Study On Damage Mechanism Of Water Diversion Tunnel In Glacial Period

Due to the cold and arid region of China,the unique climatic conditions,with the change of the outside temperature,the water in the ice can according to the process of ice formation and melting be divided into three stages: the period of freezing,freezing period and thawing period.When the water delivery project is carried out in winter,the ice will cause different degrees of persecution to the water conveyance structures at various stages.In order to alleviate the water shortage problem in Western China,our country has built the the water conveyance project which bring water of DATONG river to QingWangChuan,and Yintao project.However,such a large investment in construction and operation period due to suffer from cold and drought climate,which causes a series of problems of diversion tunnel of freezing thawing damage and diversion tunnel geological defects,leakage thawing damage and diversion tunnel geological defects,leakage,water diversion channel dry equipment failures.The structural safety and water supply efficiency have a serious impact,leading to the project’s service life is not long,it can not reach the expected goal of project planning and construction,and resulte in a series of social contradictions.Therefore,it is of great significance to study the failure mechanism of the diversion tunnel based on the winter water conveyance in the cold and dry regions.Based on the research at home and abroad,this paper studies the damage of water diversion tunnel in cold and dry area by theoretical research,laboratory test and numerical simulation method.This paper focuses on the collision simulation problem of the interaction between ice and diversion tunnel.The contact collision algorithm of symmetric penalty function algorithm in finite element is used to study the contact collision algorithm of the ice induced impact tunnel.Take the water conveyance project which bring water of DATONG river to QingWangChuan of the diversion tunnel(Pandaoling tunnel)as an example,analyzes the damage mechanism of the headrace tunnel.Apply ANSYS software to establish the tunnel model and ice model;both use 3D Solid164 solid element simulation;the material is defined as linear elastic material;the unit division uses free meshing;use of free contact;define boundary conditions;and then use LSDYNA SOLVER solver to solve and post-processing.Finally,found the different flow rate,different ice plane size,different ice thickness and so on under the conditions of the ice floe on the deformation of the diversion tunnel and its impact.Specific work is as follows:(1)Study the influence of ice velocity on impact force and deformation of lining,it is found that the change is basically linear,and determined calculation formula of simple collision condition;(2)Study the influence of ice plane size on the impact force and deformation of lining,it is found that the change relation was nonlinear;(3)Study the influence of ice thickness on the impact force and deformation of lining,it is found that the change is basically linear,and determined calculation formula of simple collision condition.Then,through the indoor experiment,the experimental study was carried out to study the single-slope experiment of the tunnel test,and the whole evolution process of the edge wall of the tunnel was simulated.We have analysised the impact of the headrace tunnel on the flow velocity,the size of the ice plane,ice thickness and so on under the conditions of the ice floe.And through the experimental model to verify the basic simulation with the numerical consistency.It indicates that numerical simulation is convenient and feasible.The research of this paper will provide scientific basis and technical support for the design,construction and operation and maintenance of the diversion tunnel in the cold and arid area,and enrich the basic scientific research content of ice hydraulics.