On December 15, the Liuwu Railway 4 Standard Sanpuling Tunnel undertaken by China Railway Shanghai Engineering Bureau was successfully completed 5 days ahead of schedule. This is the first tunnel to break through in the bid section, marking a phased breakthrough in the tunnel construction of the project and providing valuable experience for the subsequent construction of the same type of tunnel.
Liuwu Railway 4 standard total length 21421 kilometers, bridge-tunnel ratio of 775%, this section includes 4 tunnels. Located in Fengmenao Village, Guiping City, Guangxi, the Sanpuling Tunnel is a single-hole double-lane tunnel with a design speed of 160km h, a total length of 969 meters, and a maximum buried depth of about 100 meters. The inlet and outlet sections of the tunnel pass through the sandstone regolith layer, the rock mass is broken, and there is a bedding geology, the surrounding rock has poor stability, and it is easy to produce undesirable geological phenomena such as collapse and blocking, and the terrain and geographical conditions are complex and changeable.
Before the construction of the tunnel, the project department set up a tunnel advanced geological forecasting team to do a good job of advanced forecasting for geological survey, hydrological monitoring inside and outside the tunnel, advanced geological drilling, deepening blast holes, and toxic and harmful gas testingIn the tunnel construction, the project department has always adhered to standardized management, strictly followed the special construction plan of the tunnel, followed the principle of "pipe advance, strict grouting, short excavation, strong support, early closure, and diligent measurement", and adopted a new generation of walking intelligent lining trolley, hydraulic inverted arch trestle and other advanced equipment, tunnel lining arch anti-voiding early warning device, anti-top compressive stress monitoring, vault plug-in vibrator, soft lap joint and "V" groove and other new tooling technology, The 3D scanning technology is applied to the whole process of tunnel construction, which realizes the intelligent control of the whole tunnel construction and provides technical support for the safe and smooth breakthrough of the tunnel.
In order to reduce the impact of blasting on the stability and bearing capacity of the surrounding rock, the project department takes the application of "concentrating smooth surface blasting" technology as the key research object, and continuously adjusts the blasting parameters and construction methods according to the changes of the surrounding rock and the data of 3D scanning, so that the amount of over-excavation in each cycle is continuously reduced, which effectively reduces the construction cost and greatly improves the construction efficiency.
It is reported that the Liuwu Railway is an important part of the Liuzhou-Guangzhou Railway, and is an important general-speed railway channel from the southwest region to the Pearl River Delta in the national "Medium and Long-term Railway Network Planning". Invested and constructed by Guangxi Communications Investment Group, the total length of the main line is 238167 km/h with a design speed of 160 km/h. After the completion of the project, it can alleviate the shortage of the passing capacity of the regional road network of the national railway, shorten the transportation distance and reduce the transportation cost, and promote and drive the economic development of the regions along the Guangxi line. (China Railway Shanghai Engineering Bureau).