摘要
为探究富水砂土地层盾构隧道开挖面支护压力与地层变形特征的关系,通过自主研发的离心模型试验系统,依托武汉地铁8号线大盾构越江隧道工程,研究了不同埋深情况下的开挖面支护压力对开挖面稳定及地层变形特征的影响,得到了开挖面支护压力与地表变形之间的关系曲线。研究结果显示:(1)当隧道埋深较浅(<1.5D,D为盾构直径)时,支护压力对地表变形的大小及扰动范围的影响均随着埋深的增加而减小;当隧道埋深较深(>1.5D)时,不管支护压力过小还是过大,开挖面支护压力对地层变形的影响很难延伸到地表。(2)当支护压力过大时,对地层的扰动呈现为鱼尾型,主要可分为挤密区、顶隆区、顶沉区以及沉降区,其中地表距离开挖面约1D范围内为沉降区,1D~2D范围内为隆起区。(3)当支护压力过小时,对地层的扰动主要为沉降,影响范围为开挖面前方1D左右,且随着埋深的减小,影响范围会增大。该研究通过离心模型试验得到了不同埋深条件下基于变形控制的支护压力设定范围的建议值,旨在为实际工程中支护压力的控制提供指导。
In this study a centrifugal model test system was developed to explore the relationship between the face support pressure and ground deformation characteristics of shield tunnel in water rich sandy soil. Based on Wuhan Metro Line 8 large shield tunnel project, the influence of face support pressure on the face stability and ground deformation characteristics under different buried depths was investigated. The correlation curve between excavation face support pressure and surface deformation was obtained and the results show that: 1) When the cover of tunnel is shallow(<1.5D, where D is shield diameter), the influence of support pressure on surface deformation decreases with the increase of tunnel depth;when the tunnel is deep(>1.5D), no matter the support pressure is too small or too large, the influence of the excavation face support pressure on the ground deformation is difficult to extend to the surface. 2) When the support pressure is too high, the disturbance to the stratum takes on a “fishtail type”, which can be divided into compaction area, uplift area and settlement area induced by the jacking of excavation face as well as the settlement area. The settlement area is within 1D from the surface to the excavation surface, and the uplift area is within 1D-2D. 3) When the support pressure is too small, the main disturbance to the ground is settlement, and the influence range is about 1D in front of the excavation face. Additionally, the influence range will increase as the buried depth decreases. Based on centrifugal model test, the suggestion value of the range of support pressure premised on deformation control for different buried depths is obtained, which aims to provide guidance for the control of support pressure in practical engineering.
作者
罗维平
袁大军
金大龙
陆平
陈健
郭海鹏
LUO Wei-ping;YUAN Da-jun;JIN Da-long;LU Ping;CHEN Jian;GUO Hai-peng(Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;China Railway 14th Bureau Group Co.,Ltd.,Jinan,Shandong 250014,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第S02期345-354,共10页
Rock and Soil Mechanics
基金
国家自然科学基金“高铁联合”基金(No.U1834208)
中央高校基本科研业务费专项资金(No.2020YJS141)。
关键词
富水砂层
盾构开挖面
支护压力
地层变形
离心模型试验
water rich sand strata
shield tunnel face
support pressure
ground deformation
centrifuge model test
作者简介
第一作者:罗维平,女,1994年生,博士研究生,主要从事盾构隧道施工方面的研究工作。E-mail:limpkinweiping@163.com
