弹黏塑性模型及其在预压处理软基沉降计算中的应用

发布时间：2018-05-22 11:04

本文选题：预压荷载 + 工后沉降　；参考：《岩土力学》2014年04期

【摘要】：以准确计算预压荷载作用下软土路基的工后沉降为目的,分析了不同预压法加固软土地基时土体的应力变化。提出了用弱化应力路径变化过程的弹黏塑性模型表示软黏土的应力-应变关系。结合经典比奥固结理论,推导了预压荷载作用下土体沉降计算的有限单元法。通过具体算例,验证了所提方法。结果表明:(1)不同预压方法的加固机制和应力路径均不相同。堆载预压法加固软基是一不等向的正压固结过程,真空预压法则是在负压作用下的等向固结过程;(2)弹黏塑性模型是不受瞬时施加应力的大小及具体应力路径变化过程影响的软土流变模型,运用于预压荷载作用下的软基时具有不考虑应力路径和不划分主次固结的优越性;(3)在比奥固结理论中,用弹黏塑性模型反映软土的物理方程时,可计算软基考虑了弹黏塑变形性质的固结沉降和工后沉降;(4)弹黏塑性模型的软土体黏性参数?/V和塑性参数?/V对竖向位移都有比较明显的影响。
[Abstract]:In order to accurately calculate the post-construction settlement of soft soil subgrade under preloading, the stress changes of soft soil under different preloading methods are analyzed. An elastic-viscoplastic model for the process of weakening stress path is proposed to represent the stress-strain relationship of soft clay. Based on the classical Bio consolidation theory, the finite element method for calculating the settlement of soil under preloading is derived. The proposed method is verified by an example. The results show that the reinforcement mechanism and stress path of different preloading methods are different. The reinforcement of soft foundation by surcharge preloading method is an unequal positive consolidation process. The vacuum preloading rule is an isotropic consolidation process under negative pressure. The elastic-viscoplastic model is a rheological model of soft soil which is not affected by the magnitude of the transient applied stress and the variation process of the specific stress path. When applied to the soft foundation under preloading, it has the advantage of not considering the stress path and not dividing the primary and secondary consolidation. In Biot consolidation theory, the elasto-viscoplastic model is used to reflect the physical equation of soft soil. It is possible to calculate the viscosity parameters of soft soil in the elasto-viscoplastic model considering the consolidation settlement and the post-construction settlement of elastic-viscoplastic deformation. The viscosity parameters of soft soil (P / V) and the plastic parameter (P / V) have obvious effects on the vertical displacement.
【作者单位】：延安大学建筑工程学院;河海大学岩土力学与堤坝工程教育部重点实验室;河海大学土木与交通学院;
【基金】：河海大学岩土力学与堤坝工程教育部重点实验室开放基金项目(No.GH201101) 国家自然基金项目(No.51309199) 国家科技支撑计划项目(No.2013BAJ06B00) 陕西省教育厅项目(No.12JK0922)
【分类号】：TU447;TU433

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