强夯处理软基的工后沉降

Post-construction settlement of soft ground after dynamic compaction

是否可有效减小软基工后沉降是衡量软基处理方法有效性的重要指标.从工后沉降的角度分析了强夯动力固结法处理深厚软基的有效性.实测结果表明:强夯可在淤泥层中产生较大的孔压增量,且影响深度较大.但强夯所致的孔压增量在瞬间产生,也在很短时间内消散.强夯前后软基的沉降速率相同,强夯对软基的固结沉降基本没有影响,处理后软基的工后沉降仍达360～800mm.在本文所述的工况条件下,强夯动力固结处理淤泥软土是无效的.

It is disputed whether dynamic compaction could effectively improve soft foudation even with vertical drains. It is presented in this paper that high excess pore water pressure at a depth of 8 m could be produced during dynamic compaction in a practical ground improvement engineering. However, most of the excess pore water pressure dissipated within several hours, and the rest eliminated in several days, compared with the slow dissipation of excess pore pressure under fill preloading. The rates of settlement of soft foundation were the same before and after dynamic compaction, and the post-construction settlement could be as high as 360～800 mm. Therefore, dynamic compaction is invalid in ground improvement under the conditions as stated in the case.