交叉隧道塑性区分布规律、成因及支护探讨

DISTRIBUTION OF PLASTIC ZONES IN EXISTING TUNNEL DUE TO NEW CONSTRUCTION CLOSELY ABOVE THE TUNNEL AND THEIR MECHANISM AND REINFORCEMENT,A CASE STUDY IN BEIJING

在既有隧道区间上方近距离进行新车站的施工,是地下工程研究中难度较大的问题。本文运用数值模拟方法对北京市地铁五号线东单站上跨地铁一号线,采用浅埋暗挖法施工过程中隧道塑性区分布问题进行了研究,得出在杂填土、砂土、粘土互层条件下大跨度车站底板受既有线存在的影响其塑性区基本以车站轴线为对称轴的矩形分布、既有隧道区间塑性区不同部位的变化幅度,其中以两侧壁最大,并进行了锚杆支护模拟,保证了土体的稳定。

Building a new station closely above an existing tunnel is a relatively difficult problem in underground construction. This paper uses numerical simulation methods and analyzes the distribution of plastic zones in the tunnel of the No. 1 Subway Line during the above construction of the Dongdan station for the No. 5 Subway Line in Beijing. It found that the symmetrical andrectangular distribution of plastic zones for the large - span station floor s influenced by existing line. Changing extent of different parts were also found on the plastic zones of the existing tunnel under backfill, sandy soil, clay interbedding,. The plastic zone valuesabout the side face of the existing line are the largest. Simulation on the reinforcement scheme was also conducted to guarantee the stabilization of the surrounding ground.