某新建铁路九霄山隧道地应力及岩爆的预测和评价

Prediction and evaluation of in-situ stress and rock burst in Jiuxiaoshan tunnel of a new railway

九霄山隧道位于武陵山脉的中段西南侧,洞身围岩属坚硬完整—较坚硬完整岩石,洞身稳定性好,隧道进出口及断层带、裂隙带、浅埋部位的强—弱风化变粒岩稳定性较差。地应力及岩爆测试表明:K33+930—K34+520、K35+090—K36+850、K37+200—K38+190段硬质岩地段属高应力区,开挖过程中可能发生岩爆;K36+850—K37+200段属极高应力区,开挖过程中有岩爆发生。岩性变形辨别发现:隧道埋深大于210.5 m时,洞身为极高应力区,有发生软岩大变形可能;隧道埋深在114.5~210.5 m时,洞身为高应力区,软质岩地段基坑可能有隆起现象,成形性较差。

The Jiuxiaoshan Tunnel is located in the southwest of the middle section of Wuling Mountains.The surrounding rock of the tunnel body is intact hard-relatively in tack hard rock,and the stability of the tunnel body is good.The stability of strong-weak weathered granulated rock in tunnel entrance and exit,fault zone,fissure zone,and shallow buried area is poor.In-situ stress and rock burst tests showed that K33+930—K34+520、K35+090—K36+850、K37+200—K38+190 are high stress areas,and rock burst may occur during excavation;K36+850—K37+200 are extremely high stress areas,rock burst occurred during excavation.lithologic deformation showed that when the tunnel depth is more than 210.5m,the tunnel body is a very high stress area,and large deformation of soft rock may occur;when the tunnel depth is between 114.5~210.5 m,the hole body is a high stress area,the soft rock section foundation pit may have the uplift phenomenon,the formability is poor.