基于一系列不同围压、不同含水率条件下的冻结砂土的三轴压缩试验,在一个宽泛的含水率范围内,研究了围压与含水率对冻结砂土破坏应变能密度的影响特性。试验结果表明:含水率为30.6%的冻土试样容易发生塑性破坏,其他含水率的冻土试样容...基于一系列不同围压、不同含水率条件下的冻结砂土的三轴压缩试验,在一个宽泛的含水率范围内,研究了围压与含水率对冻结砂土破坏应变能密度的影响特性。试验结果表明:含水率为30.6%的冻土试样容易发生塑性破坏,其他含水率的冻土试样容易发生脆性破坏。围压对破坏应变能密度的影响可以分为低围压阶段、中围压阶段、高围压阶段,并且含水率对临界围压有重要影响。含水率对破坏应变能密度的影响也可以分为两种类型:当围压较低时(50 k Pa),随着含水率的增大,破坏应变能密度有一个初始增加的阶段,在含水率约为30.6%时破坏应变能密度达到最大值600 k Pa,之后随着含水率的继续增大,破坏应变能密度转而减小,达到60 k Pa后含水率的进一步增大不再影响破坏应变能密度,即此时冻土的破坏应变能密度接近于冰的破坏应变能密度;当围压较高时(大于等于500 k Pa),与低围压阶段相比,破坏应变能密度没有初始增加的阶段。展开更多
A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreove...A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreover,the cohesive elements are inserted into the adjacency of finite elements as the possible cracking paths.The spatial variation of the material properties is considered using a 2-D random field,and the stochastic harmonic function method is adopted to simulate the sample of the fracture energy random field in the analysis.Then,the simulations of concrete specimens are given to describe the different failure modes of concrete under tension.Finally,based on the simulating results,the probability density distributions of the stress-strain curves are solved by the probability density evolution methods.Thus,the accuracy and efficiency of the proposed model are verified in both the sample level and collection level.展开更多
文摘基于一系列不同围压、不同含水率条件下的冻结砂土的三轴压缩试验,在一个宽泛的含水率范围内,研究了围压与含水率对冻结砂土破坏应变能密度的影响特性。试验结果表明:含水率为30.6%的冻土试样容易发生塑性破坏,其他含水率的冻土试样容易发生脆性破坏。围压对破坏应变能密度的影响可以分为低围压阶段、中围压阶段、高围压阶段,并且含水率对临界围压有重要影响。含水率对破坏应变能密度的影响也可以分为两种类型:当围压较低时(50 k Pa),随着含水率的增大,破坏应变能密度有一个初始增加的阶段,在含水率约为30.6%时破坏应变能密度达到最大值600 k Pa,之后随着含水率的继续增大,破坏应变能密度转而减小,达到60 k Pa后含水率的进一步增大不再影响破坏应变能密度,即此时冻土的破坏应变能密度接近于冰的破坏应变能密度;当围压较高时(大于等于500 k Pa),与低围压阶段相比,破坏应变能密度没有初始增加的阶段。
基金supported by the National Natural Science Foundation of China(Grant Nos.90715033,51261120374,51208374)
文摘A random medium model is developed to describe damage and failure of concrete.In the first place,to simulate the evolving cracks in a mesoscale,the concrete is randomly discretized as irregular finite elements.Moreover,the cohesive elements are inserted into the adjacency of finite elements as the possible cracking paths.The spatial variation of the material properties is considered using a 2-D random field,and the stochastic harmonic function method is adopted to simulate the sample of the fracture energy random field in the analysis.Then,the simulations of concrete specimens are given to describe the different failure modes of concrete under tension.Finally,based on the simulating results,the probability density distributions of the stress-strain curves are solved by the probability density evolution methods.Thus,the accuracy and efficiency of the proposed model are verified in both the sample level and collection level.
