秦岭公路隧道2号竖井地应力与岩爆分析

利用水平圆柱形激波管对激波驱动的可压缩性气固两相流进行了试验研究. 利用压电式压力传感器、电荷放大器、示波器及计算机组成的压力信号测试系统, 对激波 与颗粒作用前后的气相参数进行测量及分析. 试验中测得了激波在管中的传播速 度, 波后气流的压力, 反射激波、透射激波的压力和速度等. 分别考察颗粒、装载 比、驱动气源以及入射激波马赫数等因素的差异对气相参数的影响. 试验结果表明: 激波与颗粒群相互作用时, 会产生反射激波和透射激波, 其强度与驱动气源、颗粒大小、颗粒装载比等参数有关; 激波衰减率随着装载比、马赫数的增大而减小. 研究指出, 在颗粒群被激波加速的初始阶段, 颗粒间的弹性碰撞起着重要的作用.

ANALYSIS OF IN SITU GEO STRESS AND ROCKBURST |AT NO.2 VENTILATION SHAFT TUNNEL OF QINLING HIGHWAY TUNNEL

The No.2 ventilation shaft of Qinling highway tunnel is mainly located in the mixed gneiss stratum. The main technical problems encountered in the shaft excavation are high in situ geo stress and rockburst.  The paper examined the engineering geology of the shaft and the geo stress measurement results of nearby engineering by hydraulic fracturing method. Then, the geo stress field in the shaft area is calculated and regressed  with 3D finite element method. It is shown that the geo stress in the shaft area has a high horizontal geological structure stress and is ly distributed in zones. The maximum horizontal geo stress is 28.7 MPa. The vertical geo stress is controlled by weight of rockmass. Based on the geo stress field, the rockburst prediction in the shaft is made according to the Tao's rockburst criteria. The depth of rockburst failure area is estimated  with the constant deviatoric stress criterion of brittle rock mass. The results show that there are high possibilities of occurring weak and moderate rockbursts.  The maximum depth of failure is 0.6 m in the surrounding rocks of the shaft. The  results from the geo stress and rockburst analysis are well compared  with the actual situations of rockbursts after shaft excavation.