Research On Optimization Of Center Wall Thickness Of Plastic Concrete Core Earth-rock Dam

The concrete core wall is one of the main anti-seepage types of earth-rock dam engineering.Especially in the reinforcement and reinforcement works of earth-rock dams,the concrete core wall has been widely adopted due to its good anti-seepage effect and convenient construction.Decades of practice show that there are some disadvantages in the use of rigid concrete for wall materials.The main disadvantages are the high elastic modulus of rigid concrete and uneven settlement with the surrounding soil.This can easily lead to cracks in the wall and the anti-seepage effect is significantly reduced,which is detrimental to dam safety.Plastic concrete has the advantages of small permeability coefficient,strong adaptability to deformation of surrounding soil,low elastic modulus,large ultimate strain,and increased strength as the confining pressure increases.It is widely used in the reinforcement and reinforcement of earth-rock dams.In recent years,many experts and scholars in China have begun to consider the use of plastic concrete for earth-rock dam seepage.The finite element method is used to study the stress-deformation of the plastic concrete impervious wall structure of dam foundation,but plasticity is used in the dam body.There is relatively little research on the stress-deformation structure of the seepage control structure of the concrete core wall.At the same time,there is no unified theory and calculation method for the selection of the thickness of the plastic concrete core wall.Generally,it is based on the engineering experience.Therefore,it is necessary to study the stress-deformation of plastic-concrete-core earth-rock dams and to use numerical analysis method to design the thickness of plastic concrete core walls.In this thesis,seven groups of plastic concrete core wall earth and rock dams with different heights are taken as the research object.The height of the dam is 40 to 100 meters,and the height of the dam is a step of 10 m.Each group of high-rise heart wall dams selected six different core wall thicknesses for finite element numerical analysis,mainly including the following:1.Using finite element ABAQUS software,finite element models of earth-rock dams with different heights and different thicknesses of core walls were established.According to the ABAQUS software,the seepage analysis of earth-rock dams with different heights and different core-wall thicknesses was carried out.The seepage flow and permeability gradient of earth-rock dams with different dam heights and different core thicknesses under flood conditions were calculated.Calculate and determine the infiltration line inside the dam.2.Based on the secondary development platform of ABAQUS software,a subroutine of Duncan's E-B constitutive model was written.The subroutine is used to analyze the stress and deformation of earth-rock dam with plastic concrete core.It can be seen that the stress-deformation results of the dam body and the core wall are more accurate,which overcomes the lack of the finite element ABAQUS software lacking the constitutive model of earth-rock material.3.The influence of the wall thickness on the stress-deformation of the wall was studied.The BP neural network optimization algorithm was used to calculate the optimal core thickness of each group of high earth-rock dams,and the functional relationship between the height of the dam and the wall thickness was established.4.To check the anti-sliding stability of upstream and downstream slopes of plastic concrete core earth-rock dams with optimized core thickness obtained from optimization analysis.