关键词: 断层泥, 高温高压, 应力-应变, 岩化, 稳定滑动, 地震

Abstract: The mechanical properties of fault gouge of Honghe fault zone were studied at temperatures up to 600℃, confining pressures up to 700 MPa and strain rate of 4.4×10^-5/s, At room temperature and high pressure the stress-strain curves of gouge were characterized by linear and non-linear stages of deformation, at high temperature and pressure the non-linear deformation was presented in the curves. The failure strength of gouge increased with increasing confining pressure at the same temperature, and de creased with increasing temperature at the same confining pressure. As the content of calcite in gouge was more than 20 %, the failure strength at high temperature decreased with increasing confining pressure, this anomalous change in mechanical behavior of gouge may be related to the plastic deformation and solid-gas transition induced by calcite and to the decreasing effective pressure caused by increasing pore fluid pressure. The a-coustic emission activity occurred in the gouge specimen during deformation, but no stress drop was observed in the stress-strain curve. After the differential stress reached the failure strength, the gouge specimen underwent a gradual failure process. The initial and effective elastic modules were determined from the stress-strain curves of gouges, the former were smaller than the latter. The gouge was lithified at T≥400℃ and σ₃≥300 MPa confining pressure, according to the lithifying conditions of temperature and pressure, the existing depth of clayey gouge does not exceed 10-15 km, Because the failure of gouges took a gradual character, it is favorable for the active fault with gouge to slide stably.

Key words: Fault gouge, High temperature and pressure, Stress-Strain, Lithification, Stable sliding, Earthquake