水压致裂法在隧道原地应力及脆性破坏预测分析中的应用——以广西荔玉高速文圩隧道为例

Application of hydraulic fracturing method in prediction analysis of in-situ stress and brittle failure of tunnels:A case study of Wenxu Tunnel of Liyu Expressway in Guangxi

以广西荔玉高速文圩隧道为研究对象,通过水压致裂法获取隧道洞身钻孔145.14~243.37 m深度内的地应力数据,并基于实测数据采用修正的Sheorey公式及应力强度比法分别对隧址区原地应力及脆性破坏进行预测分析。结果表明:原地应力预测值与工程区周边的实测应力水平吻合度较好,隧道左右幅Ⅲ级围岩区可能出现中等脆性破坏的占比分别为6.9%、7.6%。预测结果为隧道的设计及科学施工提供了依据,也可为今后类似工程提供经验参考。

This paper taking the Wenxu Tunnel of Liyu Expressway in Guangxi as the research object,the in-situ stress data of the borehole in the hole body at a depth of 145.14-243.37 m are obtained by hydraulic fracturing method,and the in-situ stress and brittle failure in the tunnel site area is predicted and analyzed by using the modified Sheorey formula and stress intensity ratio method on the basis of the measured data.The result shows that the predicted value of in-situ stress is in good agreement with the measured stress level around the engineering area,and the proportion of moderate brittle failure in the left and right surrounding rock gradeⅢareas of the tunnel is 6.9%and 7.6%.The prediction result provides a basis for the design and scientific construction of the tunnel,and can also provide the experience reference for similar projects in the future.