Abstract: The conventional threeverticalbencheswithsevenareas excavation method does not have a good result in terms of deformation control of the surrounding soil mass in the excavation of tunnels in expansive soils. It has an important engineering implication of optimizing this conventional excavation method so that it can be used in the expansive soils. This paper presents a case study of the optimized method used in the tunnel excavation in expansive soils in Taixing Railway No. 2 Bid Package project. The deformation of the surrounding soil mass was monitored and the improved excavation method was proposed.

Key words: Tunnel in Expansive Soils, Threebenches with Sevenareas Excavation Method, Construction Monitoring, Improvement of Excavation Process, Stiff Support at Tunnel Shoulders