高压力下原状层间错动带三轴不排水剪切特性及其影响因素分析

针对某大型水电站揭露的原状层间错动带试样，模拟现场快速施工可能会产生的不排水边界条件，在围压5～30 MPa的高压力条件下开展了不固结不排水三轴试验，并结合试样物理性质的差异，分析讨论了原状层间错动带的力学特性。试样试验曲线和破坏模式主要由高围压控制：其应力-应变关系曲线均为应变硬化型且破坏后呈腰鼓状为塑性破坏。此外，较湿颗粒发生了大规模的颗粒破碎，其是造成高饱和度试样强度包线的趋势线随围压降低的根本原因。试验结果明显受物理性质影响造成了试验数据离散性，敏感性分析表明，围压P和饱和度 对初始弹性模量 和破坏强度 的影响最大，其次是孔隙比e，颗粒粒径（ ）分布对其影响程度最小。根据试样剪切特性建立的强度特征（ 和 ）初步预测公式可供实际工程参考。

Undrained shear behaviour of intact infilled joint soil with triaxial shear tests under high pressure and its influence factor analysis

The unconsolidated and undrained triaxial test is carried out on the intact infilled joint soils exposed at some major hydropower station under high pressure whose confining pressure is between 5 and 30 MPa to simulate the undrained boundary condition generated by rapid construction in-situ, and the mechanical behaviour of the infilled joint soils is discussed with the variation of physical property for each sample. The experiment results and failure mode are mainly controlled by high confining pressure: all the stress-stain relationships belong to strain hardening type, besides the samples after failure are presented as waist drum, and plastic failure occurrs. Moreover, a large amount of particle crushing occurrs among the wet particles, it is considered as the prime reason for the trend line of strength envelope decreasing with the increased confining pressure. The test data show discreteness for the effect of variation of physical property, and the sensitivity analysis (partial correction coefficient) indicates that: confining pressure p and saturation degree have a major effect on the initial elastic modulus and failure stress ; the void ratio e and the particle size distribution ( ) have the minimal effect. In addition, the equation proposed according to the shear behaviour can be used to estimate the strength features ( and ) of the infilled joint soils preliminarily in practice.