强夯法加固夹砂粘土吹填场地的现场试验研究

江苏省连云港赣榆港区陆域采用航道和港池的疏浚土方吹填形成作业港区,吹填工艺以绞吸式疏浚为主,疏浚涉及土层为粘土和砂土,由此形成了粘土和砂土的混合土地基。为了提高地基承载力和均匀性,采用了强夯法对地基进行加固,但是目前对夹砂粘土地基强夯加固的理论和实践较少。为此,以砂夹粘土构成的混合土地基为对象,测试了多种能量单点夯击时的地基土夯沉量、孔压和夯坑周围土体强度等参数,探讨了强夯法加固该类地基的加固深度和水平影响范围。结果表明：对于该类地基而言,有效加固深度修正系数取0.35~0.5为宜;强夯过程中,孔压与强度的增长范围不对应,即孔压影响范围远大于强度影响范围。

Site Test on Sand-clay Mixing Hydraulic Filled Ground with Dynamic Compaction

Ganyu por area in Lianyungang in Jiangsu Province was hydraulically filled with the dredging earthworks from the channel and harbor which were composed of two layers of soils, i. e. clay and sand. As hydraulic filling with the above soils together, the sand-clay mixing founda- tion was deposited. In this case, the dynamic compaction method was adopted to improve the bearing capacity and uniformity of the foundation. The change of single pointrs compaction settle- ment, excess pore pressure and soil strength after compaction were measured first, and then, the strengthened depth and horizontal influence area was discussed later. The results showed that the modification coefficient of effective improvement depth ranged from 0.35 to 0.5, and improve- ment zones were not consistent in respect of pore water pressure and soil strength, in other words, the influenced range of pore water pressure is larger than that of soil strength. These re- sult could deepen the understanding of the dynamic compaction method in this kind of founda- tion.