To investigate the feasibility of using the large size simple shear test device to replace the direct shear test device

• Main Authors: Gao-zhi-hua, 高志華
• Other Authors: Lai-jun-ren
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/08868719282222088171

碩士 === 朝陽大學 === 營建工程系碩士班 === 87 === Abstract Gravel formation is widely distributed in the central region of Taiwan. The difficulties of under ground excavation in gravel layers will be encountered in the construction of several large transportation projects. In the design of lateral earth pressure for the supporting system of under ground excavation, he shear strength parameters are the most important property to be obtained. Therefore, how to find out the mechanical strength parameters of gravel layer promptly and correctly is one of the most important research topic in geotechnical engineering. Previous study indicates that the distribution of stress and strain is more uniform in a simple shear device then in a direct shear device. Therefore, a new apparatus which can perform tilt table test, direct shear test, as well as simple shear test was designed in this study to investigate the influence of testing methods on the shear strength of gravel, and the feasibility of using direct simple shear test instead of direct shear test for obtaining the shear strength parameters of gravel. Results of this study indicate that at low normal stresses, due to the effects of stacking the shear strength of samples with largest grain diameter equal to 3-inches is higher than the strength of sample with smaller grain size. However, this trend is less significant at higher normal stresses. It also shows that for duplicated samples under the same normal stress, because the simple shear test does not force the sample to be failed along a pre-defined failure plane, the shear strength obtained from simple shear test is less scatter then results from direct shear test.