深埋水工隧洞复合冻结施工关键技术研究

Research on Key Technology of Composite Freezing Construction of Deep Buried Hydraulic Tunnel

引洮供水一期工程总干渠7号隧洞中部,长48.0 m、埋深244.0 m洞段穿越新近系含水疏松粉(细)砂极软岩地层,采用一次全深冻结竖井工作面,单循环“地面垂直+洞内水平复合冻结法”掘进。为掌握深埋地层冻结设计与施工技术,结合工程实践,对含水疏松粉(细)砂岩工程地质特性,以及“复合冻结法”设计、温度场、制冷系统与施工等关键技术进行了研究。“复合冻结法”掘进安全通过极软岩地层,获得全面成功,取得重大技术突破与创新,填补了国内200.0 m以上深埋隧洞(隧道与巷道)洞内“水平冻结”工法技术的空白,开创了国内深埋水工隧洞“冻结法”施工技术的先导开端,标志着我国地下工程建设“冻结法”设计与施工技术全面跃上新台阶。

In the middle part of No.7 tunnel of the main canal of the first stage of Taohe River Water Diversion Project,the length is 48.0 m and the buried depth is 244.0 m.It passes through the Neogene water?bearing loose silt(fine)sand and very soft rock strata and adopts a fully deep frozen shaft face and single cycle“vertical ground+horizontal compound freezing method in tunnel”tunneling.For the purpose of freezing design and mastering construction technology in deep buried strata,combined with engineering practice,the engineering geological characteristics of water?bearing loose silt(fine)sandstone and the design of“composite freezing method”,the temperature field were stud?ied.The key technologies such as refrigeration system and construction were studied.The“compound freezing method”could safely pass through the very soft rock strata,and achieved great technical breakthrough and innovation,thus filling the gap of“horizontal freezing”tech?nique in the deep buried tunnels above 200.0 m in our country.The construction technology of“freezing method”for deep buried hydraulic tunnel in China has been initiated,which indicates that the design and construction technology of“freezing method”for underground engi?neering construction in our country has leaped to a new level in an all?round way.