The Application And Study Of TST In The Tunnel Geological Prediction

In recent years, with the rapid increasing of our national economy, the magnitude of infrastructure projects of high-speed railway and is increasing in a high speed, and there are more and more large tunnel construction projects as well. However, factors such as construction safety, construction schedule etc. which affect the completion of entire construction project are numerous and have become vital in tunnel construction. As the preparatory works for tunnel construction projects, such as survey data, are not always completely accord with actual situations and usually have some errors, the design of tunnel construction projects will also be unreasonable with the limitation, so affection of tunnel construction will be more obvious. There were many geological factors that influence the safety of tunnel construction, such as integrity of rock, air slake degree of rock, watery layer, joint fissure, fault fracture zone, crustal stress etc. These factors can cause a lot of construction safety accidents in different degrees, such as landslip, collapse, water burst and mud burst. In this way, the construction schedule will be affected, and economic losses are caused, it can even results in personnel safety accidents.Based on previous research and combined with a engineering example of Niubujing tunnel advanced geological prediction, this paper analyzes the impact and elimination method of the near-surface noise, summarizes the reasons of accuracy and erroneous judgment when TST is introduced in the work of Niubujing tunnel advanced prediction. Study main conclusions are as follows:(1)Comprehensively analysis and appraisals the current methods of tunnel advanced prediction, explained superiority of TST from those aspects of the basic theory of Seismic wave scattering wave method, each rock attribute parameter values with scattered waves and numerical analysis to get valid information, and quickly and accurately locate bad in front of the tunnel face geological location, size and occurrence.(2) Tunnel construction process disturbances, such as sound waves, surface waves, interference of construction of electricity will be reduced the quality of the data collected, using the energy removal, F-K filtering methods and multi-point gain of the time domain, frequency domain for the ground reflected wave is removed.(3) The TST forecast data of Niubujing were analyzed and summarized showed us TST tunnel surrounding rock classification accuracy of 67%, on Fractured, water-rich layer prediction accuracy of about 70%, forecast effect basically meet the requirements of tunnel construction, it can be used in geological prediction tunnel.