Comprehensive Application Research Of Forward Modeling In TSP Tunnel Geological Prediction

In tunnel engineering,the geological conditions in front of the tunnel face are complex and changeable,and adverse geological bodies such as caves and faults are often encountered,which can easily lead to geological disasters such as collapse,mud inrush and water inrush,seriously affecting the progress of construction,and even leading to catastrophic accidents.Tunnel advanced geological prediction is an effective method to solve this problem,can timely grasp and feedback the potential adverse geological bodies in front of the tunnel face,which provides early warning for various geological disasters and reduce the probability of geological disasters.TSP advanced prediction system is the most commonly used medium and long distance advanced geological prediction technology at home and abroad,which has the advantages of long single prediction distance and short construction time,can timely grasp and feedback the mechanical properties and structural changes of rock in the range of 150 m ahead of the face,and identify bad geological bodies.However,due to the relatively complex work of field data collection,data processing and interpretation,technical personnel rely more on experience to judge and interpret bad geological bodies,and there are often some misstatements and omissions in practical work.In view of the above problems,this paper carried out the following research :(1)This paper introduces the basic theory of seismic waves,expounds the working principle of TSP advanced prediction system,and combs the whole process of seismic data acquisition,data processing and interpretation.(2)The Tesseral-2D full-wave field simulation software is used to forward simulate the common adverse geological bodies such as water-bearing caves,fault interfaces and weak interlayers in the process of tunnel advanced geological prediction,and the seismic response is obtained.Starting from the phase,energy and frequency of wave group,the seismic response characteristics are summarized,and the characteristics of their influencing factors are analyzed.A set of quantitative analysis of forward simulation chart is formed,which provides theoretical reference for data interpretation.(3)According to the characteristics of engineering geological conditions of Jiuwandashan No.2 tunnel and Dongxishan tunnel,combined with the existing survey and design data,the analysis and evaluation of tunnel engineering geological conditions are completed.The measured data of TSP are compared with the actual excavation,and the detection effect of TSP advanced prediction system on karst caves and faults is analyzed to provide guidance and suggestions for advanced geological prediction in tunnel construction.