软土中无筋刚性桩复合地基支承路堤的整体稳定实用计算方法

为了合理评估无筋刚性桩复合地基支承路堤的稳定性,基于已进行的软土地基上刚性桩复合地基支承路堤的破坏机理研究,提出了刚性桩复合地基的整体稳定性简化分析方法,结合3个典型算例,与基于桩身抗剪强度的传统复合地基稳定方法进行了对比分析。结果表明：基于传统的复合地基稳定计算方法,采用桩身抗剪强度将显著高估路堤稳定性,桩身等效抗剪强度法可更好地反映刚性桩复合地基的破坏机理;采用等效荷载法、等效砂桩法和等效抗剪强度法计算得到的路堤稳定安全系数很接近;采用英国BS 8006规范方法、等效荷载法、摩擦接触法计算得到的路堤稳定安全系数显著依赖于桩土应力比。建议对无筋刚性桩复合地基支承路堤采用多种简化分析方法进行分析,保证设计的冗余度。

Practical Calculation Method for Stability of Embankment on Soft Subgrade Reinforced with Unreinforced Rigid Piles

In order to reasonably evaluate the stability of embankment supported on composite ground reinforced with unreinforced rigid piles,based on the study of the failure mechanism of embankment on soft subgrade reinforced with rigid piles,different simplified stability analysis methods were suggested and compared with traditional method by performing numerical analysis of three typical examples of embankment.The results indicate that embankment stability can be highly overestimated when using the traditional method and the equivalent shear strength method can better reflect the failure mechanism of embankment reinforced with rigid piles.The safety factors by the equivalent load method and the equivalent sand pile method are fairly close to that by the equivalent shear strength method.The pile-soil stress ratio has great influence on the safety factors with the BS 8006 method,the equivalent load method and the friction contact method.It is suggested that more than one simplified method be used when performing the overall stability analysis for embankment supported on composite ground reinforced with unreinforced rigid piles in order to ensure the redundancy of the design.