基于圆孔扩张理论的碎石桩承载力计算方法

本文深入研究碎石桩复合地基的受力变形机理，利用摩尔库伦弹塑性材料的剪胀特性，同时引入应力跌落三折线模型，视筋箍碎石桩承受上部荷载时的径向鼓胀为圆孔扩张，将产生变形的桩周土体分为弹性区和塑性区两部分，运用Vesic圆孔扩张理论分别建立了弹性区和塑性区桩周土体的应力场和位移场表达式，进而利用桩体影响半径处土压力为静止土压力的假设，求出了桩周土对碎石桩的径向围限力，再结合被动土压力公式导得了碎石桩的单桩承载力计算式。为验证该方法的可行性，本文结合实际工程数据对所推导的承载力计算式进行了验证分析，结果表明计算值与实测值吻合。

Calculation method for the bearing capacity of stone columns based on the cavity expansion theory

In this article, the deformation mechanism of gravel pile composite foundation is thoroughly examined. The dilatancy of Mohr-Coulomb elastic-plastic materials and the three-fold line model are adopted to optimize this research. The radial bulging of the physique gravel pile which bears the upper loads is taken as the hole expansion. The elastic and plastic zones are divided into two parts and the stress field along with displacement field of the soil around the piles in the elastic and plastic zones is respectively established by suing the Vesic circular expansion theory. The influence of the earth pressure is assumed as the static earth pressure and the calculation formula of the bearing capacity of the single pile of gravel pile is obtained by combining the formula of passive earth pressure. In order to verify the feasibility of this method, this paper is combined with the actual engineering data on the derived bearing capacity calculation and good agreement is found between the results obtained with the proposed data. The results show that the calculated values are in good agreement with the measured values, indicating that the proposed method is reasonable.