安徽怀宁某地区地应力测量结果及其构造分析

In-situ stress measurements in an area in Huaining,Anhui and their structural analysis

通过水压致裂法对安徽怀宁某地区进行原位地应力测量,为后续洞室施工提供基础设计参数。本次测量采用单回路测试系统,最大开挖深度为203.2m,获得了10段地应力测量值。测量结果表明:最大主应力值为9.32MPa,小主应力最大值为7.48MPa,最大主应力方向平均为北东74.5°,地应力结构为σ_(H)>σ_(h)>σ_(v),可知当地地应力场主要受到水平构造应力场控制。实测的大小主应力均大于中国地区区域内的平均水平,主要是受到断层地貌以及花岗岩岩层的影响;实测的此片区最大水平主应力优势方向为北东向,与区域构造线重合;在开挖洞室时,洞轴线走向应当与所测的最大主应力方向尽量一致。

In-situ stress measurements were carried out in an area in Huaining,Anhui by hydraulic fracturing method to provide basic design parameters for subsequent cavern construction.In this study,a single loop test system was adopted,the maximum excavation depth was 203.2 m,and in-situ stress measurements of 10 sections were obtained.The measurement results show that the maximum principal stress value is 9.32 MPa,the maximum of minimum principal stress value is 7.48 MPa,the average direction of the maximum principal stress is 74.5°,and the in-situ stress structure isσ_(H)>σ_(h)>σ_(v).It can be seen that the local in-situ stress field is mainly controlled by the horizontal tectonic stress field.The measured maximum and minimum principal stresses are all greater than the average levels in China,and are mainly affected by fault geomorphology and granite rock strata.The measured dominant direction of the maximum horizontal principal stress in this area is NE,which coincides with the regional tectonic line.During the excavation of the cavern,the direction of the axis of the cavern should be as consistent as possible with the direction of the measured maximum principal stress.