摘要
为揭示盾构掘进参数对既有铁路路基沉降的影响规律,本文依托北京地铁16号线丰益桥南站至丰台站双线盾构隧道下穿既有铁路线路工程进行案例分析.将盾构掘进过程分为盾构穿越前、盾构穿越中和盾构穿越后三个阶段.实测数据表明,路基沉降在盾构穿越前逐渐增大,在盾构穿越过程中急剧增大,在盾构穿越后趋于稳定.将盾构管片及时封闭成环,施作补偿注浆、二次注浆,有利于控制路基沉降.此外,盾构掘进参数对控制路基沉降具有至关重要的作用.研究结果表明:盾构掘进速度越快引起的路基沉降越大,继而引起较大的土仓压力,并伴随刀盘扭矩和盾构总推力的骤减;由于盾构过程中出土量易于控制,因此其对路基沉降影响不大;然而,如果同步注浆量控制不当,将导致既有路基向上隆起.本研究为盾构开挖下穿多条既有铁路线路引起的路基变形控制以及盾构掘进参数设置提供参考和指导.
Abstract
This paper presents a case study on the subgrade settlements of four national railway lines induced by twin shield tunnel excavations.The development characteristics of subgrade settlements can be divided into three stages.The monitoring data indicate that subgrade settlements increase gradually before the shield machine crossing the monitoring region,then increase sharply during the shield machine crossing,and finally approach to be stable after the shield machine crossing.Immediately splicing the segments into rings,implementing the compensation and secondary grouting facilitate the control of subgrade settlements.Operational parameters play a crucial role in controlling the subgrade settlements.The effects of the operational parameters of the shield machine on the subgrade settlements are analyzed.The investigation reveals that excessive shield driving velocity causes large subgrade settlements,accompanied by the sudden reduction of rotation torque and total thrust.The excavated earth volume affects the subgrade settlements insensitively because of its easily controlling.Synchronous grouting volume can rise the existing subgrade if not controlled appropriately.Great subgrade settlements cause large earth pressures to be exerted at the chamber.Some valuable references and guidance are given through this paper for the operational parameter setting of shield machines and deformation control of multiple railway lines due to the shield tunnel excavation beneath.
基金项目
National Natural Science Foundation of China(52108363)
Postdoctoral Research Foundation of China(2021M700654)
Postdoctoral Research Foundation of China(2023T160074)
Key Laboratory of Urban Underground Engineering of Ministry of Education,China(TUL2022-01)
Liaoning Revitalization Talents Program,China(XLYC1905015)
key Project of Liaoning Education Department,China(LJKZZ20220003)
NETL
NSTL
万方数据