Carst region double-arch road tunnel construction method

The invention discloses a carst region double-arch road tunnel construction method, which comprises the following steps; 1. carrying out construction preparation; 2. carrying out construction at channel openings; 3. adopting a three-pilot-tunnel method for constructing the channel inlet opening section, and adopting a step digging method for digging during the three-pilot-tunnel method construction; 4. adopting a middle-pilot-tunnel method for constructing the middle communication section of the channel, and adopting a full cross section method for digging during the middle-pilot-tunnel method construction; 5. adopting the three-pilot-tunnel method or the middle-pilot-tunnel method for constructing the channel outlet opening section, adopting the step digging method for digging when the middle-pilot-tunnel method is adopted for digging construction of the channel outlet opening section, and synchronously carrying out secondary lining construction from the front part to the back part in the digging construction process of the channel inlet opening section, the middle communication section of the channel and the channel outlet opening section. The invention has the advantages of reasonable design, simple and convenient construction, safe and reliable construction process, flexible construction mode, short construction period and greatly simplified construction steps, and effectively overcomes various defects during the traditional carst region double-arch road tunnel construction.