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本文利用边界积分方程方法,以基于三角形网格的全空间格林函数及离散积分核计算为基础,进行了最常见的弯折断层的破裂传播过程模拟.为了去除边界积分方程方法中格林函数计算存在的高度奇异性,研究采用分部积分等方法对动力学方程进行了重整化和离散化处理.地震力学过程可以被视为断层由静摩擦转为动摩擦的过程,对于震源破裂过程的动力学模拟,摩擦准则起着重要作用,本研究采用常用的滑动弱化摩擦准则.计算引入Courant-Friedrich-Lewy比值来表达场点的影响,并控制计算的收敛性和稳定性.通过与典型算例的比对,检验了方法的正确性和有效性.地震破裂能否穿越断层弯折部位继续传播是震源动力学研究的重要内容,基于此,本文建立了多种理论弯折断层模型,模拟了断层弯折对地震破裂传播的控制作用,并通过改变断层周边初始应力场、断层弯折角度大小以及滑动弱化距离大小等来分析各个因素对破裂传播的影响.模拟结果表明:断层面上初始破裂区域内外的应力越高,破裂越容易越过断层弯折部位继续传播;初始破裂区域半径越大,或滑动弱化距离越小,破裂也越容易发生,并越过弯折部位继续传播.同样的初始条件,断层弯折角度越大,断层弯折作为障碍体,对破裂传播的阻碍作用越显著.小的弯折角,其破裂传播过程与平面断层差别不明显,基本仍以椭圆方式对称向两侧传播.
In this paper, the boundary integral equation method is used to simulate the rupture propagation of the most common bent fault based on the full-space Green’s function and the discrete integral kernel of the triangular mesh. In order to eliminate the existence of the Green’s function in the method of boundary integral equation , The author studied how to reconstruct and discretize the dynamic equations by using the integral integral method, etc. Seismic mechanics process can be regarded as the process of the transition from static friction to dynamic friction, and the dynamic simulation of the source rupture process , And the friction criterion plays an important role. In this study, the commonly used sliding weakening friction criterion is adopted. The Courant-Friedrich-Lewy ratio is introduced to express the influence of field points and to control the convergence and stability of the calculation. By comparing with the typical example To verify the correctness and validity of the method, whether the earthquake rupture can continue to propagate through the faulty bend is an important part of the study of source kinetics. Based on this, a variety of theoretical bending fault models are established in this paper to simulate the faulty bend Fold the earthquake rupture propagation control, and by changing the initial stress field around the fault, fault bending angle And the influence of various factors on crack propagation are analyzed.The simulation results show that the higher the stress inside and outside the initial rupture zone on the fault plane, the easier it is for the rupture to propagate beyond the bend of the fault. The larger the initial rupture zone radius, Or the weakened sliding distance is smaller, the crack is more likely to occur and continue to propagate beyond the bending part. The same initial condition, the larger the fault bending angle, the more the fault bending acts as the obstacle, Of the bending angle, the propagation of the rupture and the plane fault difference is not obvious, the basic still elliptical way symmetrical to both sides of the spread.