【摘要】 如何利用有限的地应力资料对整个工程区地应力状态进行评估及预测一直是工程设计中的难点之一。文章利用水压致裂法对巴基斯坦某水电站的3个钻孔进行了地应力测量,通过测量获得了工程区地壳浅部现今地应力特征,并利用侧压系数变化规律对深部地应力值进行了预测。测试结果表明:在123~346 m测量深度范围内,地应力值一般随着深度的增大而升高,最大水平主应力量值为4.28~13.86 MPa,最小水平主应力量值为3.02~8.19MPa;在隧道埋深最大处,水平主应力则达到了40 MPa,表明工程区应力场以水平应力为主。利用强度应力比法和Hoek-Brown岩体强度估算方法对工程区应力状态进行了评价,研究表明工程区处于高地应力状态。测试结果说明最大水平主应力优势方向为NEE向,该方向与前人研究成果较为一致,工程区现今构造应力场与印度板块和欧亚板块相互碰撞有着密切关系。根据实测地应力测量结果及地应力预测结果,对水电站输水隧洞围岩大变形进行了探讨,结果表明:当埋深超过300 m时,围岩将发生大变形;当埋深超过800 m时,围岩将发生严重的挤压变形。更多还原

【Abstract】 It is difficult to evaluate and predict the geostress state of a construction area if no sufficient relative documents are available. Geostress is measured in three boreholes using the hydraulic fracturing method at a hydropower station in Pakistan. The characteristics of shallow geostress are obtained, and deep geostress is predicted using a variation law of lateral pressure coefficients. The test results show that: geostress increases with the depth of overburden within a range of 123~346 m, with the maximum horizontal principal stress being 4.28~13.86 MPa, and the minimum horizontal principal stress being 3.02~8.19 MPa; and the horizontal principal stress reaches 40 MPa at the maximum depth, indicating that horizontal stress is dominant at the construction site. The stress state at the construction area is evaluated by using the strength-stress ratio and Hoek-Brown rockmass strength estimaton method. The results show that the geostress of the construction site is high; the predominant direction of the maximum horizontal principal stress is NEE, which is in agreement with that of previous research work; and the current tectonic stress of the construction site has a close relationship with the collision between the India and Eurasia plates. Based on the measured geostress and predicted geostress, it is determined that large deformation of surrounding rock will occur if the overburden exceeds 300 m, and severe squeezing-induced deformation will occur if the overbuden exceeds 800 m.更多还原