【摘要】 建立掘进机与土体间的摩擦力、后续管道与土体间的摩擦力、开挖面前顶管推力、土体损失四个因素下竖向顶管法施工的力学模型.前三个因素引起的土体变形解根据弹性力学Mindlin解得到;土体损失引起的土体变形解通过随机介质理论得到,最后二者相加获得多因素下总的土体变形理论解.通过算例对计算结果进行了分析,研究了开挖面前顶管推力的改变对土体变形的影响。研究结果表明,土体竖向位移的最大值随z的增大基本呈减小趋势;竖向顶管施工引起土体隆起的范围在距顶管横截面中心线D～10D之间,土体隆起值随着深度的增加而增加;水平位移的最大值出现在距竖向顶管横截面中垂线2.5D处;开挖面前顶管推力对竖向位移的影响范围主要在距顶管横截面中心线±2.5D之间,在影响范围内,其引起的竖向位移随开挖面前顶管推力的增加而逐渐增大;在0<z<0.5D时,开挖面前顶管推力引起的水平位移主要表现为较小的朝向竖向顶管的移动;在0.5D<z<4D时,主要表现为远离竖向顶管的移动,且随着深度增加,水平位移越大。因此,在竖向顶管施工时,需重点关注±2.5D范围内的竖向位移以及0.5D<z<4D范围内的水平位移。更多还原

【Abstract】 Under the influence of four factors(friction force between soil and roadheader, friction force between soil and subsequent pipes, the thrust of the pipe in front of the excavation and soil loss), the mechanical model of construction of vertical pipe jacking method is built. Baseed on the Mindlin solutions in elastic mechanics, soil deformation caused by the first three factors are calculated. In addition, soil deformation caused by soil loss can be calculated according to stochastic medium theory. By superposing soil deformation of these two parts, the theoretical solution of total soil deformation under multiple factors can be calculated. The results are analyzed through an example, the influence of the change of frontal thrust in front of the excavation on soil deformation are studied. The results show that the maximum value of soil vertical displacement decreases with the increase of z. The range of the soil uplift zone caused by vertical pipe jacking construction is between D and 10 D from the centerline of the vertical pipe jacking cross section, the value of soil uplift increases with the increase of the depth. The maximum value of horizontal displacement appears at 2.5 D from the vertical line of the vertical pipe jacking cross section. In terms of the thrust of the pipe in front of the excavation, the influence range on the vertical displacement is mainly from-2.5 D to 2.5 D from the centerline line of the cross section. The vertical displacement caused by it increased with the thrust of the pipe in front of the excavation. The horizontal displacement caused by the thrust of the pipe in front of the excavation is mainly moves towards the vertical pipes when z is between 0 and 0.5 D and the value is low. However, when z is between 0.5 D and 4 D, it moves away from the vertical pipes and increases with the depth. Therefore,in the vertical pipe jacking construction, it is necessary to Concentrate more on the vertical displacement when it is±2.5 D from the vertical line of the cross section and the horizontal displacement when 0.5 D<z<4 D.更多还原