地铁盾构施工对邻近建筑物桩基的影响研究

在地铁工程建设中,盾构法施工得到推广使用。而当近距离侧穿建筑物的桩基时,盾构推进会对桩基周围土体及桩基产生影响,从而引起地表沉降,危及建筑物的安全。此文以深圳地铁某隧道区间盾构施工近距离侧穿一建筑物桩基为工程背景,选取桩基与隧道间距最小的断面,采用有限元软件,建立数值计算模型,研究盾构推进对桩基周围土体及桩基的影响程度,以及造成的地表沉降。研究结果表明:桩身最大侧向位移出现在隧道轴线位置附近,桩的竖向沉降量沿桩长变化很小,桩身弯矩沿桩身分布,有正弯矩区和负弯矩区,桩身轴力沿桩长逐渐增大,到隧道轴线位置时达到最大值。隧道顶正上方地表沉降最大,为12.6 mm,两侧沉降量逐渐减少,形成一个横向沉降槽。

Research on the Influence of Shield Construction Method Construction on Adjacent Building~ Pile Foundation

During the construction of the subway, shield construction method is widely used. When close side pass through the building pile foundation, shield construction will impact on soil around pile and pile founda tion, which cause the surface subsidence and endanger the safety of the buildings. Taking an interval shield tunnel construction in Shenzhen metro as the engineering background and choosing the minimum cross section of pile foundation and tunnel interval, the influence degree of the soil around pile and pile foundation and the caused surface subsidence are researched through setting up the numerical calculation model and the finite element software. The results show that： Maximum lateral displacement of pile ap pears near the tunnel axis, vertical settlement of pile along the pile length changed little, pile bending moment distributes along the pile body, there is a positive bending and negative bending moment, pile shaft axial force increased gradually along the pile length, the maximum value appears at the tunnel axis position. The surface subsidence above tunnel roof is maximum that is 12.6 mm. Subsidence on both sides is gradually reduced and forms a horizontal sedimentation tank.