粉土地基强夯加固效果影响因素数值模拟研究

以绍兴新东线软基加固工程为背景，采用ABAQUS对强夯加固粉土地基进行模拟，结合现场实测数据分析了夯击次数、夯击能、落距和水位对强夯加固效果的影响。结果表明:锤侧土体塑性应变等值线近似于半椭圆形，随夯击次数的增加，塑性区逐渐增大，且其增量以夯锤侧下方为主；不同夯击能下，强夯的有效加固深度与累积夯沉量比值介于4~5；“轻锤高落”产生的锤土接触应力峰值较“重锤低落”大，但衰减速度更快；地下水位越高，浅部土体强夯产生的超静孔隙水压力及其增幅越大；降低水位可显著提升强夯加固深度。

Numerical simulation study on influencing factors of reinforcement effect of silt foundation

Based on the reinforcement project of soft foundation of Xindongxian Highway in Shaoxing City，ABAQUS was used to simulate the compaction of silt foundation，combining with measured data，the effects of tamping times，tamping energy，drop height and water level on the reinforcement effect of dynamic compaction are analyzed.The results show that the plastic strain contour line of the soil on the side of pounder similar to semi-elliptical shape，and the range of plastic zone increase gradually with the increase of tamping times，its increment mainly distributed on the side lower of the pounder；under different tamping energy，the ratio of effective reinforcement depth to cumulative settlement is between 4 and 5；the peak contact stress generated by a larger height of drop is greater，it attenuates faster than that by a smaller of drop；the groundwater level is higher，the excess pore water pressure and its increment produced by the dynamic compaction of shallow soil are greater；the reinforcement effect can be obviously promoted by reducing the water level.