考虑裂隙与湿胀效应的膨胀土边坡渗流变形耦合分析方法

Coupled analysis method of seepage-induced deformation in expansive soil slope considering cracks and swelling effect is an urgent research topic, which has important academic significance and engineering application value. Based on theories of unsaturated soil mechanics and seepage mechanics, methods of experiment, theoretical analysis and numerical simulation are used. Permeability characteristics of expansive soil with cracks are studied by experimental methods, water control mechanism of fracture surface in soil preferential flow, and water interaction pattern of fracture and matrix domains are revealed. Considering the wet swelling and dry pinching effect, the preferential flow model reflecting slope fracture - matrix domain flow characteristics is established through theoretical analysis. Swell and shrink properties and unsaturated mechanical properties of expansive soil are studied to reveal the swelling effect, the strength softening characteristics and the influence law. Unsaturated constitutive model of expansive soil considering cracks and swelling effect is established. Based on field engineering geological investigation and in-situ measurements of cracks in soils, the multi-level fracture network model for coupled seepage and stress fields in expansive soil slope is established. With the hydraulic circulation analysis mode of instantaneous seepage field solution under unified strength - constitutive back analysis - unit strength parameters generalization - stress and strain fields solution, the coupled analysis method of slope seepage and stress in expansive soil slope is established with numerical analysis module, providing analysis tools for expansive soil slope stability.

考虑裂隙与湿胀效应的膨胀土边坡渗流变形耦合分析方法是一项亟待研究且具有重要学术意义和工程应用价值的课题。基于非饱和土力学与渗流力学理论，采取试验、理论分析与数值模拟相结合的研究方法，以试验探讨含裂隙膨胀土的渗透特性，揭示裂隙膨胀土裂隙面控水机理，阐明裂隙域与基质域水分交互作用模式，考虑土的湿胀干缩效应，通过理论推导建模，建立可反映边坡湿胀干缩效应和裂隙域-基质域流动特征的优势流模型。以试验探讨膨胀土胀缩性能与力学特性，揭示膨胀土湿变效应与强度软化特性及影响规律，以理论建模的方法，建立考虑裂隙与湿胀效应的膨胀土非饱和本构模型。基于现场工程地质勘察和裂隙调查，构建膨胀土边坡多重裂隙网络模型，采用整体强度全量求解瞬态渗流场-流固耦合本构反分析-概化单元强度参数-二次求解应力应变场的水力滞回分析模式，建立边坡渗流-应力耦合分析方法，并开发相应的数值分析模块，为膨胀土边坡稳定性分析提供工具。

考虑裂隙与湿胀效应的膨胀土边坡渗流变形耦合分析方法是一项亟待研究且具有重要学术意义和工程应用价值的课题。基于非饱和土力学与渗流力学理论，采取试验、理论分析与数值模拟相结合的研究方法，以试验探讨了含裂隙膨胀土的渗透特性，揭示了裂隙膨胀土裂隙面控水机理，以及裂隙域与基质域水分交互作用模式，构建了UN-EX模型与IRSM-SSI模型两类SWCC本构模型，弄清了不同初始控制条件与边界条件下的含裂隙膨胀土的饱和-非饱和渗流特性；以试验探讨了膨胀土胀缩性能与力学特性，研制并改进了膨胀土三向膨胀应力测试装置，分析了均质与非均质膨胀土各项异性膨胀变形机理，揭示了应变约束与应变控制条件下膨胀土三向胀缩特性，揭示了膨胀土湿变效应与强度软化特性及影响规律；以理论建模的方法，建立了考虑裂隙与湿胀效应的膨胀土非饱和本构模型，编制了流固耦合方程数值解子程序。基于现场工程地质勘察和裂隙调查，构建了膨胀土裂隙边坡模型，采用整体强度全量求解瞬态渗流场-流固耦合本构反分析-概化单元强度参数-二次求解应力应变场的水力滞回分析模式，建立了边坡渗流-应力耦合分析方法，并开发了相应的数值分析模块，阐明了裂隙膨胀土边坡含水率与变形的时空变化规律及其耦合作用模式，揭示了结构性裂隙控制作用下膨胀土边坡失稳破坏机理，为膨胀土边坡稳定性分析提供了工具。