Study On Static And Dynamic Stability Of Damp Slope Section Of Dahuaqiao Rcc Gravity Dam

Gravity dams are one of the most commonly used major hydraulic structures in water conservancy projects.The anti-sliding stability problem of gravity dam is an old and common problem,and it is also a major key technical issue that directly affects engineering safety,investment and construction period.In China,more than 20 gravity dams have been constrained by such problems,such as Gezhouba Erjiang sluice gate,Zhuzhuang Reservoir,Shuangpai Reservoir,Dahua Hydropower Station,Changshao Hydropower Station,Ankang Hydropower Station,Daheiting Reservoir,Gravity dams such as Tianshengqiao II Hydropower Station,Qilitun Reservoir,Hengren Reservoir,Three Gorges Dam Left Bank Dam,and Xiangjiaba Hydropower Station all encounter deep(shallow)anti-sliding stability problems.Due to the limitations of theory,methods and experimental methods,the design theory of gravity dam anti-sliding stability,especially deep anti-sliding stability,has yet to be improved.It is necessary to carry out in-depth systematic research on the comprehensive analysis and safety assurance technology of gravity dam anti-sliding stability,and form an effective theory and method system for anti-sliding stability analysis of gravity dams,in order to promote the anti-sliding stability of gravity dams,especially deep anti-sliding stability.More progress in surveying and design technology has provided strong technical support.Seismic load is an important design load that cannot be avoided in the operation of gravity dam,which has a great impact on the safety of gravity dam.The dynamic response of concrete gravity dam under seismic loading is a complex nonlinear process,which is affected by many factors,such as seismic wave spectrum characteristics,dynamic characteristics of dam material,seismic inertia force,ground motion water pressure,ground motion earth pressure and The dynamic interaction between the dam and the dam foundation.Due to the limitation of geological conditions of river valleys,gravity dams are often built on dam foundations with more complicated geological conditions.The deep anti-sliding stability of dams under various loads is an important issue in dam design.The deep antisliding stability problem of the riverbed dam section can be simplified to a two-dimensional problem according to its force characteristics;however,the steep slope dam section built in the valley is affected by the sliding force along the axis of the dam,and its stress state and the riverbed dam section The large change in the ratio,therefore,the anti-sliding stability of the bank slope section is a complex three-dimensional problem.Therefore,it is necessary to investigate the spatial stress state of the bank slope section and combine the geological conditions to conduct a special study on the stability of the bank slope section.In order to comprehensively and systematically understand the static stability of concrete gravity dam and the dynamic stability under earthquake action,this paper takes the gravity dam of Dahuaqiao Hydropower Station of Minjiang River as the object,establishes a three-dimensional mechanical model,and adopts ABAQUS to calm the Dahuaqiao gravity dam.Dynamic numerical simulation analysis.This paper mainly carries out the following aspects:(1)Starting from the theory,this paper briefly describes the nonlinear finite element theory and theoretical knowledge of dynamic finite element commonly used in gravity dam analysis,and compares the advantages and disadvantages of mode decomposition reaction spectrum method and time history analysis method.Applicability of dam section stability analysis.The application of reaction spectrum method and time history analysis method in ABAQUS is realized by numerical analysis.(2)In this paper,the basic data of the Dahuaqiao gravity dam project in Minjiang River are combed and analyzed.It is found that the dam foundation rock structure is complex.The parameter reduction method based on Hoek-Brown criterion is used to study the mechanical parameters of rock mass,and the structural plane is obtained.Rock mass parameters.(3)The load on the Dahuaqiao gravity dam project was analyzed,and the combination of calculated load conditions was determined.The three-dimensional finite element model of the calculation and analysis of the Dahuaqiao shore slope dam section was established and adopted by ABAQUS.The three-dimensional static strength reduction analysis is carried out,and the stability coefficient of deep anti-sliding stability of gravity dam under different load conditions is obtained.The comprehensive stability is analyzed.The sliding failure mode of the steep slope section of gravity dam is elaborated.(4)Based on the time history analysis method and the mode decomposition reaction spectrum method,the seismic dynamic analysis of the Dahuaqiao shore slope dam section was carried out by using ABAQUS,and the stability of the bank slope dam section under the seismic load was considered.It shows that the safety factor of the anti-sliding stability of the dam body obtained by the time history analysis method and the vibration mode decomposition reaction spectrum method is relatively close.The safety factor obtained by the response spectrum method is conservative and more practical for practical engineering,which can provide an effective basis for practical engineering.Through static and dynamic calculation,the static anti-sliding stability and dynamic anti-sliding stability of gravity dam of Dahuaqiao Hydropower Station on Minjiang River are analyzed comprehensively.The seismic dynamic characteristics of gravity dam of Dahuaqiao Hydropower Station are analyzed.Through the calculation and analysis,the failure process,force characteristics and damage characteristics of the typical dam section of Dahuaqiao are given.The key points for the seismic design of the gravity dam of Dahuaqiao Hydropower Station are proposed.