基坑围护桩作用下地层支护应力分析及应用

吴行州

Analysis and Application of Stratum Support Stress Under Action of Foundation Pit Retaining Pile

WU Xingzhou
摘要:
[目的]基坑围护桩在建筑施工中起着至关重要的作用。为确保基坑施工安全稳定地进行,需对基坑在围护桩支护作用下的地层支护应力分布规律进行深入研究。[方法]提出了围护桩作用下地层内部支护分析模型及理论计算公式,基于弹性力学半弧线平面内作用均布应力的解答方法,推导分析了不同围护桩间距下,桩间土体内部支护应力的分布规律,揭示了基坑围护桩下,桩间土体内部成拱的力学机理。以济南轨道交通4号线林家庄站为例,对围护桩作用下的地层支护应力进行了计算分析。[结果及结论]在桩侧土压力作用下,周边地层支护应力随桩间距的增大而减小;在相同桩间距下,周边地层支护应力随桩侧土压力的增大而增大。地层内部连续的支护应力与合理桩间距是确保围护桩有效成拱的关键。
Abstracts:
[Objective] Foundation pit retaining piles play a vital role in building construction. In order to ensure the safety and stability of foundation pit construction, it is necessary to make in-depth study on the stress distribution law of stratum support under the action of foundation pit retaining piles. [Method] The analysis model and theoretical calculation formula upon the stratum internal support under the action of retaining piles are put forward. Based on the solution method of the uniform stress in the half-arc plane of elasticity, the distribution law of soil internal support stress between piles is deduced and analyzed under different retaining pile distances. The mechanical mechanism of the soil arch between the piles and under the foundation pit retaining piles is revealed. The stratum support stress under the action of the retaining piles is calculated and analyzed with the example of Linjiazhuang Station on Jinan Metro Line 4. [Result & Conclusion] Under the pile side soil pressure, the support stress of the surrounding stratum decreases with the increase of pile distance. At the same pile spacing, the support stress of surrounding stratum increases with the increase of pile side soil pressure. The continuous support stress inside the stratum and reasonable pile spacing are the key to ensure effective arch formation of the retaining piles.
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