The Research And Application Of TSP Response Characteristics Under Different Geological Conditions

One of the key and difficult points in tunnel construction is to understand the unfavorable geological conditions in front of the tunnel.affected by natural geological condition,surrounding rock frequent landslides,water,flood sediment tunnel diseases,etc.In order to minimize in the tunnel engineering of landslide,such as sudden outburst flood water and mud tunnel diseases,in order to understand in detail the conditions of engineering geology and hydrogeology conditions in front of the working face,the advanced geological forecast technology as a discipline gradually rise,Various advanced methods for the prediction of tunnel geology came into being.Among them,TSP seismic reflection method is one of the most rapid,widely used,and most effective prediction methods in recent years.The advantage of this method is that the forecast range is wide,the distance of the forecast is longer,the construction interference of the tunnel is relatively small,and the detection is more accurate.These advantages are irsubstitute for other methods.Research on TSP response characteristics under different geological conditions can improve the accuracy and reliability of forecasting,can more accurately identify the bad geological condition in front of the constraints,more reliable for surrounding rock engineering classification,can further increase the construction safety,avoid economic losses.In addition,it can also establish the TSP interpretation signs in the bad geological conditions,which is very instructive to the engineering application.Therefore,it is very important to study TSP response characteristics under different geological conditions.This paper introduces the basic theory of the TSP tunnel geological advanced prediction method and basic principle,basic principle of numerical simulation,the TSP tunnel advance geological forecast data acquisition process,the TSP tunnel geological advanced prediction data processing procedures and matters needing attention,and TSP is established on the geological advanced prediction model of faults and karst,forward modeling was carried out on the model,combined with a typical project example,the extracted from forward modeling results and engineering examples,the TSP response characteristics of the faults and karst,established the TSP interpretation symbol of faults and karst.The main research contents and achievements are as follows:(1)The comprehensive comparison and analysis of the various tunnel advance geological forecast method.the TSP tunnel geological advanced prediction method using negative apparent velocity method principle,the original data were collected by processing,the bad geological condition in front of the tunnel can be effectively detected,such as fault fracture zone,karst and so on.(2)By studying the numerical simulation,some faults and karst model is established,including the different direction of the fault,and carries on the forward modeling,and the result of inversion and its correctness was verified.The wave field snapshots and TSP seismic records of seismic waves can be obtained by performing the forward simulation,and the propagation rules and response characteristics of seismic waves in tunnels can be clearly understood.(3)The seismic wave field snapshot and TSP seismic record obtained through the forward modeling,and finally combined with a large number of engineering examples,the TSP response characteristics of fault and karst were obtained by comparison and analysis,and a set of TSP interpretation signs of fault and karst were established.(4)Some solutions are proposed to improve the quality of raw data acquisition and to solve the multiple resolution and blind zone of single geophysical prospecting method,and it is pointed out that the TSP seismic reflection wave method can not make accurate prediction for some special unfavorable geological conditions,such as high ground stress region,gas bearing construction(gas,etc.),further research is required in these aspects.