三维地应力BWSRM测量新方法及其测井机器人在重大工程中的应用

A NEW 3D IN-SITU ROCK STRESS MEASURING METHOD:BOREHOLE WALL STRESS RELIEF METHOD(BWSRM) AND DEVELOPMENT OF GEOSTRESS MEASURING INSTRUMENT BASED ON BWSRM AND ITS PRIMARY APPLICATIONS TO ENGINEERING

地壳上层岩体的应力状态是地壳最重要的性质之一,获取岩体应力状态最直接、可靠的手段是原位地应力测量。首先简要回顾地应力测量的研究历程及其发展现状,分析岩石力学与工程中常用的几种地应力测量方法和技术。重点介绍钻孔局部壁面应力解除法(BWSRM)这一新的三维地应力测量方法的原理,以及基于BWSRM的地应力测井机器人研制过程和具体实施步骤。最后给出地应力测井机器人在锦屏水电站埋深达2 430 m处科研试验洞内的试验结果。研究表明,测点位置的围岩地应力以水平主应力为最大主地应力,而接近竖直方向的地应力分量则为最小主地应力;第一和第二主应力量值比较高,而且两者量值也比较接近。

It is important to conduct a research on the stress state of the rock masses in the upper earth＇s crust. In-situ rock stress measurement is the basic and reliable access to obtain the stress state of the rock masses. The development of in-situ rock stress measurement and state-of-art of research on it are overviewed. Then, several in- situ rock stress measuring methods and techniques are briefly analyzed in rock mechanics and engineering. A new method, borehole wall stress relief method（BWSRM） to determine the in-situ 3D rock stress tensor in a single drilled borehole is deliberated. An original geostress measuring instrument typed by BWSRM-H01 is designed and manufactured based on the principle of in-situ rock stress measurement with BWSRM. The in-situ test for rock stress with BWSRM is carried out at an experimental tunnel in Jinpin~ II hydropower station, China, wherethe buried depth of overburden is about 2 430 m. It is shown that the two principal stress components close to the horizontal direction are the maximum and intermediate principal stress respectively; while the stress component close to vertical direction is just the minor principal stress in the testing site. The magnitudes of the maximum and the intermediate principal stress are high; and both of them are very close.