Investigation on the Performance of Pipe Roof Method Adjacent to the Underground Construction

Abstract

In this paper, the behaviour of the pipe roof method with different pipe roofs disposition schemes including the pipe roof gate system and L-shaped system is discussed in terms of ground settlement reduction in the condition of underground space construction adjacent to the existing structure by using numerical simulation method. Considering the construction sequences of parallel underground tunnels with rectangular cross sections, the appropriate parameters and ground response characteristics of the corresponding pipe roof methods are evaluated by the ground surface displacement. The results indicated that the construction impacts from new buildings can be reduced by the pipe roof method. However, the theoretical performance of pipe roofs is highly dependent on the spacing between two structures.Generally, the L-shaped system is more effective in case of the distance (D) that is less than or equal to 1/2 width of box culvert (R) under the condition of a new structure constructed nearby the existing building. When two structures are constructed simultaneously, the excavation and the construction of structures influence each other reciprocally. The conclusions could provide a reference for the pipe roof method with the application scenario of adjacent building protection.

Numerical Simulation Study on Frost Heave during the Freezing Phase of Shallow-Buried and Undercut Tunnel Using the Freeze-Sealing Pipe Roof Method

“…Construction of urban underground tunnels, as one of the important solutions, currently faces major technical challenges, such as the safety risks of underpass operating tunnels or existing buildings, tunnel construction in soft soil layers with high water content, and predicting and regulating settlement deformation [4,5]. Tunnel excavation frequently results in the deterioration of rock and soil mass and surface deformation of the project and its surrounding environment, resulting in underground pipeline rupture, serious ground settlement, or even collapse, cracking, and damage to adjacent structures [6,7].…”

Numerical Study on Water Sealing Effect of Freeze-Sealing Pipe-Roof Method Applied in Underwater Shallow-Buried Tunnel

“…The pipe-roof (PR) method is one of the important support methods in the shallow buried excavation construction [1,2]. It uses micropipe jacking technology to jack in steel pipes around the proposed underground building; the steel pipes are connected with locking ports and injected with waterproof materials to form a watertight underground space, and then the next step of soil reinforcement and excavation is carried out under the protection of the pipe roof [3][4][5].…”

Deformations of Subway Tunnels Induced by the Overcrossing Jacked Box Tunnels

“…Zhang et al [14] studied the response of roadway and subway tunnel to pipe jacking construction through three-dimensional numerical simulation. Ma et al [15] discussed the influence of construction sequence on the existing structure by numerical simulation. Lavasan a et al [16] found that different backfill grouting simulation methods have little impact on the axial force of lining whereas the longitudinal stiffness of the existing tunnel lining is one of the major factors affecting the deformation.…”