摘要
简述了国家地震局“八五”攻关二级课题(85-04-06-02)的研究结果。发展了一套宽频带、大动态、多通道自动化数字记录系统及相应的软件,实现对构造变形中的应力、应变、位移、声发射、波速等物理场的高精度多点动态观测;在双轴加载条件下研究了简单断层、拐折断层、共线不连续断层、张性和压性及复杂雁列式断层等典型构造在变形破坏过程中应变场、断层位移场、声发射事件时空强分布及波速场的演化,并对典型失稳事件的前兆特征进行分析,揭示了物理场演化及失稳前兆与构造类型及其变形阶段、失稳机制的关系;应用三重非线性数值模拟方法研究典型构造及复杂构造的应力场,提出由应力场增强和应力调整等全局性原因与局部断裂弱化、扩展等造成的应力扰动场是有差异的,这可能是造成中长期和短期异常出现于不同部位的原因;以弱化段为中心,最大剪应力增量场的八瓣式分布和平均应力增量场的四象限分布,可作为识别发震构造的标志。作者还就进一步的研究提出了一些建议。
This paper is a brief summary of a project sponsored by SSB (85-04-06-02). In the project, a digital recording system with multi-channel, wide dynamic scale and the corresponding software have been developed, which makes the multi-point dynamic measurements with high accuracy for the field of stress, strain, fault displacement, acoustic emission and wave velocity during deformation come true. The evolution of physical field, during deformation of fault system, with typical geometric textures has been studied under biaxial loading. The precursors of typical instability events have been analyzed, the relation between evolution of physical field and instability precursor with fault geometry, deformation stage and instability mechanism has been discussed. By using the triple-nonlinear numerical simulation, the stress field of fault system with typical and complex geometric textures has been studied. It has found that the incremental stress field caused by change in driving force is quite different from that caused by fault propagating or weakening, which may be the reason the long-, medium-, and short-term anomalies often occur at different localities. Eight-petaline pattern of maximum shear stress and four-quadrant pattern of the mean stress, centered the weakening segment of fault, may be considered as possible sign of the seismogenic fault. On summarizing the project, some suggestions for further research are proposed.
出处
《地震》
CSCD
北大核心
1995年第S1期55-65,共11页
Earthquake
关键词
岩石力学实验
数值模拟
断层组
声发射
应变
断层位移
前兆现象
Rock mechanical test, Numerical simulation, Fault set, Acoustic emission, Strain, Fault displacement, Precursor phenomena
