Abstract: The collapse hazards are frequently encountered in the tunnel excavations, especially, in the emergency stopping zone. The economical and life loss induced by these failures are often huge and the even uncountable. This paper presents a case history of remediation of the collapse at Yangbajing No. 1 Tunnel on December 4th, 2018. The reinforcement method was able to be proposed based on the collapse and geotechnical and geological information at the site. The following measures were used during the remediation: the ground penetrating radar was used to control the quality of the construction in the collapsed zone so that the following collapses were avoided.

Key words: Collapses, Caved Cavity, Remediation Methods