真空动力固结饱和软土地基室内模型试验

Indoor model test on vacuum dynamically consolidated saturated soft soil foundation

为研究土层沉降变化和孔隙水压力长消对真空动力固结软土加固效果的影响,设计了真空动力固结室内模型试验装置并进行了针对具体工程项目的试验模拟。通过夯击能变化调节,对真空动力固结处理土层的沉降变化规律和孔隙水压力长消规律进行了分析。试验研究结果表明:夯坑夯沉量和土层表面沉降与夯击击数及夯击能呈正比例变化,但应合理控制夯击击数;多遍真空主动降水和夯击反复作用导致土层竖向压缩量的增长速度呈递减趋势,分层土体的孔隙水压力增幅差异明显,且浅层土体孔压增幅大于深层土体孔压增幅,夯击引起的超孔隙水压力逐渐减小;真空动力固结有效加固深度修正系数αd围绕3.0浮动,且随着夯击能的增加,该系数呈现增大趋势。

In order to study the influence of soil settlement and pore water pressure on the vacuum dynamic consolidation of soft soil,the device for vacuum dynamic consolidation test was designed,and the relevant test was carried out. Through the adjustment of tamping energy,the dissipation of pore water pressure was analyzed,as well as the soil settlement. Experimental results show that,with the change of tamping times and tamping energy,the tamping settlement and soil surface settlement have a positive proportional relationship,but tamping times should be reasonably controlled. Manytimes of vacuum precipitation and repeated compaction lead to the decrease of soil vertical compression. There are obvious differences between the pore pressure growths of different layers of soil,and the increase of pore pressure of shallow soil is larger than that of deep soil. The excess pore water pressure caused by tamping is gradually reduced. The correction factor for the effective reinforcement depth of the vacuum dynamic consolidation is around 3,and it increases with the enlargement of the tamping energy.