Tunnel construction method for karst geology

The invention relates to a karst geology tunnel construction method which comprises the following steps: exploring a to-be-excavated soil body to obtain the information of a karst cave in the soil body; excavating a soil body to form a tunnel penetrating through the karst cave, and constructing corresponding to the tunnel to form a primary lining; a drainage pipe is pre-buried in the bottom of the karst cave, and a grouting pipe is led into the top of the karst cave; and slurry is prepared, the slurry is injected into the karst cave through the grouting pipe to fill the karst cave, and water in the karst cave is discharged outwards through the drainage pipe. The problems that a traditional treatment mode is long in construction period and high in construction cost are effectively solved, the filling material can be rapidly cured by improving the filling material, the tunnel is not affected, the construction efficiency is improved, the construction cost is reduced, and the construction progress is guaranteed.