基于主动式纠偏的曲线顶管施工力学特性研究

Research on the Mechanical Characteristics of Curved Pipe Jacking Construction Based on Active Deviation Correction

曲线顶管施工技术在市政管线工程中得到越来越广泛的应用。在分析曲线顶管施工机理的基础上,提出并对比分析了3种管节纠偏方案,进而结合主动式纠偏方案的施工特点,对三维曲线顶管施工过程中管土间挤压作用力进行计算分析,并推导了管节顶进摩阻力计算公式,其后对管线平面夹角、管线半径及管径大小3个摩阻力影响因素进行单因素分析。考虑管外注浆对管土接触状态的影响,进而引入土压力作用系数对顶进摩阻力计算公式进行修正,并通过对比分析顶进摩阻力的现场实测值、规范建议值及公式计算值,给出了土压力作用系数的建议取值范围。研究表明:主动式纠偏方案在管节姿态调整、施工扰动控制及管身衬砌受力等方面优于其他两种纠偏方案;顶管施工过程中管土间的挤压作用力呈三维复杂状态,不能进行简单的叠加;管线平面夹角对管节转动摩阻力有显著影响,管线半径对侧向顶推摩阻力和管节转动摩阻力均有一定的影响,而管径大小则主要影响地层土压力摩阻力的数值;管土接触状态是真实存在的,其土压力作用系数的取值范围大致在0.2~0.6之间。

Curved pipe jacking construction technology is increasingly used in municipal pipeline engineering.Based on the analysis of the construction mechanism of curved pipe jacking construction,three kinds of pipe correction programs were proposed and compared. Combined with the construction characteristics of active deviation correction program,the compression force between pipe and soil during the construction process of the threedimensional curve pipe jacking was calculated and analyzed. The calculation formula of the jacking friction resistance during the pipe jacking process was deduced. Three friction resistance influencing factors,including the pipeline plane angle,pipeline radius and pipe diameter,were analyzed. Considering the effect of grouting outside the pipe on the contact state between the pipe and soil,the earth pressure effect coefficient was introduced to modify the jacking friction resistance formula. By comparing and analyzing the field measured values of the jacking friction resistance,the standard recommended value and the formula calculated value,the proposed value range of the soli pressure action coefficient was given. The research results showed that the active deviation correction scheme was superior to the other two deviation correction schemes in terms of pipe joint attitude adjustment,construction disturbance control and pipe lining stress level. The pressing force between pipe and soil was a three-dimensional complex state during pipe jacking construction,which cannot be superimposed. The angle of the pipeline plane had a significant influence on the rotational friction of the pipe joint. The radius of the pipeline had a certain influence on the lateral thrust friction and the rotational friction of the pipe joint,while the pipe diameter mainly affected the value of the friction caused by ground. The contact state of the pipe and soil is real,and the range of the soil pressure action coefficient was roughly between 0.2 and 0.6.