Mechanical responses of existing tunnel due to new tunnelling below without clearance

Abstract With the development of urban subway, there are more projects of new subway construction below existing subway. The project is more challenging if the new subway is excavated below the existing subway with no pillar in between. In this research, we propose an analytical solution to investigate the mechanical responses of the existing tunnel due to new tunnel construction below without clearance. We put forward a superposition method based on the Winkler model to simulate the absence of the springs under the existing tunnel at the intersection of the new and existing tunnel. The proposed solution is successfully validated by FEM simulation. The influences of the input parameters of the model, including the range of deleted springs, the coefficient of subgrade reaction, and the equivalent bending stiffness, on the deflection and the bending moment of the existing tunnel, are studied. The research can serve as a reference to ensure both the safety and the serviceability of existing tunnels in case of new tunnelling below existing tunnel without clearance.

[1]  Pierpaolo Oreste,et al.  Three-dimensional numerical simulation of a mechanized twin tunnels in soft ground , 2014 .

[2]  David M. Potts,et al.  Twin Tunnel Interaction: Surface and Subsurface Effects , 2001 .

[3]  Charles Wang Wai Ng,et al.  Three-dimensional influence zone of new tunnel excavation crossing underneath existing tunnel , 2016 .

[4]  Shaojun Li,et al.  Dynamic design method for deep hard rock tunnels and its application , 2016 .

[5]  John A. Hudson,et al.  Specifying the information required for rock mechanics modelling and rock engineering design , 2010 .

[6]  Jin-Jian Chen,et al.  Prediction of tunnel displacement induced by adjacent excavation in soft soil , 2013 .

[7]  R. D. Mindlin.  Force at a Point in the Interior of a Semi-Infinite Solid , 1936 .

[8]  C. Ng,et al.  A comparative study of the different responses of circular and horseshoe-shaped tunnels to an advancing tunnel underneath , 2016 .

[9]  Xiating Feng,et al.  Analysis of EDZ Development of Columnar Jointed Rock Mass in the Baihetan Diversion Tunnel , 2016, Rock Mechanics and Rock Engineering.

[10]  A. B. Vesic,et al.  Bending of Beams Resting on Isotropic Elastic Solid , 1961 .

[11]  M. Biot,et al.  Bending of an infinite beam on an elastic foundation , 1937 .

[12]  Wang Guo-feng,et al.  Application of CRD + Top-bracing Control Technology in Close-attached Under-crossing Engineering , 2013 .

[13]  Zhiguo Zhang,et al.  Evaluation of deformation response for adjacent tunnels due to soil unloading in excavation engineering , 2013 .

[14]  Kazuhiko Kawashima,et al.  EVALUATION PROCEDURE FOR SEISMIC STRESS DEVELOPED IN SHIELD TUNNELS BASED ON SEISMIC DEFORMATION METHOD , 1989 .

[15]  Jian Yu,et al.  Soil-pipe interaction due to tunnelling: Assessment of Winkler modulus for underground pipelines , 2013 .

[16]  Feng Yu,et al.  Effects of above-crossing tunnelling on the existing shield tunnels , 2016 .

[17]  Pj Bennett,et al.  Behaviour of an old masonry tunnel due to tunnelling-induced ground settlement , 2010 .

[18]  Li Xinggao,et al.  Response of a double-decked metro tunnel to shield driving of twin closely under-crossing tunnels , 2012 .

[19]  Harvey J. Burd,et al.  Model testing of closely spaced tunnels in clay , 1998 .

[20]  John A. Hudson,et al.  Numerical methods in rock mechanics , 2002 .

[21]  Bahtiyar Ünver,et al.  Analysis of interaction between tunnels in soft ground by 3D numerical modeling , 2011 .

[22]  D. Potts,et al.  Numerical investigation of the effects of tunnelling on existing tunnels , 2017 .

[23]  C. Rogers,et al.  Movements in the Piccadilly Line tunnels due to the Heathrow Express construction , 2002 .

[24]  Maosong Huang,et al.  Simplified analytical method for evaluating the effects of adjacent excavation on shield tunnel considering the shearing effect , 2017 .

[25]  Isam Shahrour,et al.  Numerical analysis of the interaction between twin-tunnels: Influence of the relative position and construction procedure , 2008 .

[26]  Robert J. Mair,et al.  Monitoring the Behaviour of an Existing Royal Mail Tunnel: London Underground Bond Street Station Upgrade Works , 2017 .

[27]  Wancheng Zhu,et al.  2D numerical simulation on excavation damaged zone induced by dynamic stress redistribution , 2014 .

[28]  K. Soga,et al.  Soil-pipe interaction due to tunnelling: comparison between Winkler and elastic continuum solutions , 2005 .

[29]  W W NgCharles,et al.  Three-dimensional centrifuge and numerical modeling of the interaction between perpendicularly crossing tunnels , 2013 .

[30]  Qianqian Li,et al.  Effects of twin tunnels construction beneath existing shield-driven twin tunnels , 2015 .