基于试桩实测规律的大直径钻孔桩荷载传递分析

发布时间：2018-01-06 21:11

本文关键词：基于试桩实测规律的大直径钻孔桩荷载传递分析　出处：《公路交通科技》2017年09期 　论文类型：期刊论文

【摘要】：为建立适合黄河中下游以中密~密实粉土、粉细砂及可塑~硬塑粉质黏土为主要冲积地层条件的大直径钻孔桩承载变形计算分析方法,基于郑州市三环快速路工程6个场地18根试桩现场试验结果,在分析桩侧摩阻力和桩端阻力随桩土相对位移和桩端位移发挥规律的基础上,建立大直径钻孔桩桩侧荷载传递模型和桩端承载模型,并给出计算参数取值;通过工程实例计算分析验证计算方法的可行性与合理性,在此基础上,改变桩径、桩长等参数,进一步计算分析该场地条件下大直径钻孔桩承载及变形规律。结果表明:大直径钻孔桩桩径越大,Q-s曲线拐点越明显;荷载较小时,增加桩径对提高大直径钻孔桩承载变形性能的影响更显著;大直径钻孔桩承载性能的提高幅度随桩长增大明显减小,通过增加桩长来提高大直径钻孔桩承载性能存在有效性之问题;未注浆大直径钻孔桩呈现较明显的刺入破坏模式,桩径越大,桩长越小,发生刺入破坏时桩顶沉降变形越小;桩端后注浆可提高大直径钻孔桩有效桩长,随桩长及桩径增大,提高单桩极限承载力量值越大。
[Abstract]:For the middle and lower reaches of the Yellow River in dense dense silt, silty sand and bored pile with large diameter plastic hard plastic silty clay is mainly alluvial stratum bearing deformation calculation analysis method, Zhengzhou City Ring Road expressway project 6 site 18 test field test results based on the pile based on the analysis, with the relative displacement between pile and soil and the pile displacement development laws of pile side friction resistance and end resistance, the establishment of large diameter bored pile load transfer model and pile end bearing model, and gives the calculation parameters; calculation method analysis verified by engineering example, the feasibility and rationality, on this basis, the change of pile diameter, pile length parameter further, the calculation and analysis of site conditions of large diameter bored pile bearing and deformation. The results show that the large diameter bored pile diameter increasing, Q-s curve inflection point is obvious; the load is small, the increase of pile diameter on the increase The influence of the diameter of bored pile bearing and deformation performance more significantly; large diameter bored pile bearing performance increase with increasing pile length significantly decreased by increasing the pile length to improve the effectiveness of the existing problems of bearing capacity of large diameter bored pile; large diameter bored grouting pile has no obvious piercing damage model, the bigger the pile diameter the length of the pile, the smaller the punch through failure of pile top settlement deformation is smaller; the pile end post grouting can improve the large diameter bored pile with effective pile length, pile length and pile diameter, the greater the value of improving bearing capacity of single pile.

【作者单位】：郑州大学土木工程学院;郑州大学综合设计研究院有限公司;
【基金】：国家自然科学基金项目(51508522) 郑州市重大科技专项课题项目(113PSHKS439)
【分类号】：U443.154
【正文快照】： 0引言伴随着高层建筑、桥梁工程的大量建设,具有较高承载性能的大直径钻孔桩应用越来越广泛。目前,大直径钻孔桩的研究主要基于现场载荷试验进行承载及变形性状分析[1-4]。大直径钻孔桩承载特性是较为复杂的,且与桩周土层性状密切相关,对于黄河中下游以中密~密实粉土、粉细砂

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