柔性荷载作用下桩筏加固地基变形特性试验研究

发布时间：2018-01-03 20:33

本文关键词：柔性荷载作用下桩筏加固地基变形特性试验研究　出处：《西南交通大学学报》2017年01期 　论文类型：期刊论文

【摘要】：针对深厚软土地区桩筏加固地基,通过原位长期观测试验,研究柔性荷载作用下桩筏加固地基与天然地基的地基面总沉降、地基分层沉降和侧向变形、地基土孔隙水压力等,对比分析两种地基变形规律的差异性,总结提出了柔性荷载作用下桩筏加固地基的受力变形机理.研究结果表明:桩筏结构相对于天然地基,其总沉降减小至24%、差异沉降减小至0.9%,说明其整体刚度较大,有利于均化地基荷载、约束地基侧向变形,使地基总沉降和差异沉降都有很大程度降低;桩筏加固地基沉降主要发生于下卧层,占总沉降的90%;路堤荷载大部分由桩筏结构承担,桩筏结构地基中超孔隙水压力相对于天然地基降低了70%,从而减小了地基沉降量.
[Abstract]:In view of the foundation strengthened by pile-raft in deep soft soil area, the total settlement, layered settlement and lateral deformation of the foundation strengthened by pile-raft and natural foundation under flexible load were studied by long-term observation in situ. The difference of deformation law between the two kinds of foundation is compared and analyzed, such as pore water pressure of foundation soil. The stress and deformation mechanism of pile raft reinforced foundation under flexible load is summarized. The results show that the total settlement of pile raft structure is reduced to 24 and the differential settlement is reduced to 0.9% compared with natural foundation. It shows that the overall stiffness is large, which is favorable to homogenize the load of the foundation, constrains the lateral deformation of the foundation, and reduces the total settlement and differential settlement of the foundation to a great extent. The settlement of pile-raft strengthened foundation mainly occurred in the subhorizontal layer, accounting for 90% of the total settlement. The load of embankment is mostly carried by the pile-raft structure. The excess pore water pressure in the pile-raft structure foundation is reduced by 70 percent compared with the natural foundation, thus reducing the settlement of the foundation.
【作者单位】：西南交通大学土木工程学院;中铁第四勘察设计院集团有限公司;四川高速公路建设开发总公司;
【基金】：中央高校基本科研业务费专项资金资助项目(2682015CX008EM) 国家自然科学基金资助项目(51378441)
【分类号】：TU472
【正文快照】： 我国软土地区修建高速铁路和高速公路遇到了沉降控制难度极大的挑战,尤其是路基沉降与不均匀沉降控制[1-2],目前常采用碎石桩、搅拌桩、CFG桩、管桩等复合地基技术措施进行处理[3-6].路堤边坡推力效应作用下,复合地基两侧的散体桩基常发生剪切失稳破坏[7],半刚性或刚性桩常发

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