管夯深层加固方法的软基现场工艺试验

Field Technological Test on Soft Ground Improvement by the In-Tube Deep Dynamic Compaction Method

为了克服传统强夯法加固软土地基的局限性,提出了一种管夯深层加固方法,并介绍了管夯深层加固方法所用机械设备、加固原理和施工工艺,同时,在福建省某软土地基处理项目中开展了管夯深层加固方法的现场工艺试验,分析了管夯填料用量和深层降水方式等影响因素.结果表明:所提出的管夯深层加固方法能够有效避免管内夯击过程中超静孔隙水压力的积累,且在夯后静置约1 d即可消散超静孔隙水压力;采用管夯深层加固方法加固后,增加了淤泥质土中粗粒填料比例,使得地基土体的锥尖阻力和锥侧阻力均成倍增长,地基有效处理深度可达15 m以上,从而克服了采用传统强夯法出现的超静孔隙水压力消散周期长、有效加固深度浅的缺陷.

To overcome the shortcomings of traditional dynamic compaction method, a new technique of intube deep dynamic compaction was proposed. The equipment, reinforcement mechanism and construction procedures of this new method were described. Based on the field test in Fujian, some factors such as filler content and deep dewatering were monitored during reinforcement. The test results show that the accumulation of excess pore water pressure during the tamping process can be effectively avoided by the intube deep dynamic compaction method, and the excess pore water pressure will dissipate completely after 1 day of dynamic consolidation. When the sand grains are added into the soil, the tip resistance and cone side resistance increased exponentially after the reinforcement, and the effective depth of foundation treatment can reach more than 15 m in depth. The defects of the long period of dissipation of excess pore pressure and shallow depth of the effective reinforcement in conventional dynamic consolidation method are overcame.