Tunnel construction method for crossing karst water-rich section

Abstract

The invention relates to a tunnel construction method for crossing a karst water-rich section. The method is characterized by comprising the following steps of: step 1, when the tunnel construction isclose to the karst water-rich section, predicting the underground water development condition and stratum information by adopting an advanced geological prediction method; step 2, drilling a water detecting hole by adopting advanced horizontal hole drilling, and detecting the water inrush position, the water inrush amount and the water inrush pressure of the karst water-rich section through the water detecting hole; step 3, digging a tunnel face leading guide pit in the contour line of a tunnel according to the predicted water inrush position for drainage and pressure reduction, wherein the water inrush position is located on the side wall of the leading guide pit; step 4, grouting by adopting an advanced small conduit, carrying out advanced support on the tunnel to form a grouting ring for water isolation, and preventing underground water from flowing into surrounding rock in front of a tunnel face; and 5, excavating a tunnel body, plugging the water detecting hole, and excavating the tunnel body by controlled blasting. According to the tunnel construction method, the risk of water inrush on the tunnel face can be effectively reduced, and the tunnel construction safety is guaranteed.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a tunnel construction method for crossing karst water-rich sections. Background technique [0002] With the rapid development of the national economy and the urgent needs of the people for the development of transportation, the road and railway-based transportation methods in China have developed rapidly, and the number of tunnel projects built in karst water-rich areas with extremely complex topography and geology is increasing day by day. The groundwater existing in the formation is one of the important factors that generate tunnel construction risks and cause construction accidents. At present, many engineering examples show that in the mountains of karst areas, the groundwater often has high water pressure. If the tunnel construction cannot be discovered in time and appropriate drainage and pressure reduction measures are taken, it is very easy to burst mud and wa...

AI Technical Summary

Problems solved by technology

[0003] Chinese invention patent CN109578007A discloses a construction method for excavation and drainage of tunnels crossing high-angle thrusting water-rich sand-rich faults. A circuitous pilot pit and a high-level drainage tunnel are set on the same side of the main tunnel as the construction tunnel, and the water is discharged through the high-level drainage tunnel. Although this method can discharge the water in the fault to a large extent, in addition to the construction of the main tunnel, it is necessary to build a roundabout pilot pit and a drainage tunnel, which will greatly disturb the surrounding rock in the area and increase the investment cost. Extend the construction period

Chinese invention patent CN110630325A discloses a method for draining water from long-distance tunnels by using horizontal directional drilling, and draining water through horizontal guides, transverse passages and boreholes. Although this method has a large daily water inflow and the length of the section to be excavated reaches more than 800 meters The tunnel has a good drainage effect, but it needs to set up 3 retaining walls, the process is complicated, and the exit below is a residential area or a factory area, which is not applicable, and has great limitations.

Both of the above two inventions built drainage tunnels for drainage, failed to make full use of the main tunnel, and significantly increased investment costs

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