摘要
基坑开挖卸荷易引起近接既有隧道的变形,对既有隧道运营安全造成威胁。本文在现有地铁保护的主动和被动控制措施基础上,提出了高压气囊桩地铁保护技术,并采用模型试验和数值模拟方法,研究了不同气囊压力条件下,土体(隧道)的水平位移变化规律,以及气囊排布方式对模型隧道的保护效果,结果表明:随着气囊与隧道之间的距离由1.8m减小到1.3m、0.8m,土体的最大水平位移所处的深度也由-4m变化到-3.5m和-2m,最大水平位移位置逐渐变化到气囊埋深附近;隧道水平位移回零的气囊压力也由约800kPa减小到400kPa,土体(隧道)位移由正变负,本方案中气囊压力800kPa为宜;气囊距隧道越近,保护效果越佳,多排气囊比单排气囊保护效果好,气囊交叉布设比平行布设效果好,综合考虑成本因素,建议采用双排交叉方式,可为工程实践提供参考。
The unloading of foundation pit excavation is easy to cause the increase of adjacent to the exist⁃ing tunnel,which poses a threat to the operation safety of the existing tunnel.On the basis of the existing ac⁃tive and passive control measures of subway protection,this paper puts forward the subway protection tech⁃nology of high pressure airbag pile,and uses the methods of model test and numerical simulation to study the horizontal displacement of soil(tunnel)under different airbag pressure conditions,and the protection effect of airbag arrangement on model tunnel.The results show that as the distance between the airbag and the tunnel decreases from 1.8m to 1.3m and 0.8m,the depth of the maximum horizontal displacement of the soil changes from-4m to-3.5m and-2mm,and the maximum horizontal displacement gradually changes to the buried depth of the airbag.The pressure of airbag returning to zero of horizontal displacement in tunnel is also reduced to 400kPa,and the displacement of soil(tunnel)changes from positive to negative.In this scheme,the pressure of airbag 800kPa is suitable;the closer the airbag is to the tunnel,the better the pro⁃tection effect is,and the protection effect of multi-row airbag is better than that of single-row airbag,and the effect of cross arrangement of airbag is better than that of parallel arrangement.Considering the cost fac⁃tors,it is suggested that double-row crossing mode should be adopted,which can provide reference for en⁃gineering practice.
作者
倪福兴
叶俊能
刘干斌
陆幸
司壹恒
NI Fu-xing;YE Jun-neng;LIU Gan-bin;LU Xing;SI Yi-heng(Institute of Geotechnical Engineering,Ningbo University,Zhejiang Ningbo 315211,China;Ningbo Rail Transit Group Co.,Ltd.,Zhejiang Ningbo 315010,China)
出处
《防灾减灾学报》
2023年第1期53-61,共9页
Journal of Disaster Prevention And Reduction
基金
国家自然科学基金项目(52008214)
宁波市科技计划公益项目(202002N3116)。
关键词
基坑开挖
隧道保护
高压气囊
有限元法
模型试验
foundation pit excavation
tunnel protection
high pressure airbag
finite element method
model test