硫酸盐渍土中灌注桩竖向承载力演变规律

发布时间：2018-03-25 04:25

本文选题：硫酸盐渍土　切入点：灌注桩　出处：《哈尔滨工业大学学报》2017年06期

【摘要】：盐渍土中硫酸盐含量极高,对灌注桩具有极强的腐蚀作用从而影响其承载特性,为明确和分析混凝土灌注桩在硫酸盐盐渍土腐蚀下竖向承载力的演变规律,以及桩径、桩长对灌注桩腐蚀后承载力变化规律的影响,根据硫酸盐环境下混凝土劣化的腐蚀反应和机理,建立了硫酸盐渍土腐蚀环境下单桩承载力的评价模型;结合案例对硫酸盐渍土地区混凝土灌注桩的侧阻力、端阻力及桩体强度进行研究,分析和对比了桩长及桩径对硫酸盐腐蚀下灌注桩的承载特性演变规律的影响.结果表明:硫酸盐渍土腐蚀作用下灌注桩的侧阻力、端阻力及桩体强度均发生变化;桩侧阻力受到腐蚀产物积累、膨胀引起的桩周混凝土劣化和桩侧应力重分布的影响,同时也依赖于桩长及桩径变化;端阻力则由于单桩竖向有效面积的减小而降低;硫酸盐腐蚀作用下桩体强度降低幅度较大.由此可知,相同腐蚀条件下,增加桩径可有效提高抵抗硫酸盐腐蚀引起的承载力损失;实际设计中应考虑增加桩径的方法抵抗硫酸盐腐蚀引起的承载力损失.
[Abstract]:The sulfate content in the saline soil is very high, which has a strong corrosion effect on the cast-in-place pile and thus affects its bearing characteristics. In order to clarify and analyze the evolution law of the vertical bearing capacity of the concrete cast-in-place pile under the corrosion of the sulphate saline soil, and the pile diameter, According to the corrosion reaction and mechanism of concrete deterioration in sulphate environment, the evaluation model of bearing capacity of pile under sulphate soil corrosion environment was established. The side resistance, end resistance and pile strength of concrete cast-in-place piles in sulphuric acid saline soil area are studied in this paper. The influence of pile length and diameter on the evolution of bearing characteristics of cast-in-place piles under sulphate corrosion is analyzed and compared. The results show that the lateral resistance, end resistance and pile strength of cast-in-place piles under sulphate soil corrosion are all changed. The pile side resistance is influenced by the corrosion product accumulation, the concrete deterioration caused by the expansion and the stress redistribution of the pile side, and it also depends on the pile length and diameter change, while the end resistance decreases because of the decrease of the vertical effective area of the single pile. The strength of pile decreases greatly under sulphate corrosion. Therefore, under the same corrosion condition, increasing pile diameter can effectively increase the bearing capacity loss caused by sulfate corrosion. The method of increasing pile diameter should be considered in actual design to resist the bearing capacity loss caused by sulphate corrosion.
【作者单位】：同济大学地下建筑与工程系;岩土及地下工程教育部重点实验室(同济大学);
【基金】：国家自然科学基金(51178341)
【分类号】：TU473.1

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