宝塔山特长隧道地应力场研究及岩爆预测

为了确定宝塔山特长隧道的围岩应力状态，采用水压致裂法进行了地应力测试，并根据测试成果，通过有限元回归分析，预测了整个隧道围岩的应力分布。测试结果表明:宝塔山隧道深埋段地应力场以自重应力场为主导，在测试深度内最大水平主应力值为2.3~8.4MPa，具中等应力水平，最大水平主应力方向为N53°E，与隧道走向的夹角较大，即地应力对隧道围岩稳定性不利。最后，根据地应力资料对隧道围岩进行了施工期岩爆预测分析，表明隧道岩爆等级为弱-中等岩爆，但在完整坚硬岩石区，发生中等岩爆的可能性比较大。

A study of the geostress field of the surrounding rocks of the Baota mountain tunnel and rock burst forecast

In order to determine the stress state of the surrounding rocks of the Baota mountain expressway tunnel , geostress measurements with the hydro fracturing method were carried out. Based on the testing results, the geostress field in the project area is analyzed with finite element and linear multivariable regression methods. The results of regression analyses indicate that the values of the maximum vertical principal stress are larger than the gravity stress along the tunnel axis. Vertical stress field is dominated in this area. Within the measured depths, the maximum horizontal stress ranges from 2.3 to 8.4MPa, and this stress level can be classified as a middle level. The dominant direction of the maximum horizontal stress is about N53°E, the angle between the direction of the maximum horizontal stress and the direction of the tunnel axis is relatively big for this tunnel，and is adverse to the stability of the tunnel and the surrounding rock mass. Based on the data of geostress， rock burst of the surrounding rocks of the tunnel during construction is analyzed and forecast. The results show that the possibility of weak and moderate rock burst in the tunnel exists and the moderate rock burst exists during construction in the complete and hard rock tunnel segments.