摘要
首次针对西北地区典型深厚回填砂岩碎屑及湿陷性黄土场地,进行孔内深层超强夯(SDDC)工法结合强夯法复合地基工后浸水试验。结果表明:(1)复合地基受水浸湿时,竖向渗透最大影响深度为8~10 m,径向最大影响宽度为2~4 m,建议在处理大厚度回填砂岩碎屑时,基础外缘处理宽度2~4 m即可;(2)复合地基受水浸湿时地表及深部土体沉降较小,湿陷得到有效消除,在满足变形和承载力的要求下,建议处理深度达到10 m即可,可不考虑因地表浸水引起的地基土附加沉降变形;(3)长期监测深部土体,1年累计最大沉降量较小,满足规范对地基沉降变形要求,地基处理基本消除了回填土自重下的固结沉降;(4)复合地基受水浸湿后承载力满足设计要求,达到原回填土承载力特征值的2倍。
This study pioneers post-construction immersion tests on composite foundations treated with the super down-hole dynamic consolidation and dynamic compaction methods in typical thick sandstone backfill and collapsible loess sites in northwestern China.The results show the following:First,during water immersion,the composite foundation exhibited a maximum vertical permeability influence depth of 8-10 m and a radial influence width of 2-4 m,suggesting a recommended treatment width of 2-4 m at the foundation peripheries for thick sandstone backfill layers.Second,settlements of surface and deep soil remained minimal during immersion so that the collapsibility can be effectively eliminated.A treatment depth of 10 m is proposed to meet the deformation and bearing capacity requirements without considering the additional foundation soil settlement from surface water infiltration.Third,the long-term monitoring of deep soil revealed a negligible maximum cumulative settlement in 1 year,complying with the code-specified settlement and foundation deformation,indicating the near-complete elimination of the consolidation settlement under backfill self-weight.Finally,the post-immersion bearing capacity of the composite foundation satisfied the design criteria,reaching twice the characteristic value of the original backfill.
作者
张海峰
李振军
滕光亮
白学伟
张进虎
宋振江
ZHANG Haifeng;LI Zhenjun;TENG Guangliang;BAI Xuewei;ZHANG Jinghu;SONG Zhenjiang(Gansu Institute of Architectural Design and Research Co.,Ltd.,Lanzhou 730000,Gansu,China)
出处
《地震工程学报》
北大核心
2025年第4期822-831,共10页
China Earthquake Engineering Journal
基金
甘肃省建筑设计研究院有限公司公司科技发展基金(KY2020-KC03)。
关键词
SDDC工法
强夯法
浸水试验
砂岩碎屑回填区
super down-hole dynamic consolidation(SDDC)method
dynamic compaction
immersion test
sandstone backfill areas
