真空预压法加固砂井地基的沉降固结分析

Settlement Construction Analysis of Sand-draind Foundation Strengthened by Vacuum Preloading Method

我国沿海及平原地区软土广泛分布,真空预压法多用于工程中软土地基的处理。文中通过对浦东机场第三跑道软土地基进行真空预压数值模拟分析,研究地基处理中的真空预压法对地基沉降的影响。结果表明,当固结时间为90 d时,对塑料排水板打设深度分别为20 m和25 m 2种情况下的地基竖向沉降、侧向变形、总孔隙水压力及超孔隙水压力的结果进行对比分析发现:同一土层,离真空加固区越近,土层发生的沉降变形越大,且多发生在真空预压前期;随着塑料排水板打设深度的增加,真空预压产生的固结沉降也越大,侧向变形呈增大趋势,最大侧向位移发生在加固区的边缘;加固区真空度的传递效果良好。

Soft soil is widely distributed in coastal and plain areas in China.Vacuum preloading method is often used for the treatment of soft soil foundation in engineering.Through the finite element numerical simulation of vacuum preloading on the soft soil foundation of the third runway of Pudong Airport,the impact on soft soil foundation settlement by vacuum preloading method is analyzed.After consolidating for 90 days,numerical results of vertical settlement,lateral deformation,total pore water pressure and excess pore water pressure are compared under the condition of plastic drainage board installed to a depth of 20 m and 25 m.As results,for the same soil layer,the volume of settlement will increase when the layer is closer to the vacuum reinforcement area.And the foundation settlement is always occurred in early stage of vacuum preloading.The consolidation settlement and lateral deformation caused by vacuum preloading are increasing with installing depth of plastic drainage board,the maximum lateral displacement is at the edge of the reinforcement area,and the transmission effect of vacuum in reinforcement area is good.