioration of lining concrete applied to the surface of tunnels constructed using the New Austrian Tunneling Method (NATM). We analyzed tunnel inspection records to learn about cracks and blisters caused due to concrete deterioration. In this report, we present findings regarding when cracks and blisters start appearing and in which part of the tunnel and at what scale they are likely to take place. We also report the results of the analysis on other issues including the relationship between cracks and blisters.

＜抄録＞　既設トンネルを拡大する掘削(以降、拡大掘削)と、何も無い地山への新たなトンネル掘削を解析により比較し、拡大掘削の方が支保構造への負担が小さいことや、掘削時の切羽がより安定的となる可能性等が確認された。また、拡大掘削では既設トンネルの覆工の一部が不安定化する可能性があり、活線施工時の防護工の必要性が示唆された。
In this study, we compared the re-excavation of an existing tunnel with the construction of a new tunnel. The study found that reexcavation causes less stress on the tunnel support structure and is more likely to keep the tunnel facing stable. The study also suggested that protection should be installed when re-excavation is carried out without road closure, because the tunnel lining can become unstable during the re-excavation.

＜抄録＞　積雪寒冷地の舗装には、高い耐久性と十分な走行安全性を確保するための性能が求められる。そこで、新たな表層用アスファルト混合物の検討が行われ、北海道型SMAと呼ばれる混合物の導入が提言された。本レポートでは、北海道型SMAの基本性状を述べるとともに、開発の経緯、北海道開発局における導入状況等について紹介する。
Road pavement for cold, snowy regions needs to ensure high durability and driving safety. To meet these conditions, we have been studying a new type of asphalt mixture for road surface and recently proposed a new mixture called high-performance SMA. In this report, we explain the basic characteristics of this new SMA, its developmental process, and cases of road pavement using highperformance SMA in the area of the Hokkaido Regional Developmental Bureau.

＜抄録＞　国道127号の老朽化した坂下トンネルにおいて、プロテクタを使用した活線施工によりNATMにてトンネル拡幅工事を実施した。本報文では、トンネル拡幅工事についての施工方法・施工上の課題について報告し、施工性の向上について検討する。
Tunnel widening with protectors was conducted for the aged Sakashita tunnel of National Route 127 using the New Austrian Tunnelling Method (NATM) with one of the two road lanes left open for traffic. In this report, we address issues related to the construction method and process and discuss how workability can be improved in this type of construction.

＜抄録＞　国土交通省では発注者と受注者が共に長期的な品質確保を意識し、ライフサイクルコスト削減や長寿命化の実現を図ることを目的に長期性能保証制度の導入を進めている。本報告では、施工中に加えて工事完了後一定期間の性能を保証する、舗装工事及びトンネル工事の「長期性能保証」制度に関して、概要や取り組み状況を報告する。
In Japan, the Ministry of Land, Infrastructure, Transport and Tourism has been promoting the introduction of a long-term performance assurance system in order to raise the awareness of the contractee and the contractor in ensuring a decent quality level of infrastructure and realizing less lifecycle cost and longer service life. In this report, we outline the long-term performance assurance system developed for pavement and tunnel construction to guarantee a certain level of pavement and tunnel performance during and after the construction, as well as explain the recent progress of the project.

＜抄録＞　冬期道路の立ち往生車の発生に関し、発生状況に関するデータ分析や現場ヒアリング等をもとに特徴を把握して原因や課題等を整理している。これらの整理結果や現場との対話を通して、道路構造上の工夫により課題解決する方向性をまとめることを目指している。本稿では、立 ち往生車の発生の基本傾向をとりまとめた結果を報告する。
In this research, we studied how and why vehicles get stuck on the road during the winter season by analyzing data and interviews collected from such incidents. This report summarizes the basic trend of the incidents in question, aiming to present a research direction for finding solutions by modifying the existing road structure, based on the analysis results and dialogue with road management personnel.

＜抄録＞　2019年3月に設立40周年を迎えた土木研究センターは、「土木に関する調査、試験および研究の促進に努めるとともに、その成果の普及を図る」という使命を果たすべく、時代の変化に柔軟に対応してきた。本文は、これまでの歩みを振り返るとともに、土木技術分野の課題解決に向けた研究成果の活用、民間技術開発の支援などの新たな取り組み、方向性を紹介し、引き続きの活用、支援を願っている。
The Public Works Research Center marks its 40th anniversary in March 2019. With the mission of promoting investigation, testing, and research in the field of civil engineering and actively disseminating the outcomes, the center has been fulfilling its responsibilities while flexibly meeting social needs that have changed over time. In this report, we reflect on our past achievements and overview new directions and plans, such as maximizing the use of research outcomes to solve civil engineering problems and supporting the development of new technologies in the private sector.

＜抄録＞　長期間水中に暴露してASRを進展させたディープビーム供試体に対し、既設道路橋のフーチングを想定して上面側からのあと施工鉄筋によるせん断補強を施し、載荷実験を行った。本稿では載荷実験の結果とせん断補強効果の評価について報告する。
To investigate the effect of bar-anchor shear force reinforcement, we conducted load testing on deep-beam test pieces. With the test pieces degenerated due to ASR by leaving them in water for a long period, the load testing was carried out after applying shear force reinforcement by inserting bar anchors from the upper surface of the pieces, assuming an application of footing to road bridges. In this report, we present the test results and the evaluation of the effect of the shear force reinforcement.

＜抄録＞　本研究では、従来から一般的に下水処理手法として用いられている標準活性汚泥法を改良した新規省エネルギー型下水処理技術の開発を目的とした。標準活性汚泥法の曝気槽の前段半分を部分循環式嫌気性ろ床に置き換え、曝気に要する電気エネルギーを半減させた処理手法において、有機物の安定した除去を達成した。
This research was conducted to develop a new energy-saving wastewater treatment system by improving the conventional activated sludge process, which has been commonly used for wastewater treatment up to today. The improvement was made by replacing the front half of the activated sludge tank with a partially cycling up-flow anaerobic packed bed reactor. The research verified the new system for the capability of removing organic matters consistently while consuming merely half the electricity the conventional process uses for aeration.

＜抄録＞　2018年7月の西日本豪雨では、尾道・松江自動車道でも斜面変状が発生し、一部では切土のり面に設置されたグラウンドアンカーが破断したり、破断には至らないものの降伏強度を超える過緊張状態になったりしたが、大規模な土砂崩落には至らず、通行止めも数日で解消され た。本報告では尾道自動車道吉舎IC、松江自動車道高野ICでの斜面変状、アンカーの損傷状況、応急対策並びに恒久対策について紹介す る。
As in other roads, slope deformation also occurred in Onomichi and Matsue Expressways as a result of the western Japan heavy rain in July 2018. Ground anchor slopes were found ruptured in some slopes, and, if not ruptured, they were under overstrain exceeding the yield strength in other slopes. However, the problems with ground anchors did not lead to large-scale slope failures, and the road closures were lifted only after several days. This report outlines the cases of slop deformation found around the Kisa interchange of Onomichi Expressway and the Takano interchange of Matsue Expressway, as well as damage caused to the anchors and emergency and permanent measures for deformation control.

＜抄録＞　地域・地質・降雨条件を同一とした時の山地上流域からの流出土砂量の空間的ばらつきについて、航空レーザ測量データと解析雨量を用い 分析を行った。山地上流域からの単位面積当たりの流出土砂量は、一定程度条件を同一にした場合でも流域によってはばらつきが生じるこ と、頻度分布は対数正規分布で表現できることを示した。
This study compared mountainous watersheds in spatial variability in sediment discharge volume while controlling geographical, geological and rainfall conditions, using LiDAR survey data and radar-rain gauge analyzed precipitation. The results found that the sediment discharge volume per unit area varied among the watersheds even when the three conditions were kept identical. The study also confirmed that the frequency distribution can be represented by the lognormal distribution.

＜抄録＞　本研究では、代表的な既往災害と指標値を紐付けることにより、指標値から土砂災害の規模を容易に想起できるように試みた。ここでは、 既往の代表的な土砂災害について、「土砂移動マグニチュード」を算出した結果及び災害時に簡便に算出する手法について報告する。
In this study, we developed a new system by assigning index values to representative sediment disasters in the past so that the user will quickly understand the scale of a sediment disaster in reference to an index value. In this report, we present the “sediment movement magnitude” calculated for the selected sediment disasters and explain the method invented for a simple calculation of the magnitude when a disaster occurs.

＜抄録＞　地方自治体が管理する橋梁の日常点検を「簡易橋梁点検チェックシート」を用いて橋の利用者や管理者で行い、橋面上の汚れの程度が確認できる「橋マップ」を活用した地域での清掃活動を行い、予防保全活動へ繋げるという「セルフメンテナンスふくしまモデル」について述べ た。
In this report, we explain “Self-Maintenance Fukushima Model,” a municipal effort practiced in Fukushima Prefecture, Japan, to maintain the safety of local bridges. In this effort, bridge users and managers in each municipality conduct regular inspections of bridges in their area using “Simple Bridge Inspection Check Sheets” and also clean the bridges according to “Bridge Maps,” which show each bridge’s level of need for cleaning.

＜抄録＞　平成30年度に、長大PC橋である各務原大橋の定期点検においてロボット点検技術を活用した。ロボット点検技術を活用した事前調査を、 道路橋定期点検要領に基づく近接目視に先立って実施した。参加したロボット点検技術の完成度が高まるとともに、橋梁点検車両による橋面片側交通規制期間を10日間から4日間に短縮できた。
In 2018, we introduced robotic technology for the periodic inspection of Kakamigahara Ohashi, a long-span PC bridge in Kakamigahara of Gifu Prefecture, Japan. A preliminary inspection with robotic technology was carried out before a close visual inspection required by the official guidelines for periodic road-bridge inspection. The new approach helped improve the quality of robot inspection and shortened the half road closure period during the inspection from 10 to 4 days.

＜抄録＞　中津干潟に流入する舞手川河口において、隣接砂丘地の侵食と河口閉塞を防ぐために袋詰め玉石製の河口導流堤の試験施工を行った。その後ドローンによる空中写真撮影と現地調査を行った。この結果、河口への土砂逆流防止を図る上での導流堤効果が確認され、また河口導流堤の西側隣接部において回復した砂州においてカブトガニの産卵が行われるなど、当初の予定を上回る成果が得られた。
A field test of a river-mouth jetty composed of gravel net, which aimed at the prevension of beach erosion of the sand dune area around the river mouth and river-mouth closure, was carried out at the Maite River mouth facing the Nakatsu tidal flat in Oita Prefecture. Aerial photographs were taken using a drone as well as field observation. It was concluded that this method was effective for preventing sand transport toward the river mouth. Also, a spwning ground of horseshe crabs was recovered by the construction of the river-mouth jetty.

＜抄録＞　平成29年に「ダム再生ビジョン」が策定され、既設ダムを有効活用する「ダム再生」が推進されている。本報告では、ダム再生を推進する方策の一つとして放流設備増強技術を述べるとともに、代表事例として長安口ダム改造事業を取り上げて、再開発事業の水理設計の内容を報告する。
Since a national policy, “Dam Upgrade Vision,” was developed in 2016, dam upgrading has been underway to promote the effective use of existing dams. This report explains innovative technology to improve water release facilities as one of the dam upgrading measures and details hydraulic design employed in the project by taking the Nagayasuguchi Dam Improvement Project for example.

＜抄録＞　ダム再生ビジョンでは「ダムの長寿命化」などで堆砂対策の必要性が掲げられており、既設ダムを半永久的に活用するため堆砂対策技術を発展させていく必要性が増してきている。本稿では今後の堆砂対策技術の発展に資すると考えている土木研究所で開発中の貯水池の水位差を活用した新技術（潜行吸引式排砂管）の開発状況について紹介する。
As “Dam Upgrade Vision,” a policy proposal, addresses the importance of sedimentation control measures in relation to dams’ service life, it is increasingly urgent to improve sedimentation control technology to keep existing dams in service as long as possible. This report provides an overview of burrowing-type sediment removal suction pipes, which are currently under development at the Public Works Research Institute of Japan. This new technology is designed to use the water head deference to control sedimentation and expected to contribute to progress in sedimentation control technology in the future.

＜抄録＞　ダム貯水池は、通常100年分相当の堆砂を考慮した上で必要容量を確保するよう計画される。しかし、想定以上に堆砂が進行すると、長期的にダム機能を維持するため、各ダムの特性に応じた対策が求められることがある。そこで、合理的な堆砂対策を選定するため、中長期的な発生費用だけでなく、治水面での持続的な効用発揮にも着目したダム貯水池堆砂対策の評価手法について検討したので報告する。
Dam reservoirs are typically designed to ensure sufficient storage capacity needed for flood control and water use by taking into account 100 years’ worth of sediment. However, if sedimentation progresses faster than expected, additional measures, tailored to cope with specific conditions, may be taken to keep dams properly functioning for a long period. To select practical sedimentation control measures for such cases, we have been studying methods to evaluate the economic feasibility of possible measures by estimating not only their medium- to long-term cost and also long-term benefit especially from maintaining flood control function of a dam reservoir.

＜抄録＞　土砂バイパストンネルのような流速が大きい水路を流下する礫量を推定するため、最大15m/s程度の流速条件にて実験水路上流から礫を投入し、水路下流に設置したプレート型センサで礫を検知する実験を行った。そして、検知した波形を用いて礫流下量を推定する手法を提案し た。
It is important to understand the amount of sediment flowing in a sediment bypass tunnel designed for reducing sedimentation in a dam reservoir. To this end, a method for estimating the amount of gravel flowing in a high-speed flow is required. In this study, we conducted flume experiments with a high-speed flow of about 15 m/s to devise a method for estimating gravel discharge rates by grain size category using a plate-type sensor and analyzed the experimental data. The estimation method was then verified using both acoustic and vibration sensors.

＜抄録＞　鶴田ダム再開発事業は、一刻も早い治水効果の発現を目指し、安全面を確保しつつも、常に効率的な施工方法、施工計画を模索しながら進捗し、平成31年1月に無事完了いたしました。また、国内最大級のダム堤体削孔、大水深での水中作業などにおいて、多くの先駆的な技術を採用することで、ダム再生技術の飛躍的な発展をもたらすことができました。
The Tsuruta Dam redevelopment project was completed successfully in January 2019. While taking adequate safety measures, the project was carried out trying out more efficient construction approaches and planning to put the dam back into flood control practice as soon as possible. The project utilized many highly advanced techniques and technologies, including dam body drilling of the largest scale nationwide and underwater operation at greater depths, contributing to drastic progress in dam redevelopment technology.

＜抄録＞　天竜川ダム再編事業は、天竜川中下流部沿川の洪水被害軽減を目的として、利水専用ダムである佐久間ダムへ新たに洪水調節機能を確保するとともに、堆砂対策を実施するものである。今回は、堆砂対策に関する検討状況についてその概要を報告する。
The Tenryugawa dam reorganization project aims to mitigate flood damage in the middle and lower Tenryugawa River by adding the flood control function to Sakuma Dam, a dam now exclusively used for water utilization, and taking sedimentation control measures. This report outlines the planning of sedimentation control measures.

＜抄録＞　深層崩壊が発生するおそれのある斜面を事前に抽出するため、空中電磁探査により得られる地盤の比抵抗分布の分析に基づく崩壊危険度や崩壊面の位置を推定する方法を検討した。比抵抗分布から、比抵抗が変化する位置に着目し、ボーリング調査結果と比較を行った。その結果、比抵抗分布は比較的精度良く岩盤風化状況を表現していることが分かった。
In mountainous regions, deep-seated landslides occur occasionally. Such landslides often cause debris flows and induce landslide dams in some cases. Previous studies employed topographical and geological surveys and hydrological observation to detect slopes with high landslide risk. However, these methods are often costly and time-consuming. To solve this problem, we developed a new method for identifying high-risk slopes by introducing air-borne electromagnetic survey. This method can obtain the resistivity distribution of the ground in a wide area at one time. To verify the applicability of the risk assessment, we compared the depth at which the resistivity changes in the vertical direction with the weathering depth of the boring core. We found that the spatial variation of resistivity, such as changes in resistivity in the vertical direction, can indicate the status of bedrock weathering.

＜抄録＞　三環状の整備が進む首都圏高速道路ネットワークでは混雑緩和のため適切な交通分散を図ることが今後重要である、そのためにはまず現状の交通流動を把握する必要がある。本稿では、交通シミュレーションにETC2.0プローブ情報や車両感知器情報を活用して交通流動を推計する手法の概要および再現性の検証結果について報告する。
As the three ring roads in the Tokyo metropolitan area are now near completion, more attention is being drawn to the importance of taking appropriate operational measures to distribute traffic so that congestion can be alleviated. For that, firstly it is necessary to understand current traffic conditions. In response, we have been studying ways to improve traffic simulation by incorporating information from ETC2.0 probes and vehicle detectors. In this report, we provide an overview of a new approach to estimate the traffic condition of the expressway network in the Tokyo metropolitan area and report the test results on its reproducibility.

＜抄録＞　自然由来重金属等含有土を覆土のみで盛土内部へ利用する状況を模擬した盛土に、長雨や豪雨に相当する降雨を与え、盛土内への降雨浸透状況を調べた。その結果、要対策土を覆土のみで盛土内に利用し、盛土表面の一部を遮水する簡易な対策でも、要対策土への降雨の到達やそれに伴う重金属等の溶出の抑制が期待できると考えられた。
In this research, we studied the permeation of rainwater into a model embankment by giving mock rainfall equivalent to long-term or torrential rainfall. The embankment was filled with naturally contaminated soil in its inside with its surface covered with earth. The results found that it is possible to prevent the rainwater from reaching the naturally contaminated soil lying under the earth cover and thus keep pollutants from eluting and spreading by applying simple water-shielding measures to part of the embankment surface.

＜抄録＞　本稿は、国土交通省の事業評価結果をデータベース化した事業評価カルテ等に蓄積された多様なストック効果の実例を、新規事業採択時評価の結果と比較分析し、これらの実例を将来の新規事業採択時の評価等で効果的に活用するための方法について考察したものである。
The Ministry of Land, Infrastructure, Transport and Tourism has created databases of the evaluation results of various infrastructure construction projects. Using these databases, we analyzed different types of projects by comparing the stock effects arising after their implementation and the stock effects estimated when they were evaluated for adoption as new projects. This report discusses approaches for the effective use of the analyzed cases for the adoption of new projects in the future.

＜抄録＞　本報は、植生工による侵食・表層崩壊の抑制効果について、施工直後から根系の活着により保護工が成立するまでの降雨に対する性能の変 化を明らかにし、表層すべりに対し施工直後から効果を発揮する植生のり面保護工法、補助工法を提案することを目的に実施した実験的検討結果を紹介するものである。
This report presents the results of the experimental study that was conducted to propose the effective supplementary construction method on the planting slope protection works for surface failure by rainfall. In this research, focusing on the effect of planting works for controlling erosions and surface failure during from the period immediately after the construction to the period when the protection was completed with the plants taking root, we clarified how rainfall would affect it.

＜抄録＞　原位置液状化強度を把握するための試験方法には、多くの課題が残されている。そこで、原位置液状化試験法として振動式コーンの試作・検証を行っている。本研究では、振動式コーンによる原位置液状化試験法の確立に向けて、室内土槽実験の結果から、計測データの解釈方法、原位置液状化強度の評価方法について検討した。
Many problems remain unsolved regarding test methods for measuring in-situ liquefaction resistance. To address this situation, we have been developing and testing vibration cones to be used in an in-situ liquefaction test method. In order to establish an in-situ liquefaction test method using vibrating cones, we examined how measured data should be interpreted and how in-situ liquefaction resistance should be evaluated, based on the results of the indoor soil tank experiments.

＜抄録＞　道路橋床版を保護することを目的とした、耐久性、防水性に優れた新たな橋面舗装材料として4種類のグースアスファルト混合物および1種類の床版防水層を開発し、試験施工にて、施工性、防水性、耐久性等を確認したところ、概ね良好な結果が得られた。
In an effort to develop new pavement materials with adequate durability and water resistance to provide better protection for road bridge slabs, we have developed four types of goose asphalt mixture and one type of floor-slab waterproof layer. We tested them by applying them to bridges and confirmed generally favorable results after examining them for workability, water resistance, durability, and other properties.

＜抄録＞　土木研究所では、2010年よりインドネシア国道路研究所と天然ロックアスファルト（アスブトン）の利用用途の拡大に向けて共同研究を進めている。本稿では、筆者らがこれまでに検討してきたアスブトンの道路舗装用アスファルトとしての性状試験結果、橋面舗装材料への適用可能性の検討結果等について紹介する。
The Public Works Research Institute of Japan has been involved in joint research with the Institute of Road Engineering of Indonesia since 2010 to expand the use of natural rock asphalt (AsButon). In this study, we conducted property tests on AsButon for road pavement bitumen and examined its applicability to bridge-deck pavement. In this report, we present these research activities to utilize AsButon.

＜抄録＞　平成28年熊本地震で被災した道路橋の基礎の損傷調査に基づき、基礎の損傷調査における高周波衝撃弾性波法の適用性について、ボアホールカメラ調査との対比により検討した。また、基礎の損傷について、構造形式や地形条件に着目して分析し、大口径深礎及び複数列の杭基礎の場合に基礎が地形条件の影響を受けにくい傾向を確認した。
Based on the results of the investigation of damage to road bridge foundations in the 2016 Kumamoto earthquake, we examined the applicability of high-frequency impact-echo to foundation damage investigation by comparing with bore-hole camera investigation. We also analyzed the foundation damage according to structural types and topographical conditions and confirmed that the foundation is less likely to be affected by topographical conditions in the case of the caisson-type pile foundation and the multiple-row pile foundation.

＜抄録＞　高田河川国道事務所管内の国道8号は、日本海沿いを通るため冬期波浪などによる塩害損傷を受けた橋梁が多く、その対策が必要となっている。このため平成21年度より塩害橋梁架替え事業を進めており、本稿では管内の塩害橋梁の概要と塩害対策の取組について報告する。
Since National Route 8 under the jurisdiction of the Takada Office of Rivers and National Highways runs along the Sea of Japan, many bridges corrode due to salt damage caused by winter waves and other factors. As effective measures need to be taken to address this problem, a salt-damaged bridge replacement project has been underway since 2009. In this report, we outline the conditions of saltdamaged bridges in our service area and the salt damage control measures we have so far taken.

＜抄録＞　東北地方における道路橋RC床版の損傷は増加傾向にあり、指針類を整備し対策に取り組んでいるところである。本稿では、RC床版の土砂化の実態と補修の課題について述べる。
More damage cases of RC-slabs for highway bridges have been reported in the Tohoku region of Japan. Maintenance guidelines have been prepared and necessary measures have been taken to address the problem. This report explains how deterioration of RC-slabs is progressing and what issues have been pointed out in terms of maintenance.

＜抄録＞　2005年の鋼道路橋塗装・防食便覧で導入された塗替え時の重防食塗装仕様は、橋梁の長寿命化に役立つと期待されているが、実際の塗替え時に採用される割合は2～3割程度に止まる。本文では、工事コストや素地調整の使用性向上などの課題を改善など、技術的な改善案を検討するなど展開に必要な提案を行う。
High performance coating (Rc-Ⅰ system) for bridge repainting, whose specifications are listed in the Steel Road Bridge Coating and Corrosion Control Handbook in 2005 published by Japan Road Association, is expected to be highly effective in extending the service life of road bridges. However, Rc-Ⅰ system has been applied in only 20 to 30% of the bridge repainting cases. This report discusses technical improvement ideas regarding, for example, construction cost and surface preparation for coating and proposes practical plans to expand the use of high performance coating.

＜抄録＞　杭基礎の支持層未到達による不具合を避けるためには、支持層となり得る地層の深さ等の変化を面的に把握する必要がある。本報文では、ボーリング調査を補完してサウンディングを実施することにより地層の深さ変化を面的に把握する技術について現地試験により検討した結果を報告する。
In order to prevent problems caused by the failure of the pile foundation to reach the supporting layer, it is essential to understand geological features in the construction area, such as the depth of the stratum assumed to be the supporting layer. For this purpose, we tested a sounding technique in addition to the boring survey in a construction site. The test results are presented in this report.

＜抄録＞　盛土等の軟弱地盤対策においてコスト縮減を目的として、図-1に示すように深層混合処理工法と浅層混合処理工法を組み合わせて用いる場合がある。深層混合処理工法と浅層混合処理工法を組み合わせて用いる工法は、低改良率化によるコスト縮減のみならず、深層改良杭と未改良地盤との沈下量の差により発生する不陸抑制でも大きな効果が期待できる。浅層改良体の厚さを薄くしたり、深層改良杭領域の改良率を低くしたりして組み合わせると、浅層改良盤の下部に引張り応力が発生したり、深層改良杭が浅層改良盤を突き抜ける押し抜きせん断が発生したりする。本報告では浅層改良盤に発生する変状を確認するため、遠心力載荷模型実験を実施したので実験概要並びに損傷状況について紹介する。
The deep mixing method and the shallow mixing method are used in combination for cost reduction in applying soft-ground control measures to embankments and other types of soft ground. The combined use of the two methods is expected to be significantly beneficial not only in reducing cost by maximizing the low improvement rate but also in controlling unevenness caused by the difference in settlement between deep improvement piles and unimproved ground. On the other hand, some problems have been reported regarding tensile stress underneath the shallow improvement layer or punching shear caused by deep improvement piles penetrating the shallow improvement layer, when the shallow improvement body is too thin or the improvement rate is too low around the deep improvement piles. In this report, we outline centrifuge model tests conducted to observe deformations in the shallow improvement layer and explain the deformations found in the layer.

＜抄録＞　本研究では、補強土壁の補修方法の確立に必要なこぼれ出しの詳細な進行過程の解明と従来から実施されているこぼれ出しに対する補修方法の要否の判定及び効果を確認することを目的として、実大模型実験を行った。本報告では、その実験について報告する。
In this study, we conducted real-scale model tests for the following reasons: to detail the process of how leakage develops to establish a repair method for reinforced soil walls and to determine whether or not the conventional leakage repair method should be applied and evaluate the effect when applied. This report explains the experiments and results.

＜抄録＞　近年の大規模地震において、山地部の谷埋め道路盛土が大規模崩壊する事例が多く発生している。地震に対して安全安心な道路盛土とするには、地震時の盛土の変形挙動を把握し、効果的な耐震補強を行うことが必要である。本報告は、谷埋め盛土の変形挙動の把握を目的に実施した遠心力載荷模型実験について紹介するものである。
In recent large earthquakes, many cases of large-scale slope failure have occurred in mountain path embankments. To construct mountain path embankments highly resistant to seismic activity, it is crucial to understand the deformation behavior in the embankment during an earthquake and apply effective seismic reinforcement. This report describes centrifugal model tests conducted for these purposes.

＜抄録＞　河川堤防は、河川水や降雨の作用により、のり尻付近の小さな変状から始まり、徐々に崩壊範囲が拡大する場合がある。このような進行性破壊に関する大型模型浸透実験を行い、変状進行形態等を明らかにし、これらを元に進行性を考慮した新たな比較的簡便な評価法を提案した。また、進行性を有するすべりに対する、より安価な対策工も提案する。
Due to the impact of river water and rainfall, minor deformations in the toes of river embankments can expand gradually to other parts of the embankments and result in large-scale failure. To understand the deformation process regarding such progressive failure, we conducted large-scale a model seepage experiment. Considering the findings of the deformation process, we also developed a new evaluation method that is simpler than the conventional method. In this report, we also propose a less costly measure to control progressive sliding failure.

＜抄録＞　大槌第2トンネル工事の発生土の一部から基準を超過する砒素が確認された。岩砕は土壌汚染対策法の対象外だが、溶出量試験を実施し、粒径2mm以下で基準不適合、かつ、粒径40mm以下で基準適合する岩砕を監視型盛土として施工し、地下水質モニタリングの結果、問題のない結果が得られた。
Arsenic exceeding the standard level was confirmed in part of the soil generated from the Otsuchi No.2 tunnel construction. Although the Soil Contamination Countermeasures Act is not applied to rock fragments, we conducted leaching test and banking monitoring for rock fragments with particle sizes of 2 mm or smaller that did not meet the standard and those with particle sizes of 40 mm or smaller that met the standard. Groundwater monitoring was then conducted, and the results concluded that the soil in question was posing little environmental threat.

＜抄録＞　現在事業中の「すさみ串本道路」では、近接する近畿自動車道紀勢線（田辺～すさみ）の実績から、土工区間等において地質条件に起因する法面崩壊等の変状が発生することが懸念されている。本稿では、すさみ串本道路事業において、そのような変状が発生するリスクを「地質 リスク」として分析・評価した結果について報告する。
The Susami-Kushimoto Road project is currently proceeding, but there is a concern that deformations such as slope collapse may occur in earthwork and other sections because of the geological condition in the area. Such phenomena have been reported in the Kinki Expressway Kisei Line between Tanabe and Susami, which runs near the Susami-Kushimoto Road. In this report, we present the results of analysis and assessment conducted for such possible deformations we defined as georisk in the operation of the Susami- Kushimoto Road project.

＜抄録＞　国内のグラウンドアンカーの荷重増加事例の実態、緊張力が作用している状態でも設置・交換可能なアンカー荷重計測手法、追加対策後の荷重変化予測手法等の研究を紹介し、今後のアンカーの荷重増加への対応の高度化に向けた展望を述べる。
In this report, we explain domestic cases where load on ground anchors increased and a measurement system with devices that can be installed and replaced even when an anchor is in tension. We also study an analysis method that can predict load on anchors after additional countermeasures. Then, we overview approaches to the rationalization of urgent countermeasures for increased load on anchors.

＜抄録＞　コンクリート工の生産性向上の一つの方策として、現場での省人化が可能なプレキャスト製品の積極的活用が考えられる。プレキャスト製品を広く普及させるには、プレキャスト製品のコスト縮減が必要である。そのため、コスト構造等の製造実態を詳細に把握し、寸法の標準化等の方策を検討した。
Precast products, which is expected to help save labor in construction, are a promising option for improving the productivity of concrete work. However, cost reduction is necessary for the widespread use of precast products. To this end, we investigated the manufacturing process, including the cost structure, in detail and studied cost reduction measures, such as the standardization of product dimensions.

＜抄録＞　近年、国土交通省直轄事業において、マネジメント業務を官民の技術者が一体となって行う事業促進PPPを導入しているが、標準的な実施手法が確立しておらず、大規模災害時等の必要なときに速やかに導入する上で課題となっていた。そこで、国土技術政策総合研究所では、実施状況や課題を分析し、実施手法を提案した。
In recent years, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has employed an approach called Public-Private Partnership (PPP) for Project Acceleration to manage MLIT-led projects as a joint effort of engineers from the public and private sectors. However, because the standard procedures to carry out PPP for Project Acceleration have not been established, its timely implementation is sometimes difficult, particularly in a time of a large-scale disaster. To realize the speedy implementation of PPP for Project Acceleration, the National Institute of Land and Infrastructure Management proposes standard procedures, based on the analyses of past cases of PPP for Project Acceleration -driven projects and problems that emerged in them.

＜抄録＞　道路橋の鋼床版のデッキプレートとUリブの溶接ルート部からデッキプレート板厚方向に進展する疲労亀裂が発見されている。この亀裂は、溶接内部から発生し、貫通しても舗装下に隠れているため目視による確認が困難である。本稿では、この亀裂の発生の有無を把握するために開発した超音波を利用した2種類の調査技術の概要と現場適用事例を紹介する。
Various types of fatigue cracks have been recently observed in existing orthotropic steel deck bridges. Among such fatigue cracks, invisible cracks have been observed at the rib-to-deck welded joints. Cracks of this type are hard to detect visually because they start from the inside of the welded joints and are hidden under pavement even if they have reached the top surface of the deck plate. To detect such invisible cracks, we have developed two nondestructive inspection methods using ultrasonic waves. In this report, we introduce these methods and their applications related to crack inspections.

＜抄録＞　下水道の圧送管路は、調査に使用する機材を入れるための開口部が存在しない等の理由により、これまで管内部の調査ができていない状況である。圧送管路の腐食に起因する事故も発生し、調査の必要性が高まっていることから、国の下水道革新的技術実証事業（B-DASH）で取りまとめられた下水道圧送管路の腐食調査技術の、本県の適応事例を報告する。
Inspection of the inside of pressure sewer pipelines has been impossible because there are no openings to place inspection devices inside the pipes. However, accidents due to corrosion have been reported, and the need for such inspection has been growing. In response, Shiga Prefecture inspected pipelines using the corrosion inspection technology designed for pressure sewer pipelines, which was approved through the innovative sewerage technology demonstration project (B-DASH) led by the Japanese government. The findings are presented in this report.

＜抄録＞　京都市上下水道局では、汚泥消化タンク施設の再整備にあたり、消化ガスから不純物を取り除く設備として新型の消化ガス精製装置を導入した。本装置の特徴及び本装置を活用した精製消化ガスの有効利用について報告する。
As part of the improvement project for sludge digestion tanks, the Kyoto City Waterworks and Sewerage Bureau introduced a new digestion gas refining system which removes impurities from digestion gas. This report explains the main features of the new system and the effective use of refined digestion gas.

＜抄録＞　有明海沿岸道路は、軟弱な有明粘土が厚く堆積する地域で計画された4車線の地域高規格道路である。当該道路は整備効果の早期発現を図るため暫定2車線で開通した。交通量の増加に伴い円滑な道路交通を確保するため、一部区間で腹付け盛土工事により暫定形状から完成形状への移行を行った。腹付け盛土の設計・施工・供用後の状況等を報告する。
The Ariake Sea Coastal Road is a four-lane, high-standard road planned to be constructed in an area characteristic of a thick layer of soft Ariake clay. To serve for the area’s socio-economic needs as soon as possible, the coastal road initially opened as a two-lane road. As the traffic increased, additional construction was carried out for more traffic capacity by widening the road embankment to changing some sections from two lanes to four lanes. In this report, we explain the planning and implementation of the embankment widening project and the current condition of the improved road sections in service.

＜抄録＞　広場における広場利用者の行動を定性的に把握するための4つの観測手法を取り上げ、中心市街地に立地する2つの典型的な広場において同手法を用いた観測を行い、広場の空間構成が広場利用者の行動に与える影響を分析し、広場の設計の方向性を示した。
In this study, we observed the behavior of people in two typical public spaces located at the city center using four observation methods designed to help understand such behavior qualitatively. The results were analyzed to understand the effect of the spatial design on the public-space users, and some implications for public-space design were derived from the analysis.

＜抄録＞　道路空間の利活用においては、道路管理者、交通管理者、利活用事業実施主体、地域住民、道路利用者等関係者間の合意形成が課題となっている。道路空間の利活用促進に向けて、道路空間の利活用事例89件の分析をもとに、合意形成を円滑に進めるためのポイント、交通機能への影響の把握方法、事業効果の考え方等を整理した。
To promote the use of road spaces, it has been a challenge to build a consensus among stakeholders, including road managers, traffic managers, road space utilization project managers, and local residents. In this study, we analyzed 89 cases of road space utilization projects and sorted out important considerations to build a consensus effectively and efficiently, approaches to analyze the effect of road space utilization projects on traffic, and viewpoints to evaluate the effectiveness of such projects.

＜抄録＞　平成31年4月に「道路構造令の一部を改正する政令」が施行され、道路構造令上に「自転車通行帯」に関する規定が新たに導入された。本稿では、自転車通行空間の整備を促進する上での参考になるよう、これまでの自転車通行空間に関する取組の経緯、国土技術政策総合研究所の取組、道路構造令の改正概要について報告する。
In April 2019, a cabinet order was enforced to partially revise the order on road structure standards by adding to them new regulations on bicycle lanes. In this report, to support the efficient implementation of bicycle lanes, we review the efforts regarding bicycle lanes that have been made so far in general and those specifically made by the National Institute of Land and Infrastructure Management. The revisions to the road structure standards are also outlined.

＜抄録＞　本報告では、本来、大きな景観向上効果が期待でき潜在的なニーズも高い良好な景観資源を有する自然・田園域で無電柱化を実施した場合の景観向上効果や、地中化以外での沿道環境に応じた多様な手法を提案する。また、寒冷地での課題克服やコスト縮減にむけた技術開発について紹介する。
In rural areas, which tend to have rich landscape resources, the undergrounding of utility lines is expected to benefit landscapes greatly, so the need for such undergrounding is high. This study investigates the degree to which undergrounding improves landscapes in rural areas and proposes additional methods for improving the roadside environment in such areas. Technological development toward resolving the problems and reducing the costs associated with such undergrounding in cold regions are also introduced.

＜抄録＞　味の素スタジアム（東京都調布市）前の国道20号において、無電柱化実施後の路面復旧にあわせて、地上機器の配置計画や小型化、道路植栽と歩道舗装の改善について修景検討を行った。本稿では路面復旧工事に着手した修景整備の取り組み状況について報告する。
In planning a road restoration project after removing utility poles from a section of National Route 20 near the Ajinomoto Stadium in Chofu City, Tokyo, the improvement of the landscape and environment in the area was also discussed, including the arrangement and downsizing of pad-mounted transformer and the improvement of roadside planting and sidewalk pavement. In this report, we explain the landscape and environment improvement works currently underway as part of the road restoration project.

＜抄録＞　京都市における無電柱化の取り組みは、緊急輸送道路や避難路などの幹線道路での整備に加え、世界文化遺産や京町家等の歴史的建造物が多く残り，景観保全が特に必要な地域での整備を推進している。本稿では、歴史的建造物が多く残る京都五花街の一つ先斗町での無電柱化の取り組みを紹介する。
Kyoto City has been promoting removal of utility poles not only in major roads such as ones designated for emergency transportation and evacuation but also where landscape conservation is particularly important, such as World Cultural Heritage sites and local streets with kyo-machiya and other historic buildings. This report focuses on an undergrounding project in Pontocho, one of Kyoto’s traditional entertainment quarters, where many old townhouses still remain.

＜抄録＞　全国各地におけるまちなか広場マネジメントの取り組みを44件収集し、関係者の役割分担や資金の流れに基づくマネジメントスキームの体系的な整理を行い、各類型のメリット・デメリット等の特徴を明らかにした。また、関係者に対するヒアリング調査を通じて、マネジメント実践上の課題と課題解決のアイデアを整理した。
In this study, the authors collected information on 44 cases of public square management in Japan, which were classified into 7 groups according to their responsibility assignment and cash flow. According to the results of comparative analysis, advantages and disadvantages of each category were identified. The authors also carried out interviews with those involved in public square management to figure out practical issues they currently face and suggest possible solutions.

＜抄録＞　供用中の道路トンネルにおける実態調査を実施し、換気対象物質の濃度について計測するとともに、その結果を用いて自動車1台当たりの排出量を算出した結果について報告する。
In this study, we inspected the present conditions of road tunnels in service and measured the concentration of exhaust fumes. This report presents emissions per vehicle calculated based on the concentration measurements.

＜抄録＞　本研究では熊本地震により損傷した俵山大橋を対象として、橋に残された損傷痕や支承の損傷状態から得られた事実を積み重ね、さらに撤去された支承を用いて載荷実験等を行い、支承に作用する力や橋の挙動メカニズム、さらに地震の影響を受けた支承の残存性能を推定した。
Focusing on the Tawarayama Ohashi Bridge damaged due to the Kumamoto Earthquake, we estimated the force acting on the bridge’s bearing supports and the bridge’s behavior by investigating the damage traces found on the bridge and the damage types found on its bearing supports and by conducting loading and other tests on the bearing supports removed from the bridge. Based on the collected information and data, we also estimated the residual capacity of the bearing supports affected by the earthquake.

＜抄録＞　地盤工学会により「岩石の一軸引張り試験方法 (JGS2552-2015)」が基準化されているが、固化材改良土に対する試験方法は確立されていない。固化材改良土の一軸引張り試験を適切に行うためには、供試体と試験機との接着方法と共に、局部的な弱部が試験結果に影響することがないよう均質な供試体の作製が重要となる。そこで、3種の地盤材料に固化材を混合した固化材改良土を作製し、一軸圧縮試験と一軸引張り試験を実施した。本報告では、固化材改良した土に対する供試体の締固め方法、均質な供試体を作製するための混合試料の調整方法、生石灰改良における供試体作製時の消化時間について検討した結果を報告すると共に、種々の固化材を用いた改良土の一軸圧縮強度と一軸引張り強度の関係について報告する。
Though the Japan Society of Geotechnical Engineers has standardized the Method for direct tension test on rocks (JGS 2552-2015), a method for testing solidified improved soil has not been established. To conduct a direct tension test on solidified improved soil, the production of homogeneous test pieces is essential to prevent their weaker parts from affecting test results, in addition to take precautions in adhering the test piece and the tester. We prepared solidified improved soil by mixing solidifying agents and three types of ground soil and conducted direct tension test and unconfined compressive tests. As a result, this report presents the following: a compaction method to create test pieces using different types of solidified improved soil; a method for optimizing solidifying agents to prepare homogeneous test pieces; and the experimental results regarding the digestion time during the production of test pieces after mixing soil and quicklime. We also report the relationship between the uniaxial tensile strength and the unconfined compressive strength concerning improved soil using different types of solidifying agents.

＜抄録＞　膨大な下水道管路を適切に維持管理していく上で、リスク評価による措置の優先順位付けが重要となっている。今回、下水道管路におけるリスクの一つである管路閉塞に着目し、地方公共団体へのアンケート調査結果を基にその発生傾向を整理したため、その結果を報告する。
To properly maintain and manage a considerable number of sewer pipes, it is important to conduct risk assessments and decide which problem should be prioritized over others. In this study, selecting sewer blockages from among many risks related to sewer pipes, we conducted questionnaire surveys for local governments and analyzed the tendency of sewer blockage occurrence. This report presents the results of the analysis.

＜抄録＞　動的遠心模型実験によりプレキャストアーチカルバートの損傷メカニズムの解明と補強方法の選定を行った。損傷メカニズムについては縦断方向の荷重によって損傷したことが分かった。補強方法は縦断方向に連結することが効果的であり、脚部と頂部を補強することにより、脚部のみに比べ、補強量を低減できることが分かった。
In this study, we analyzed the damage mechanism of precast arch culverts and selected the best reinforcement method by conducting dynamic centrifugal model tests. The results found that precast arch culverts can be most effectively reinforced when they are connected longitudinally. They also revealed that the amount of reinforcement can be reduced when the reinforcement is applied to both leg and top parts of the culverts instead of only to their leg part.

＜抄録＞　災害に強い強靱な道路ネットワークを実現するためには、耐荷性向上対策を実施すべき既設道路構造物の構造条件等の提示が求められる。本検討では被災した既設橋梁基礎の統計分析により洗掘被害を受けやすい河川特性や橋梁基礎の構造条件を抽出することを試みたので、その検討の概要について紹介する。
To build road networks that are resilient to disasters, it is essential to have detailed information, such as structural conditions, regarding existing road-related structures that need additional measures to increase their load carrying capacity. In this study, we conducted statistical analysis for existing bridge foundations damaged during a disaster to identify the characteristics of rivers where scours often occur and the structural conditions of bridge foundations susceptible to scours. This report outlines the results of the study.

＜抄録＞　平成30年度で、本格的なメンテナンスを行うための統一的な基準に基づき、1巡目の定期点検が完了した。今後、地方公共団体の負担は、補修補強などの対策に拡大するので、技術支援の必要性もより高まってくる。本レポートでは、九州における地方公共団体の定期点検結果や技術支援の主な取組状況や今後の課題・対応などについて報告するものである。
In 2018, the first round of regular bridge inspections, which was performed before moving on to full-scale maintenance, was completed in compliance with the standardized inspection guidelines. Considering that local governments will soon have to engage in the repair and reinforcement of bridges as well, the importance of technical assistance by the national government will further increase. In this context, this report presents the results of the regular inspections conducted by the local governments in the Kyusyu area and explains main technical assistance programs currently provided and issues and solutions expected in the future.

＜抄録＞　北千葉導水路は、運用開始から約20年経過した施設であり、毎年300日以上運用されている利用頻度の高い施設である。そのため、ポンプ施設、導水管等設備の老朽化が顕在化している。本稿では、点検で確認された導水管の腐食状況、腐食の原因及び補修方法等について報告する。
The Kita-Chiba conveyance channel is in operation over 300 days annually and has been in service for about 20 years. Therefore, its pump unit, conduits and other equipment have increasingly become deteriorated. In this report, we explain the corrosion status of the conduits, the causes of the corrosion, and repair methods.

＜抄録＞　防護柵の設置基準・同解説に基づき、据置型車両用防護柵について大型車を用いた実車衝突試験により、衝突現象解析および大型車の誘導性能等の評価を行った。
Based on the guidelines and instructions regarding the installation of traffic barriers, collision tests using large vehicles was conducted to evaluate temporary traffic barriers. The results were used to analyze the collisions and assess the barriers’ performance in redirecting large vehicles.

＜抄録＞　災害発生後の復旧工事等に用いられる無人化施工では、一般的に安全地域に構築した運転建屋から建設機械の操作を行う。しかし災害によって発生した交通環境悪化による運転建屋構築時間の遅延が、無人化施工の迅速展開への課題のひとつとなっている。本報では、対応策として頭部装着型ディスプレイ（HMD）の活用を提案し、検証実験の結果を述べる。
When unmanned construction system is used in restoration projects after disasters, the operator is usually in a control room built in a safe area. After a disaster, however, severely affected traffic conditions delay the construction of a control room, which in turn hampers a timely operation of unmanned construction. As a solution, we proposed the introduction of head-mounted displays to unmanned construction operations and used them in construction experimentally. The results were presented in this report.

＜抄録＞　平成30年7月豪雨では広島県において甚大な土砂災害が発生した。広島西部山系砂防事務所では、平成30年7月豪雨により土砂災害で甚大な被害を受けた地域において緊急的な砂防事業を実施し、平成31年4月から恒久対策に取り組んでいる。本稿では、緊急対策、対策工事の課題及び工法を中心にその概要を報告する。
In July 2018, large-scale sediment disasters occurred in Hiroshima Prefecture. The Hiroshima West mountain range Sabo Office quickly started emergency construction works in the affected areas. Since April 2019, the effort has been shifted to a long-term project. In this report, we mainly explain the emergency construction works and related issues.

＜抄録＞　火山噴気に起因する土石流の発生時において、土砂災害防止法に基づく緊急調査を実施する際に求められる調査内容を考慮し、立ち入り困難地域でもデータが取得できるよう、火山灰堆積量観測、火山灰堆積状況及び浸透能の把握を目的にUAVによる流域調査手法について開発した。
When debris flows may occur due to volcanic eruptions, emergency field surveys need to be conducted according to the Sediment Disaster Prevention Act. We have developed a basin survey method using UAV for emergency field surveys even in the off-limits area to collect the data of volume of ash fall, and investigate conditions of ash fall and infiltration capacity.

＜抄録＞　本報文では、MMSにより取得した点群データを道路管理の高度化・効率化に活用するため、「路面損傷の確認」のうち発生頻度が高いポットホールの検知を対象とし、計測時の走行位置、速度及びMMSの性能等の取得条件と検知可能な規模との関係を分析した結果について報告した。
Point cloud data have been found useful to improve the quality and efficiency of road management. This research was conducted, focusing on the detection of road surface damage, particularly potholes, which are generated highly frequently. We analyzed data to understand the relationship between detectable pothole sizes and data measurement conditions such as the location and speed of the vehicle and the specification of the Mobile Mapping System. This report presents the results of the analysis.