基于统一强度理论考虑拉压模量不同散体材料桩承载力计算

BEARING CAPACITY OF AGGREGATE PILE WITH DIFFERENT RATIO OF TENSION MODULUS TO COMPRESSION MODULUS BASED ON UNIFIED STRENGTH THEORY

考虑岩土类材料拉压模量不同和应变软化特性,运用空间轴对称的统一强度理论分析了柱形孔扩张问题,推导出了圆孔扩张问题的应力场、位移场及最终扩张压力的统一解表达式,并在此基础上推导出了散体材料桩极限承载力计算公式。将该公式应用于某高速公路碎石桩复合地基中碎石桩极限承载力的计算,计算值与试验值吻合良好。最后,分析了不同拉压模量比、软化特性参数及其他计算参数对计算结果的影响。分析结果表明:采用传统弹性理论,不考虑拉压模量不同及应变软化的计算方法,会带来较大的误差。

A unified analytical solution to cylindrical cavity expansion is derived by considering different ratio of tension modulus to compression modulus and strain-softening behavior. The stress field, strain field, displacement field and final expansion pressure are obtained. On the basis of this, the calculation formula of the limit bearing capacity of aggregate pile is obtained, and the formula is applied to calculate the limit bearing capacity of gravel pile in a highway gravel pile composite foundation. The calculation results agree well with the in situ measured values. In the end, the influence of different ratio of tension modulus to compression modulus, parameter of strain-softening behavior and other parameters on calculation results is discussed. The analysis results show that neglect of difference between the tension modulus and compression modulus and the strain-softening behavior will lead to significant calculation errors.