Research On The Prediction Of Waterinrush Disaster In Super-Long Water Delivery Tunnel Of Qinling

Abundant water sources and abundant water supply are the prerequisite for ensuring agricultural development.Through the diversion of water in a certain area,the rational allocation of water resources and the safety of agricultural water can be ensured,and the problem of water resources imbalance between different regions can be solved.As a typical building in water diversion project,the super long tunnel is affected by the complexity of its own length,buried depth and geological conditions,geological problems such as water gushing and rock burst occur frequently.Therefore,it is of great significance to make a systematic study for water-inrush during the construction of water conveyance tunnel to protect agricultural water use.In this paper,the super-long water diversion tunnel in Qinling of Hanjiang to Weihe River Project was taken as an example.In view of the water-inrush problem in the long diversion tunnel under complex geological conditions in Qinling area of Northwest China,a complete forecasting method of water-inrush was developed and studied.This article has carried on the following research work:(1)In view of the complex topography and geological conditions of the ultra-long tunnel in the Qinling Mountains,along with adverse geological conditions(such as faults and cruzed belts).It proposed three classification methods(stratigraphic lithology and fault classification;groundwater runoff modulus classification;improved classification of underground runoff modulus)to division the hydrogeological units by different hydrogeological features.Division and Evaluation of watery degree of the super long water conveyance tunnel of Qinling Mountains by Classification,the occurrence of the water-inrush and the preliminarily prediction of the location of water-inrush can be reflected simple and intuitive.(2)Through the analysis and research on the mechanism of disaster and its environment of water-inrush,and the summary investigation of the main influencing factors of water-inrush.This paper establish seven evaluation indexes system which including stratigraphic lithology,dip of rock strata,height difference between groundwater level and tunnel floor,water-rich grade,surface catchment area,width of fracture broken belt and development degree of broken belt.Based on the quantitatively evaluates the risk level of water-inrush hazard via the attribute mathematics method,a method to evaluate the risk level of water-inrush hazard of long tunnel was set up.(3)According to division of watery degree of the super long water conveyance tunnel of Qinling Mountains,the mathematical model of the possible inrush water segment is constructed.Dividing different working conditions according to different fault permeability coefficients,and the influence degree of fault on the water-inrush is calculated and analyzed.The larger the fault permeability is,the greater the volume of water-inrush.According to different hydrogeological units to establish different mathematical models,more accurate predicted the amount of water-inrush.The amount of water-inrush by predicted was verified in the construction process of Qinling tunnel.This method is used to predict the amount of water-inrush in the non-through section of Qinling tunnel and provide guidance basis for preventing water-inrush and safety construction.