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把昌平花岗岩切割成20多种含两组断层交汇情况的模型.断层物质用2毫米厚的石膏模拟.模型受单轴应力的作用.实验中得出四种破裂组合情况:1.滑动破裂型 发生在两组断层与主压应力轴σ_1的交角一组大于45°,一组小于45°的情形下.其中,当断层物质石膏湿度为10—15%时,先在大角度面上产生剪切破裂,后沿小角度面产生最终磨擦滑动.在应力位移曲线上表现为两次应力降.当断层物质石膏湿度小于5%时,则只沿小角度面上产生磨擦滑动.应力位移曲线为单应力降。2.压楔型 发生在两组断层与σ_1夹角均大于45°的情况下.其应力位移曲线为阶梯式上升型.断层位移方向反复.3.张楔型 发生在两组断层与σ_1夹角均不大于30°时.应力位移曲线为单应力降.4.双滑或双破型 发生在两组断层与σ_1夹角均在30°和45°之间.应力位移曲线为连续的两次应力降.根据应力位移曲线和应力声发射累积数曲线的相似性,主破裂前的声发射累积数与主破裂时峰值应力的相似性以及断层组合与声发射组合的关系中,看出声发射过程对构造条件是敏感的.文中还对不同断层组合下可能出现的地震前兆进行了讨论.
The simulated granite cut gypsum Shohei groups containing 20 kinds of fault models the fault situation intersection material with thickness of 2 mm by the action of uniaxial stress model experiment burst four kinds of combinations obtained:... Ruptured sliding in the case of two faults occurring with the primary stress axis σ_1 set pressure is greater than a 45 ° angle of intersection, a group of less than 45 °. wherein, when the fault substance plaster humidity 10-15%, to produce a large cutting surface angle cracking cut, to produce the final friction after sliding along the low angle side. manifested as stress twice the drop in the stress-displacement curve. when the fault substance plaster humidity less than 5%, only a small angle to create friction along the surface of the slide. displacement curves of stress Single stress drop. 2. wedge pressure fault occurs in the two groups were the σ_1 angle greater than 45 °. Stress-displacement curve is a step up type. .3 repeated fault displacement direction. Zhang wedge fault occurred in both groups with interposed σ_1 The angle is less than 30 °, the stress-displacement curve is single-stress drop.4.Double-slip or double-breakage occurs when the angle between both sets of faults and σ_1 is between 30 ° and 45 ° .The stress-displacement curve is continuous similarity relationship, before the sound emitted major rupture in combination with the similarity of acoustic fault peak stress cracking when the cumulative number of the main drop emitted secondary stress combined transmit the cumulative curve of the stress-displacement curves and stress sound, sound seen The emission process is sensitive to the tectonic conditions, and the possible precursors for different faults are also discussed.