广东地区大直径超长钻孔灌注桩荷载传递特性试验研究

发布时间：2018-05-08 20:23

本文选题：桩基础 + 大直径超长桩　；参考：《岩石力学与工程学报》2015年04期

【摘要】：通过广东软土地区大直径超长钻孔灌注桩大吨位静载试验,分析该地区大直径超长钻孔灌注桩承载特性及荷载传递机制,为该地区大直径超长桩的理论研究和工程应用提供宝贵的参考数据。实测结果研究表明:试桩的Q-s曲线呈缓变型,桩端承载力分担总荷载比例均低于15%,表现为摩擦桩特性;随桩顶荷载增加,桩土相对位移沿桩身的递增幅度呈先增大后减小的趋势,淤泥质粉质黏土和淤泥达到极限侧摩阻力所需的桩土相对位移分别为17和6 mm,砂土达到极限侧摩阻力所需桩土相对位移为22~27 mm,桩身上部土层侧摩阻力发生不同程度的软化;桩身上部粉质黏土的桩土相对位移为18~23 mm,在桩土总的相对位移达40 mm时,下部粉质黏土层侧摩阻力达到极限值的87%以上,桩土相对位移继续增大时,侧阻增加趋势较为平缓,并逐渐接近于极限值;风化砂岩侧摩阻力随桩土相对位移的增加而增大,极限荷载下侧摩阻力未完全发挥;桩端阻力随着桩端沉降量的增加呈加工硬化型。
[Abstract]:The bearing characteristics and load transfer mechanism of large-diameter and super-long bored cast-in-place piles in soft soil area of Guangdong Province were analyzed by static load test of large-diameter super-long bored piles at large tonnage. It provides valuable reference data for theoretical research and engineering application of large diameter and super long pile in this area. The measured results show that the Q-s curve of the test pile shows a slow variation, and the bearing capacity of the pile tip is less than 15 percent of the total load, which shows the characteristics of the friction pile, and increases with the load on the top of the pile. The relative displacement of pile and soil increases first and then decreases along the increasing amplitude of pile body. The relative displacement of pile and soil for silty clay and silt to reach the ultimate lateral friction is 17 and 6 mm respectively, and the relative displacement for sand to reach the ultimate lateral friction is 2227 mm. The relative displacement of silty clay in pile body is 18 ~ 23 mm. When the total relative displacement of pile and soil reaches 40 mm, the lateral friction resistance of the lower silty clay layer reaches more than 87% of the limit value. When the relative displacement of pile and soil continues to increase, the increasing trend of lateral resistance is relatively gentle. The lateral frictional resistance of weathered sandstone increases with the increase of the relative displacement of the pile and soil, but the side friction is not fully exerted under the ultimate load; the resistance of the pile end shows the work hardening type with the increase of the settlement of the pile end.
【作者单位】：同济大学岩土及地下工程教育部重点实验室;同济大学地下建筑与工程系;广东潮惠高速公路有限公司;深圳中广核工程设计有限公司;
【基金】：广东省交通运输厅科技计划项目(2012 01 001) 国家自然科学基金资助项目(41202193,41272295)
【分类号】：TU473.1

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