| Summary: | 碩士 === 國立交通大學 === 土木工程系所 === 96 === Large-scale of the rock slope failure formed the Li-Shan colluvial deposits. The deposits are composed of fractured slate and its weathered soils. Due to the weathering, erosion, and frequently sliding, the nature of the deposits is heterogeneious. Hence, the mechanical behavior and mechanical properties of colluviual deposits are difficult to be determined because of difficult sampling.
The study aims to investigate the mechanical bechanical of the weakest material of the deposits, grey clay with slate detritus. A series of physical property tests and consolidated undrained triaxial tests was performed on the specimens prepared from high quality drilling cores. Based on the experimental results, the influence of slate block content and distribution on the triaxial strength, stress-strain cure, and failure mode is dicussed.
According to test results, the rock content of the specimens includes 10% less of slate block and 80 % more of matrix soil (grey clay); three types of the shape of slate block were observed including subround, round, and sheet or subangular. Some of the specimens exhibit the long axis of the slate block parallel to the ends of the core, which reflects the fact that the layer of the deposit (grey clay with slate deteritus) are formed by slope shear failure. Due to the content of slate deteritus less than 10 %, the triaxial strength is not influenced by the content of slate deteritus, but depends on the magnitude of confining pressure. However, the stress-strain cure and failure more are dependent of the distribution of slate deteritus in the specimens.
Key Word : Colluvial Deposits , Mechanical Behavior, Block content, Slate Deteritus, Matrix,Consolidated Undrained Triaxial Test.
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