April 23，China Railway Shanhe First StationTBM（Full-face hard rock tunnel boring machine）“Dayu”The longest high-altitude hydraulic tunnel in China——Yunnan Napahai Flood Control and Regulation Tunnel Project Successfully Launched，It marks the official entry of the project.TBMConstruction phase。

 

Napahai Flood Control Tunnel Project is located in the northwest of Jiantang Town, Shangri-La City, Diqing Tibetan Autonomous Prefecture, Yunnan Province.，The average altitude is over 3200 meters.。The whole length of the flood discharge tunnel is 10.235 kilometers，AmongTBMConstruction length of 9303m。This project is the first to be adopted in China.TBMThe longest high-altitude hydraulic tunnel excavated。

 The rocks of Napahai spillway tunnel are mainly limestone and dolomite.，The texture is relatively hard，The maximum burial depth is 624 meters.，Affected by plateau topography and geomorphology，There are regional large faults.，It is very easy to cause water gushing.、Rock burst、Landslides and so on，The construction is extremely difficult。

 

In view of the above problems，The actual construction conditions of Napahai Tunnel are comprehensively considered by China Railway Shanhe United Brothers.，Ventilation of high altitude and long distance tunnel、A series of technical problems, such as rail transportation with small section and large slope, and long-distance and rapid excavation with small section at high altitude, have been solved accurately.，Yes, the tool、Shields、Promote innovative improvements in support and other systems。Finally, it took more than six months to complete.TBMDesign and manufacture，Offline in Deyang, Sichuan on February 27th， Commissioning, installation and acceptance completed on March 31。

“Dayu”TBMThe working length of the whole machine is about 285 meters.，The main engine is 20 meters long，Diameter 4.64 meters，Weight about 1000 tons，Continuous tunneling can be realized.，Rock breaking can be completed at the same time、Support、Ventilation and other operations，Small environmental pollution on the construction site，And that operation of personnel is less，The tunneling speed is fast，High efficiency，It is estimated that the excavation will be about 500 meters per month.，It will effectively meet the requirements of construction period.。

After the completion of the Napahai flood control tunnel project, the villages around the Napahai Lake will be effectively protected.、Farmland、The road around the lake、Shangri-La City、Flood control safety of Diqing Shangri-La Airport and ecological environment and landscape of Napahai Wetland，The project also laid the foundation for China Railway Shanhe to re-enter the southwest market.。