Effects of Different Construction Sequences on Ground Surface Settlement and Displacement of Single Long Pile due to Twin Paralleled Shield Tunneling

Abstract

Shield tunneling activities inevitably pass through pile foundations at close distance in densely urban areas. Various studies have investigated the interaction between newly constructed tunnels and existing pile foundations. However, the influence of different construction sequences of twin paralleled shield tunneling on single long pile is seldom considered. A case was found in the project of Changsha Metro Line 5, where the twin paralleled tunnels were constructed near the Wanjiali Viaduct piles. A three-dimensional finite element model was established to analyze the pier settlement, ground surface settlement trough, and the vertical and horizontal displacement of pile under different construction sequences in layered soil. The results show that the adjacent pile and surrounding environment are affected substantially with the change of construction sequence of twin paralleled tunnels. The construction sequence of condition (b), in which the tunnel closer to the pile foundation is first constructed and then the tunnel farther away from the pile foundation is second constructed, can reduce the settlement of pier by 13.1%, the maximum surface settlement by 7.0%, the maximum vertical displacement of pile foundation by 7.9%, and the maximum horizontal displacement by 6.9%. The present findings can provide reference for similar projects.

Numerical Model Validation for Detection of Surface Displacements over Twin Tunnels from Metro Line 1 in the Historical Area of Seville (Spain)

“…As already mentioned above, the boundary condition monitor point in the Y-axis should be selected in the middle of the geometry (Y = 20), and validation points are selected at X = 6, and X = −12. Therefore, for the first excavation and second excavation points, (6,20) and (−12, 20) are selected for the validation of surface settlement in simulation with FLAC3D.…”

“…Recent advances in computational technologies have made it possible to implement such methods for the modelling of complex geotechnical problems [18]. Consequently, through the development of different software, it is possible to determine the calculation of surface settlement curves through the application of FDM [19], FEM [20], and FVM [21] through different approaches and computer software. The accuracy of the results obtained shows that the simulated cases can be very specific, and that the range of parameters and criteria to be used is strongly conditioned by the conditions of each investigation.…”

A Simplified Method for the Stress Analysis of Underground Transfer Structures Crossing Multiple Subway Tunnels

“…Given the convenience and cost-effectiveness of the finite element method, numerous studies on the impacts of tunnel excavation on nearby existing pile foundations were conducted through this method [15,16]. This encompassed an exploration of various aspects, mainly including the influence of diverse geometric parameters [17], the impact of different construction parameters [18,19], the distinct effects of tunnel excavation on individual pile and group piles [20,21], and the varied effects of the construction sequence of doubletrack tunnels on pile foundations [22,23].…”

Study on deformation of tunnel pile foundation based on discrete element method and finite difference method

“…Among them, finite difference method (FDM) and finite element method (FEM) as continuous medium method are mainly utilized in numerical simulation. Huang et al [ 11 ] established a 3D FEM model to analyze the displacement of pile induced by double-tunnel construction under different construction sequences. The results show that the change of construction sequence of double-parallel tunnel has great influence on adjacent piles.…”