Abstract: To deal with the mud and water gushing disaster in Neogene waterrich semidiagenesis of fine sand in Wangjiazhai tunnel of LinxiangQingshuihe highway, the occurrence and mechanism of the mud and water gushing disaster are analyzed, the construction treatment schemes such as advance tight pipe shed, horizontal highpressure jetgrouting pile, and curtain grouting, and the advantages and disadvantages of drainage in the tunnel and surface dewatering by deep well are comparatively analyzed. Additionally, numerous field tests are conducted on the Wangjiazhai tunnel, a disaster prevention scheme of "prioritized geology, dewatering first, short footage, strong advance support, auxiliary grouting, fast ring forming, and multiple measurement" is established, and key construction techniques of "surface deep well dewatering, comprehensive drainage in tunnel, tight pipe shed, tight small conduit, surrounding 〖JP2〗grouting reinforcement, fourbench fivestep staggered excavation method, and rapid emergency response" are summarized. Site practice shows that the average monthly footage has gradually increased to 36.5 m, making a significant increase of about 16 times the average monthly footage of 2.1 m in 2021, which has essentially addressed the problem of mud and water gushing disaster in Wangjiazhai tunnel and ensured the rapid and successful excavation of the tunnel.

Key words: highway tunnel, waterrich fine sand semidiagenetic rock, mud and water gushing prevention