基于超前地质预报的隧道围岩稳定性靶向数值模拟研究

Targeted Numerical Simulation Study on the Stability of Tunnel Surrounding Rock Based on Advanced Geology Forecast

针对TSP超前地质预报技术的不足,通过对反射波信息的精细分析,结合地质勘查资料及现场施工情况,并通过TSP反射信息获取前方岩体部分力学参数,对隧道围岩的稳定性进行靶向超前数值模拟计算,对比分析不同施工工法下的围岩位移变化特征、塑性区及孔隙水压分布情况。结果表明,相较于二台阶法,三台阶法施工的围岩拱顶下沉、净空收敛及塑性区分布等均较小,二台阶法施工的围岩变化位移亦在规范允许范围之内,围岩状况稳定,对隧道高风险段施工工法转换及围岩稳定性的超前分析有一定的参考价值。

Aiming at the shortcomings of TSP advanced geology forecast technology, the careful analysis of reflected wave infor-mation was conducted. Then, combined with geological survey data and on-site construction conditions, the some mechanical parameters of rock mass in front of the tunnel were obtained by TSP reflection information. After that, the targeted numerical simulation calculation on the stability of tunnel surrounding rock was conducted. And the displacement characteristics, plastic zone distribution and pore water pressure distribution of surrounding rock were compared and analyzed under different construc- tion methods. The results showed that compared with two-step method, three-step method used for construction had the ad-vantages of small vault subsidence, headroom convergence and plastic zone distribution. However, the displacement change of surrounding rock under the construction of two-step method was also within allowable scope of criterion, and the surrounding rock condition was stable. Therefore, the study had a certain reference value for the construction method transformation at the high-risk section of tunnel and the advanced analysis of surrounding rock stability.