静钻根植桩挤土扰动圆孔扩张理论研究

STUDY ON DISTURBANCE OF SOIL SQUEEZING BY STATIC DRILLING GROUNDED PILE

  • 摘要: 绿色环保的静钻根植桩技术在地铁或敏感性建筑附近能否应用,目前还缺乏理论分析手段。对此,结合静钻根植桩的施工特点,首先给出扰动分析物理模型与基本假设;然后,基于圆孔扩张理论推导植桩施工引起的桩周土体应力与应变,结合连续条件建立桩侧极限扩孔压力与塑性区范围的关系式;在理论与实测比较检验该法可靠性的基础之上,开展多工况算例分析。结果发现:相较于传统预制桩施工方法,植桩施工极限扩孔压力下降48%,桩周土体塑性区影响范围下降57%;增加桩侧水泥土内摩擦角和粘聚力,植桩施工极限扩孔压力增大,扰动塑性区范围减小。研究成果为精细化评估静钻根植桩施工扰动效应提供了理论基础。

     

    Abstract: At present, there is still a lack of theoretical analysis on the application of green static drilling rooted pile technology in the vicinity of subway or sensitive buildings. Based on the construction characteristics of static drilling rooted pile, the physical model of disturbance analysis and basic assumptions are given. Then, based on the theory of circular hole expansion, the stress and strain of soil around pile caused by pile planting construction are derived, and the relationship between the limit reaming pressure and the plastic zone range is established in combination with continuous conditions. On the basis of the comparison between theory and actual measurement, the reliability of the method is tested. The results show that: compared with the traditional prefabricated pile construction method, the limit reaming pressure of pile planting is reduced by 48%, and the influence range of soil plastic zone around pile is reduced by 57%. When the friction Angle and cohesiveness of cement soil on the side of pile are increased, the limit reaming pressure of pile construction is increased, and the range of disturbance plastic zone is reduced. The research results provide a theoretical basis for fine evaluation of disturbance effect of static drilling rooted pile construction.

     

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