Shear Strength Index Test Analysis And Its Application In The Supporting Engineering

Based on the study and research achievements, this paper focuses on the study ofshear strength index of silt and silty clay in Handan. Combining with the specificexample of project, shear strength indexes are checked and compared with:Firstly, this paper studies the background of the shear strength, the development ofthree triaxial tests and the research status of the strength of soils in Handan; Secondly,this paper analyses the formation and composition, structural characteristics, geologicaland hydrological and meteorological characteristics of soils and other objectiveconditions in Handan; Thirdly, with the method of three triaxial test, this paper focuseson the shear strength index of the silt and silty clay in Handan, which is obtained on thecondition of unconsolidated-undrained and consolidated-untrained; Finally, with thehelp of the design soft called Lizheng deep excavations, taking the examples of specificproject, the both of the shear strength indexes are checked and analyzed.Through the three triaxial test, this paper obtained the specific method of saturationand the test indexes in the process of three triaxial test, focusing on Handan area, theshear strength indexes of silt and silty clay in Handan area on different drainedconditions and the result that shear strength indexes on the consolidated-untrainedcondition are more than the ones on the unconsolidated-untrained condition. By fittingthe experimental data, this paper also achieved four sets of correlation curves andequations.Through the calculation, analysis and comparison of the project examples, thesafety factor obtained by the use of shear strength parameters of theconsolided-untrained test is bigger. The standard allows the use of CU test indexes,engineering design using CU test result is more reasonable. When the shear strengthindex of CU test is unavailable, it can also be obtained by the conversion formula givenin this paper.As the most important parameter in the process of the design of retaining andprotection for excavations, shear strength index should be reasonably chosen.