Study on Launching Technology with Shallow Overburden for Large Diameter Double-mode Shield in Water-rich Pebble Soil Layer
Shield launching is a key step in the shield tunneling process,and its construction quality is directly related to the safety of the originating shaft and its surrounding environment.The launching with shallow overburden for large diameter double-mode shield in water-rich pebble soil layer is faced with problems such as soil erosion,poor sealing effect of tunnel portal and difficult breaking of tunnel portal.According to the stratum conditions and construction environment conditions at the exit end of the shield section of Zirui Tunnel,the comprehensive measures of occlusion concrete pile + sleeve valve tube grouting reinforcement + dewatering are used for strata reinforcement,the reinforcement cage of the rataining piles at the portal is replaced with glass fiber reinforcement to ensure the rapid and safe lauching of the shield,and two extended steel ring sealing devices and supporting measures are arranged to strengthen the sealing effect.Finally,a suite of launching technology with shallow overburden for large diameter double-mode shield is formed,which is suitable for water-rich pebble soil layer.
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维普
