杭州紫之隧道交叉口渐变段施工工艺流程

该文介绍了杭州市紫之隧道(紫金港路-之江路)工程中交叉口渐变段大跨段隧道、小净距隧道、下穿匝道隧道的施工工艺流程。渐变段大跨段隧道施工,利用匝道上台阶作为超前导洞,完成超前导洞后再横向扩挖至设计断面,最后进行纵向开挖。小净距隧道施工,净距小于1.5m时,采用C35混凝土对下部岩柱换填,净距大于1.5m时,对两相邻隧道间的岩柱进行对拉锚杆和注浆处理。下穿匝道隧道施工,先对围岩进行预先加固,采用管棚并注浆加固围岩,开挖时,采用CD工法开挖并及时进行钢架支护。

Construction Technological Process for Gradual Changing Section at the Intersection of Zizhi Tunnel in Hangzhou

The construction techniques are introduced for the gradual changing section of large-span tunnel, small-distance tunnel and under-crossing ramp and tunnel of Zizhi tunnel （Zijingang Rd.-Zhijiang Rd.） in Hangzhou. In the gradual changing section of large-span tunnel construction, ramp steps are used as the pilot headings to make lateral expanding excavation for design section and lead to longitudinal excavation. For the small-distance tunnel construction, C35 concrete is adopted to fill lower rock pillar when the distance is smaller than 1.5m. And the rock pillar is treated with rock bolt and slip casting when the distance is larger than 1.5. For the under-crossing ramp and tunnel construction, the surrounding rock is reinforced in advance by mak-ing pipe shed and slip casting. CD construction method is adopted and steel frame is applied in support during excavation.