Analysis Of Monitoring Data And Safety Evaluation Of A Clay Core Dam

Reinforcement is the main measure to ensure the safety of the built earth-rock dam.Heightening and reinforcement of the dam is one of the more common forms of reinforcement.Some dams have even undergone multiple heightening and reinforcement of the dam body,and there is often a long-time interval between different heightened fillings.Multiple heightening and filling with long intervals make the earth-rock dam present different filling characteristics from ordinary earth-rock dams.This will have a certain impact on the mechanical properties of the dam.The safety evaluation research on multiple heightening and strengthening earth-rock dams is of great significance for further guiding the danger elimination and reinforcement of earth-rock dams.This paper first analyzes the monitoring data of a clay core dam that has undergone multiple heightening and reinforcement.And then uses numerical methods to calculate the mechanical properties of the dam body.The analysis of the clay core dam is carried out in terms of stress,deformation,seepage,and dam slope stability.The dam carries out safety evaluation research,the main research contents are as follows:(1)Analyze the monitoring data based on the actual measured data on the dam body settlement and dam body leakage characteristics.The results show that the horizontal displacement and dam settlement of the clay core dam show a gradual stabilization trend.The piezometer measurement value is relatively stable,and the seepage flow is 6.0 L/s periodic change,the clay core wall and the high-pressure jet cut-off wall of the dam foundation have played an obvious anti-seepage effect,and the dam is operating in good condition.(2)The finite element method was used to carry out the three-dimensional stress and deformation calculation of the clay core dam.And the influence of the dam body’s phased reinforcement and filling on the dam body’s stress and deformation was studied.The results show that the stress and deformation distribution of the clay core dam is in good agreement with the measured results,and the dam has operated well after being heightened and reinforced in stages.Repeated heightening and reinforcement filling has little effect on deformation,but it causes a certain stress mutation effect between different heightened filling bodies,and there is a problem of deformation coordination in the two phases before and after the dam.(3)Using a three-dimensional finite element model,a three-dimensional steady-unsteady seepage analysis of the clay core dam under different working conditions was carried out.The results show that the head line of the Reservoir is low,the seepage flow is small,the seepage gradient at the exit point of the core wall is much smaller than the allowable seepage gradient,and no seepage damage will occur.Repeated heightening and reinforcement make the shape of the core wall different from the straight core wall,causing a certain difference in the seepage field distribution,but it will not have a significant impact on the overall seepage field.(4)Considering the zoning characteristics of the dam body’s staged heightening and strengthening and filling,the finite element strength reduction method is used to analyze the stability of the upstream and downstream slopes of the river bed dam section and the bank slope dam section.The results show that the clay core dam,which has been heightened and strengthened many times,has good slope stability,and the retaining wall can significantly improve the safety factor of the downstream dam slope.