Study On The Comprehensive Treatment Of Karst Along The Tunnel Of Chengdu-Guizhou Newly-built Railway Line

The Yujingshan tunnel,located in Weixin County,Yunnan province of Chenggui railway,has passed coal series and soluble rock formations,of which the D3K279+515-D3K280+310 section is the limestone of the lower Permian Qixia maorkou formation(Plm+q),and the karst is well developed in this stratum,and the giant karst cave can not be avoided in the line.The karst caves are the largest karst caves in the history of engineering,and the problem of bad karst geology has been greatly challenged,and it has become an urgent problem to be solved.Therefore,the treatment scheme for large karst caves has become a research topic to be explored.In this paper,the geological environment,morphological characteristics and engineering characteristics of the karst hall are studied by literature collection,field survey and numerical simulation,and the following work is made in this paper.1.consulting the literature at home and abroad and collecting data to understand the morphological characteristics,development mechanism and general rules of karst development,summarize the treatment schemes for Karst karst cave at home and abroad,and determine the general situation of the regional engineering geology and hydrogeology of the Yu Jingshan tunnel.2.according to the field geophysical prospecting,drilling and dynamic exploration,the location,shape,scale and water filling condition of the karst hall are determined on the basis of field geophysical prospecting,drilling and dynamic exploration.According to geological survey and geotechnical water test,the engineering geological characteristics and hydrogeological characteristics of the rock and soil in the karst hall are determined,and the detailed geological model is established and the qualitative analysis is established.The stability of the karst hall and the reliable basis for the treatment plan are put forward.3.use the finite element technology to establish the geological model,use ANSYS to analyze the overall stability of the karst hall;use the stereographic projection technology to analyze the local unstable rock mass in the hall;use the FLAC SLOPE to evaluate the stability of the piled slope of the filling,and then study the whole tunnel chamber in the karst hall.And put forward reliable basis for proposing the treatment plan of the karst hall.4.to sum up the previous management scheme of karst in tunnel and railway,and put forward the corresponding treatment plan according to the specific engineering geology and hydrogeological conditions of the karst Hall of the jade Jingshan tunnel.