Mechanism of faults acting on in-situ stress field direction

Liu Zhongchun; Lyu Xinrui; Li Yukun; Zhang Hui

doi:10.11743/ogg20160311

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Mechanism of faults acting on in-situ stress field direction
Vol. 37, Issue 3, Pages: 387-393(2016)
Online First：08 June 2016，

Published：2016
DOI： 10.11743/ogg20160311
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DOI：

Liu Zhongchun, Lyu Xinrui, Li Yukun, et al. Mechanism of faults acting on in-situ stress field direction[J]. 2016, 37(3): 387-393. DOI： 10.11743/ogg20160311.

摘要

断层附近区域地应力方向相对于远离断层区域存在明显变化。前人利用实验及有限元模拟等手段研究了断层对其附近区域地应力方向的影响规律，但是缺少从力学机理角度解释这些规律的研究。研究总结了单一断层附近最大水平主应力方向变化规律，利用孔口问题弹性力学解析解揭示了这种规律的力学机理，并以某单元为例，研究了多断层区域最大主应力方向沿断层走向上的变化。结果表明，断层端部区域最大水平主应力朝着断层走向偏转，应用孔口问题弹性力学求解可以获得理论证明，塔河某单元的地应力计算结果也验证了这种规律。

Abstract

Direction of in-situ stress near a fault is significantly different with that far away from the fault.Experimental approaches and finite element simulation method were previously used to study the patterns of faults acting on in-situ stress field direction

but these patterns were never explained in respect of mechanical mechanism.The regularity of elasticity mechanical mechanism were reveals by using the analytical solution of elliptic orifice problems based on study of the change patterns of the maximum horizontal principal stress direction near a single fault.And a block was taken as an example to study the change of the direction of maximum principal stress along fault strike in areas with multiple faults.The results show that the maximum horizontal principal stress deviates to the fault strike at the ends of faults.The phenomenon can be well explained with the aid of orifice problem of elastic mechanics analytical solution.The calculation results of in-situ stress in one unit of Tahe oilfield also verify the rule.