[关键词]
[摘要]
轻型井点降排水在基坑施工临时降排水方案中应用极为广泛, 但因影响因素较多, 施工中常会出现原设计方 案降深不足而影响施工或降深过大造成浪费的情况。采用三维有限元方法, 以南水北调干渠镇平段一断面为例, 分 析了多层地质结构条件下, 井深、井点间距及井底地层特性对轻型井降深的影响。结果表明, 若井底位于强透水层, 轻型井降深随井深增加而增大; 若井底位于相对不透水层, 轻型井井深对降深没有影响; 井点间距越大, 降深越小。 此外, 井底强透水层越厚, 无效降深越小; 当强透水层厚底大于5 m 时, 无效降深基本恒定, 但井点间距越大, 该值也 越大。
[Key word]
[Abstract]
Light w ell dew atering is widely used in the t empor ary dew atering scheme of foundation pit. H ow ever, it is affected by many fact ors and insufficient or ex cessive draw dow n can impact the co nstr uct ion o r cause waste. In this paper, a cro ss sect ion in Zhenping of the main channel in t he South2 to2Nor th Water Transfer Pr oject w as taken for ex ample, and the finite element meth2 o d w as ado pted to analy ze the effects o f well dept h, well spacing, and well bo ttom character istics on the draw down in the lig ht well w ith mult ila yer geo lo gic structure. T he results showed that( 1) the dr awdow n in the light well increases w ith the increasing of w ell depth w hen the w ell bott om is in the st rong ly permeable la yer; ( 2) well depth has insig nificant effects o n the dr awdow n when t he w ell bo ttom is in t he r elatively impermeable lay er; ( 3) the draw down decr eases w ith the increasing of w ell spacing ; ( 4) the invalid draw down decr eases w ith the incr easing of the thickness o f the str ongly permeable layer w here the w ell bottom occur s; and( 5) t he inv alid draw down is nea rly constant w hen the thickness of the st rong ly permeable layer is higher than 5 m, and the invalid draw down increases with t he increasing of w ell spacing.
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[基金项目]
三峡大学人才科研启动基金项目( KJ2012B034)