马蹄形盾构机研制关键技术及工程应用

Key Technology and Engineering Application of Horseshoe-Shaped Shield Machine

为提高马蹄形隧道机械化施工水平,以蒙华铁路白城隧道项目为依托,研制马蹄形盾构机。其关键技术包括:提出低扰动多刀盘、多驱动协同开挖技术,推导小刀盘扭矩系数计算公式;研究马蹄形管片分块方式,设计1种多自由度变曲率管片拼装机,解决变曲率、大重量管片的拼装难题;研究双螺旋输送机联合出渣技术,基于Fluent仿真分析对开挖面进行流场仿真,通过压力监控及反馈实现双螺旋输送机土仓压力实时控制;设计梭式盾体结构,给出无铰接盾构机最小转弯半径计算方法,并提出相应的纠滚措施。研制的盾构机在施工过程中掘进性能良好,能满足安全、快速、环保施工的要求。针对出现的排渣不畅问题,提出利用高压水射流技术对渣土进行切割冲刷,在螺旋输送机上部设置2个推土器装置;而对出现的顶推力过大问题,则采取增大下部3个刀盘的直径等改造措施。改造后的马蹄形盾构机在蒙华铁路白城隧道的成功应用,使得马蹄形隧道使用盾构法施工成为现实。

Based on the project of Baicheng Tunnel of Menghua Railway,a horseshoe-shaped shield machine is developed to improve the mechanized construction level of horseshoe-shaped tunnel.Its key technologies include:low disturbance multi-cutterhead,multi-drive collaborative excavation technology and the calculation formula for the torque coefficient of small cutterhead.The partition method of horseshoe-shaped segments is studied and a segment erector with multiple degrees of freedom variable curvature is designed to solve the erection problem of variable curvature and heavy segments.The flow field simulation is carried out on the excavation face based on Fluent simulation analysis to study the combined muck removal technology of twin-screw conveyor,and the real-time control of the excavation chamber is achieved through pressure monitoring and feedback.The shuttle type shield structure is designed.The calculation method for the minimum turning radius of shield machine without articulation is given and the corresponding measures for rolling correction are proposed.The developed shield machine performs well in the construction process,which can meet the requirements of safety,rapidness and environmental protection construction.In view of the problems occurred in muck removal,high pressure water jet technology is proposed to cut and scour the muck.Two muck pushing devices are installed on the upper part of the screw conveyor.For the problem of excessive thrust,the modification measures to increase the diameter of the lower three cutterheads are adopted.The successful application of the modified horseshoeshaped shield machine in the Baicheng tunnel of Menghua Railway makes the construction of horseshoeshaped tunnel using shield method a reality.