砂土中灌注桩侧摩阻力的一个计算模型

当前针对灌注桩桩侧摩阻力的确定方法还存在明显缺陷,描述灌注桩侧摩阻力的计算模型极为缺乏。结合Березаицев松散体极限平衡的轴对称理论及夹心墙土压力理论,考虑了圆拱挤压效应的影响,修正了惯用挡土墙理论设定土压随深度线性增长产生的不收敛效应,提出了卸荷条件下灌注桩桩侧阻力的一个计算方法:在桩上部使用Березаицев解析解、在桩下部使用夹心墙理论;或者沿桩身全部应用夹心墙的理论。同时使用某高架工程现场测试结果进行了验证。结果表明:虽然计算值和实测值存在一定误差,但大体吻合,说明计算模型简便实用具有相当的安全性,适于工程初步估算使用。具备一定的工程实践和理论应用价值,并为进一步深入研究提供科研思路和参考。

A Calculation Model of Skin Friction of Bored Piles in Sand

There are many disadvantages of the existing methods in determining the skin friction of bored piles, and a few calculation models of skin friction bored piles exist. In this paper, a calculation method of skin friction of bored piles is provided considering arching and squeezing effect, combined with limit equilibrium axisymmetric theory about loose substance stated by Berezaitzev (Березаицев) and interlayer wall theory, which correct non-convergence effect resulted by prevalent theory of retaining wall with assumption that the soil pressure increases with depth linearly: Analytic solutions of Berezaitzev is used in upper side of piles, and the interlayer wall theory is used in deep soil around piles, or the interlayer wall theory is used along entire length of piles. Then the model is proved on the basis of measuring data in some viaduct road projects. The result indicates that:Calculation value and measured value are close on the whole though some error exists between them, which demonstrates that the mathematical analytical model is available to be used for primary estimation in engineering because it is simple and useful, on the other hand, it is quite safe. Anyway, the established model has certain practical and theoretical value, which can supply scientific reference for further study.