单轴压缩下非饱和黏土动态力学性能试验研究

黏土作为一种松散多孔材料，其波阻抗较低，采用传统分离式霍普金森压杆(SHPB)试验装置进行单轴压缩试验时，存在透射信号弱、应力不平衡等问题。针对以上问题，提出利用石英压电晶体测定试样的应力并监测试样两端的应力平衡，采用入射波整形技术，考察应变率、含水率对非饱和黏土动态力学性能的影响规律。试验结果表明，非饱和黏土试样的单轴抗压强度与应变率及含水率的关系密切，强度随着应变率的提升而上升，但随着含水率的提升而下降。通过对试验结果的分析，分别提出单轴抗压强度与含水率及应变率之间的关系式，并通过拟合确定参数，拟合结果较好。

Experimental study of dynamic mechanical behaviors of unsaturated clay subjected to uniaxial loading

During testing low impedance materials such as clay by conventional split Hopkinson pressure bar (SHPB), the transmission strain pulse is always too weak to be collected correctly. In addition, the clay specimen will not deform homogeneously during the test, which makes it impossible to get valid data. To overcome these problems, the quartz transducer technique and the controlled loading pulse were introduced to test the unsaturated clay specimen with different moisture contents under different loading rates. Besides, the stress equilibrium in the specimen was monitored by quartz transducer mounted at the two end faces of the specimen. The results indicate that the compressive response of the unsaturated clay is sensitive to moisture content and strain rate, which the axial compressive strength decrease with the increase of moisture content, but increase with the increase of strain rate. Furthermore, the relationship of the axial compressive strength with the moisture content, and the normalized axial compressive strength with the strain rate are given respectively. The fitting curves are better consistent with the experimental data.