鸿图嶂隧道突涌水预测及防治措施

Prediction and prevention of sudden water gushing in the Hongtuzhang tunnel

预测复杂地质条件下深埋隧道施工掌子面前方水文特征对保障施工安全有着极为关键的作用。以广东省鸿图嶂隧道预测及防治隧道涌突水为例,将可控源音频大地电磁测深法应用于隧道开挖区域水文特征调查,确定可能发生的涌突水区域,并采用全断面超前帷幕注浆的方式进行防治。研究结果表明:可控源音频大地电磁法探测深度较大、抗干扰能力强、横向分辨率高。应用此方法预测到未来待施工的区段有5处存在较大涌突水可能,开挖结果显示可控源音频大地电磁探测很好地还原了埋深超过700 m的场地实际情况,解决了前期工作中其他技术方法不能很好地对断层的深部空间形态及其富水情况等特征进行准确判断的问题。针对探测结果和开挖情况,采用全断面超前帷幕注浆堵水方案对断层裂隙进行了有效封闭,达到了安全掘进和限量排放水的目的,从而降低了因隧道涌突水造成的不必要损失。这一方法的实践应用为隧道突涌水的预测做了很好的验证,并为相应的灾害防治提供了技术支撑。

Prediction of hydrogeological conditions in front of the palm face in the construction of deep-buried tunnels under complex geological conditions is extremely critical to ensuring the construction safety.Previous works in the study site revealed that the traditional investigation methods cannot describe the geological and hydrogeological characteristics very well and have big deviation from the realities,causing unpredicted tunnel water inrush during the construction.To better predict the geological and hydrogeologic situation in the deep-buried tunnel and determine the possible flood water inrush area,we applied the controllable source audio magnetotelluric method in the Hongtuzhang tunnel construction in Gongdong province.The results show that this new method can better determine the true geological and hydrogeologic condition in the deep-buried tunnel,and match the actual excavation results.Especially this method predicted a potential gushing water inrush point,which was proved to have a maximum gushing water amount of 2300 m^3/h.Based on this detailed founding,we used the advance curtain grouting method to effectively seal the corresponding fault,which limits the water outflow and makes the excavation process in safe.Application of this method is a good test example for the prediction of tunnel water gushing,and can provide a better technology backup for the prevention of related geologic hazard.