填海造陆工程预压法加固软基现场监测试验研究

介绍了采用预压法加固吹填淤泥与海相沉积淤泥的围海造陆工程分区软基处理方法与现场监测试验,对该工程B2区堆载预压与真空堆载联合预压法加固过程中淤泥层的沉降变形、孔压、真空度及深层土体位移等观测结果进行了分析。结果表明：吹填淤泥经过预压处理后,压缩比高达33.2%,为相邻海相沉积淤泥的1.6～1.8倍,前者加固效果明显高于后者;吹填淤泥的孔压消散速率慢于相邻海相沉积淤泥,卸载前,孔压还未消散完,而后者孔压已基本消散;真空度沿淤泥层传递效果较好,表层与底层较好,中间层次之;真空与堆载预压荷载作用下,表层淤泥位移朝向加固区内,中间层淤泥位移朝向加固区外,不影响地基的稳定性。

Study on In-site Monitoring Tests for Soft Clay Foundation by Urcharge Preloading Reinforcement in Reclamation Land Projects

Partition soft clay foundation improvement methods and in-situ monitoring tests of land reclamation projects are introduced, which applies surcharge preloading method to treat dredged fill and marine deposit silt. The settlement deformation, pore water pressure, vacuum degree and deep soil displacement of silt foundation are analyzed in B2 site during surcharge preloading and vacuum- surcharge preloading reinforcement. The results are as follow ： after foundation improvement, the greatest compression ratio of dredged fill is 33.2% , and it is 1.6 - 1.8 times as the neighboring marine deposit silt, and the reinforcement effect dredged fill is prior to underlying marine deposit silt; The dissipation velocity of pore water pressure for dredged fill is slower than the neighboring marine deposit silt, and the dissipation of pore water pressure has not been finished, while the dissipation of pore water pressure marine deposit silt has been basically finished before unloading; A significant transmission effects for vacuum degree along silt layer are shown, and the better with the surface and the bottom layer, the good with the interlayer; Under the combination effect of vacuum and surcharge preloading, the displacement of the surface silt layer is towards to the reinforcement region, the middle layer silt is deviated from the reinforcement region, the foundation stability is not affected.