异步真空预压法处理超软土的室内试验及机理

Model test and mechanism of reciprocating water absorption vacuum preloading treated ultra-soft soil

针对真空预压处理超软地基过程中出现的排水板滤膜外土颗粒聚集现象,提出并通过室内试验研究一种新型真空预压方式——异步真空预压法。该法对相邻的竖向排水体在同一时间下施加不同的真空度,实现对超软土的异步真空吸水预压,缓解因土颗粒单向迁移造成排水体滤膜及膜外土体的淤堵。通过室内试验发现,真空度调节对真空预压的处理效果具有明显影响,同时,异步吸水真空预压排水量是常规真空预压的1.1倍,效果优于常规真空预压;通过对异步真空预压法的机理分析,认为异步真空预压法可保持零速面移动范围内的细颗粒含量,防止细颗粒的过量迁移,有助于缓解超软土的固结排水中的淤堵问题。

To counter the phenomenon of particle aggregation in the process of vacuum preloading treatment in the process of ultra-soft soil,a new type of water absorption,reciprocating water absorption,is put forward to be applied in vacuum preloading reinforcing the ultra-soft soil. With different vacuum degrees of the adjacent vertical drainages（ PVD） at the same time,we realize the asynchronous vacuum water absorption of the ultra-soft soil. It is found through the model experiment that the drainage capacity of reciprocating water absorption is 1. 1 times of that of regular water absorption. The analysis of mechanism of reciprocating water absorption vacuum reloading method reveals that this method can prevent fine particles from excessive migration and contribute to the consolidation of ultra-soft soil drainage.