Study on Stress Field Distribution during the Construction of a Group of Tunnels Using the Pile–Beam–Arch Method

Abstract

To study stress field distributions during the construction of a group of tunnels using the pile–beam–arch method, the excavation for an underground station of Beijing subway line 7 was taken as an engineering problem, and a numerical structural model of a tunnel group was built with the aid of software. In this model, four stress-monitoring planes were set up to extract the data obtained from monitoring stress. The construction of the pilot tunnels was simulated according to six established construction schemes, and images were generated for the stress field distribution on each monitoring plane using different schemes. Finally, a verification of physical model tests was carried out. The results show that the effect of excavation on vertical stress in pilot tunnels has a range that is essentially equal to twice the width of the station. After the excavation of pilot tunnels, peaks appeared both at the tops of the pilot tunnels and between the bottoms of the tunnels; moreover, valleys appeared both at the bottoms of the pilot tunnels and between the tops of the tunnels. Pilot tunnels located at the top of the group were less affected during excavation than the tunnels located at the bottom of the group both in stress concentration factor and in the point of extreme stress. Finally, the model verified the numerical simulation results of the stress variation law.

Research on the Prediction of the Time of Initial Support of Soft Rock Tunnel Based on the Optimized Longitudinal Deformation Profile

“…The "space-time effect" of the excavation face can be divided into two stages: the "spatial effect" and "time effect" [21,22] (as shown in Figure 11); the "spatial effect" mainly acts on the S 1 section, whereas the "time effect" corresponds to the rheology of the surrounding rock, which is mainly reflected in the S 3 section. However, the initial support of the tunnel is generally completed in the BC section and the CD section is mainly the equilibrium and stable stage of the interaction between the surrounding rock and the supporting structure.…”

Mechanical Difference Analysis of Single-row and Double-row Side Piles in Stations by PBA Method Based on Model Test

“…The selection of lining significantly influences the stress state of the underground structure (Su et al, 2022;El Raouf et al, 2023). The PBA method, important in controlling surface settlement and improving construction safety, has been gradually finding applications in subway construction (Yu et al, 2019;Li et al, 2022;Huang et al, 2022). In station construction, the side piles play an important role in the station's supporting system.…”

The Influence of Pile-Beam-Arch Construction on the Stratum and Station Support Structure

“…In the process of excavation, vertical bearing structures are primarily composed of concrete-filled steel tube columns (STCs) [17,18]. At present, most studies on the subway construction mainly focuses on settlement, eccentric compression columns, and impact on surrounding buildings, while there is almost no impact on the internal structure of the station.…”