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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 important influence on the deformation and safety of nearby buildings. In this paper, the three-dimensional finite element model of foundation pit-building is established, and the influence of excavation on the foundation of shallow foundation frame under the condition of different angles with foundation pit is analyzed. The inclination, horizontal displacement, Internal force and main tensile strain distribution characteristics of the frame. The results show that when the angle between the building and foundation pit forms, the wall will incline and horizontal and vertical horizontal displacements will be produced. When α = 90 ° and the building structure is located just above the lowest point of the settlement trench outside the pit, the vertical wall tilt is the largest. When α = 30 °, the horizontal wall inclination is the most significant. The horizontal displacement of horizontal and vertical walls occurs at α = 30 ° and D = 5 m. As the building gradually moves away from the excavated surface of the foundation pit, the relative deflection of the longitudinal wall of the façade of the building will be gradually reduced from the lower The concave deformation mode transforms into “∽” deformation mode and convex deformation mode, meanwhile, the building will gradually turn from clockwise rotation to clockwise clockwise deformation. Beam and column bending moment values on the side near the foundation pit of the frame are large, and the bending moment at the beam end is the largest when α = 90 °. In addition, larger single deformations or smaller composite deformations may result in larger principal tensile strains of the longitudinal walls, thereby reducing the structural reliability of the building.