Experimental study on sliding instability mechanism of faults with different dip angles
The laboratory test method of fault friction slip is proposed,and the evolution laws of stress,strain,acoustic emission and temperature field are studied in the process of fault friction slip with differ-ent dip angles.Based on the laws,the energy mechanism of fault slip instability under the influence of fault dip angles is analyzed.Results show that the developed laboratory test method for simulating fault friction slip can effectively carry out the friction slip test of faults with different dip angles,different fault surface characteristics,different lithological combinations or different stress conditions.The anti-sliding capacity of fault and the degree of frictional failure on fault surface decrease with the increase of fault dip angle.Before the fault slide,the strain at different positions of the fault surface produces differ-entiation,and the strain differentiation of the vertical fault surface occurs earlier than that of the parallel surface.The synergy of strains at different positions of fault surface increases as the fault dip angle in-creases before slip becomes instable.The AE signal intensity decreases with the increase of fault dip an-gle.In the slip destabilization stage,the AE b-value increases significantly with the increase of dip angle,and there is fewer large-scale micro fracture.Besides,the fault surface is always in a heating state during the friction slip process.With the increase of fault dip angle,the heat released during the fault slip process and the temperature increment in the instability stage evidently decrease.The fault with large dip angle is not conducive to energy accumulation,but it is prone to slip and releases energy many times to induce rock burst of fault-coal structure instability,while the fault with small dip angle is conducive to accumulating more energy and releasing more energy in one slip time which is more likely to induce strong dynamic load rock burst.
rock burstfault slip dip angleacoustic emission(AE)temperature field
万方数据
维普
