岩石错动面的非匀阻性与突发失稳

RESISTANCE NONUNIFORMITY AND SUDDEN INSTABILITY OF SLIDING ZONE IN ROCKS

断层错动面的非匀阻效应是决定失稳型式和是否发震的重要因素之一。实验研究表明:凹凸不平的错动面只有当凹凸部在错动中被铲削至相对平直而使阻力相对均匀的情况下才可能突发失稳,并可用非匀阻系数ζ定量地表示错动面凹凸和非匀阻程度。通过比较锯切面与破裂面凹凸程度的差别,以及二者不同的应力降大小,进一步建立了一种实验确定非匀阻系数的新方法,给出了花岗闪长岩、花岗岩和石英岩破裂面的非匀阻系数与相对不平度的关系.从而为外推判断断层发震的可能性提供了依据。

The nonuniform-resistance effect of faulting surface is one of the important factors determining the instability mode and whether earthquake occurs or not.The experimental studies show that the sudden instability can take place along a wavy and rough sliding surface only as it is relatively flattened and smoothed after the asperities were cut and broken in the sliding process and unevenness and resistance nonuniformity of sliding surface can be indicated as a so-called nonuniform-resistance coefficient,which is a relative measurement of the displacement for uniformization,A new method for experimental determining the value of nonuniform-resistance coefficient is proposed by comparing the different unevennesses and stress drops between sawcut and fracture surfaces in rocks and the relatioins between the nonuniform-resistance coefficient and relative waviness for granodiorite,granite and quartzite are given in this paper,which may provide a basis for judging the possibility of earthquake along a fault.