真空联合堆载预压加固长江漫滩相软基孔压测试分析

结合长江江苏镇江段某码头堆场地基采用真空联合堆载预压法加固处理工程,通过现场钻孔埋设孔隙水压力计,对长江漫滩相软土地基加固过程中孔隙水压力的发展变化过程进行了测试分析。结果表明:真空预压区,加固30d后地基中孔隙水压力变化基本稳定,且土中超静孔隙水压力的消散受该深度排水板中真空荷载的影响十分显著;排水板中真空荷载随深度衰减,衰减速率与排水板周围土层性质密切相关;通过现场测试得到排水板周围为长江漫滩相淤泥质粉质黏土时,真空荷载沿排水板深度衰减速率约为3kPa/m。

Test and Analysis on Pore Water Pressure in Yangtze River Floodplain FoundationReinforced by Vacuum Combined Surcharge Preloading

A terminal storage yard along the Yangtze River was reinforced using vacuum combined surcharge preloading in Zhenjiang, Jiangsu, China. The pore water pressure was measured and analyzed during preloading by installing pore water pressure gauges in the Yangtze River floodplain foundation. The results show that the pore water pressure tends to be relatively stable after 30 days in the reinforced foundation treated by vacuum preloading. Meanwhile, the excess pore water pressure dissipation is significantly affected by the distribution of vacuum pressure along the depth of prefabricated vertical drains (PVDs). The vacuum pressure in the PVDs decreases with the depth, and the decay rate is closely related to the properties of soil layer around PVDs. For the Yangtze River floodplain silty clay, the decay rate is about 3 kPa/m.