真空预压法中开泵率对加固效果的影响  

Influence of Working Pumps Ratio on Reinforcement Effect by Vacuum Preloading Method

作　　者：吴跃东[1,2] 惠炜 Wu Yuedong;Hui Wei(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,P.R.China;Geotechnical Engineering Research Center of Jiangsu Province,Nanjing 210098,P.R.China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,南京210098 [2]江苏省岩土工程技术工程研究中心,南京210098

出　　处：《地下空间与工程学报》2018年第4期1077-1082,共6页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51279049);中央高校基本科研业务费项目(B1504805)

摘　　要：运用真空预压法加固软土地基,主要通过真空度、沉降量和固结度控制施工进度,而对射流泵开泵率要求甚少。为避免施工方出于节约电费或降低后期沉降速率等目的肆意减少开泵率并影响加固效果,结合江苏省连云港市某真空预压工程,从真空度、表层沉降、分层沉降、孔隙水应力等监测指标方面对开泵率对加固效果的影响进行了相似场区不同开泵率下的对比研究,结果表明,在真空预压中期提高开泵率,各项监测指标变化明显,深层土体变化滞后,加固效果提升显著。在真空预压后期保持高开泵率,各监测指标无太大的变化,反而趋于稳定。故认为真空预压中期合理的开泵率设置在80%以上,而规范中规定的真空预压后期开泵率保持80%并不合理,在保证真空度的前提下宜适当减少开泵率。When reinforcing the soft soil foundation with the vacuum preloading method,the construction process is usually controlled by monitoring the vacuum degree,settlement quantity and the degree of consolidation. However,few requirements need to be met on the ratio of working jet pumps. In order to avoid reducing ratio of working pumps optionally by construction side for the purposes of saving electricity cost or decreasing the settlement rate at the final stage and so on,comparison and analysis which were based on a vacuum preloading project in Lianyungang,Jiangsu Province were carried out on the different ratio of working pumps in similar places depending on vacuum degree,surface settlement,layered settlement,pore water pressure and other monitoring indexes. It showed that if the ratio of working pumps is increased in the middle stage of vacuum preloading,all kinds of monitoring indexes change obviously which means that reinforcement effect is increasing significantly and the changes in deep soil lag behind that in shallow soil. However,if the high ratio of working pumps is maintained in the later stage of vacuum preloading,most kinds of monitoring indexes have little change and even tend towards stability. So the suggested ratio of working pumps in the middle stage of vacuum preloading is more than 80% and the ratio of working pumps in the later stage is suggested to be reduced appropriately while maintaining the vacuum degree other than be maintained at 80% in accordance with the construction specification of vacuum preloading method in the application of surface-layer improvement technique.

关 键 词：真空预压 开泵率 真空度 表面沉降 分层沉降 孔隙水应力 

分 类 号：TU471.8[建筑科学—结构工程]