李建东, 王旭, 张延杰, 刘博诗, 李盛, 李泽源. 2018: 大厚度黄土地基超长群桩承载特性模型试验研究. 工程地质学报, 26(6): 1708-1714. DOI: 10.13544/j.cnki.jeg.2017-567
    引用本文: 李建东, 王旭, 张延杰, 刘博诗, 李盛, 李泽源. 2018: 大厚度黄土地基超长群桩承载特性模型试验研究. 工程地质学报, 26(6): 1708-1714. DOI: 10.13544/j.cnki.jeg.2017-567
    LI Jiandong, WANG Xu, ZHANG Yanjie, LIU Boshi, LI Sheng, LI Zeyuan. 2018: MODEL TESTS FOR BEARING BEHAVIOR OF LARGE DIAMETER AND SUPER LONG PILE GROUP IN LARGE THICKNESS LOESS SITE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1708-1714. DOI: 10.13544/j.cnki.jeg.2017-567
    Citation: LI Jiandong, WANG Xu, ZHANG Yanjie, LIU Boshi, LI Sheng, LI Zeyuan. 2018: MODEL TESTS FOR BEARING BEHAVIOR OF LARGE DIAMETER AND SUPER LONG PILE GROUP IN LARGE THICKNESS LOESS SITE. JOURNAL OF ENGINEERING GEOLOGY, 26(6): 1708-1714. DOI: 10.13544/j.cnki.jeg.2017-567

    大厚度黄土地基超长群桩承载特性模型试验研究

    MODEL TESTS FOR BEARING BEHAVIOR OF LARGE DIAMETER AND SUPER LONG PILE GROUP IN LARGE THICKNESS LOESS SITE

    • 摘要: 大厚度黄土地基中大直径长桩、超长桩的应用急剧增多,但黄土地基中超长桩的承载变形机理、侧阻和端阻的发挥性状与普通桩差别较大。采用研制的黄土相似材料填筑模型,分别进行超长单桩和群桩竖向抗压静载试验,分析桩顶荷载作用下荷载-沉降、桩身轴力、桩侧阻力、桩端土体塑性区发展变化规律。研究结果表明:超长单桩在竖向荷载作用下,荷载主要由桩侧阻力承担,桩侧阻力由上向下逐步发挥,属纯摩擦桩,单桩破坏形式为刺入破坏,桩端土体塑性变形影响范围约为1.1 d。与单桩相比,超长群桩基础桩端承载力有较大幅度的提高,桩身轴力衰减深度范围有所减小,侧阻力沿桩身逐渐增大,桩端土层的影响范围约为1.25 d,与超长单桩的影响范围较为接近。本文的研究方法和结果可为大厚度黄土地区超长桩基的承载特性研究提供参考。

       

      Abstract: Application of large-diameter long piles and super long piles in large thickness loess foundation has increased sharply. However, bearing deformation mechanism, lateral resistance and end bearing capacity of super long piles in loess foundation differ from those of the ordinary piles. Vertical compression static load tests of super long single pile and pile group are conducted respectively. The similar material is applied as filling of model test. Laws of development of load settlement, pile shaft force, lateral resistance and soil plastic zone at the end of pile under the vertical load are analysed. Test results show that load of super long single pile is mainly undertaken by lateral resistance of pile under the vertical load, which is gradually developed from top to bottom. It belongs to pure friction pile, and the failure mode of single pile is punching failure. The influence scope of plastic deformation of pile end soil is about 1.1 times of pile diameter. Compared with the single pile, the end bearing capacity of super long pile group is greatly improved, and pile shaft force attenuation depth of the pile has decreased, and lateral resistance increases gradually along the pile body. Influence scope of the pile end soil layer is about 1.25 times of diameter, which is close to the influence scope of super long single pile. Research method and results in this paper can provide reference for research on bearing characteristics of super long piles in large thickness loess foundation.

       

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