Research On Advanced Identification And Comprehensive Prediction Of Water Inrush In Tunnels

The advanced prediction of water inrush from tunnel is one of the key techniques to ensure the safety of tunnel construction,three main problems included,accurate location,scale quantification and real-time prediction of the potential disaster geological unit.This paper mainly discusses how to promote the solution of the first two problems and does something to help to solve the third one.Based on the actual work carried out in the Micangshan project,how to predict water body accurately and efficiently by using multivariate prediction technology as geological or geophysical method was studied.Taking TSP as an example,the advance identification method of inrush water is deduced from two aspects of quantitative and qualitative.Finally,the method of comprehensive prediction was combined.The research results are as follows:(1)Based on Micansghan project,Collecting and analyzing the multi-source geological and geophysical information,as survey data,field investigation,face catalog statistics,auxiliary geophysical prospecting,similar conditions and so on,to get simple and rapid prediction.Rough zoning of water rich zones was carried out by means of investigation data and field investigation.After analysing the face catalog information,some special water bearing structures were predicted successfully.Illustrated handbook of GPR was arranged to be tools for identification.Three simplified geophysical models of water bodies were proposed by using engineering analogy.(2)In order to study the response characteristics of seismic method to water bearing structures,two geological-geophysical models of water bodies were proposed.Considering the influence of tunnel body,the staggered finite difference code was introduced to simulate the seismic wave fields.The results showed that the velocity and energy indices can be used to detect water bodies.However,the size or distribution of geological body can affect the collecting information.(3)The parameters got from TSP system were detailedly researched.Combined with large amount of data frome field prediction and indoor rock experiment,comprehensive identification reasoning was completed.The quantitative lithology identification empirical formulas were completed.The value range of the surrounding rock integrity quantitative identification indexes were got.The empirical formulas for quantitative identification of surrounding rock water storage were deduced.Moreover,the quantitative identification index values of simplified water storage structure model were obtained;The qualitative identification method of water bodies by using TSP was studied deeply.Identification method in using illustrated handbook of TSP was proposed,and detailed illustrated handbook was sorted out.In order to make up the limitation,qualitative identification characteristics of TSP in complex water-rich condition were summarized.Then,according to the real forcasting word in Micangshan project,identification method in using illustrated handbook of TSP was tested,and proved successful.(4)The comprehensive prediction method of tunnel water inrush was combed.Combined with the actual layout of double parallel tunel,the operation plan of comprehensive forcast on water inrush was drawn.The implementation of the three-level prediction is proposed to get comprehensive prediction of tunnel inrush water in front of tunnel face.And,The four-level prediction method was proposed on this basis.Finally,the EXCEL is used to establish the database of empirical interpretation,and the prediction is organized and inherited by the means of query screening.(5)In the prediction work of the inclined shaft and main line of the Micangshan project,the comprehensive prediction method of water inrush was adopted and got success.All those cases showed that the method was not only accurate,but also flexible and efficient.