TY - JOUR
T1 - Close construction effect and lining behavior during tunnel excavation with an elliptical cross-section
AU - Afshani, Alireza
AU - Akagi, Hirokazu
AU - Konishi, Shinji
N1 - Funding Information:
The authors greatly acknowledge the Tokyo Metro Co. Ltd for providing the measurement data used in this study.
Publisher Copyright:
© 2020
PY - 2020/2
Y1 - 2020/2
N2 - Tunnel excavations near existing structures impose additional loads on the nearby structures and influence the stress-strain regime of the soils. In the present study, the ground response during the close construction of tunnels and the structural behavior of a segmental lining with an elliptical-shaped cross-section were investigated. The effect of nearby structures and the influence distance for a nearby excavation were discussed in terms of the changes in volume loss around the tunnel, the horizontal soil deformation, and the distribution of internal forces. Furthermore, the structural behavior of the lining was tested by showing the capacity of the reinforced concrete section and by considering the crack development in the elliptical-shaped segment. The results demonstrated that the influence distance of the elliptical-shaped tunnel excavated in coarse-grain soils was approximately four times the minor diameter of the tunnel and that the axial force increased slightly in the part of the lining close to the existing structure when the pillar width was increased. Furthermore, it was demonstrated that crack development is an important issue in tunnels with an elliptical cross-section near the spring line; and therefore, a safe zone corresponding to the onset of several cracks with an allowable width and average crack spacing was recommended.
AB - Tunnel excavations near existing structures impose additional loads on the nearby structures and influence the stress-strain regime of the soils. In the present study, the ground response during the close construction of tunnels and the structural behavior of a segmental lining with an elliptical-shaped cross-section were investigated. The effect of nearby structures and the influence distance for a nearby excavation were discussed in terms of the changes in volume loss around the tunnel, the horizontal soil deformation, and the distribution of internal forces. Furthermore, the structural behavior of the lining was tested by showing the capacity of the reinforced concrete section and by considering the crack development in the elliptical-shaped segment. The results demonstrated that the influence distance of the elliptical-shaped tunnel excavated in coarse-grain soils was approximately four times the minor diameter of the tunnel and that the axial force increased slightly in the part of the lining close to the existing structure when the pillar width was increased. Furthermore, it was demonstrated that crack development is an important issue in tunnels with an elliptical cross-section near the spring line; and therefore, a safe zone corresponding to the onset of several cracks with an allowable width and average crack spacing was recommended.
KW - Close underground excavation
KW - Elliptical cross-section lining
KW - Ground surface settlement
KW - Influence distance
KW - Permissible crack width
KW - Segment crack
KW - Segment section capacity
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U2 - 10.1016/j.sandf.2019.12.006
DO - 10.1016/j.sandf.2019.12.006
M3 - Article
AN - SCOPUS:85078951509
SN - 0038-0806
VL - 60
SP - 28
EP - 44
JO - Soils and Foundations
JF - Soils and Foundations
IS - 1
ER -