Study on the Disturbance Patterns of Roadheader Construction of Large-section Railway Tunnel Under-crossing Existing Buildings in Karst Stratum
To investigate the disturbance patterns caused by the railway tunnel excavated by the boom-type road-header,which crosses undere the existing surface structures in karst strata,a karst cavity unit extraction algorithm was proposed,the three-dimensional refined finite element model was established based on a roadheader-excavated railway tunnel project,the ground settlement,the settlement and tilt rate of the existing surface structure were ana-lyzed,and the impact of karst filling quantity on surface settlement trough was explored.The results indicate that:(1)Due to the foundation stiffness of the existing surface structure,the settlement trough caused by the boom-type roadheader construction exhibits segmented characteristics:it is approximately linear under the building and con-forms to Peck formula form outside the building;(2)During the under-crossing process,the settlement and tilt rate of the existing surface structure show a three-staged variation trend,corresponding to the three-stage construction of boom-type roadheader;(3)The impact of karst cavity filling quantity on surface settlement exhibits a staged trend:When the filling quantity is less than 70％,the maximum surface settlement decreases with increasing filling quantity.When the filling quantity exceeds 70％,the maximum surface settlement remains stable.
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维普
