Katsuya Okada

A risk estimation method of railway embankment collapse due to heavy rainfall

Abstract Slope collapses of embankments and cut slopes along railways are often triggered by heavy rainfall of a typhoon, etc., and have much influence on the running safety of trains. It is of vital importance to find out the risky sites along the railway to control railway operations. For this purpose, it is desiable to develop a practical damage estimation method which can accurately predict the risks of slope collapse and can be simply applied by many railway workers. This paper deals with a method of estimating the railway embankment collapse in times of heavy rainfall based on a multivariate analysis. The critical rainfall is proposed to be defined as a product of the amount of accumulated rainfall and the maximum hourly rainfall. This value is also determined by a function whose variables include information on the embankment such as soil and structural properties, the surface ground geotechnical characteristics, the catchment and seepage, and the empirical rainfall. Therefore, the risk evaluation for embankments can be performed with the critical rainfall value.

EXPERIMENTAL STUDY ON DEFORMATION MECHANISM OF ASHLAR MASONRY WALLS DURING AN EARTHQUAKE

材料の入手が容易なために，鉄道沿線の切土のり面の防護や盛土ののり尻に設けられることが多い石積壁は，開業当時に造られて，今も供用されている．このような石積壁は，通常標準図をもとにして造られることが多いが，昭和初期以前に造られたものについては，その構造が明らかでない．また，その構築方法は，専門職の技能と経験によって発達してきているため，特に，耐震性能については未解明な部分が多い．このような特徴を有する石積壁の実態調査を行い，鉄道沿線に現存する石積壁の標準的な構造を明らかにした．また，この標準的な石積壁を対象として模型振動台実験を行った．積み方（空積および練積），高さ，基礎に働く水平抵抗に着目し，地震時の挙動に及ぼす影響と変形発現のメカニズムを明らかにした．