基坑开挖过程中TJ-1模拟月壤变形特性的试验研究

采用空心圆柱扭剪仪对TJ-1模拟月壤试样进行基坑开挖应力路径的试验模拟，以研究地球重力场环境下TJ-1模拟月壤在地基开挖过程中的变形及非共轴特性。试验结果表明：应力路径对TJ-1模拟月壤的变形影响显著；开挖过程中坑底及连续墙外侧模拟月壤因变形过大而破坏，坑底位置土体受连续墙挤压的影响发生明显的剪缩现象；连续墙内外土体明显的非共轴现象是开挖所致偏应力、应力主轴转幅及旋转速率耦合作用的结果，且上述因素在不同位置影响程度也不相同，坑底位置以应力主轴的转幅及旋转速率的影响为主，基坑外侧则是偏应力比、转幅及旋转速率共同作用的结果。

Deformation behaviors of TJ-1 lunar soil simulant during excavation

Torsion shear tests are conducted by use of a dynamic hollow cylinder apparatus in Tongji University on the TJ-1 lunar soil simulant subjected to stress paths of excavation in order to investigate its deformation behaviors and non-coaxiality during the excavation under the earth environment.The test results indicate that(1) the stress path significantly affects the deformation behaviors of the TJ-1 lunar soil simulant;(2) the soils at the bottom of the pit and outside the diaphragm walls fail due to large deformation;(3) the soils at the bottom exhibit a tendency of contraction;(4) the soils adjacent to the diaphragm walls show remarkable non-coaxiality due to the coupled effects of stress ratio,rotation amplitude and rotation rate of the principal stress;and(5) the non-coaxiality of soils at the bottom of the pit is mainly affected by the rotation amplitude and rotation rate of the principal stress direction,while the non-coaxiality of soils outside the wall is controlled by the stress ratio,rotation amplitude and rotation rate of the principal stress direction.