【作者】 杨志文；

【导师】 李文博； 张旭；

【作者基本信息】 内蒙古科技大学 ， 土木工程（专业学位）， 2025， 硕士

【摘要】 叠落盾构隧道施工中新建隧道开挖易导致既有隧道管片出现开裂、错位、沉降与隆起等状况,因此对于既有隧道的保护措施尤为关键。本文基于北京地铁清河小营桥站至清河站叠落盾构隧道工程,针对现场应用的新型模块化钢支撑加固措施,采用现场监测和数值模拟方法,研究了其对既有隧道的加固效果和其本身的受力特征,还深入分析了不同因素对其加固效果的影响。主要研究内容和结论如下:(1)基于对现场监测数据的分析,得到了既有隧道的变形和模块化钢支撑应力规律。结果显示,新建上行隧道施工会造成既有下行隧道管片上浮。现场采用加固方案后,既有隧道拱顶竖向变形最大值为4.24 mm。模块化钢支撑的四个竖撑位置的测点均呈现拉应力,且左侧竖撑应力值大于右侧,最大拉应力达到5.78 MPa。各监测数据均未超出控制标准值,说明了模块化钢支撑加固方案在现场实施的可行性。(2)基于对依托工程的三维精细化数值模拟计算,明确了模块化钢支撑的控制变形效果和其受力特征。结果显示,模块化钢支撑使得既有隧道的拱顶竖向变形和水平收敛变形最大值分别降低了23.6%和82.8%。模块化钢支撑的拉应力集中在竖撑,压应力集中在环撑和横撑部位,三根纵撑承受的应力较小。钢支撑的应力变化范围主要集中在监测管片的前后10环位置附近,为其现场的循环布置提供参考。(3)通过研究钢支撑结构形式对模块化钢支撑加固效果的影响得出,原设计方案使用控制变形效果更好,整体受力更加均匀,但材料成本更高且通行受限,施工现场应综合考虑,选择合适的支撑形式。随着钢支撑模块由仅环撑逐渐增加至全支撑,其对既有隧道的控制变形能力也逐渐增强,其中,竖撑能显著减小环撑上的拉应力,从而抑制竖向隆起变形,横撑则分担了环撑所承受的压应力,增强了支撑体系的整体性的同时提升了整个体系的抗压能力。(4)通过研究隧道设计参数和盾构掘进参数对模块化钢支撑加固效果的影响得出,既有隧道竖向变形受新建隧道与既有隧道平面夹角变化的影响十分显著。经分析,新建隧道上穿既有隧道施工场景下,钢支撑对既有隧道的控制变形效果较其他位置情况下更为突出。其中,两隧道竖向间距越大,既有隧道的变形和支撑应力也会越小。另外,增大土仓压力和注浆压力有助于抑制管片隆起变形。更多还原

【Abstract】 The excavation of new tunnels in the construction of stacked shield tunnels can easily lead to cracking,dislocation,settlement and uplift of existing tunnel segments,so the protection measures for existing tunnels are particularly critical.Based on the stacked shield tunnel project from Qinghe Xiaoyingqiao Station to Qinghe Station of Beijing Metro,this paper uses on-site monitoring and numerical simulation methods to study the reinforcement effect of the new modular steel support reinforcement measures applied in the field,and also analyzes the influence of different factors on the reinforcement effect.The main research contents and conclusions are as follows:(1)Based on the analysis of the field monitoring data,the deformation of the existing tunnel and the stress law of the modular steel supports are obtained.The results show that the construction of the new upward tunnel will cause the uplift of the existing downward tunnel segments.After the reinforcement scheme is adopted on site,the maximum vertical deformation of the existing tunnel vault is 4.24 mm.The measuring points of the four vertical bracing positions of the modular steel supports all show tensile stress,and the stress value of the left vertical bracing is greater than that of the right side,and the maximum tensile stress reaches 5.78 MPa.The monitoring data did not exceed the control standard value,indicating the feasibility of the modular steel supports reinforcement scheme in the field.(2)Based on the three-dimensional refined numerical simulation calculation of the supporting project,the control deformation effect and stress characteristics of the modular steel supports are clarified.The results show that the modular steel supports reduces the maximum vertical deformation and horizontal convergence deformation of the vault of the existing tunnel by 23.6%and 82.8%respectively.The tensile stress of the modular steel supports is concentrated in the vertical supports,the compressive stress is concentrated in the ring support and the transverse support,and the stress of the three longitudinal supports is small.The stress variation range of the steel supports is mainly concentrated near the front and rear 10 rings of the monitoring segment,which provides a reference for the on-site cyclic arrangement.(3)By studying the influence of steel supports structure on the reinforcement effect of modular steel supports,it is concluded that the original design scheme has better control deformation effect and more uniform overall force,but the material cost is higher and the traffic is limited.The construction site should be considered comprehensively and the appropriate supports form should be selected.As the steel supports module gradually increases from only the ring support to the full supports,its ability to control the deformation of the existing tunnel is also gradually enhanced.Among them,the vertical support can significantly reduce the tensile stress on the ring support,thereby suppressing the vertical uplift deformation.The horizontal support shares the compressive stress borne by the ring support,enhances the integrity of the supports system and improves the compressive capacity of the entire system.(4)By studying the influence of tunnel design parameters and shield tunneling parameters on the reinforcement effect of modular steel supports,it is concluded that the vertical deformation of existing tunnel is significantly affected by the change of plane angle between new tunnel and existing tunnel.After analysis,the control deformation effect of steel supports on the existing tunnel is more prominent than that in other positions under the construction scenario of the new tunnel crossing the existing tunnel.Among them,the larger the vertical spacing between the two tunnels,the smaller the deformation and supports stress of the existing tunnel.In addition,increasing the soil pressure and grouting pressure is helpful to restrain the uplift deformation of the segment.更多还原