固体三轴高压下红河断裂带周城断层泥力学性质的研究

在固体三轴高压和应变率4.4×10^-5s^-1下研究了红河断裂带周城断层泥的力学性质。研究结果表明,在差应力作用下,断层泥应力-应变曲线表现出与试件压实、屈服和碎裂流动等不同变形机制对应的非线性,线性等阶段性变化特征。干、湿断层泥破坏应力σ_c随围压σ₃的变化关系分别为在较高围压下,σ_c随σ₃呈线性变化。含水量对变形特征和破坏应力水平有重要影响。干、湿断层泥有效弹性模量E_ed和E_em以及（潮）湿断层泥的初始模量E_om均随围压增加而增加,但干断层泥初始弹性模量E_od近似保持常数。同时,E_oded,E_omem,E_em>E_ed。在试件变形过程中有声发射事件显示,但数量少,辐射弹性波能量小。断层泥试件破坏型式表现为渐进式碎裂流动特征,因此,断层泥变形有利于断层活动呈现稳滑。

Studies on the Mechanical Properties of Zhoucheng Fault Gouge of Honghe Fault Zone under High Pressures

The mechanical properties of Zhoucheng fault gouge of Honghe fault zone were studied under high pressure in triaxial compression equipment with solid confining medium and at strain rate of 4.4&;#215;10-5s-1. It shows that the stress-strain curves of gouge exhibit linear and nonlinear deformation characteristics which correspond to the different deformation mechanisms of compact, yield and cataclastic flow of gouge specimen. The relations between the failure strength (σc) of gouge and the confining pressure (σэ) areσc = 23.7э30.56 (for the dry gouge)σc = 10.4э30.62 (for the moist gouge).The moisture content is an important factor which influences the deformation characteristics and the failure strength of gouge. The effective elastic moduli, Eed and Eem, of dry and moist gouge and the initial elastic modulus, Eom, of moist gouge increase with increasing confining pressure, and the initial elastic modulus, E0d, of dry gouge is nearly constant. The acoustic emission events occurre during the deformation. Under high pressure the progressive failure processes take place in the gouge specimen, so the deformation of gouge is favorable to stable sliding of the active fault.