【摘要】 断层泥是组成断层的地质材料中力学性质最薄弱的部分,为了解断层泥的物理力学性质对断层附近地面运动特性和工程结构破坏特征的影响,利用室内常规土工试验方法研究龙门山断裂带深溪沟段含断层泥的原状断层物质的物理力学性质。薄片鉴定试验结果表明,土样中的黑色土和灰色土的矿物成分基本类似,灰色部分为断层角砾岩,黑色部分为一般意义上的断层泥,黑色土中的褐铁矿使其颜色偏深。基本物理性质试验结果表明,黑色土的颗粒粒径小于灰色土,相对密度略低于灰色土。直剪试验结果表明,断层泥的孔隙率越高,剪应力峰值越低,饱和土样的剪应力峰值普遍高于非饱和土样;断层泥的剪切破坏呈塑性或半脆性破坏特征,剪应力随剪切位移的增大不断增加;黑色和灰色土界面是断层泥抗剪的薄弱面。更多还原

【Abstract】 Mechanical property of fault gouge is the weakest in the geological materials composing the fault.In order to understand the influences of physico-mechanical properties of fault gouge on the characteristics of ground motion near fault and the damaged styles of structures,the direct shear tests on undisturbed samples of fault materials containing fault gouge from Longmenshan fault are conducted using conventional soil test method in laboratory;and investigations into natural fault material structures and mineral distributions are carried out.The slice identification results show that,mineral composition of black fault gouge is similar to that of gray breccia and the color of black is caused by limonite.The basic physical property test results show that the grain size of black gouge is smaller than that of gray gouge,distribution of grain size is very inhomogeneous,and the specific gravity of black gouge is less than that of gray gouge.Direct shear test results show that shear strength of fault materials with low void ratio is higher than that with high void ratio;and the peak shear stresses are larger for these specimens with high water content compared to those of specimens with low water content but the same void ratio.The maximum shear stresses do not appear until the shear tests stop,instead,the entire shear displacement is characterized by strain hardening or perfectly plastic behavior.The shear strength reaches the lowest for those specimens with shear zone in the interface between different layers.更多还原