主应力轴循环旋转下饱和黏土累积孔压显式模型

EXPLICIT MODEL FOR CUMULATIVE PORE PRESSURE OF SATURATED CLAY UNDER CYCLIC ROTATION OF PRINCIPAL STRESS AXIS SUBJECTED TO CYCLIC LOADING

交通荷载下饱和黏土累积孔压消散是导致交通荷载下路基沉降的重要因素。在详细介绍黏土空心圆柱试样制作过程的基础上,在各向等压条件下,分别对黏土试件在100,150,200 kPa压力下固结,而后进行主应力轴旋转角连续变化范围分别为[-15°,15°]、[-30°,30°]、[-45°,45°]和[-60°,60°]的不排水循环加载试验,循环次数为10 000次。得到了循环累积孔压的变化受静偏应力、初始固结压力及空心圆柱试样主应力轴连续旋转角影响的规律。运用修正动偏应力水平来考虑初始静偏应力和动偏应力对不排水累积孔压的影响,建立了常剪应力循环主应力轴偏转角循环加载下累积孔压模型。通过非各向等压固结循环扭剪试验累积孔压值对所建立的累积孔压模型的正确性进行验证。

The cumulative pore pressure dissipation of saturated clay is an important factor in the settlement of roadbed under traffic load. According to the characteristics of making the hollow cylindrical specimens of saturated clay, it was introduced the fabrication process of saturated clay hollow cylindrical specimen in detail. The specimens were consolidated under 100 kPa,150 kPa, and 200 kPa, then, the undrained cyclic loading test was done with the change in the principal stress axis rotation continuous range being[-15°,15°]、[-30°,30°]、[-45°,45°] and [-60°,60°] , therefore, the effect rules that were confining pressure, the principal stress axis rotation angle and the static deviator stress respectively on the cycle cumulative pore pressure were obtained. Using the modified dynamic deviator stress level to consider the effect of initial static deviator stress and dynamic deviator stress on the undrained cumulative pore pressure, the cumulative pore pressure model of constant shear stress cycle deviation angle of principal stress axis under cyclic loading was established. Through the cumulative pore pressure value of non-isotropic consolidation cyclic torsional shear test, the correctness of the established cumulative pore pressure model was verified.