Research on the Law of Inverted Arch Uplift and Ballastless Track Arching Deformation in Railway Tunnels
The inverted arch uplift and the resultant ballastless track arching deformation in the railway tunnel have become the primary reasons for speed restrictions in specific sections of HSR lines.The occurrence of inverted arch uplift diseases is closely related to mudstone expansion and groundwater seepage.Based on the local effects of mudstone expansion force and high water pressure at the tunnel bottom,as well as the resultant local effects on the tunnel bottom structure,this paper proposes a structure-load calculation model for inverted arch uplift and ballastless track arching deformation.The calculation results indicate that the effects of tunnel bottom load and insufficient inverted arch thickness on inverted arch uplift and ballastless track arching deformation exhibit non-linear characteristics.When the load exceeds 1 MPa and the inverted arch thickness is deficient by more than 0.2m,the inverted arch uplift and ballastless track arching deformation increase sharply.Weak areas such as construction joints in the inverted arch may result in the occurrence of peak values of arching deformation.Under the same conditions,the arching deformation in single-track tunnels can be reduced by more than 90％.
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