饱和尾矿砂复合地基受力与变形分析

发布时间：2018-03-07 22:19

本文选题：饱和尾矿砂　切入点：复合地基　出处：《长安大学》2017年硕士论文　论文类型：学位论文

【摘要】：尾矿砂地基具有高饱和、高压缩和空间分布不均匀等特点。尾矿砂地基所表现出的低承载力和高变形特点使公路建设遇到该类地基时必须要进行人工处理。为了理清人工处理后的复合地基的荷载传递机理、沉降变形机理和荷载分担情况,确定出较为合理准确的复合地基承载力和沉降计算方法,本文依托王繁高速公路项目,采用室内模型试验手段,开展CFG桩、水泥土搅拌桩和碎石桩复合地基以及碎石垫层四种地基受力和变形方面的研究。论文借助模型试验模拟测试出的饱和尾矿库地区CFG桩、水泥土搅拌桩和碎石桩复合地基以及碎石垫层分别在51.7kN、71.7kN、91.7kN、111.7kN、131.7kN荷载作用下土层的沉降值、土压力值、孔隙水压力值、桩身应变等数据,分析了四种复合地基的受力变形规律,重点分析了桩侧摩阻力值、孔隙水压力值和土压力值模型试验数据,修正了各复合地基的承载力和沉降计算公式,主要结论如下:1.通过对模型试验中的桩侧摩阻力值分析,给出了粘结材料桩复合地基桩侧摩阻力分布简图和分布表达式,同时得到了粘结材料桩复合地基桩侧最大摩阻力值位置随荷载增加逐渐下移的规律,其最大摩阻力值位置由距桩顶0-1/5倍桩长范围逐渐移动到距桩顶4/5-1倍桩长范围内;2.通过对模型试验中的孔隙水压力和土压力分析,给出了饱和尾矿砂地区四种复合地基在上部单侧排水条件下加固区土体孔隙水压力和有效应力沿深度分布图示;3.基于模型试验各分析结论,修正了饱和尾矿砂地区CFG桩、水泥土搅拌桩和碎石桩复合地基承载力和沉降计算公式。本论文的研究成果明确了饱和尾矿砂复合地基的受力与变形性状,同时修正的承载力和沉降计算公式可为类似工程处理方案的设计和施工提供一定参考。
[Abstract]:The tailings foundation has high saturation. The characteristics of high compression and uneven spatial distribution. The characteristics of low bearing capacity and high deformation of tailing sand foundation make it necessary to carry out manual treatment when highway construction meets this kind of foundation. The load transfer mechanism of the foundation, Based on the settlement deformation mechanism and load sharing, a reasonable and accurate calculation method of bearing capacity and settlement of composite foundation is determined. Based on the Wangfan Expressway project, the CFG pile is carried out by indoor model test method. The study on the stress and deformation of cement-soil mixing pile and gravel pile composite foundation as well as four kinds of gravel cushion foundation. The CFG pile in saturated tailings reservoir is simulated and tested by model test in this paper. The settlement value, soil pressure value, pore water pressure value and pile strain of four kinds of composite foundation under the load of 51.7 KN, 71.7 KN, 111.7 KN and 131.7 KN, respectively, are analyzed, and the deformation laws of the four composite foundations are analyzed. The model test data of pile side friction value, pore water pressure value and earth pressure value are analyzed emphatically, and the calculation formulas of bearing capacity and settlement of each composite foundation are revised. The main conclusions are as follows: 1. Through the analysis of pile side friction value in model test, The distribution diagram and distribution expression of frictional resistance on pile side of composite foundation with bonded material pile are given, and the law of maximum frictional resistance value of pile side of composite foundation with bond material pile is obtained gradually with the increase of load. The position of the maximum frictional resistance is gradually moved from 0-1 / 5 times to the top of the pile. 2. Through the analysis of pore water pressure and soil pressure in the model test, the position of the maximum frictional resistance value is gradually shifted to the range of 4 / 5-1 times the pile length from the top of the pile to the top of the pile. The distribution of pore water pressure and effective stress along the depth of four kinds of composite foundation in saturated tailings area under the condition of upper side drainage is given. Based on the analysis results of model test, the CFG pile in saturated tailings area is modified. The calculation formula of bearing capacity and settlement of cement soil mixing pile and gravel pile composite foundation. The research results of this paper have made clear the behavior of bearing force and deformation of saturated tailings composite foundation. The modified calculation formula of bearing capacity and settlement can provide some references for the design and construction of similar engineering treatment schemes.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU470

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