长距离重叠隧道连续下穿平瓦房施工技术

为确保盾构长距离连续下穿古旧平瓦房施工,针对重叠隧道小间距、长距离的施工特点,采取“先下后上、前后错开、支撑加固”的总体施工原则,阐述盾构掘进参数控制、夹层土注浆加固和下线洞内临时支撑台车进行下线隧道加固等关键措施。根据对古旧平瓦房监测、评估结果验证，成功完成了下穿大面积古旧平瓦房的施工,以期为今后采用盾构法施工的重叠隧道长距离、连续下穿古旧平瓦房施工管理提供经验借鉴。

Construction Technologies for Long-distance Boring of Stacked Tunnel underneath Buildings

The Shichahai Station-Nanluoguxiang Station-China Art Gallery Station section on Line 8 of Beijing Metro is a small-spaced long-distance shied-bored stacked tunnel section. The tunnel crosses underneath buildings. The construction principle of ＂ upper tunnel tube bored first and lower tunnel tube bored later, keeping some horizontal distance between the face of the lower tunnel tube and that of the upper tunnel tube, and supporting the lower tunnel tube by supporting trolley＂ is followed for the mentioned tunnel section. Key construction technologies, including shield boring parameter control, consolidation of soil between the upper tunnel tube and the lower tunnel tube by means of grouting, supporting the lower tunnel tube by temporary supporting trolley, are adopted in the construction of the mentioned tunnel section, so as to guarantee the safe and successful construction of the stacked tunnel. The monitoring and estimation made show that the technologies used are rational and proper. The paper can provide reference for the construction of similar stacked shield-bored tunnels crossing underneath buildings in the future.