组合物探方法在十八里堡隧道超前地质预报中的联合应用

Combined Geophysical Exploration Methods Applied in Advanced Geological Prediction in Shilibao Tunnel

我国地形复杂多样,岩体工程地质条件复杂,隧道施工的规模和修建难度逐年增大。由于隧道围岩结构复杂,极易发生地质灾害,不仅影响施工进度,而且带来严重安全隐患。因此,查明前方不良地质体已列为隧道施工前首要解决的问题。地质预报的物探方法主要有地震波法、探地雷达法和瞬变电磁法。单一的物探方法抗干扰能力弱,易受到施工环境的干扰,造成预报结果的误判。为了保障隧道施工安全、有效进行,需进行互补的多种物探预报方法,完善解译指标体系和资料联合解释方法,以提高预报地质灾害的准确度。此次选择这3种组合物探方法可对不同地质灾害的预报结果相互制约,通过地震法获得的构造异常、雷达法高精度岩性界面、瞬变电磁法电性异常综合解释,并结合工程地质勘察资料及掌子面素描结果,避免单一方法的多解性,提高了预报结果准确率,验证了综合物探预报方法的可行性。

The terrains in China are complex and diverse,and the geological conditions in geotechnical engineering are complicated,while the scale of tunnel construction and the construction difficulty are increasing each year.Due to the structural complex of tunnel surrounding rocks,geological disasters are very likely to occur,affecting the construction progress and bringing potential severe safety hazards.Therefore,finding out the harmful geological body ahead of tunnel has been listed as the first problem to be solved before tunnel construction.The main geophysical prospecting methods applied to geological prediction are seismic wave detection technology,ground-penetrating radar method,and transient electromagnetic method.However,the single geophysical detection method is weak against interference and vulnerable to interference from the construction environment,resulting in misjudgment of predicted results.In order to guarantee safe and effective tunnel construction,complementary multiple geophysical forecasting methods are needed to improve the interpretation index system and joint data interpretation methods to improve the accuracy of predicting geological hazards.This paper selects three combined geophysical prospecting methods to constrain each other’s prediction results for different geological hazards.Structural anomaly is obtained by the seismic wave method,high-precision lithologic interface is gained by radar method,and electrical anomaly is achieved by transient electromagnetic method.Combined with engineering geological exploration data and face sketch results,the multiple solutions of a single method are avoided,the accuracy of prediction results are improved,and the feasibility of a comprehensive geogeophysical prediction method is verified.