Research of Reinforcement System of Pile When Shield Tunneling Passes Through Existing Line
李润轩Ll Run-xuan
（中铁第一勘察设计院集团有限公司城轨院,西安710043 )
( China Railway First Survey and Design Institute Group Co.,Ltd.,Xian 710043,China )
摘要:在远期规划线下穿既有线的案例逐渐增多的背景下,既有线变形控制措施成为当下研究热点,本文提出一种素混凝土桩加固体系,以成都地铁5号线上下交叠隧道为工程实例,通过Midas CGTS有限元软件建立三维模型对比分析地铁隧道在采取素混凝土桩加固体系前后施工对既有隧道结构的变形特征,结合现场数据,明确地表沉降和既有隧道沉降的影响规律,验证了数值建模方法的可靠性。研究表明:素混凝土桩辅以袖阀管注浆的组合加固后上覆既有结构的变形从沉降普遍变为隆起,且隆起值符合控制标准;既有隧道竖向位移.水平位移峰值及地表沉降在加固后分别减小100%(隆起减小67.22%)、74.07%.80.48%,加固效果显著，现场数据表明,地表沉降和既有隧道拱顶沉降在下穿过程中急剧增大,采用素桩加固体系后明显减小,对比数值模拟结果,两者吻合程度较好，地表沉降和拱顶沉降的误差分别为21.4%和33.9%。本研究可为类似工程施工提供指导。
Abstract: Under the background of the increasing number of cases of crossing the existing line under the long-term planning, thedeformation control measures of the existing line have become the current research focus. In this paper, a plain concrete pile reinforcementsystem was proposed. Taking the overlapping tunnel of Chengrdu Metro Line 5 as an example, the deformation characteristics of the existingtunnel structure before and after the constnuction of the plain concrete pile reinforcement system were compared and analyzed by building3D modlels through the Midas CTS finie element software.Combined with the site data, the inluence nules of surface setlement andexisting tunnel settlement are clarifiedl, and the reliability of the numerical moleling method was verified. The research shows that thedeformation of the overlying existing structure changes from settlement to uplit after the combination of plain concrete pile and sleeve valvepipe grouting. and the uplif value meels the control standanl;The vertical displacement，horizontal displacenent peak and surfacesettlement of the existing tunnel are reduced by 100%(the uplif is reduced by 67.22%)，74.07% and 80.48% respectively afferreinforcement, and the reinforcement effect is significant. The field data shows that the suface settlement and the setlenent of the existngtunnel vault increase sharply during the underpass process, and decrease significantly after the adoption of the plain pile reinforcementsystem.Compared with the numerical sinmulation results, the two are in good agreement, and the erros of suface settlement and vaultsettlement are 21.4% and 33.9% respectively. 'This study can provide guidance for the construction of similar projects.
关键词:地下工程;素混凝土加固桩;盾构下穿;地基加固;数值分析
Key words: underground engineering; plain concrete reinforced pile; shield underpass;foundation reinforcement; numerical analysis
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