高填方路基后处理机理及优化设计

【作者】 童怀峰；

【导师】 郭院成；

【作者基本信息】 郑州大学 ， 结构工程， 2005， 硕士

【摘要】 目前,软土路基处理技术主要集中在先处理方面,包括土性改善和复合地基两类常用方法。先处理技术中地基处理过程需占用工程的有效工期,且在后期施工过程中复合地基土中有效应力增长过程落后于荷载的施加速度,使软土高填方路基的后期沉降变形较大,且稳定时间长,严重影响高速公路的正常使用。无砂砼小桩后处理技术是刚刚发展起来的新技术,其具有排水固结、胶结、竖向增强置换等多重作用,适用于处理公路路基工程中可能遭遇的饱和软土、粉质粘土、粘性土和人工填土中的素填土和含少量大块碎屑的杂填土地基。可用于填土前处理,也可用于填土后处理,其后处理方法的独特性是其他处理方法难以做到的。其在路基工程中的成功应用为高速公路软基及不良地基和桥台填方区处理提供了一条新的途径,有着极其重大的技术经济价值。 本文基于饱和软土条件下对无砂砼小桩后处理技术的处理机理和优化设计进行了分析和研究。 1.在无砂砼小桩后处理技术中,施工的填方平台位置是涉及处理效果和经济合理的关键性技术参数。本文依据应力路径的基本概念和太沙基破坏模型,通过地基中一点的有效应力和孔隙水压力的转化关系反演得到无砂砼小桩后处理施工的填方平台位置。为方便工程应用本文给出了该填方高度的一个计算公式。 2.对不同类型原状土地基和高填方路基,后处理技术设计的控制性能和处理目标是与处理机理密切相关的,高填方路基后处理机理研究是后处理技术研究与应用的理论基础,由此确定各种条件下路基后处理的目标和技术性能。本文依据无砂砼小桩在路基后处理过程中的施工技术特点,借助于砂井固结理论对饱和软土条件下的后处理固结过程和后处理机理进行了分析,为无砂砼小桩后处理技术的优化设计研究奠定了基础。 3.高填方路基后处理技术的优化设计理论,是基于无砂砼小桩特点,研究其成孔压浆过程中的地基土应力、应变发生、发展过程,并由此优化决策后处理技术的关键性技术参数。本文在对饱和软土条件下后处理固结过程和后处理机理分析的基础上,进行了基于固结度和承载力控制条件下的后处理技术的优化设计更多还原

【Abstract】 At present, the research of processing technology for soft soil ground lies in the treatment before filling, which include the improvement of soil texture and composite foundation, the processing of groundwork need to occupy and use the effective time limit of a project. In the construction of the composite foundation get behind with the velocity of load application, which result in the major settlement of highway thick filling area after construction and the lasting of stabilization time, which seriously affect the nomal use of highway. The post-processing technology of small non-sand concrete pile is a new technology, which was developed in the recent years. The post-processing technique of small non-sand pile possessed multiple function such as consolidation、 cementation、 swell replacement in vertical and so on, which apply to treat saturation soil、 powdery clay、 clay、 simple-filling and mixed-filling foundation which were encountered in the highway bed engineering. The post-processing technique not only apply to treat bed before filling, but also apply to treat bed after filling, the superiority of the post-processing technique was not possessed by other treatment technique. The success of applications for the post-processing technique in the highway engineering provide a new approach for the treatment of highway soft-foundation and bridge head filling, which have great importance for technique and economy.The mechanism of treatment and optimal design of the post-processing technology of small non-sand concrete pile was analyzed and researched on the condition of saturation soil.1. The plateform height of thick filling area in the post-processing technology is the key technical parameter, which touched on the treatment effect and economical reasonableness. On the basis of the basic concepts of stress-path and sabotage model of Terzaghi, the plateform height of thick filling area is obtained by counterdeduce the relationship between effective stress and pore water pressure of a point of groundwork. A calculation formula of plateform height is given for the convenient application of engineering.2. The control property and treatment target of the post-processing design has much to do with treatment mechanism under different soil and highway thick filling area conditions. The study of mechanism of the post-processing is the theoretic basis of the research and application of the post-processing technology, the target and technical property of the post-processing of the different subgrade is based on the theory. This text depend on the technological characteristics of small non-sand concrete pile in the course of construction and the consolidation theory, the consolidation analysis and treatment mechanism of the post-processing technologyunder saturation soil condition is completed, which lay the foundation for optimal design of the post-processing technology.3. The optimal design theory of the post-processing of highway thick filling area is based on the characteristics of small non-sand concrete pile, which research the production and development process of stress and strain of foundation soil in the course of drilling and grouting, and which optimize the key technical parameter of the post-processing technology. On the basis of the analysis of consolidation and treatment mechanism of the post-processing under saturation soil condition, the research of optimal design of the post-processing technology on the control of consolidation degree and carrying capacity is completed, which is of reference for the design and construction of the post-processing technology.4. The validity and application and rationality of the post-processing technology with small non-sand concrete pile is proved through application of project and analysis of measured production.更多还原