基于夯击能和夯沉量的强夯参数优化分析

OPTIMIZATION PARAMETERS OF DYNAMIC COMPACTION BASED ON COMPACTION ENERGY AND COMPACTION SETTLEMENT

对回填全风化泥质粉砂岩地基，采用强夯法处理。首先，通过建立强夯能级与击实试验击数及最优含水量的关系，进行不同击实功下的击实试验，从夯击能的角度对强夯设计参数进行优化。其次，采用理论推导、曲线拟合的方法建立夯沉量与击实度之间的关系式，通过在不同夯沉量时钻孔取样、测定试件的击实度，以验证夯沉量与击实度的关系式，进而提出以夯沉量检测击实度的方法，对强夯施工参数进行优化。试验结果表明：击实试验击数对最优含水量的影响较大，击实试验的击数宜按现场单位体积夯击能与击实试验单位体积击实能基本相等的原则确定。利用夯后沉降量与夯后土体击实系数的关系式，通过夯沉量控制土层击实度，其值与现场实测击实度相差3．25％，误差较小，说明利用拟合关系式由夯沉量估算击实度是可行的。浅层平板荷载试验和瑞利波试验结果表明：夯后地基承载力、有效加固深度均满足设计要求，说明优化后的强夯参数科学、合理。

Dynamic compaction was used to improve the strongly weathering muddy siltstone foundation. Firstly, the parameters of dynamic compaction were optimized by taking compaction test under different compaction energies and constructing the relationship among compaction energy, hits of compaction test and optialum water content. Secondly, the formulation between compaction settlement and degree of compaction was established by theoretical derivation and curve fitting, which was verified by measuring the compaction degree of the specimens from drilling holes under different compaction settlements. Based on it, a method determined compaction degree by compaction settlement was established, which could optimize the construction parameters of dynamic compaction. According to test results, the hits of compaction test had great impact on optimum water content and it was advisable to decide the hits of compaction test according the principle that the field compaction energy equaled unit the energy of laboratory compaction test in volume. The error between calculating values of compaction degree by proposed formulation and from field tests was about 3.25% , which proved that there were a good agreement between the calculating values and the ones from field testing. The loading test and Rayleigh wave test showed that foundation bearing capacity and improvement depth after dynamic compaction could meet the design requirements, which showed that the optimized parameters of dynamic compaction were scientific and reasonable.