扬州瘦西湖盾构隧道工程施工关键技术

扬州下穿瘦西湖盾构段采用直径为14.93 m的泥水盾构施工,成功穿越1 275 m硬塑膨胀性黏土地层,有效解决盾构刀盘结泥饼、泥水舱及管道易堆积堵塞、刀盘扭矩大、盾构推进速度慢、泥水分离困难等一系列施工难题,是我国迄今为止在膨胀土地区进行的最大直径的泥水盾构施工工程。从扬州瘦西湖隧道的工程重难点出发,结合现场具体情况,系统总结隧道盾构施工中的全断面黏土地层高效环流及出渣技术、膨胀土地层盾构适应性改造技术、硬塑黏性土地层的盾构施工技术与开挖面稳定性控制技术,0.42 MPa高压气环境下动火焊接技术、小半径曲线精准接收技术和双层大直径隧道内部结构快速施工技术等,对我国膨胀性黏土地区大直径泥水盾构技术的发展具有重要的参考意义。

Key Technologies for Construction of Shield-bored Slender West Lake Tunnel in Yangzhou

The lake crossing section of Slender West Lake Tunnel in Yangzhou is constructed by a 14.93 m slurry shield. The shield has bored through 1 275 m long stiff plastic expansive clay strata successfully and has overcome a series of technological difficulties such as cutterhead blocking, slurry chamber and slurry pipe blocking, huge cutter head torque, low shield boring speed and difficulty in slurry separation. So far the tunnel is the largest tunnel in China bored by slurry shield in expansive clay strata. In the paper, the effective slurry circulating and mucking out technology when boring through the full face clay strata, the technology to modify the shield to adapt to the expansive soil strata, the shield boring technology and the excavation face stability keeping technology in the stiff plastic clay strata, dynamic welding technology under 0.42 MPa pressure, accurate shield arriving technology on small radius curve and rapid construction technology for the internal structures of the two storey shield bored tunnel are summarized. The paper can provide reference for the development of the slurry shield boring technology in expansive clay strata in China.