地铁上穿工程中抗浮钢拉杆的参数优化

Parameter Optimization of Anti-floating Steel Tie Rods in Metro up Crossing Engineering

目的研究地铁上穿工程中不同钢拉杆参数对既有结构上浮的影响,为钢拉杆抗浮施工设计提供指导和借鉴。方法基于北京某地铁上穿工程,利用FLAC3D软件建立数值模型进行分析,研究上穿过程中钢拉杆长度、角度、间距等参数变化对既有结构变形的影响。结果钢拉杆长度增加时,既有结构上浮位移变小,但同时钢拉杆对既有结构的约束效果也逐渐减小,长度对既有结构上浮的约束能力在3个参数中约占19.79%;钢拉杆角度的变化对既有结构位移影响较小,在3个参数中比重约占1.16%;钢拉杆间距增加时,既有结构竖向位移逐渐增大,且两者近似呈线性关系,其对结构上浮影响最大,比重约占79.05%。结论在北京地区相似地质和工程条件下,钢拉杆的最优长度为4.5 m,角度建议取12°~24°,间距取1.0~2.0 m。

In order to provide guidance and reference for the anti-floating construction design of steel tie rod,this paper studies the influence of different parameters of steel tie rod on the floating of existing structure in subway overpass project.Based on a subway overpass project in Beijing,a numerical model was established by FLAC3D software to analyze the influence of the length,angle,spacing and other parameters of the steel tie rod on the deformation of the existing structure.When the length of steel tie rod increases,the floating displacement of the existing structure becomes smaller,but at the same time,the restraint effect of steel tie rod on the existing structure gradually decreases.The constraint ability of the length to the floating of the existing structure accounts for about 19.79%of the three parameters.The change of steel tie rod angle has little influence on the displacement of the existing structure,accounting for about 1.16%of the three parameters.When the distance between steel drawbars increases,the vertical displacement of the existing structure increases gradually,and the relationship between them isapproximately linear,which has the greatest impact on the floating of the structure,accounting for about 79.05%.Under the similar geological and engineering conditions in Beijing,the optimal length of steel tie rod is 4.5 m,the angle is recommended to be 12°to 24°and the spacing is 1.0~2.0 m.