Application Of Recycled Coarse Aggregate Plastic Concrete In Honghua Erji Dam Seepage-proof Wall

With the development of our country’s economy,the construction production activities are increasing day by day,and the construction waste is also increasing,among which the waste concrete is the most.The treatment of waste concrete has become an important issue.It is an important way to recycle it into recycled coarse aggregate.The preparation of plastic concrete with waste concrete has a strong application prospect,but the research on the properties of recycled plastic concrete is not deep enough.In this paper,the basic mechanical properties of recycled coarse aggregate plastic concrete under uniaxial stress and triaxial stress are studied,and the stress and seepage characteristics of the cutoff wall of a dam foundation are analyzed.The effect of five groups of recycled coarse aggregate replacement ratio(0,30%,50%,80%,100%)on the uniaxial mechanical properties of plastic concrete was studied.The results show that with the increase of replacement rate of recycled coarse aggregate,the compressive strength of recycled plastic concrete decreases gradually;the peak strain and maximum volume strain increase gradually;the stress-volume strain curve of recycled plastic concrete gradually extends outward.When the substitution rate is less than 50%,the values of compressive strength,peak strain and maximum volume strain of recycled plastic concrete change slightly.When the substitution rate is more than 50%,the substitution rate has a greater impact on its values.The basic mechanical properties of recycled plastic concrete and primary plastic concrete under four cyclic loading modes are studied,and the results of uniaxial monotonic loading are compared and analyzed.It is found that the strength of recycled plastic concrete under cyclic loading is slightly lower than that under uniaxial monotonic loading,and the hysteretic area of stress-strain curve increases with the increase of maximum stress in cyclic loading.The stress-(volumetric)strain of recycled coarse aggregate plastic concrete and primary plastic concrete under triaxial loading were studied.The test results show that the compressive strength,peak strain and maximum volume strain of recycled plastic concrete increase with the increase of confining pressure in conventional triaxial tests with equal lateral pressure,and the relationship between strength and confining pressure conforms to Coulomb failure criterion.The cohesion of recycled plastic concrete is lower than that of original plastic concrete,and the internal friction angle of recycled plastic concrete is similar to that of original plastic concrete.The constitutive equations of recycled plastic concrete and original plastic concrete are fitted.Under the condition of true triaxial test with unequal lateral pressure,when the second principal stress is fixed,the first principal stress,peak strain and maximum volume strain of recycled plastic concrete increase with the increase of the third principal stress.The failure criterion of recycled plastic concrete under triaxial stress is established.Based on the three-dimensional finite element method,the stress and seepage characteristics of recycled plastic concrete cutoff wall in Honghuaerji dam foundation of Inner Mongolia are analyzed.The simulation results show that it can effectively reduce the stress around the wall and the deformation of the soil,coordinate the deformation between the impervious wall and the surrounding rock and soil,and effectively reduce the total head of the dam,pore water pressure,hydraulic gradient and other parameters,so as to achieve better impervious closure effect.