不排水桩复合地基下卧层固结分析

发布时间：2018-01-05 03:29

本文关键词：不排水桩复合地基下卧层固结分析　出处：《长安大学学报(自然科学版)》2016年06期 　论文类型：期刊论文

【摘要】：对于深厚软土地基,不排水桩常常未能打穿软土而形成悬浮桩复合地基。具有一定厚度下卧层的悬浮不排水桩复合地基,其整体固结速率主要取决于下卧层土的固结速率,目前尚未有较为简单的计算方法对下卧层土的固结速率进行估计。基于悬浮不排水桩复合地基平均超静孔隙水压力解答,推导出复合地基下卧层固结度的解析解。利用该解析解进行参数分析,研究了不排水桩的贯入比、置换率和桩土压缩模量比对复合地基下卧层固结速率的影响。研究结果表明:对于水泥土桩等刚度较大的不排水桩复合地基,其下卧层土的固结速率主要取决于桩的贯入比;下卧层土的固结速率随不排水桩贯入比的增加而增大;增加不排水桩的置换率,下卧层土的固结速率略微增大。在把握下卧层固结特性的基础上,将复合地基加固区视为下卧层的半透水边界,基于半透水边界地基的一维固结理论,提出不排水桩复合地基下卧层固结度分析的等效半透水边界法,建立了考虑不排水桩贯入比和置换率影响的半透水边界厚度的计算公式。通过与解析解计算的下卧层固结速率的比较,证明了下卧层固结度等效半透水边界法的正确性和有效性。
[Abstract]:For the deep soft soil foundation, the undrained pile often fails to break through the soft soil to form the suspension pile composite foundation, and the suspended undrained pile composite foundation with a certain thickness of lying layer. The overall consolidation rate mainly depends on the consolidation rate of the underlying soil. At present, there is no simple calculation method to estimate the consolidation rate of subhorizontal soil. Based on the solution of average excess pore water pressure of suspended undrained pile composite foundation. The analytical solution of the consolidation degree of the horizontal layer under the composite foundation is derived, and the penetration ratio of the undrained pile is studied by using the analytical solution to carry out the parameter analysis. The effect of replacement ratio and compression modulus ratio of pile to soil on the consolidation rate of horizontal layer under composite foundation. The results show that: for undrained pile composite foundation with equal stiffness of cement soil pile. The consolidation rate of the underlying soil is mainly determined by the penetration ratio of the pile. The consolidation rate of the underlying soil increases with the increase of the penetration ratio of undrained piles. When the replacement rate of undrained pile is increased, the consolidation rate of the subhorizontal soil increases slightly. On the basis of grasping the consolidation characteristics of the underlying layer, the consolidation area of the composite foundation is regarded as the semi-permeable boundary of the underlying layer. Based on the one-dimensional consolidation theory of semi-permeable boundary foundation, an equivalent semi-permeable boundary method is proposed to analyze the degree of consolidation of horizontal layer under undrained pile composite foundation. A formula for calculating the thickness of semi-permeable boundary considering the influence of penetration ratio and replacement rate of undrained pile is established. The validity and validity of the equivalent semi-permeable boundary method for the consolidation degree of the lower horizontal layer are proved.
【作者单位】：上海理工大学环境与建筑学院;河海大学道路与铁道工程研究所;
【基金】：广东省交通运输厅科技计划项目(201102021) 上海理工大学国家级项目培育基金项目(16HJPY-MSO3)
【分类号】：TU472
【正文快照】： 0引言复合地基中的竖向增强体有粘结材料桩和散体材料桩2种类型。碎石桩和砂桩等散体材料桩的渗透性远大于桩周土,荷载作用下它在桩周土中形成排水通道,故称为排水桩;水泥土桩、CFG桩和低标号混凝土桩等粘结材料桩的渗透性非常小,称为不排水桩。复合地基固结理论是复合地基理

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