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Comparison of Construction Schemes and Layout of Temporary Facilities for
the Entrance/Exit Section of a Large-section Loess Tunnel on High and Steep
Slope
(Erchu Co.,Ltd. of China Railway Tunnel Group, Langfang 065201)
Abstract When a tunnel is built in the gully and hilly area of the Loess Plateau, the portal is usually located on the
loess steep wall in the halfway of the "V"-shaped gully. Due to great height difference, narrow portal site, uneasy accessing and difficult layout on the construction site, improper construction at the portal of a large-section loess tunnel may easily cause hazards and engineering accidents. Especially, the blind heading may cause collapse accidents very easily, for no large pipe roofs are installed form the outside of the tunnel and it is not easy to understand the buried depth conditions at the portal section. In order to ensure the construction safety of tunnel entrance/exit section, taking the entrance of the Lanshan tunnel on Baoji-Lanzhou passenger dedicated line as an example, four construction schemes are drawn up, namely excavating the tunnel entrance by backfilling portal site, excavating the tunnel entrance by building the temporary road, excavating the tunnel entrance by transverse adit and excavating the tunnel exit by three-bench method, as well as excavating the tunnel entrance by transverse adit and then excavating the tunnel ex?
it by single-side drift method. The four schemes are analyzed and evaluated in terms of safety,environmental impact,construction period, cost, feasibility, etc. to select the best one, which is successfully applied in the entrance/exit construction of the Lanshan Tunnel. By installing a separate batching plant and a stairway to connect the living area on the half-mountain platform and the construction site at the bottom of the gully, the problems of narrow area and difficult layout on the construction site are solved.
Abstract：
When a tunnel is built in the gully and hilly area of the Loess Plateau, the portal is usually located on the
loess steep wall in the halfway of the "V"-shaped gully. Due to great height difference, narrow portal site, uneasy accessing and difficult layout on the construction site, improper construction at the portal of a large-section loess tunnel may easily cause hazards and engineering accidents. Especially, the blind heading may cause collapse accidents very easily, for no large pipe roofs are installed form the outside of the tunnel and it is not easy to understand the buried depth conditions at the portal section. In order to ensure the construction safety of tunnel entrance/exit section, taking the entrance of the Lanshan tunnel on Baoji-Lanzhou passenger dedicated line as an example, four construction schemes are drawn up, namely excavating the tunnel entrance by backfilling portal site, excavating the tunnel entrance by building the temporary road, excavating the tunnel entrance by transverse adit and excavating the tunnel exit by three-bench method, as well as excavating the tunnel entrance by transverse adit and then excavating the tunnel ex?
it by single-side drift method. The four schemes are analyzed and evaluated in terms of safety,environmental impact,construction period, cost, feasibility, etc. to select the best one, which is successfully applied in the entrance/exit construction of the Lanshan Tunnel. By installing a separate batching plant and a stairway to connect the living area on the half-mountain platform and the construction site at the bottom of the gully, the problems of narrow area and difficult layout on the construction site are solved.
LI Dongshun
.Comparison of Construction Schemes and Layout of Temporary Facilities for
the Entrance/Exit Section of a Large-section Loess Tunnel on High and Steep
Slope[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(2): 220-227
2021, Vol. 58 