摘要
针对浅覆土矩形顶管施工时存在地表隆起过大的风险,应用MIDAS GTS岩土数值软件动态模拟大口径矩形顶管掘进施工过程,探究其在不同覆土厚度、开挖面顶进压力、摩擦阻力下引起的地表隆起规律,并与现场监测数据进行对比分析.结果表明:顶管顶进时地表监测点的隆起规律与数值计算结果基本吻合;顶管开挖面顶进压力、管节与地层的摩阻力引起的地表隆起在开挖面附近叠加达到峰值;地表的隆起峰值随覆土厚度的减小而线性增加,当开挖面顶进压力为100 kPa、管节摩阻力为35 kPa时,顶管覆土厚度每减小0.1H (H为矩形顶管高度),地表隆起峰值增大约6.00 mm;浅覆土顶管地表隆起随顶进压力和管节摩阻力的增长规律可分为缓慢增长阶段和非线性快速增长阶段;为降低浅覆土顶管工程上覆土被顶破的风险,需要合理控制开挖面顶进压力及其波动、在管节外周形成厚度均匀的减摩泥浆套,确保地层稳定和顶管工程的安全.
In view of the risk of excessive surface uplift in rectangular pipe jacking construction under the condition of shallow-buried soil,the finite element software MIDAS GTS was applied to simulate the dynamic process of large-diameter rectangular pipe jacking,and to explore the law of surface uplift caused by different thickness of soil covering,different jacking pressure of excavation face and different friction between pipe joint and soil,and to compare and analyze with the field monitoring data.The results show that the uplifting rule of surface monitoring points during pipe jacking is basically consistent with the numerical calculation results.The surface uplift caused by the jacking pressure on the excavation surface of the pipe jacking and the frictional resistance between the pipe joints and the formation is superimposed to reach a peak value near the excavation surface.As the thickness of the overburden decreases,the peak value of the surface uplift increases linearly.When the jacking pressure of excavation face is 100 kPa and the friction resistance of the pipe joint is 35 kPa,the peak value of surface uplift increases about 6.00 mm when the soil jacking thickness decreases for 0.1H(H is the height of rectangular pipe jacking).The growth law of surface uplift in shallow-buried soil jacking pipe with the increase of jacking pressure and joint friction can be divided into two stages:slow growth stage and nonlinear rapid growth stage.In order to reduce the risk of overburden soil being broken in shallow-buried soil pipe jacking project,it is necessary to take reasonable measures to control the jacking pressure and its fluctuation on the excavation surface,and to form an antifriction slurry sleeve with uniform thickness around the pipe joint,so as to ensure the stability of stratum and the safety of pipe jacking project.
作者
钟小春
何纯豪
李永运
王子仪
陈洁
ZHONG Xiaochun;HE Chunhao;LI Yongyun;WANG Ziyi;CHEN Jie(College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,China;Second Engineering Co.,Ltd.,of CTCE Group,Suzhou 215131,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2023年第3期603-612,共10页
Journal of Southwest Jiaotong University
基金
国家自然科学基金(52178387,51678217)。
关键词
浅覆土
数值模拟
矩形顶管
地表隆起
shallow-buried soil
numerical simulation
rectangular pipe jacking
surface uplift
