盾构近距离下穿河底大直径承压管道施工关键技术

Key Construction Technology for Shield Tunnel Passing Underneath Pressure Pipeline with Large Diameter Under the Bottom of River at a Close Distance

成都地铁5号线九兴大道~神仙树区间采用土压平衡盾构施工,盾构隧道需下穿肖家河底大直径承压管道。为确保管线的正常供水,盾构通过前在风险段上下游设置隔水围堰并采取了河水导流措施,利用Q235钢管对原管道进行了临时改迁,并对部分管道进行了永久置换,盾构通过时严格控制各掘进参数并加强渣土改良措施减小土体扰动和损失,盾构通过后采用洞内外注浆结合的方式减小土体损失对管道带来的风险,通过上述系列措施相结合的方法保障了盾构施工期间承压管道的正常供水和管线结构安全。

Jiuxing Avenue-Shenxianshu section of Chengdu Metro Line 5 is constructed with earth pressure shield, and this tunnel passes underneath large-diameter pressure pipelines under the bottom of Xiaojia River. Before the shield reaches the risk section, waterproofing cofferdams are set at upstream and downstream of the section, and Q235 steel pipes are used to relocate the pipelines temporarily and some of the pipelines are replaced permanently to ensure the water supply of the pipelines. When the shield passes the risk section, tunnelling parameters are controlled strictly and muck conditioning measures are improved to reduce soil disturbance and soil loss. After the shield passes the risk section, the slurry is injected both inside and outside to reduce the risk of soil loss. By taking a series of measures aforementioned, the water supply and structural safety of pressure pipelines are ensured during construction period.