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.
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.
XU Gancheng1 YUAN Weize1 LI Chengxue1 ZHAO Shunli2 ZHU Yonghe2
.Hydraulic Fracturing Test on In-Situ Stress and Its Distribution Characteristics in an Engineering Site[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(4): 163-169
2021, Vol. 58 