西南地区某隧道围岩岩爆预测研究

岩爆预测一直是地下工程领域中的世界性难题。本文以西南某隧道工程为例，从岩爆形成的3个条件:岩石岩爆倾向性、岩体完整性和高地应力环境3个方面着手，应用最大储存弹性应变能指标Es和岩石脆性系数B，对深埋隧道区段内可能发生岩爆的石英砂岩、灰岩岩体进行岩爆倾向性分析预测； 基于地应力测量数据资料，采用地质过程动态模拟的有限元分析方法，反演分析隧道工程区岩体地应力场，对隧道高应力区段作出判断； 根据现场所取样品试验结果综合分析隧道围岩的物理力学性质、岩石单轴抗压强度等。在分析和总结前人岩爆预测预报方法的基础上，以工程地质分析为基础，详细阐明隧道岩爆发生的条件，并以岩体力学和非线性科学理论为指导，采用地质综合分析、应力强度比法对隧道可能发生岩爆的部位及其强度进行综合预测。

PREDICTION OF ROCKBURST AT WALL ROCKS OF TUNNELS IN SOUTHWEST

The prediction of rockburst is a great challenge for the construction of underground engineering. We take a tunnel in southwest China as a case study. We consider the three conditions inducing rockburst as:rockburst occurring probability of rock mass, the integrity of rock mass and the high in-situ stress. We take the maximum stored elastic strain energy(Es) and the rock brittleness modulus(B) as the indicators. We then analyze the rockburst occurring probability of quartz sandstone and limestone in the deep tunnel. Based on the collected in-situ stress data we collected, with the assistance of finite element method which immediately simulates the geological process, we launch a back analysis on the stress field of the rock mass in the tunnel area and consequently obtain the high in-situ stress-section in the area. Utilizing field sampling tests, we study the physical and mechanical properties of the wall rocks like the uniaxial compressive strength of intact rock. We summarize the previous rockburst predicting methods, employ the comprehensive engineering geological analysis, elaborate the conditions causing tunnel rockburst. Then, we use the theory of rock mass mechanics, the non-linear science as guidance, the geological comprehensive analysis method and the stress intensity ratio method to predict the location and intensity of rockburst that may occur in the tunnel area.