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本文利用线性弹性饱水多孔介质中平面应变剪切位错以速度V平隐运动时产生孔隙压力的耦合形变-扩散解,研究了与间歇性蠕动有关的井水位变化。对于大的Vr/2c(其中r是距位错的距离、c是扩散率),其解接近于Wesson(1981)分析由蠕动事件引起的水位变化所使用的去耦弹性解的形式。这两个解之间的差在距断层平面10个扩散长度内(20c/V)是显著的。更准确地说,耦合解预示着位错后面的孔隙压力改变符号,并在数量上比去耦解预期的要小的多。对于泊松比是0.3、Skempton系数为0.8以及剪切模量为30GPa的非泄漏介质,在V=1公里/天、C=1.0米~2/秒时,耦合解预示每滑动一毫米,最大孔隙压力变化13.7kPa(173毫巴)。耦合解的频谱被限制在一个中心值与V成正比和与从观测点到断层的距离大约成反比的频带上。因此,接近断层平面,耦合解占用的频带可能超过了水井反应的范围。耦合解能用来解释Johnson(1973)观测到的和由Wesson(1981)用去耦解模拟的同一与蠕动有关的水位变化。尽管在岩石材料特性和蠕动事件速度方面存在着不确定性,但耦合解预报的水位变化在幅度上可与实际观测到的变化相比。
In this paper, we use the coupled deformation-diffusion solution of pore pressure induced by plane strain shear dislocation in linear elastic saturated water porous media to generate velocity-V flat-hidden motion and study the variation of well water level associated with intermittent creep. For large Vr / 2c (where r is the distance from the dislocation and c is the diffusivity), the solution approximates the form of the decoupling elastic solution used by Wesson (1981) to analyze the water level changes caused by the creeping events. The difference between these two solutions is significant within 10 diffusion lengths (20c / V) from the plane of the fault. More precisely, the coupling solution predicts a change in the pore pressure behind the dislocations and is much smaller in magnitude than expected for decoupling. For a non-leaky medium with a Poisson’s ratio of 0.3, a Skempton coefficient of 0.8 and a shear modulus of 30 GPa, the coupling solution predicts a maximum of one milliliters per sliding at V = 1 km / day and C = 1.0 m ~ 2 / Pore pressure changes by 13.7 kPa (173 mbar). The spectrum of the coupling solution is limited to a band centered on a value proportional to V and about inversely proportional to the distance from the observation point to the fault. Therefore, close to the fault plane, the frequency band occupied by the coupling solution may exceed the well reaction range. Coupling solutions can be used to explain the same creep-related changes in water level observed by Johnson (1973) and decoupled by Wesson (1981). Despite uncertainties in rock material properties and creep event speed, the coupled-solution predicted water level changes in amplitude can be compared with the actual observed changes.