Mesoscale simulation study on triaxial test of cementitious weathered material mix proportion based on PFC
The construction of cemented sand and gravel dam has the advantages of convenient local raw materials,economic-environmental protection and rapid construction.However,it is difficult to determine the mix ratio of cementitious weathered materials.The indoor test has the problems of difficult sampling,long test period and high cost.The intelligent algorithm does not consider the influence of material particle characteristics and mineral composition,and a large number of training samples need to be given.To further explore the feasibility of applying particle flow method to the mix ratio design of cementitious weathered materials.PFC3D particle flow was used to simulate triaxial tests on cementitious materials with different cement,fly ash and weathered material contents.The shear resistance and deformation failure characteristics of cementitious weathered materials with different mix ratios were discussed to obtain the best mix ratio finally.The research results are showed as follows.(1) The peak stress of cementitious weathering material increases gradually with the increasing cement content under the same confining pressure and fly ash content.Meanwhile,the small proportion of fly ash is beneficial to improve the shear strength of cementitious weathering material for the same cement content.The increasing fly ash proportion can conversely weaken the shear performance of cementitious weathering material.(2) The content of fly ash and cement has a great influence on its shear characteristics.Within the reasonable proportion of the two contents,the deformation and failure mechanism can show that the shear failure displacement decreased,the anti-rotation ability and the amount of bonded particles increases with the increasing content of cement and fly ash,so the shear strength of the cementitious weathering material is effectively improved.(3) The optimum mix ratio of cementitious weathering material from the triaxial simulation is cement∶fly ash∶weathering material=1∶0.95∶18.38,and this ration is verified by the indoor large triaxial tests.The relative errors between the simulated value and the experimental value of the shear strength of the cementitious weathered material are small.The particle flow method has good applicability to simulate the shear characteristics of different proportions of cementitious weathering materials,and this method can effectively improve the design efficiency of the mix ratio of cementitious weathering material.
万方数据
维普
