巨粒土大型三轴试验研究

通过大型三轴试验,对巨粒土在低围压下的应力-应变特性、抗剪强度特性以及水对强度和变形的影响进行了分析。结果表明:在较低围压情况下,应力-应变曲线表现为弱应变软化型或应变硬化型,其形态主要决定于围压的大小,而其体变特征首先表现出体积收缩,随着轴向应变的增加,逐渐转为体积膨胀,随着围压的增大,剪胀逐渐减弱并过渡到完全体缩,但体缩率逐渐减小直至趋于稳定;巨粒土的抗剪强度随着应力水平的变化,表现出非线性特性,一般随着围压增大,强度参数?降低;水对巨粒土的压缩特性和剪切特性有重要影响,主要表现为压缩系数增大,抗剪强度降低。

Large-scale triaxial test study of behavior of over coarse-grained soils

The stress-strain relationship, shear strength behavior and the influence of water on strength and deformation under low confining pressures are analyzed detailedly via large-scale triaxial test. Test results indicate that under low confining pressures over coarse-grained soils are characterized by weak strain softening or strain hardening. The form rests with the value of confining pressure. At the same time, volume shrink happens first and cubic dilation develops gradually with the increase of axial strain. The sample varies from dilation to volume shrink with the increase of confining pressure. But the shrinkage degree decreases little by little till stability. The shear strength of over coarse-grained soils shows nonlinear characters with the stress level. It decreases generally with the increase of confining pressure. Water has important effect on the compression characters and the shear characters of over coarse-grained soil. It mostly makes the compression coefficient degree increase and the parameter of shear strength decrease.