The Application And Research Of Asphalt Concrete Diaphragm Wall In The Reinforcement Of Earth-rock Dam

It adopts three-dimensional finite element method to make a numerical simulation analysis of deformation coordinated property of core-wall and transition layers on two sides on some homogeneous earth dam with bituminous concrete core-wall in Yunnan province, to study the change law of thickness of core-wall to dam body seepage-proofing. Calculate dam body and constitutive model of core-wall with Duncan E-B model, and core wall with different thickness is carried on analogy calculation, respectively, and contrast the deformation coordination law among them and the effect of seepage-proofing of core wall are compared.The simulated calculation of the different slope of the downstream face of the core wall is carried out, and compared the rule of the stress and deformation of each other. By adopting the method of linear elastic fracture mechanics theory of asphalt concrete core wall is the discriminant analysis of hydraulic fracturing may occur.According to the analysis results, the settlement and the stress distribution of dam body and core wall is symmetrical, stress and strain regularity in a reasonable range, but the core wall has been produce different degree of arch effect, so the possible existence of hydraulic fracturing need for research. Through the asphalt concrete core wall on hydraulic fracturing criterion, in addition to the left and right on both sides and the top parts, core wall on the surface of the upstream water pressure is far less than the minimum principal stress. Results show that the asphalt concrete core wall on the possibility of hydraulic fracturing is very small. The main finding are as follows:(1) Using ansys workbench software to calculate the stress and deformation calculation is reasonable, the results of hydraulic fracturing will not happen, also won’t happen tension and compression and shear damage. Under the condition of core wall thickness at 0.3 m,0.4 m and 0.5 m, most of the horizontal displacement meet the deformation coordinated property, to the flow direction of the river the horizontal displacement value is increased with the increase of core wall thickness, and the arch effect is more obvious, which indicates more adverse to horizontal displacement of the core-wall. The sedimentation of core wall and transition layer is getting larger with the increase of elevation, and with the increase of core wall thickness, the maximum of sedimentation is reduced. In terms of transition layers on two sides, the upper sedimentation of the core-wall is small, while the bottom sedimentation is big, the whole core-wall has "be stretched " phenomenon on the height direction, which provides necessary condition for core-wall arching effect.(2) Core wall with compressive stress as priority, local area in tension, but the maximum compressive stress and the maximum tensile stress value has not been more than the strength of the asphalt concrete, therefore, the stress of the core wall is safe. through calculation, there is no hydraulic fracturing damage.(3) After adding bituminous concrete core-wall into dam body, seepage line is decreased obviously, and seepage-proofing effect is getting better, and the seepage flow decreases with the increase of core wall thickness.(4) After joining core wall to dam, reduce deformation of the dam downstream, the upstream deformation increase, and increase the large and small principal stress of the dam. Along with the increase of theta, the maximum principal stress decrease gradually. Core wall along the flow direction of the river to the maximum horizontal displacement occurred near the height of 2141.0m, core wall inner have different degrees of "arch effect". Through the minimum principal stress of core wall compared with the upstream surface water pressure, whether core wall may occur hydraulic fracturing for the discriminant analysis, through calculation and analysis:in addition to the dam crest area, the water pressure value is far less than the minimum principal stress value of core wall, core wall hydraulic fracturing will not occur.