提出一种利用三轴仪分析应力路径及结构物粗糙度对饱和砂土和结构物接触面强度特性影响的试验方法.通过制作含一定倾角斜面结构物的三轴试样,使得剪切过程中土体沿预设破坏面发生滑移, 结构物斜面粗糙度可进行控制调整.利用三轴仪控制轴压和围压变化,实现不同应力路径下的加载.对饱和福建标准砂和不同粗糙度钢结构物进行不同应力路径下固结排水剪切接触面试验,并对比接触面直剪试验,验证了该方法的有效性.结果表明:在滑动刚发生时,三轴试验常法向应力剪切路径下接触面摩擦角小于常规剪切路径下的接触面摩擦角.光滑情况下,接触面直剪试验所得摩擦角比三轴试验所得摩擦角小30%~40%.粗糙情况下,直剪试验所得接触面摩擦角略小于三轴试验摩擦角,且更接近于常法向应力剪切路径下的摩擦角.

A novel test method for analyzing the influence of stress path and roughness of structure on the strength characteristics of saturated sand-structure interface by using triaxial apparatus is presented. By making a triaxial specimen with a slope structure with a certain inclination angle, the soil slides along the preset failure surface during the shearing process, and the slope surface roughness of the structure can be controlled and adjusted. A triaxial instrument is used to control the changes in axial pressure,confining pressure to achieve loading in different stress paths. The soil slides along the structure surface with a certain angle during shearing when preformed failure surface exists. The roughness of the structure can be controlled and adjusted. The triaxial apparatus is used to control the confining pressure change of the sample to realize loading under different drainage conditions and stress paths. To verify the effectiveness of the method, direct shear test and triaxial shear tests are carried out on the specimen composed of Fujian sand and steel structures with different roughness and different stress paths. The results show that at the beginning of sliding, the friction angle of the interface in the interfacial constant normal stress path is smaller than that in the conventional shear path. Under smooth conditions, the interface friction angle obtained by direct shear test is 30% to 40% lower than that obtained by triaxial test. Under rough conditions, the interface friction angle obtained by direct shear test is slightly smaller than that obtained by triaxial test, and closer to the friction angle in normal stress shear paths.