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在承压状态下岩石产生的发射kaiser效应对其在历史时期所承受过的最大应力有记忆功能。利用这种性能可以求取岩石在地质历史时期所经历过的最高应力水平。本文假定ka-iser效应对于岩石这种脆性物质是在差异应力作用下所表现出来的一种特性,从而提出声发射kaiser效应法。采用重复加载法,求出唐山地区水压致裂地应力测量钻孔中的红色妙岩历史上所承受过的最大水平差异应力为3兆帕。比现今地壳水平差异应力高3倍。由此求出唐山7.8级地震应力降为8.7巴,与天然地震记录的计算结果一致。说明利用声发射kais-er效应法求取历史最大差异应力是可行的。由顺岩芯轴向采取的岩样所估算的最大历史差异应力为5兆帕,高于垂直应力。说明唐山地区曾经承受过28—30巴的引张应力的作用。
The kaiser effect of rock emission under confined conditions has a memory function for the maximum stress it has suffered during the historical period. The use of this property can be obtained by the rock during the geological history of the highest stress level experienced. In this paper, it is assumed that the ka-iser effect is a property exhibited by the differential stress of brittle materials such as rocks, and the kaiser effect method of acoustic emission is proposed. Using the method of repeated loading, the maximum stress difference between the red rocks in the borehole of hydraulic fracturing in Tangshan region and the borehole measured in history was 3 MPa. 3 times higher than today’s crustal differential stress. Thus, the stress of the MS7.8 Tangshan earthquake is reduced to 8.7 bar, which is consistent with the results of natural seismic records. It is feasible to use the kais-er effect of acoustic emission to find the maximum differential stress in history. The maximum historical differential stress estimated from the rock samples taken along the core axis is 5 MPa above the vertical stress. Indicating that the Tangshan region had suffered the lead stress of 28-30 bar.