摘要
采用实测统计和数值模拟方法,对北京地铁区间暗挖隧道开挖后不同埋深下的地层应力、塑性区分布及地层变形3个方面进行分析研究.结果表明:1)隧道开挖后洞周切向应力升高区随埋深增大而向围岩深部转移,埋深达到20m后,应力升高区的转移减缓;2)随埋深的增大,洞周塑性区与地表塑性区由完全贯通变为逐渐分离,地表塑性区的范围逐渐减小,但洞周塑性区的范围变化不大,而塑性区以外的弹性区范围增大;3)埋深达到12 m时,地中沉降曲线出现拐点,拐点与洞顶的距离随埋深的增大而增大,埋深达到20m后,曲线拐点基本稳定在洞顶上方10 m处;4)计算结果与实测统计规律基本一致,最大地表沉降值随着埋深的增大而减小,但减小的幅度随着埋深的增大而逐渐减小.
The rules of stress redistribution and plastic zone distribution and ground deformation caused by undercutting subway tunnel under different overburden depths are studied by investigation and numerical simulation methods.Comparative statistical results and calculation results are as follows.1） Along with the increase of depth,the area of tangential stress of surrounding rock around tunnel increased transfers to deeper surrounding rock after the tunnel excavation. When depth of tunnel is or bigger than 20 m,the transfer of stress increased zone becomes mitigation.2）When depth of tunnel is smaller,the plastic zone around tunnel and near the surface completely link together.Along with the increase of depth,the two parts of the plastic zone are separated gradually.When the plastic zone near the surface decreases,the range of elastic region outside the plastic zone increases.3）When depth of tunnel is 12 m,the settlement curve will produce inflection point,and position of the inflection point increases with the increase of depth.When depth of tunnel is 20 m,position of the inflection point basically locates in 10m above the tunnel.4）The results of calculation are consistent with the statistical regularity.The maximum surface settlement values decrease with the increase of tunnel depth,and the degree of decrease slows down as the soil thickness increases.
出处
《北京交通大学学报》
CAS
CSCD
北大核心
2013年第1期27-33,共7页
JOURNAL OF BEIJING JIAOTONG UNIVERSITY
基金
国家“973”计划项目资助(2010CB732102)
国家自然科学基金资助项目(51008015)
北京市自然科学基金资助项目(8122034)
关键词
地铁隧道
埋深
地层应力
塑性区
地层变形
subway tunnel
overburden depth
surrounding rock stress
plastic zone
ground deformation
