摘要
针对地铁隧道盾构进出洞冻结加固工程中,盾构机刀盘无法切割土体中钢制冻结管的难题,提出采用塑料管作为冻结管,以实现直接切割。为获得塑料管冻结时的冻结壁发展规律,采用实体物理模型试验与有限元模型分析相结合的方法进行研究。将模拟计算数据与实体物理模型试验数据进行对比,验证了有限元计算模型的准确性;基于该模型,研究不同因素对冻结壁的影响规律。研究结果表明:PVC(聚氯乙烯)管冻结时的冻结壁发展速度约为钢管冻结时的0.85倍;PVC管冻结时,管径与初始地温对冻结壁发展速度有一定影响,冻结壁发展速度随管径增大而线性增快,随初始地温上升而线性降低;PVC管冻结时,盐水温度对冻结壁发展速度影响较为明显,两者之间近似呈线性关系,盐水温度每降低5℃,冻结壁发展速度增快6.2 mm/d。
Order to solve the problem that the cutter head of shield machine can′t cut the steel freezing pipe in the soil in the freezing reinforcement project of metro tunnel shield entry,it is proposed to use plastic pipe as the freezing pipe to realize direct cutting.To obtain the development law of freezing wall of plastic pipe during freezing,methods of physical model test and finite element model analysis are combined.The accuracy of finite element calculation model is verified by comparing data between numerical calculation results and model test results.Based on the model,the law of different factors influencing frozen wall is analyzed.Results show that:the development speed of freezing wall of PVC pipe is about 0.85 of that of steel pipe;when the PVC pipe is freezing,pipe diameter and initial ground temperature have certain impact on the freezing development speed,and the development speed of the freezing wall increases linearly with the increase of pipe diameter while decreases linearly with the increase of initial ground temperature;when the PVC pipe is freezing,saltwater temperature has evident impact on the development speed of freezing wall,demonstrating an approximate linear relationship.For every lowering 5℃of saltwater temperature,frozen wall development speed increases by 6.2 mm/d.
作者
丁航
李方政
崔兵兵
DING Hang;LI Fangzheng;CUI Bingbing(Branch Institute of Mine Construction,CCRI,100013,Beijing,China;不详)
出处
《城市轨道交通研究》
北大核心
2021年第8期187-191,201,共6页
Urban Mass Transit
基金
国家自然科学基金项目(51774183)
天地科技股份有限公司科技创新创业资金专项重点基金项目(2018—TD—ZD004)
“十三五”国家重点研发计划项目(2016YFC0600904)。
关键词
软土地层
冻结加固
塑料冻结管
冻结壁形成规律
冻结影响因素
温度场
soft soil stratum
freezing reinforcement
plastic freezing pipe
formation law of frozen wall
freezing influencing factor
temperature field
