Effect of large excavation on deformation of adjacent MRT tunnels

Sharma, Jitendra; Hefny, A. M.; Zhao, Jun; Chan, C.W.

doi:10.1016/s0886-7798(01)00033-5

Cited by 194 publications

(44 citation statements)

References 2 publications

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“…DOLEZALOVA [3] carried out a plain strain numerical FEM analysis and compared the results with field measurement data. SHARMA et al [4] reported a large excavation close to two parallel tunnels in Singapore and the field measurement results indicate the significant effects of excavation on tunnel. Based on field measurements in Shanghai, HU et al [5−6] studied the effects of construction measures such as pumping inside the pit, installation of cement-soil mixing columns and excavation regime.…”

Section: Introductionmentioning

confidence: 98%

Numerical analyses of influence of overlying pit excavation on existing tunnels

Zheng

Wei

2008

J. Cent. South Univ. Technol.

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The response of existing tunnel due to overlying excavation was studied using 2D FEM (Finite element method). Three typical locations of tunnel with respect to excavation, namely at the central line under the excavation bottom, directly under the base of diaphragm wall and outside of diaphragm, were considered. The variation of tunnel response with the change of location of tunnel was analyzed. The stress path of soil surrounding tunnel during the process of excavation was compared. Numerical analysis results indicate that the underlying tunnels at different locations under the excavation will experience convergence and divergence due to overlying excavation. Moreover, the tunnel located below base of diaphragm wall will experience distortion. The deformation is mainly due to the uneven changes of ground contact pressure on tunnel linings. Both the vertical and horizontal displacement of the tunnel decrease with the increase of the tunnel embedded depth beneath the formation of excavation.

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Section: Introductionmentioning

confidence: 98%

Numerical analyses of influence of overlying pit excavation on existing tunnels

Zheng

Wei

2008

J. Cent. South Univ. Technol.

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“…By analytical and semi-analytical methods, the excavation-soil-tunnel interaction mechanism was studied and the existing tunnel was assumed to be an elastic beam (Zhang et al, 2013a,b). Numerical analyses were conducted to evaluate the deformation response of an existing tunnel due to nearby excavation (Dolezalova, 2001;Sharma et al, 2001;Huang et al, 2013). In addition, Ng et al (2013) conducted centrifuge tests of basement excavation effects on an existing tunnel in dry sand and carried out a numerical simulation for back-analysis.…”

Section: Introductionmentioning

confidence: 99%

Investigation of response of metro tunnels due to adjacent large excavation and protective measures in soft soils

Chen

Meng

et al. 2016

Tunnelling and Underground Space Technology

226

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a b s t r a c tThe inevitable influence of large excavation in soft soils on nearby tunnels is of great concern in practice. In this paper, the influence of a nearby large excavation on existing metro tunnels of the Ningbo Metro Line 1 in sensitive soft soils is investigated and presented. Considerable displacement in the left tunnel closer to the excavation induced by the nearby excavation was revealed by field monitoring. Visible cracks and leakages were observed in left tunnel linings. Three dimensional numerical simulations are conducted to investigate the responses of the ground and left tunnel due to the adjacent excavation. The development of bending moment and displacement of the left tunnel during different construction stages of the nearby excavation is obtained. Then the interaction mechanism between the nearby excavation, surrounding soils and existing twin tunnels is investigated, which is of significance to the interpretation of the influence of the nearby excavation on the existing twin tunnels. Several protective measures for alleviating the influence of adjacent excavation on left tunnel are studied, including divided excavation, soil improvement and a cut-off wall. It is found that the left tunnel is influenced to varying degrees during different construction stages and the time effect is distinct for this large excavation in soft soils, which would be suggestive to engineers to pay more attention to the protection of adjacent tunnel during the crucial construction stages. The bending moment and displacement of the left tunnel is strongly related to the unloading effects and displacement of surrounding soils, which can be alleviated by means of proper improvement of excavation sequence. Comparatively, longitudinally divided excavation is more effective in protecting the left tunnel than soil improvement or a cut-off wall. This study is of certain reference value for protecting metro tunnels adjacent excavation in soft soils.

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“…For the convenience of shoppers and users, there is an increasing demand for deep basements for buildings which are located close to or directly above existing tunnels (Burford, 1988;Chang et al, 2001;Sharma et al, 2001;Devriendt et al, 2010;Liu et al, 2011b). Burford (1988) reported measured maximum heaves of 50 mm and 41 mm in existing twin tunnels due to an overlying 12 m deep excavation in London clay.…”

Section: Introductionmentioning

confidence: 99%