无黏性土强夯加固效果定量估算的拟静力分析法

Quasi-static analysis for quantitative estimation of improvement effect of cohesionless soil treated by dynamic compaction

提出了强夯锤–土接触面"等效拟静力"的概念;从功能原理推导了用土质参数表达的等效拟静力公式;基于压密分布的近似假设,建立了任意夯击击数时的夯坑深度和夯点下不同深度处的相对密度计算公式,进而可确定无黏性土夯后土的设计控制指标(如标准贯入击数)的深度剖面;初步探讨了计算中涉及的若干参数取值;最后,用若干实例对所建立的方法进行了初步验证,结果表明,该方法计算结果与实测结果较吻合。

The concept of ＂equivalent quasi-static force＂ between the tamper and the ground was proposed for the analysis of dynamic compaction, and the basic expression to compute the ＂equivalent quasi-static force＂ was deduced from the work-energy principle. By introducing the 1D stress-strain relation of cohesionless soil and the stress distribution, together with the empirical relations between the designations of in-situ tests and the engineering properties of granular soils, a simplified approach （quasi-static analysis） and the values of related parameters in this model were proposed for the evaluation of the improvement effect of dynamic compaction for granular soils, which could predict the crater depth, the relative density and SPT blows at different depths under the tamping points in the process of tamping. It was indicated by case studies that the proposed method and values of parameters, regardless of its high simplification, were practically feasible.