INFLUENCE ANALYSIS OF LARGE-DIAMETER METRO SHIELD TUNNEL UNDERCROSSING THE EXISTING RAILWAYS
The construction of foundation pit in soft soil area has a disturbing effect on the adjacent subway tunnel.Basing on a foundation pit project adjacent to a metro line,the deep horizontal displacement of soil,groundwater lev-el,and support axial force caused by pit construction are analysed in details.The deformation of subway tunnel of the current construction situation and subsequent deformation are calculated based on a three-dimensional finite ele-ment numerical analysis,the results from which are compared with the monitoring results,and the reliability of the numerical analysis is verified.Some conclusions have been drawn.Firstly,the maximum of deep horizontal displace-ment is located near the bottom plate of foundation pit.Secondly,removal and replacement of supports cause the deep horizontal displacement change of the bottom plate and support area.Thirdly,pit dewatering is beneficial to de-formation control of adjacent subway tunnel.Fourth,the replacement of supports causes the support axial force of ad-jacent zones increasing.Finally,the removal and replacement of support have obvious influence on the convergence of subway tunnel and the main deformation control index of subway tunnel is horizontal displacement.The conclu-sion may provide the reference for similar geological conditions.
metro shield tunnelexisting railway strcuturedouble-line grouting reinforcement
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