逆断层控制构造裂缝发育的力学机制模拟

在探讨逆断层对构造裂缝控制作用的基础上,应用Comsol有限元软件,模拟不同水平作用力、不同岩性、不同断层倾角和距断层面远近等因素影响下断层及其周边区域的应力、应变情况,并分析了不同控制因素下构造裂缝发育的规律。模拟结果表明,构造裂缝的发育程度随施加的水平应力作用增大而线性增大;岩石破裂前产生的应变量可用来描述岩石的脆性,抗压强度对岩石破裂起主导作用,而岩石的抗剪强度与岩石破裂发育有一定的相关性;逆断层倾角存在一个临界角度,使构造裂缝发育最为强烈;逆断层控制裂缝发育,距离断裂面越远裂缝发育程度越低,并存在一个发育程度骤减的范围,称为"断裂控制带",该断裂控制带的形成和分布应该与断裂的性质、规模、断距及岩石力学参数等有关。

NUMERICAL SIMULATION OF STRUCTURAL FRACTURES CONTROLLED BY REVERSE FAULT

Based on the research on development of structural fractures that controlled by reverse fault, this study has simulated the distribution of the stress, strain and the development rules of fractures under the different conditions of horizontal forces, lithological characters, fault dip and the different distances to fault location in the fault zone by using COMSOL finite element software. It is shown by the simulation results that the development degree of structure fractures increases linearly with the increase of horizontal forces. The strain generated before rock failure can be used to describe the brittle properties of rock. Compressive strength is the main factor that makes rocks rupture and the shear strength of rock has relationship with the development of rock fracture. There is a critical angle in reverse fault dip and it can make the fracture strongest developed. The fracture density decreases as the distance from the reverse fault increases and there is a damage region controlled by reverse fault where the fracture density decreases sharply. This region is closely related to the mechanics, scale, displacement of the reverse fault and rock mechanics parameters.