考虑中间主应力的灰土挤密桩复合地基极限承载力研究

Study on the Ultimate Bearing Capacity of Composite Foundation of Lime-soil Compaction Pile Considering the Intermediate Principal Stress

基于三剪应力统一屈服强度理论,考虑中间主应力的影响,推导灰土挤密桩极限承载力计算公式,分析不同参数对计算结果的影响,并采用现场静载试验进行验证。研究结果表明:中间主应力对土体的侧向极限约束力有较大影响,可用中间主应力权系数b值描述;按不同b值计算的灰土挤密桩复合地基极限承载力,随深度的增加,呈线性增加,随桩体内摩擦角的增加,则呈非线性增加,随着桩体直径的增加,呈幂函数增加,且逐渐趋于收敛;考虑中间主应力系数影响的计算值与实测值相近,计算精度较高,具有良好的适用性。

Based on three-shear stress unified strength theory and considering the influence of intermediate principal stress,the ultimate bearing formula of lime-soil compaction pile is derived,and the influence of different parameters on the calculation results is analyzed,which is verified by static load test.The results show that the intermediate principal stress has a great influence on the lateral ultimate restraint force of soil,which can be described by the intermediate principal stress weight coefficient b.The ultimate bearing of lime-soil compaction pile,which calculated by different b values,increases linearly with the depth,nonlinearly with the friction angle of pile,exponentially with pile diameter,and then tends to converge gradually.The calculated value considering the influence of the intermediate principal stress coefficient is close to the measured value,the calculation accuracy is high,and it has good applicability.