分层地基中隧道开挖对土体沉降及衬砌内力影响  

The settlement of ground and structure force due to tunneling in layered soils

作　　者：董渝 熊威 Dong Yu;Xiong Wei(Changjiang Survey,Planning,Design and Research Co.,Ltd.,Wuhan Hubei 430000,China)

机构地区：[1]长江勘测规划设计研究有限责任公司,湖北武汉430000

出　　处：《山西建筑》2024年第21期155-158,共4页Shanxi Architecture

摘　　要：由于地质条件的多样性,一些隧道常常修建在上下层土体性质差异较大的复杂地层中。多层地基中新建隧道引起的地层变形及结构内力比在均质地层中更加复杂。文章通过系列数值模拟,研究分析上下土层不同模量比和不同厚度条件下,新建隧道开挖引起的土体位移场及隧道衬砌附加应力。研究发现:随着上下层土体模量比的增加,隧道顶部的沉降逐渐减小,地层中土体变形影响范围逐渐增大,说明上硬下软地层中隧道施工对既有结构影响范围会相对增大。在拖拽作用和刚度变化的相互作用下,隧道表面沉降并非随着刚度比单调变化。衬砌上内力随着上层土体的模量增大分布变得均匀;相同模量比条件下,衬砌轴力随着软弱层深度的增大而增大。因此,在上软下硬地基中隧道施工时,尤其是软弱层埋深较大的情况,衬砌产生局部破坏的风险增高。Due to the diversity of engineering geology,many new tunnels are constructed in layered ground with the variation of soil properties.The settlement behavior of ground and the structure force of lining may significantly differ from those due to excavating in homogenous soil.In this paper,a series of numerical simulation were carried out to investigate the variation of settlement of soils and structure force of lining.The difference of modulus between upper soil and down soil,and the thickness of upper soil are particular of interest.The results indicated that,the larger the ratio of modulus of upper soil to that of down soil,the greater the settlement at the top of tunnel’s outline,and the wider the influence in ground due to tunneling.Therefore,for the cases of upper soil stiffer,tunneling will have more influence on existing structures in soils.The settlement at the surface does not change monotonically with the variation of the ratio,because of the confined effects of drag and stiffness change.With the increase of the ratio,the structure force becomes more homogenous.At same ratio,the more thickness of upper soil,the greater the axial force.Therefore,for the cases of upper soil softer,the risk of local damage of lining becomes higher,in particular when the soft soil is thicker.

关 键 词：分层地基 新建隧道 模量比 地层变形 衬砌内力 

分 类 号：TU997[建筑科学—市政工程] U452.11[建筑科学—桥梁与隧道工程]