高黎贡山深埋隧道地应力特征及岩爆模拟试验

 以中国西南地区地质作用最复杂的高黎贡山越岭隧道为例，在隧道工程地质条件分析的基础上，对最可能发生岩爆的花岗斑岩进行真三轴岩石力学试验测试，并结合原位地应力测量结果，确定不同工况下岩爆模拟试验的三向应力量值和加载、卸载方式。岩爆模拟试验结果表明，单纯卸载和卸载–加载方式都可以出现岩爆，但卸载–加载方式的岩爆明显比单一卸载方式的岩爆要强烈，说明隧道开挖后二次应力分布引起的应力集中对岩爆的发生起着十分重要的作用。岩爆破坏过程通常具有渐进性，一般先在试件表面出现岩屑剥落，有时伴有裂纹的扩展，最后才会发生岩块的弹射现象。绝大多数试件岩爆具有明显的滞后性，表现为加载或卸载一段时间后才发生岩爆；而岩爆过程持续时间却非常短(1 s左右)，具有明显的瞬时性。声发射监测结果显示，花岗斑岩在外部荷载作用下声发射强烈，对岩爆具有较好的前兆性。上述模拟结果和认识对于地质条件复杂的造山带深埋隧道工程建设具有重要的参考价值。

GEOSTRESS CHARACTERISTIC AND SIMULATION EXPERIMENT OF ROCKBURST OF A DEEP-BURIED TUNNEL IN GAOLIGONG MOUNTAIN

Taking a deep-buried tunnel in Gaoligong mountain in Southwest China where the geological action is most complex for example,on the basis of tunnel engineering geological condition analysis,the true triaxial compression tests have been performed on granophyre samples because rockburst most probably occurs. According to the in-situ geostress data,the triaxial stress values and loading or unloading styles of rockburst experiment are determined under different working conditions. The experimental results reveal that both unloading and loading-unloading styles can lead to rockburst,but the rockburst intensity of the latter is higher than that of the former,which indicates that the geostress centralization caused by secondary stress distribution has important influence on the rockburst. The process of rockburst usually has a character of gradual rupture,showing that debris flaked off from the sample surface at first,sometimes accompanying with crack propagation,and the block shooting occurs finally. Most test samples show obviously lagging,which means that rockburst always retards after a period of time when loading or unloading. But the rockburst process only lasts for very short time(about 1 s),showing obvious instantaneous character. The sound radiation monitoring data show that the granophyre samples have extensive sound radiation under outer loading process,which can be a useful factor for rockbust prediction. All above simulation test results and relevant realizations have important significance for deep-buried tunnel construction in the orogen with complicated geological condition.