综合超前地质预报在天竺山一号岩溶隧道中的应用

Application of Comprehensive Advanced Geological Prediction Method in Karst Tunnel of Tianzhushan No.1

为了降低岩溶隧道施工风险,运用综合超前地质预报方法,探明岩溶隧道掌子面前方地质灾害,保障施工安全、高效进行。由于岩溶发育的复杂性,单一物探预报方法存在多解性,易造成解译结果的不确定性,本次“以地质法为基础,长短距离物探测试相结合为核心,超前水平钻验证预报异常为手段”建立综合超前地质预报方法。以天竺山一号隧道岩溶段工程为案例,在分析勘察和设计资料基础上,采用地质素描、隧道地震波法(Tunnel Seismic Prediction,TSP)、超前水平钻探、地质雷达、瞬变电磁五种方法进行综合超前地质预报。结果表明,TSP探测成果在DK141+308—DK141+357段弹性参数异常,预报该段有岩溶发育,超前水平钻证实DK141+315—DK141+339段为粉质黏土充填岩溶,地质雷达、瞬变电磁准确探测岩溶分布位置、规模及其性质,预报结果相关验证,成果可靠。预报结论为隧道围岩变更及岩溶处理方案提供了科学依据,能有效降低隧道施工地质风险,对类似岩溶隧道超前地质预报提供参考和借鉴。

In order to reduce the risk of Karst tunnel construction,the comprehensive advanced geological prediction method is used to clarify the geological disasters in the tunnel face of the Karst tunnel and ensure the safe and efficient construction.Due to the complexity of Karst development,a single geophysical prediction method may have multiple interpretation solutions,leading to uncertainty in interpretation results.Based on geological method,the comprehensive advanced geological prediction method is established,“combined with long-distance and short-distance geophysical testing as the core,and advanced horizontal drilling as the means to verify prediction anomalies”.The case study focuses on the Karst section of Tianzhushan No.1 Tunnel.Based on the analysis of survey and design data,five methods of geological sketch,TSP,advanced horizontal drilling,geological radar(GPR)and transient electromagnetic(TEM)are used for comprehensive geological prediction.The results show that the elastic parameters of the TSP detection are abnormal in DK141+308—DK141+357,and Karst development is predicted in this section.The advanced horizontal drilling confirms that the DK141+315—DK141+339 is filled with silty clay Karst,and GPR and TEM can accurately detect the distribution location,scale and properties of the Karst.The prediction results by various methods are verified reliably.The prediction results provide scientific basis for the change of tunnel surrounding rock and Karst treatment scheme,effectively reduce the geological risk of tunnel construction,and provide reference for similar Karst tunnel advance geological prediction.