Abstract: Using the Naxu tunnel on the Funing-Longliu expressway as an example, this paper analyzes the causes of deformation acceleration and the cumulative deformation increment of a tunnel in soft rock, and proposes a combined control technique for displacement behind the working face, i.e. protective arch + locking anchor pipe + steel pipe pile at the invert bottom . The results show that by adopting this method, relative monitoring data decreases significantly and later tends to be stable, the events such as cracking, clearance intrusion and collapse of the primary support are avoided and construction safety is ensured.