摘要
深基坑开挖对邻近建筑物的变形和安全有着重要影响。本文通过建立基坑—建筑物三维有限元数值模型,分析了与基坑边成不同角度条件下的浅基础框架建筑受基坑开挖影响,重点研究了建筑物墙体倾斜值、水平位移、框架内力和主拉应变分布特点。结果表明:当建筑物与基坑边形成夹角时,墙体将发生倾斜,同时产生平行于基坑横、纵向的水平位移。当α=90°并且建筑结构位于坑外地层沉降槽最低点正上方时,纵墙倾斜最大。当α=30°时,橫墙倾斜最为显著,横、纵墙的水平位移峰值均发生在α=30°且D=5 m处。随着建筑物逐渐远离基坑开挖面,除α=30°所对应正立面纵墙相对挠曲呈明显下凹变形形态以外,建筑物正立面纵墙相对挠曲形态将逐步由下凹变形形态转变为"∽"变形形态和上凸变形形态,同时建筑物将逐步由逆时针扭转变形过渡为顺时针扭转变形。框架邻近基坑一侧的梁、柱弯矩值均较大,且α=90°时,梁端弯矩最大。此外,较大的单一变形作用或较小的复合变形作用均可能导致纵墙产生较大值的主拉应变,从而降低建筑物结构的可靠性。
Deep foundation pit excavation has an important impact on the deformation and safety of its adjacent buildings. Considering arbitrary angles between the building and foundation pit,the deformation behavior of frame buildings with shallow foundation induced by foundation pit excavation is analyzed by establishing a 3D finite element model. It focuses on the distribution rules for the tilt and horizontal displacement of the walls,the internal force of the framework and tensile strain of longitudinal walls. The results show that when the distance and angles between the building and deep foundation pit are different, walls will have tilt and transverse and longitudinal horizontal displacement. When the α = 90° and the building is located over the lowest point of the settlement trough,the tilt of longitudinal walls is the largest. When the building is not perpendicular to the pit,the largest tilt of cross walls can be observed when the building was located on α = 30°,the maximum horizontal displacement of longitudinal and lateral walls can be observed when the building was located on D = 5 m and α = 30°. When the relative distance between the building and the excavation is increasing,the sagging deformation,is in '∽'form and hogging deformation will occur except the building was located on α = 30°. At the same time,the longitudinal walls will have torsion deformation from counterclockwise to clockwise. Bending moment values of beam and column close to foundation pits were larger,and the beam bending moment are the largest when the building was located on α = 90°. In addition,a larger main tensile strain of longitudinal walls will occur by the larger single deformation or the smaller complex deformation. It will endanger the structural safety of buildings.
出处
《地下空间与工程学报》
CSCD
北大核心
2015年第S2期617-628,共12页
Chinese Journal of Underground Space and Engineering
基金
上海自然科学基金(15ZR1429400)
山区桥梁与隧道工程国家重点实验室培育基地基金(CQSLBF-Y15-1)
关键词
基坑工程
浅基础框架建筑物
墙体倾斜
角度
纵墙主拉应变
框架弯矩
foundation pit engineering
frame building with shallow foundation
tilt of walls
angle
tensile strain of longitudinal wall
internal force of framework
