多因素下大断面矩形顶管施工对地层竖向变形影响研究

为对大断面矩形顶管施工过程中引起的地表沉降进行准确预测和有效控制，依托苏州市城北路综合管廊矩形顶管项目，基于力学理论、实测数据与数值计算等分析方法对多因素下施工引起的地层竖向变形进行研究。基于弹性力学的 Mindlin解和随机介质理论，探究管周土体变形模式，推导顶管正面附加应力、侧面摩阻力、地层损失、注浆填充等引起的地层竖向变形计算公式，结合现场实测数据发现该计算方法基本符合地表变形规律；进一步利用Matlab数值分析各个因素对地层竖向变形的影响，探究大断面矩形顶管顶进时地层竖向变形的一般性规律。研究结果表明： 理论推导的地层竖向变形解析式基本符合现场实际规律，地层损失对地表土体沉降的影响程度最大，顶管机头与周围土体的摩阻力影响次之，注浆会对地表产生一定抬升效果。

Study on Influence of Large Cross section Rectangular PipeJacking Construction on Vertical Deformation of Strata under Multiple Factors

The accurate prediction and effective control of the surface settlement caused by the construction of large cross section rectangular pipe jacking are of great significance. As a result, the vertical deformation of strata caused by construction of rectangular pipe jacking project of utility tunnel of Chengbei Road in Suzhou under multiple factors is studied based on analysis methods such as mechanical theory, measured data and numerical calculations. Based on the Mindlin solution and stochastic medium theory of elastic mechanics, the soil deformation mode around the pipe is explored, and the calculation formula of vertical strata deformation caused by additional stress on the front of pipe jacking, lateral friction, formation loss, and grouting filling is deduced. The field measured data show that the calculation method is feasible. Furthermore, the Matlab is used to numerically analyze the influence of various factors on the vertical deformation of strata, and explore the general law of vertical deformation of strata when the large cross section rectangular pipe is jacking. The results show that: (1) The theoretically deduced analytical formula for vertical deformation of strata basically conforms to the actual law on site. (2) The influence of formation loss on surface soil settlement is the largest, followed by that of friction between pipe jacking head and surrounding soil. (3) Grouting can have a lifting effect on the surface.