可调节配重顶进技术在箱涵上穿地铁隧道施工中的应用

Application of Jacking Technology with Adjustable Counter Weights in Box Culvert Construction above Existing Metro Tunnels

  • 摘要: 北京城市副中心地下综合管廊工程在运河东大街处上穿北京地铁6号线郝家府站—东夏园站盾构区间,设计采用箱涵顶进方法,箱涵顶进过程中极易造成穿越段地铁区间隧道竖向位移超标。文章详细介绍了结构配重、顶力计算、顶镐配置等关键施工技术以及箱涵结构轴线和高程变化的控制要点。通过对顶进范围两侧土体进行高压旋喷桩加固,对箱涵底板下方土体进行深层注浆加固,减小了两侧土体因开挖位移产生的摩阻力,有效改善了地铁隧道上方地层的承载力。施工监测数据表明,顶进开挖引起的既有地铁隧道的变形量严格控制在地铁运营及设计要求范围内。

     

    Abstract: The comprehensive utility tunnel in the Beijing sub-center project passes above the shield-driven run? ning tunnel between Haojiafu station and Dongxiayuan station of Beijing metro line 6, the box culvert jacking technology is designed to construction the utility tunnel and it is prone to resulting in excessive vertical displacement of the existing metro tunnel during jacking construction. The key technical points concerning structure counter weight,jacking force calculation and jack configuration as well as controlling of axis and elevation variations of box culvert structure were introduced in detail. Reinforcement measures of soil mass at both sides of jacking area by high pressure jet grouting pile and soil mass beneath box culvert by deep-hole grouting were carried out, decreasing the frictional resistance induced by tunnel excavation and improving bearing capacity of the strata above the existing metro tunnel. The monitoring data show that the deformation of the existing metro tunnel caused by jacking construction is strictly controlled within the scope of the requirements of metro operation and design.

     

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