排水粉喷桩加固软土地基(2D工法)的试验研究

在分析常规粉喷桩加固软土地基存在问题的基础上,提出了排水粉喷桩复合地基加固软土地基的技术(2D工法)。该工法充分利用粉喷桩和排水板的优点,将二者有机结合,达到经济、有效加固软土地基的目的。文章介绍了该工法的基本原理和应用方法,通过详细介绍现场试验成果,论证了该工法的有效性和优越性,可在工程应用中推广。

On combined method of dry mixing with vertical drain and its practice in soft ground improvement

A remarkable combined method of the dry mixing with vertical drains (2D method) has been innovated and successfully practiced in a highway project on very soft clay in Jiangsu, China. The mechanism, construction, in-situ test and monitored results on dry mixing columns and soils between the columns are presented. It is shown that the pore water pressure in the surrounding soft clays of the dry mixing column increases significantly during the jet mixing, resulting in some problems, such as the slope failure, non-uniform mixing, and poor quality in the deeper part of the column. With the vertical wick drains placed between the columns before dry mixing, the pore water pressure caused in the construction dissipates fast, not only improving the quality of the dry mixing column but also enhancing the soil strength. Then, the bearing capacity of the composite foundation improved with 2D method increases obviously compared with the traditional dry deep mixing method. The monitored results including settlements, pore water pressure, and stress on the column and ground surface conducted in a 100 m pilot project of nighway verify the innovation method much valuable.