Basement excavation influences zones for deformation of the adjacent side tunnel

Tunnel deformation is hard to predict since the complicated geological conditions and lack of understanding of soil-structure interactions. This paper proposes basement excavation influence zones for the deformation of the adjacent tunnel, providing a way for tunnel deformation prediction. An excavation project in Cangshan District, Fuzhou, was used as a base case to generate artificial data on tunnel response at different locations. All simulations are done in the condition when the maximum horizontal displacement of the supporting structure reaches 40 mm. Given the control requirements of tunnel deformation in several codes, 5, 10, and 20 mm tunnel deformation is selected as zone boundaries. Excavation influence zones for adjacent existing side tunnel under typical soil conditions were then proposed with the boundaries. These boundaries of influence zones are simplified into a three-segment polyline and therefore divided influence zones into four parts: strong influence zone, secondary influence zone, moderate influence zone, and weakly influence zone. Three coordinate values are introduced to quantify the boundary of the influence zone, including top width L i1 , the turning point depth V i , and the bottom width L i2 of the influence zone. The application results showed the proposed excavation influence zones could provide support for tunnel deformation prediction.