各向异性对土质心墙坝水力劈裂的影响

Influence of anisotropy on hydraulic fracturing of earth core dams

应力诱导各向异性对复杂应力状态下土体的应力-应变规律有重要影响,而建立在各向同性假设基础上的常用土体本构模型并不能反映土体的这种特性,因此需要分析土体各向异性对土质心墙坝水力劈裂的影响。采用各向异性非线性弹性模型,对水荷载作用下粘土心墙坝进行有限元数值分析,并与邓肯模型计算结果比较。结果表明,各向异性模型考虑了蓄水期间从小主应力方向加荷引起的土体应力各向异性,计算得出的小主应力σ3较邓肯模型的大,且相应抗水力劈裂能力亦大,则邓肯 E-v 模型由于不能模拟蓄水期土体各向异性特性,对于水力劈裂发生的评估可能偏于危险。

Stress induced anisotropy has important influence on soil's stress-strain relationship under complex stress state. Traditional constitutive model with isotropic assumption cannot describe this character. Influence of anisotropy on hydraulic fracturing of earth core dams is analyzed herein. A new anisotropic soil constitutive model is applied to the finite element analysis of a high earth core dam. Minor principal stress σ3 got from anisotropic model is larger than that from Duncan E-v model. It is proved that the estimate of the hydraulic fracturing of earth core dams with Duncan E-v model will be more dangerous.