贵广高铁广西段位于广西盆地东北部,是连接“一带一路”的高速通道,为查明研究区的地应力分布特征,为隧道的设计提供基础资料,在广西5个不同地区开展了8个钻孔的水压致裂地应力测量工作,结果表明:研究区内最大水平主应力S_H方向主要表现为NNW-NWW,这与华南区域应力场相一致;S_H和最小水平主应力S_h的梯度小于全国平均地应力梯度。在深度小于300 m的范围内,三向主应力相对大小以S_H〉S_h〉S_v为主,在这种应力状态下有利于逆断层的活动;在深度大于300 m的范围内,三向主应力相对大小以S_H〉S_v〉S_h为主,在这种应力状态下有利于走滑断层的活动,这种应力状态与研究区以逆断兼走滑的断层结果较为一致。研究区侧压力系数的值和μ_m值(最大剪应力与平均主应之比)均表明测区内断层处于稳定状态,这与研究区属于构造稳定区的研究结果相一致。
Guangxi section of high-speed railway from Guiyang to Guangzhou, located in the northeast part of Guangxi basin, is the high-speed channel to link "the Belt and Road". In order to explore the in-situ stress state of project district and provide basic data for the design of tunnels, the hydraulic fracturing stress measurements of 8 boreholes in 5 different regions were carried out in the northeast of Guangxi Basin. The result shows that the direction of the maximum horizontal principal stress presents NNW-NWW, which is consistent with the regional tectonic stress field~ The grade coefficients of the maximum, minimum horizontal principal stresses are smaller than the average in situ stress gradient of China. The relative size oftriaxial principal stress at the depth over 300 m tends to SH〉Sh〉Sv which is prone to reverse faulting; the relative size of tri-axial principal stress at the depth below 300 m tends to SH〉Sv〉Sh which is prone to strike-slip faulting. The value of lateral pressure coefficient and tim(the ratio of the maximum shear stress to the average principal stress) in the measured area indicates that the fault in measured area is in a steady state, which also shows that the northeast part of Guangxi basin is the area with stable structure.