中主应力对黄土变形强度特性影响的试验研究

对陕西杨凌黄土进行了不同中主应力比b下的真三轴试验，研究了中主应力比b对重塑黄土的变形和强度的影响规律。试验结果表明：在一定的含水率和固结压力下，偏差应力和初始切线模量均随中主应力比b的增大而增大；在中主应力比b确定的情况下，偏差应力和强度最大值随着含水率的增大而减小。小主应变ε3在任意条件下始终表现为膨胀；中主应变ε2在固结压力为50kPa表现为膨胀，在100kPa和150kPa时，小主应变ε3随着b的增大由膨胀变为压缩，固结压力越高，决定中主应变压缩的最小b值越小。

Effect of intermediate principal stress on loess deformation and strength

The effect of intermediate principal stress on loess deformation and strength characteristics are studied using True Triaxial Apparatus under 3-D stress state. It is found that in certain water ratio and consolidation pressure, the values of initial elastic modulus and principal deviator stress increase with intermediate principal stress increasing; in certain intermediate principal stress, the values of initial elastic modulus and principal deviator stress increase with water ratio falling. Expansibility appears in the direction of minor principle stress and in the direction of intermediate principle stress when consolidation pressure is 50kPa while the direction of intermediate principle stress turns out to be from expansibility to compressibility when consolidation pressure is 100kPa and 150kPa.