某工程区水压致裂法地应力测试及其分布特征研究

Hydraulic Fracturing Test on In-Situ Stress and Its Distribution Characteristics in an Engineering Site

  • 摘要: 为探明工程施工设计需要的地应力场分布情况,在工程区的A区和B区各开展了2个钻孔的水压致裂法地应力测试工作。试验结果表明:(1)测区地应力场状态以NW—NWW向挤压为主,其中A区和B区的最大水平主应力方向分别在N49°—57°W、N72°W附近,表明两个区域的应力场具有统一性,但是由于地形地貌和构造作用的部分差异,造成两者的应力方向具有一定的差异性。(2)工程A区和B区的应力分布规律均满足SH>Sh>Sv,应力以水平构造应力为主。(3)应力场方向与周边区域接近,B区的应力集中现象与地形地貌具有较大关系,随着测试深度加深,B区和A区的应力差别逐渐减弱,且工程区的室内岩石试验结果进一步验证了应力场的分布规律。

     

    Abstract: In order to investigate the distribution conditions of the in-situ stress field, which is required for the construction and design of a project, this paper conducts in-situ stress tests on two boreholes in engineering Zone A and Zone B, using the hydraulic fracturing method. The test results show that: (1) the in-situ stress field in the testing zones is dominated by the squeezing in the NW-NWW, with the orientations of maximum horizontal principal stress in Zone A and Zone B being around N49°-57°W and N72°W respectively, indicating that the stress fields in these two zones are consistent, but due to certain differences in topography and tectonic action, the stress orientations in the two zones show certain level of variability; (2) the stress patterns in both Zone A and Zone B of the project exhibit SH>Sh>Sv, with mainly the horizontal tectonic stress; (3) the orientation of the stress field is similar to that of the surrounding zones, and the stress concentration in Zone B has a stronger relationship with the topography, the stress difference between Zone B and Zone A gradually decreases as the test depth, and the indoor test results of rocks in the engineering zone further verify the distribution pattern of the stress field.

     

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