| In these years,with the further improvement and development of my country’s high-speed railway infrastructure,in karst areas,a growing number of dangerous tunnels will be built with intricate topography and surface conditions.On account of many factors interfere,such as special terrain environmental conditions,geological survey technology and so on in the project construction,it is always hard to fully grasp the geological conditions of the tunnel project in the area in the early stage of the construction of the tunnel project.Especially in karst areas,there are faults,caves,broken zones and other bad geological bodies in the area,water inrush,mud inrush,rock burst and other tunnel engineering geological problems occur from time to time,which seriously threaten the safety of engineering construction.As a method that can forecast geological disasters ahead,advanced geological forecasting technology is of great significance to the construction of tunnel engineering.Geophysical method is a moreeconomical and convenient method,comprehensive geophysical prospecting method refers to the common use of several geophysical prospecting methods,which can effectively avoid the ambiguity of single geophysical prospecting.This article takes the San’eshan tunnel project on the Chengdu-Kunming double line as a background.After field tests,in order to improve the accuracy of advance prediction of karst tunnel,the application of integrated geophysical exploration method in karst tunnel is studied.The main research content and the results obtained are as follows:1 、 This paper discusses the basic principle,system layout,data acquisition and data interpretation methods of TSP method,puts forward the measures to improve the quality of data acquisition,establishes the TSP data image as the symbol of karst,and applies TSP method to carry out field practice in two bid sections of san’eshan tunnel,reveal that the single use of TSP method is not effective in detecting karst and water.2 、 This paper discusses the basic theory,system layout,data acquisition and data interpretation of GPR method,and puts forward better technical parameter setting.The GPR method is used to test two sections of san’eshan tunnel,it is revealed that the single use of this method has a good detection effect on karsts,but the detection accuracy of water-bearing conditions and the distribution of water-bearing rock formations is low.3、The working principle of the TEM method,system layout,data acquisition and data interpretation methods are discussed,through field tests in the two bid sections of the San’eshan Tunnel,it was revealed that the single use of the TEM method has high detection accuracy for water content.4、Aiming at the limitation analysis of single geophysical prospecting method,this paper puts forward the comprehensive geophysical prospecting method based on "TSP + GPR +TEM" in karst tunnel,and reveals that these three methods can learn from each other.The application in the San’eshan Tunnel shows that the use of comprehensive geophysical methods can greatly improve the accuracy of advance forecasting in karst tunnels. |
PDF Full Text Request