曲线顶管施工引起的地表变形预测研究

为了研究曲线顶管施工引起的地表变形,通过分析拱北隧道管幕工程曲线顶管现场实测数据,得出曲线顶管地表沉降槽的偏移曲线;在现有Peck和Loganathan地表变形计算公式的基础上,考虑曲线顶管与隧洞的相对位置对沉降槽偏移量的影响,得出经过沉降槽偏移修正的Peck和Loganathan地表变形预测公式。结果表明:1)曲线顶管施工引起的地表沉降槽曲线表现为非对称,最大沉降点可能出现在轨迹弯曲内侧,也可能偏向外侧;2)曲线顶管与隧洞相对位置引起的土体损失变化是造成沉降槽偏移的主要原因,相对位置与顶管穿越地层性质、顶进力、注浆压力和轨迹曲率半径等因素有关;3)修正的Peck公式可以较好地反映砂层和淤泥质土层中曲线顶管施工地面沉降槽偏移效应和最大沉降量。

Prediction of Ground Deformation Induced by Curved Pipe Jacking

The field deformation data monitored in curved pipe jacking of Gongbei Tunnel are analyzed; and the deviation curve of the ground settlement groove is obtained. And then ground settlement prediction formulas of Peck and Loganathan modified by deviation of ground settlement groove are obtained based on existing Peck and Loganathant formulas considering influence of relative position of curved pipe jacking and tunnel on deviation of ground settlement groove. The results show that: 1）The pipe jacking induced ground settlement groove curve shows asymmetry; and the maximum settlement point would occur to inside/outside of the curve. 2）The deviation of ground settlement groove mainly lies on soil loss induced by relative position of curved pipe jacking and tunnel; and the relative position of curved pipe jacking and tunnel can be affected by ground properties, jacking force, grouting pressure and curvature radius. 3） The modified Peck formula can well reflect the deviation of ground settlement groove and maximum settlement during pipe jacking in sandy stratum and silt soil stratum.