地震破裂过程中断裂带孔隙压与应变响应规律研究

Recently, many important phenomena in geophysics and geology, including fault slow slipping and strain energy accumulation during earthquake rupturing have involved strain and pore-pressure propagation. How such a strain and pore-pressure wave mode contributes to above-mentioned geophysical and geological phenomena is still a matter of current research and actually not well understood. In this study, based on foundation of stress waves, and with in-situ laboratory experiments, such as rock acoustic emissions, X ray scanning tomography as well as shock tube technique, the mathematics of nonlinear viscoelastic poremechanics can be established. The Green functions of strain and pore-pressure waves will be presented. The main characteristic of strain and pore-pressure waves in nonlinear viscoelastic media can be analyzed. Then, the Space-time conservation element solution element (CESE) method will have been introduced to explain certain features observed in attenuation and dispersion of strain and pore-pressure wave fields. The applications described here demonstrate what can be accomplished with the physics of strain and pore-pressure waves propagating in a fault, and enhance the understanding of earthquake dynamics.

地震破裂过程中孔隙压与应变波的传播与断裂带慢滑移和应变能加速累积密切相关，孔隙压和应变波响应规律是地震动力学研究的热点问题之一，是一个典型的流固耦合问题。本研究基于应力波理论，采用岩石压裂渗流微震、X射线CT扫描与激波管技术等室内实验，结合断裂带分布式光纤多物理量野外观测试验，建立非线性粘弹性孔隙介质力学“流固耦合”模型，提出孔隙压和应变波的格林函数解析方法，给出非线性粘弹性孔隙介质力学模型的“时空守恒元解元（CE/SE）”数值模拟算法，揭示孔隙压和应变波在非线性粘弹性孔隙介质中的传播与衰减规律。研究成果对地震破裂过程的物理识别，对强震前兆响应规律的物理解释，提供新的研究思路。

地震孕育发生过程中断层内部流体孔隙压与应变响应规律是地震预报基础研究的重要内容之一。本研究在理论分析、室内实验及野外试验观测的基础上，提出了频域-空间域多孔介质流体压力耗散波格林函数理论；建立了Darcy-Brinkman-Biot孔隙弹性力学模型；揭示了流体孔隙压与应变的传播与衰减规律；给出了求解Biot理论模型与连续介质力学模型的高阶精度时空守恒元与解元算法；得出了流体孔隙压-应变-质量传输在断层里的相互作用行为特征；获得了断层分布式光纤传感综合监测的发明专利技术；开发完成了孔隙介质流体与固体的力学相互作用高性能并行计算软件。研究成果在地球科学野外观测试验站进行了阶段性示范应用，对地震动力学基础研究和地球深部分布式光纤传感探测关键技术的发展具有科学的参考意义与应用价值。