山区软土地基处理典型方法的适用性研究

发布时间：2018-06-12 12:35

本文选题：粉煤灰垫层 + CFG桩复合地基　；参考：《重庆交通大学》2014年硕士论文

【摘要】：随着我国西部大开发战略的不断推进，近年来西部的经济迅速发展，山区高速公路网也随之逐步完善。由于山区的地形、地貌较平原和沿海地区有很大差异，故在山区公路建设中会遇到各种复杂的问题，尤其是山区软土地基处理。山区的软土具有其独特的工程特性，一些用于平原或沿海地区的软基处理方法在处理山区软基时可能达不到预期的处理效果。这就使得山区软基处理成为了一项具有代表性的研究课题。本文在对依托工程中搜集的资料中，总结贵州山区软土的物理力学特征、破坏形式，并归纳总结了用于山区软基处理的方法。根据山区公路软土的特点，本文分析了两种典型的用于山区软基处理的方法，即粉煤灰垫层法和CFG桩复合地基法。根据依托工程杭瑞高速贵州经遵毕段第16合同段的地形特征，选取粉煤灰换填垫层法处理软基，并对换填垫层设计计算，结合从依托工程处预先埋设的沉降板等监测的地基变形数据，将所选取两个断面的沉降值对比分析，在用PLAXIS软件建模分析，将计算得到的沉降值和实测的对比研究软件模拟结果的可靠度，再结合经济方面综合评价换填粉煤灰垫层法对于处理山区软基的适用性。根据依托工程杭瑞高速贵州经遵毕段第18合同段的地形特征，选取CFG桩复合地基法处理软基，并从技术上和经济上综合评价其处理山区软基的适用性。技术上是先对CFG桩复合地基进行设计，再从依托工程中监测的地基变形数据，，分析桩身完整性、单桩承载力、复合地基承载力、桩土应力比、地基表层沉降量、分层沉降量，并用PLAXIS软件建模分析，将计算结果和实测的结果对比分析，最后分析持力层刚度、桩距、桩长、褥垫层刚度对CFG桩复合地基加固效果的影响，再结合经济方面综合评价CFG桩复合地基对山区软基处理的适用性，为指导施工提供依据。
[Abstract]:With the development of the western development strategy, the economy of the western region has developed rapidly in recent years, and the highway network in the mountainous area has been gradually improved. Because the terrain and landform of mountain area are quite different from those of plain and coastal area, there are many complicated problems in highway construction in mountain area, especially the treatment of soft soil foundation in mountainous area. The soft soil in mountainous area has its unique engineering characteristics, and some soft soil treatment methods used in plain or coastal area may not achieve the expected treatment effect in the treatment of soft foundation in mountainous area. This makes the mountain soft foundation treatment has become a representative research topic. In this paper, the physical and mechanical characteristics and failure forms of soft soil in Guizhou mountainous area are summarized, and the methods for soft foundation treatment in mountainous area are summarized. According to the characteristics of soft soil in mountain highway, this paper analyzes two typical methods of soft foundation treatment in mountainous area, namely, fly ash cushion method and CFG pile composite foundation method. According to the topographic features of the 16th contract section of the Hangzhou Juanbi section of the Hangrui Expressway Project, the soft foundation was treated with the method of flyash replacement cushion, and the design calculation of the replacement cushion layer was carried out. Based on the deformation data of foundation monitored by pre-embedded settlement plates, the settlement values of the two selected sections are compared and analyzed by using plax software. The reliability of the simulation results of the calculated settlement value and the measured results is compared, and the suitability of the replacement fly ash cushion method for the treatment of soft ground in mountainous area is evaluated in combination with the economic aspects. According to the topographic features of the 18th contract section of the Hangzhou Juanbi section of the Hangrui Expressway Project, the CFG pile composite foundation method was selected to treat the soft foundation, and the applicability of the CFG pile composite foundation method to the treatment of the mountain soft foundation was comprehensively evaluated technically and economically. Technically, the CFG pile composite foundation is designed first, and then the pile integrity, single pile bearing capacity, composite foundation bearing capacity, pile-soil stress ratio, ground surface settlement, layered settlement are analyzed from the foundation deformation data monitored in the project. Finally, the effects of bearing layer stiffness, pile spacing, pile length and cushion stiffness on the reinforcement effect of CFG pile composite foundation are analyzed. Combined with economic aspects, the applicability of CFG pile composite foundation to soft foundation treatment in mountainous area is evaluated comprehensively, which provides the basis for guiding construction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

【参考文献】