基于稳定蠕变模型的软土地层桩基位移理论解

Theoretical solution of pile foundation displacement based on stable creep model in soft soil layer

基于软土地层稳定蠕变及承压桩桩基沉降位移特性,通过构建桩底土体虚拟柱状结构等效流变模型,建立桩基沉降位移时效特性叠加力学模型及其理论解。研究桩基承载模式及其与桩顶荷载的相关关系、相应承载模式下桩基沉降位移及其时效特性。结果表明,蠕变地层中的摩擦端承桩受土体的流变特性影响,桩基总位移呈现显著的时效特性且受土体的蠕变特性支配。工程实例分析验证了所建模型和理论方法在蠕变地层的适用性。该黏弹性理论解不仅可用于稳定蠕变地层桩基长时位移预测,并可方便地拓展应用于其他蠕变地层桩基失效问题计算。

The creep mechanical model of pile foundation is established based on the creep displacement of pile foundation and its equivalent time-dependent soil settlement theory.The bearing mode of pile foundation and its correlation with load on the top of pile,the settlement displacement and time-dependent characteristics of pile foundation under the corresponding bearing mode are studied.The results show that friction end bearing pile in creep stratum is affected by the rheological characteristics of soil,and total displacement of pile foundation presents significant time-dependent characteristics,which is dominated by the creep characteristics of soil.The applicability of model and theoretical method in creep formation is verified by the engineering examples.The viscoelastic theoretical solution can be used not only to predict long-term displacement of pile foundation in stable creep stratum,but also to calculate the failure of pile foundation in other creep stratum.