Study On The Early-warning And Countermeasures Of The Carst Disaster During The Tunnel Construction In The Yi Chang-Wan Zhou Railway

There are two tunnels: the Qiyueshan tunnel and the Yesanguan tunnel passing though karst mountainous region. When construction of tunnels, lspacial distribution of large-scale karst tube can lead to karst disaster which is disastrous.In this paper,to early warn and prevent the karst disater,we study the geology characteristic indexs of karst calamity,including the thickness of strata, lithology changes, fracture structure, fold structure, joint development and the indexs of groundwater characteristics. The groundwater characteristics indexs include research on water inflow and water preasure. An index system of karst disaster early warning is established in this paper,and a expert system which can assistant the early warning of karst calamity is developed.And countermeasures of karst calamity is studied,the measures are as follows:1.The design of tunnels though karst region should take drainage in consideration during construction.When the tunnel pass though karst region,especially there is a watershed in the region,the drainage scheme of large-scale water inrush should be considered.And unidirectional slope should be avoided as possible.2. Advanced detection forecast should be strengthened and elective geophysical prospecting should be done when the constructin went though dangerous zone which is detectedin karst disaster prediction. The results are interpreted in cooperation with geological technician,then providing evidence for design of drilling site during advance exploratory drilling.3.The forcast of geological information while construction.On the one hand,geological technician should re-determinate formationjithology and geological structure to acquaint with the change of geological structure.On the other hand,what is more important is that geological technician can make use of karst conduit precursor which is present during construction to make up the deficiency of advance exploratory drilling.Except Verification of geological prediction and provide information for advanced forecast,drilling parameter is needed for judement of foreside geological condition, discovery of new karstconduit, determination of inflow of water and water irruption quantity underground,water preasure and other parameter of karst disaster.