真空预压法加固广州南沙港区软基现场试验研究

Field Experiment Study on Strengthening Soft Foundation in Guangzhou Nansha Port Area by Vacuum Preloading

为研究真空预压加固大面积软基的变形及孔压变化规律,在广州南沙港真空预压试验区对地表沉降、分层沉降、侧向位移和孔压变化等进行了监测,并分析了实测数据。现场试验表明:真空预压法能使地基产生较大的沉降速率,且工后沉降较小;加固深度主要在塑料排水板打设深度范围内,但影响深度可达该深度以下3～4 m处;边界处土层沉降较小,但侧向位移较大。通过比较加固前、后土样的物理力学指标,说明真空预压法加固大面积超软弱淤泥土效果显著。

To study the laws of displacement and pore-water pressure variations induced by the improvement of large area soft ground by vacuum pretoading, the details of settlements, multi-point settlements, deep horizontal displacement and pore pressure variations were monitored and analyzed in testing area strengthened by vacuum preloading in Guangzhou Nansha Port. Field experiment showed that vacuum preloading can cause more settlement velocity and less post-construction settlement, and the effective improving depth was mainly in the range of the depth of PVD while the influenced depth was 3-4 m below the bottoms of PVD. The settlement of clay on the boundary, of foundation was less than that of soil inside the ground, while the horizontal displacement was over than that of other areas. The physical and mechanical indexes before and after soil improvement were compared, which indicated the super-soft reclamation silt was strengthened greatly by vacuum preloading.