水下爆炸冲击下混凝土重力坝毁伤缩尺效应研究OA

Scaled model testing is an important approach for studying concrete gravity dams subjected to underwater explosions;to enhance the extrapolability of scaled-test results to the prototype scale,this study investigates the damage scale effect induced by material heterogeneity.In this study,a numerical model of a concrete gravity dam sub-jected to underwater explosion was established based on mesoscopic modeling techniques,and scaled model tests of underwater explosion on a gravity dam were carried out to verify the reliability of the numerical model.The differences and applicability between mesoscopic modeling and conventional modeling approaches were investigated.On this basis,the intrinsic mechanism of damage scale effects induced by the heterogeneity of concrete materials was revealed,and the influences of explosive charge equivalence,detonation distance,and aggregate size on damage scale effects were examined.Furthermore,the relationship between damage scale effects and the characteristic wave-length of the shock(stress)wave as well as aggregate size was investigated.A damage similarity criterion for scaled underwater explosion tests of gravity dams based on the ratio of characteristic wavelength to maximum aggregate size was proposed,and its reliability was demonstrated through multiple field test cases.The results show that,in scaled underwater explosion tests of concrete gravity dams,the ratio of stress-wave characteristic wavelength to maximum aggregate size should be greater than 15,so as to avoid,as far as possible,the damage scale effects induced by mate-rial heterogeneity,make the results of scaled tests as close as possible to those of the prototype,and enhance the extrapolatability of model test results to prototype structures.