大直径贝诺特桩套管上拔机制分析

发布时间：2018-10-09 15:54

【摘要】：目前关于贝诺特桩套管沉拔机制的研究,主要针对套管贯入过程,而对高频振动上拔套管机制的研究还不全面。采用任意拉格朗日-欧拉耦合大变形有限元ALE方法,建立套管高频振动上拔的有限元-无限元耦合模型,对套管高频振动上拔机制进行详细研究。结果表明,套管高频振动上拔过程可分为缓慢和快速上拔两阶段。在套管振动上拔过程中,土体位移、应力、孔隙比和超孔隙水压力均在管端附近突变,靠管心愈近变化愈明显。分析土体参数(土体弹性模量和管-土间摩擦系数)和振动锤参数(激振频率和激振力)对振动上拔套管的影响。土体较软、管土摩擦作用较强时,土体位移和应力变化越显著。振动锤参数仅影响套管上拔速度与土体质点速度,对土体位移和应力影响甚微;振动频率接近地基固有振动频率时,上拔阻力最小,振动振率越大,振动影响范围越小。
[Abstract]:At present, the research on casing sinking mechanism of Benoit pile is mainly focused on the casing penetration process, but the research on the mechanism of casing drawing on high frequency vibration is not comprehensive. A finite element coupled finite element method (ALE) with arbitrary Lagrangian Euler coupling and large deformation is used to establish a finite element coupling model for high frequency vibration pull-up of casing. The mechanism of casing high frequency vibration pull-up is studied in detail. The results show that the high frequency vibration pull-up process of casing can be divided into two stages: slow and fast. During casing vibration pull-out, soil displacement, stress, void ratio and excess pore water pressure all change suddenly near the end of the pipe, and the closer the pipe center is, the more obvious the change is. The effects of soil parameters (elastic modulus of soil and friction coefficient between pipe and soil) and vibration hammer parameters (exciting frequency and exciting force) on the vibration casing are analyzed. When the soil is soft and the friction between pipe and soil is stronger, the change of displacement and stress of soil is more significant. The parameters of vibration hammer only affect the velocity of the casing and the particle velocity of the soil, and have little effect on the displacement and stress of the soil. When the vibration frequency is close to the natural vibration frequency of the foundation, the pull-up resistance is the least, the larger the vibration rate is, the smaller the influence range of the vibration is.
【作者单位】：福州大学土木工程学院;
【基金】：国家自然科学基金项目(No.41272299)~~
【分类号】：TU473.1

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