断裂构造对斜坡应力场影响的数值模拟及成灾机理研究

断裂构造及活动强度对斜坡体的应力场分布具有重要的影响。采用基于强度折减法的有限元法,分别以正断层和逆断层与斜坡体的组合关系为例,剖析了断裂构造对斜坡体应力场的影响及成灾机理,揭示了含有断层的斜坡体塑性区的贯通过程。研究表明,包含断层的斜坡体在应力分布特征及斜坡变形破坏机理方面与无断层的斜坡体有较大差别:含断层的斜坡体在坡面和断层面附近的最大主应力迹线与坡面或断层面相平行,在天然状态下,塑性区同时出现在坡脚和断层面后方,随着折减系数的增大,塑性区分别从坡脚和断层面后方向坡体深部和上部发展,直至断层面前后两个塑性区相贯通,坡体发生破坏,并且对坡体变形破坏的影响程度以逆断层最强,其次为正断层,断层不活动时较弱。

Numerical Simulation of Fault Structure Influence on Stress Field of Slope Body and Study on Disaster-causing Mechanism

There are some important influences of the fault structure and its activity on the slope body stress distribution.Using the FEM based on shear strength reduction method,this paper makes the study into the fault influence on the stress field of slope body and its destruction mechanism by an example of combination of the normal faults and reverse faults with the slope body and reveals the plastic zone breakthrough process of the slope body with fault.Research shows that there are obvious difference in the stress distribution and slope deformation-destruction mechanism between the fault slopes and no-fault slopes: the maximum principal stress tracing lines near the slope surface and fault surface are parallel to the slope surfaces and fault surfaces respectively in the slope body containing fault,and the plastic area occures mainly at the slope toe and behind fault plane under natural condition.As the reduction coefficient increases,the plastic areas develop respectively from the slope toe and fault plane to the deep and upper part of the slope body,until the two plastic zones impenetrate each other.The influencing degree of the fault to the slope deformation and destruction are as follows: the reverse fault is the strongest,the normal fault is the second,and the last is the inactive fault.