Research On Stress And Deformation Of Asphalt Concrete Core Wall Dam Under Different Condition

Asphalt concrete core wall dam is one of the commonly used dam types in water conservancy projects.Its stress deformation has an important impact on the engineering performance of the dam.In the process of filling and operation,the dam body will generate different degrees of stress,deformation and settlement under the action of various factors,which affect the engineering performance of the dam body.The main influencing factors can be divided into three categories: material properties,dam structure and operating conditions.In this paper,the material parameters of asphalt concrete were first determined by splitting test and static triaxial test,and on this basis,numerical simulation was performed by ABAQUS software on an asphalt concrete core wall dam as an example to analyze the stress and deformation law of asphalt concrete core wall dam during the completion and storage periods for three conditions: material properties,dam structure and operation conditions.The main findings are as follows:(1)From the viewpoint of dam material properties,the density of dam shell material was considered and the relative densities of 0.9,0.95,1.0,and 1.05 were used to explore the stress-deformation law of dam shell material density and dam body.The results showed that the stress-deformation distribution of the dam body and the core wall did not change significantly as the density of the shell material increased in the selected interval,except for the decrease in the creekward displacement of the core wall during the storage period,and the increase in the other stress-deformation indicators.When the density of the dam shell material increases,the vertical stress of the core wall increases and the arch effect coefficient increases,improving the arch effect and resistance to hydraulic splitting of the core wall.(2)The height of the dam and the slope ratio of the diagonal core wall were considered from the perspective of the dam structure.The calculation models of straight core wall dams of 50 m,70m,100 m and 140 m in height and inclined core wall dams of 70 m in height with slope ratios of 0.1,0.2 and 0.3 were established and the stress deformation law of the dams with different dam heights and slope ratios of the inclined core wall was derived through comparative analysis.The results show that when the dam height increases,the stress deformation indexes of both the dam body and the core wall increase,with the most obvious increase in the downstream displacement of the dam body and the most obvious increase in the vertical displacement of the core wall during the storage period;when the slope ratio of the diagonal core wall increases,the stress indexes of the dam body and the core wall increase,but the downstream displacement decreases during the storage period.The rise in dam height increases the arch effect of the core wall and weakens the resistance to hydraulic splitting,while an increase in the slope ratio of the diagonal core wall improves this situation.(3)Temperature variations were considered from the perspective of operating conditions.By varying the core wall material parameters,the stress deformation law of asphalt concrete core wall dams at core wall temperatures of 5°C,10°C,15°C and 20°C was analyzed.The results show that the stress-deformation indexes of the dam and the core wall change to different degrees when the temperature increases,but the reduction of the large principal stresses is most obvious in all cases.At the same time,along with the temperature rise,the strength of the core wall decreases,the deformation increases,the uncoordinated deformation with the transition material is aggravated,the arch effect of the core wall is enhanced,and the resistance to hydraulic splitting is weakened.(4)According to the total stress method,the ratios of large principal stress,medium principal stress and corresponding elevation water pressure are defined as Rc and Rs coefficients,and the effect law of different conditions on horizontal and vertical cracks in the core wall is derived by comparing the increase change of the average value of the two coefficients.The results show that the increase in dam height and temperature increase both increase the possibility of cracks in the core wall,with a greater effect on horizontal cracks.The increase in the density of dam shell material and the slope ratio of the diagonal core wall will reduce the possibility of cracks in the core wall,and the increase in the density of the dam shell material has a more obvious effect on improving the vertical cracks,while the increase in the slope ratio of the diagonal core wall will improve both to the same extent.