粉土地基真空井点降水效果及土颗粒迁移效应  

Research on the Vacuum Well-Point Dewatering and the Transport of Soil Particles in Silty Clay Ground

作　　者：聂庆科[1,2] 王英辉[1,2] 白冰[3] 贾向新[1,3] 王宗奎[3] 

机构地区：[1]河北建设勘察研究院有限公司,石家庄050031 [2]河北省岩土工程技术研究中心,石家庄050031 [3]北京交通大学土木建筑工程学院,北京100044

出　　处：《地下空间与工程学报》2015年第6期1572-1580,共9页Chinese Journal of Underground Space and Engineering

基　　金：国家重点基础研究发展计划(973计划)(2015CB057800);河北省建设科技计划项目

摘　　要：为研究粉土地基中群井条件下的真空井点降水过程及降水效果,进行了现场试验。试验表明,群井条件下,随井点间距的减小和井点深度的增大,水位下降要快得多。由于群井降水具有显著的三维空间效应,所以,群井降水引起的地下水位降低要比单排井点和单井点更为显著,同时,降水引起的地下水位下降范围也更大,这一效应随井点深度的增加更为明显。由现场取得原状土样进行的室内渗透试验表明,连续抽水后,在真空和水力的双重作用下,土层中的土颗粒有明显的迁移,导致地层中土的孔隙比增大,渗透系数也明显增大。This paper studies the processes of groundwater declining by vacuum well-point dewatering with a set of five / four-wells（ i.e. so called ＂big well＂） or sixteen-wells（ i.e. so called＂group-wells＂）. Field test results show that the groundwater level declines more rapidly with the decrease of well-spacing and increase of the depth of precipitation well. Due to the obvious 3-dimensional effect,the groundwater level will decline more rapidly than that of a single-well or a single-row of wells; at this time the influencing scope in horizontal and vertical directions will increase greatly. This effect appears to be more obvious when the depth of precipitation well increases. The laboratory tests of the in-situ samples indicate that after a long process of dewatering or a repeated dewatering,the pore void proportion of the soil layers will increase,and furthermore cause the increase of the coefficient of permeability,which shows a more rapid declining process of groundwater level.

关 键 词：粉土地基 群井效应 真空井点降水 现场试验 渗透系数 迁移效应 

分 类 号：TU473[建筑科学—结构工程]