| Infrastructure construction is an important development task in China.Tunnel engineering has played an important role in the construction of roads and railways in China.Tunnel engineering is susceptible to faults,karst and other unfavorable geological bodies in areas with complex geological conditions.Construction is more difficult and of a greater risk.How to ensure the accuracy of advance forecasting technology has always been a key research topic.This paper combines numerical simulation methods and field experimental analysis to study the effect of integrated geophysical prediction technology in complex geological conditions.The purpose is to further improve the accuracy of geological prediction in front of the tunnel face.The main research contents and research results of the thesis include the following aspects:(1)This paper studies the development history and existing problems of tunnel advance prediction in China and abroad.Combined with the study of typical geological disasters represented by faults and karst in tunnels,this paper studies the advanced prediction methods of various tunnels and clarifies them.The important role and advantages of geophysical methods are analyzed.The characteristics and shortcomings of various methods of geophysical prediction are analyzed.The limitations of single geophysical prediction methods are clarified.The combined forecasting methods of TSP technology,transient electromagnetic method and ground penetrating radar method can On the basis of exerting its own advantages,it can make up for the shortcomings of each method,verify the results of single geophysical methods,and provide more accurate forecast information for tunnel engineering.(2)The basic principles and observation methods of TSP technology,transient electromagnetic method and ground penetrating radar method are studied.The process and criteria of data acquisition and data processing interpretation are clarified.The forward numerical simulation is carried out on the basis of theoretical research.The forward modeling of TSP technology mainly simulates the propagation characteristics and response of seismic waves in faults and karst in tunnels,visually reflects the observation process and response characteristics,and comprehensively analyzes the reflection horizon and mechanics of typical geological disasters in tunnels based on field observation data.The image characteristics of the parameter map summarize the interpretation marks in the forecast of the TSP technique.The transient electromagnetic simulation model simplifies the fault and karst geological disasters into layered simulations and studies the exploration effects of transient electromagnetic methods on high-resistance bodies,low-resistance bodies and geological bodies of different sizes,combined with the field detection of unfavorable geological bodies.The geological hazard criteria for transient electromagnetic method are improved.The forward modeling of ground penetrating radar method studies the response characteristics of electromagnetic waves in fault,water filling and inflation cavity models,analyzes the causes of response characteristics,and analyzes the prediction ability of ground penetrating radar method with application examples.In the research process of the integrated geophysical prediction method,combined with the existing data interpretation standards,the interpretation marks of the tunnel advance prediction are summarized.(3)Combining the forward simulation results,the practical application of the integrated geophysical prediction method in the tunnel is analyzed.It can be found that although the TSP technology has a large detection depth and low detection precision,it is in the plane structure of fault fracture zone and weak interlayer.The detection effect will be good,but the detection effect of karst and dark river is still lacking;the transient electromagnetic method has large detection capability,relatively low precision,and is sensitive to low-resistance body,but the exploration effect on high-resistance body is general;The ground penetrating radar method has a small depth of detection and high precision,and can detect structures such as fault fracture zones and fissures,but is greatly affected by water.The integrated geophysical prediction method can complete geological prediction more accurately,can provide more reliable forecast results,and provide better safety guarantee for tunnel engineering. |
PDF Full Text Request