超前地质预报在浅埋软弱围岩隧道工程中的应用研究

Study on Application Effect of Advanced Geological Prediction in a Shallow-Buried Soft Surrounding Rock Tunnel

超前地质预报是保障隧道安全高效施工的必要环节和重要手段。浅埋软弱围岩隧道节理裂隙发育,岩体完整性差,围岩自稳能力低,隧道施工易发生坍塌等风险,探明掌子面前方地质情况对浅埋软弱围岩隧道建设具有重要意义。依托某浅埋软弱围岩隧道工程,基于地质雷达和声波反射法,对左、右线开展了超前地质预报分析,结合实际开挖情况验证了预测结果正确性。结果表明:地质雷达和HSP声波法能良好预判岩体完整性和浅埋软弱围岩隧道不良地质,多次准确预报出软弱破碎带、长大结构面等情况。隧道右线(K7+140)~(K7+220)、左线(ZK7+014)~(ZK7+094)岩性为泥岩,节理裂隙发育岩体较破碎~破碎;其中(K7+182)~(K7+192)、(ZK7+061)~(ZK7+067)段存在长大结构面。预测结果与开挖实际地质接近。

Geological forecasting is a necessary link and important means to ensure the safe and efficient construction of tunnel.Shallow-buried soft surrounding rock tunnels have developed joints and fractures,poor rock integrity,and low self-stability of the surrounding rock,making tunnel construction prone to collapse and other risks.Identifying the geological conditions ahead of the tunnel face in shallow-buried soft surrounding rock tunnels is of great significance for their construction.Based on geological radar and seismic reflection method,this paper conducts forward geological prediction analysis on the left and right lines of a shallow-buried soft surrounding rock tunnel project.The prediction results are verified by actual excavation conditions.The results show that geological radar and HSP seismic method can effectively predict the integrity of rock and the unfavorable geology of shallow-buried soft surrounding rock tunnels.They have accurately predicted soft and broken zones,as well as long-developed structural surfaces several times.The rock type of the right line from(K7+140)~(K7+220)and the left line from(ZK7+014)~(ZK7+094)is mudstone,with developed joints and fractures,and the rock is relatively broken or broken.Among them,the(K7+182)~(K7+192)and(ZK7+061)~(ZK7+067)sections have long-developed structural surfaces.The prediction results are close to the actual geology of the excavation.