彭柏兴, 王星华, 雷金山. 2009: 盆地红层嵌岩桩荷载传递性状试验研究. 工程地质学报, 17(3): 401-407.
    引用本文: 彭柏兴, 王星华, 雷金山. 2009: 盆地红层嵌岩桩荷载传递性状试验研究. 工程地质学报, 17(3): 401-407.
    PENG Baixing, WANG Xinghua, LEI Jinshan. 2009: STATIC LOADING STUDY OF BEARING CAPABILITY BEHAVIOR OF ROCK- SOCKET PILE IN RED BEDS SOFT ROCK |IN XIANG-LIOU BASIN. JOURNAL OF ENGINEERING GEOLOGY, 17(3): 401-407.
    Citation: PENG Baixing, WANG Xinghua, LEI Jinshan. 2009: STATIC LOADING STUDY OF BEARING CAPABILITY BEHAVIOR OF ROCK- SOCKET PILE IN RED BEDS SOFT ROCK |IN XIANG-LIOU BASIN. JOURNAL OF ENGINEERING GEOLOGY, 17(3): 401-407.

    盆地红层嵌岩桩荷载传递性状试验研究

    STATIC LOADING STUDY OF BEARING CAPABILITY BEHAVIOR OF ROCK- SOCKET PILE IN RED BEDS SOFT ROCK |IN XIANG-LIOU BASIN

    • 摘要: 湘浏盆地内广泛分布着内陆湖相沉积的白垩系至第三系红层软岩,具有成岩差、易风化崩解等特性,其嵌岩桩的实际工作性状与《建筑桩基技术规范》(JGJ94-94)规定不尽相同。为研究红层嵌岩桩的承载性能、桩身轴力传递规律、桩侧阻力和端阻力的发挥性状,对4根人工挖孔灌注桩进行了单桩静力载荷试验,分别采用滑动测微计和应变计来测试桩身轴力的变化。结果表明,红层嵌岩桩表现为端承摩擦桩特性,Q-s曲线呈缓变型;桩身轴力传递规律和桩侧阻力的发挥与覆盖层厚度、桩长、桩周土性质密切相关;由于红层具有较强的结构性,发挥极限侧阻所需位移仅为2~6mm,测试得到的极限侧阻力远高于规范值,表现出强化效应,使得红层嵌岩桩具有相当大的承载能力,但端阻力和侧阻力并非同步发挥。设计时应采用承载力和变形控制,参数取值应符合桩的荷载传递规律。

       

      Abstract: The red beds soft rock of the age from Cretaceous to Eogene is widespread in Xiang-Liou Basin. It is a kind of soft rock with the features of weak diagenetic process and susceptible to weathering and can easily be disingtegrated. The practical working conditions of rock-socket pile in the soft rock is different from those in the《Technical Code for Building Pile Foundations》(JGJ94-94). The vertical static load test is adopted to investigate 4 large-diameter rock-socket pile in the rock. The variation of axis force in each pile is measured by sliding micrometer and strain gauges. Hence, the bearing capacity behavior, load transfer mechanism, the lateral friction and end bearing are researched in this paper. According to the test results, the load transfer performance of rock-socket pile is similar to that of end-bearing friction pile, the Q-s curves are slowly varying. The pile length, covering and soil around pile are all important to the load transfer mechanism and action of lateral friction. For the natural structure of the red soft rock, the critical displacements of piles are 2~6 mm and the tested result is much higher than those recommended by the Specifications, which indicates that the shaft resistance is strengthened. As the result, the bearing capacity of rock-socket pile in the soft rock is very good, while the lateral friction and end bearing cannot display simultaneously. The study results show that the design standards should be controlled by the strength and the deformation of pile foundation, and the parameter used in design should accord with the load transfer law of pile.

       

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