高速公路混凝土桩复合地基沉降计算简易方法研究

发布时间：2018-02-05 22:02

本文关键词： 路基混凝土桩复合地基沉降等沉面土工合成材料　出处：《广州大学》2016年硕士论文　论文类型：学位论文

【摘要】：混凝土桩复合地基在高速公路路基中的应用越来越广泛。目前交通行业规范对混凝土桩复合地基沉降计算仍然沿用建筑工程混凝土桩复合地基沉降计算方法,该法存在计算沉降小于实际沉降的问题,导致多条高速公路出现沉降过大、桥头路段过渡不理想、蘑菇路、路基滑塌等缺陷。路基工程中混凝土桩复合地基桩、土变形不协调。复合地基加固区桩间土的面积往往占到复合地基总面积90%以上,且桩间土沉降大于桩顶沉降,混凝土桩身压缩量可忽略不计时,可以桩间土压缩变形量来代表加固区沉降量。桩身等沉面以上桩间土压缩量等于桩顶端向路堤的刺入变形量,桩身等沉面以下桩间土压缩量等于桩底端向下卧层的刺入变形量。根据高速公路路基混凝土桩复合地基特点,提出高速公路混凝土桩复合地基沉降计算简易方法。由于路基中线处沉降最大,可只计算路基中线处沉降。桩间土荷载可利用土拱效应理论计算。铺设土工合成材料时,根据土工合成材料挠度等于桩身等沉面以上桩间土压缩量的原则确定土工合成材料之下桩间土荷载。桩底端发生刺入破坏时,根据单桩竖向受力平衡条件确定中性面位置;桩底端不发生刺入破坏时,近似假设桩间土附加应力等于零处为中性面。高速公路路基宽度通常大于软土层深度,近似按照在加固区内桩、土总荷载沿深度不变的原则确定桩间土附加应力,然后采用分层总和法计算桩间土压缩量。文章最后以两个工程实例验证了此沉降计算方法的可行性和实用性。
[Abstract]:The application of concrete pile composite foundation in expressway roadbed is more and more extensive. At present, the settlement calculation method of concrete pile composite foundation is still used in traffic industry code. In this method, the settlement is smaller than the actual settlement, which leads to many freeway settlement is too large, the bridge-head section of the transition is not ideal, mushroom road, subgrade collapse and other defects. The concrete pile composite foundation pile in subgrade engineering. Soil deformation is not coordinated. The area of soil between piles in composite foundation reinforcement area is often more than 90%, and the settlement of soil between piles is larger than that of pile top, and the compression of concrete pile body can be neglected without time. The soil compression deformation between piles can represent the settlement of the reinforced area. The soil compression between piles above the equal-settlement surface is equal to the deformation of the top of the pile to the embankment. The compression of the soil between piles under the equal-settlement surface of the pile is equal to the deformation of the downward horizontal layer at the bottom of the pile. According to the characteristics of the concrete pile composite foundation of the expressway subgrade. A simple method for calculating the settlement of concrete pile composite foundation of expressway is put forward. The settlement at the center of subgrade can only be calculated. The soil load between piles can be calculated by using the theory of soil arch effect. According to the principle that the deflection of geosynthetics is equal to the compression of soil between piles above the equal settlement surface of the pile, the soil load between piles under the geosynthetics is determined. The position of neutral plane is determined according to the balance condition of vertical force of single pile. When there is no impinging failure at the bottom of the pile, it is assumed that the soil stress between the piles is equal to zero. The width of the highway roadbed is usually larger than the depth of the soft soil layer, and the pile is approximate to the pile in the strengthened area. According to the principle that the total load of soil is constant along the depth of pile, the additional stress of soil between piles is determined, and then the soil compression between piles is calculated by the method of stratified summation. Finally, two engineering examples are given to verify the feasibility and practicability of the settlement calculation method.
【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U416.1

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