摘要
真空预压加固区边界多为开敞式,这使得真空预压不可避免地会在加固区四周产生一定程度的土体位移,进而对邻近桩基产生不利影响。深厚软土地基中,真空预压边界效应对邻近桩基的影响机理及相应的保护措施仍主要依靠工程经验。鉴于此,依托浙江省乐清市南岳镇湾港区某真空预压地基处理工程,基于PLAXIS 3D流固耦合模式研究了深厚软土地基真空预压边界效应引起的土体位移、桩基位移与内力、隔离桩保护效果及桩基优化保护方案。研究结果表明:真空预压边界处的土体水平位移影响范围大于土体竖向位移影响范围,土体水平位移是诱发邻近管廊桩弯曲变形的主要原因,土体水平位移最大值出现在地表真空预压边界附近;深厚软土地基中,水泥搅拌桩对既有桩基的保护效果较为有限;在真空预压加固区边界范围进行真空联合堆载的分区处理方案可有效降低边界效应对邻近管廊桩产生的不利影响。研究结果可为评估真空预压边界效应的影响提供重要参考。
The boundary of the vacuum preloading reinforcement area is predominantly open,resulting in an inevitable soil displacement around the reinforced zone during vacuum preloading.This displacement adversely impacts the adjacent pile foundation.The influence mechanism of vacuum preloading boundary effect on the adjacent pile foundation and the corresponding protection schemes in deep soft soil foundation stil mainly depend on the engineering experience.In light of this,a vacuum preloading foundation treatment project in Wangang District,Nanyue Town,Yueqing City,Zhejiang Province,was analyzed by PLAXIS 3D fluid-solid coupling model.Soil displacement,pile displacement,and the internal force induced by the vacuum preloading boundary effect in deep soft soil foundation,were studied together with the protective impact of isolation piles.Then the protective schemes for piles was optimized.The results demonstrate that the range of influence of soil horizontal displacement at the vacuum preloading boundary is greater than that of soil vertical displacement.Soil horizontal displacement is the primary factor inducing the bending deformation of adjacent pipe gallery piles.The maximum value of soil horizontal displacement occurs near the surface boundary of vacuum preloading.In deep soft soil foundation,the protective effect of cement-mixed piles on existing pile foundations is constrained.The partition treatment approach involving vacum-surcharge preloading within the boundary range of the vacuum preloading reinforcement area can effectively mitigate the adverse impact of boundary effects on adjacent pipe gallery piles.The research findings offer significant insights for evaluating the impact of the vacuum preloading boundary effect.
作者
孙逸玮
SUN Yi-wei(Shanghai Geoharbour Construction Group Co.,Ltd,Shanghai 200434,China)
出处
《地基处理》
2024年第1期70-76,共7页
Journal of Ground Improvement
基金
国家自然科学基金(52078060)。
关键词
深厚软土
真空预压
边界效应
土体位移
邻近桩基
数值模拟
deep soft soil
vacuum preloading
boundary effect
soil displacement
adjacent pile foundation
numerical simulation
作者简介
孙逸玮(1997-),男,上海人,硕士,助理工程师,主要从事软土地基处理的研究工作。E-mail:sunyiwei@geoharbour.com。
