Study on adaptability of primary support arch cover method for large-span embedded tunnels in the upper-soft lower-hard stratum

Abstract

The Provincial Hospital Station of Guiyang Metro Line No. 2 in China is located on the upper-soft lower-hard stratum. In order to analyze the adaptability of primary support arch cover method for the project, the construction process of the main tunnel of the Provincial Hospital Station is simulated by virtue of numerical simulation. Meanwhile, the excavation process of the tunnel is simulated by the double-side drift method for comparison. The numerical simulation results show that the primary support arch cover method has advantages in settlement control, plastic zone distribution, and supporting structure safety. Only the primary supporting structure is relatively weak in the rock-soil interface and on the arch shoulders and vault, and liable to tension failure. However, the application of strengthened primary support can significantly improve this unfavorable situation. Therefore, it is suggested that the primary support arch cover method be adopted for the construction of the main tunnel of the Provincial Hospital Station. The numerical simulation results obtained by primary support arch cover method are consistent with the field data in terms of the change trend of surface settlement, and the final settlement value is also similar. On this basis, the influence of grade variation of underlying surrounding rock on surface settlement and surrounding rock plastic zone distribution caused by the two methods is further simulated, and the grade range of underlying surrounding rock suitable for primary support arch cover method is given in the article.

Statistical Analysis of Influence of Cover Depth on Loess Tunnel Deformation in NW China

“…Due to the particularity of loess, the deformation regularity in loess tunnels shows different characteristics from those in rock tunnels [12][13][14][15][16][17]. Deformation has four characteristics: scientific, timeliness, reliability, and convenience, and is widely used to evaluate tunnel stability and ensure construction safety [18][19][20][21][22][23][24][25].…”

Numerical simulation of large-scale structural systems

“…Construction process of large-scale tunnels is a challenging task and needs a detailed numerical simulation supported by field tests in terms of the settlement gradient and the final settlement value. In an article by Wang et al, 14 ''Study on adaptability of primary support arch cover method for large-span embedded tunnels in the upper-soft lower-hard stratum,'' the authors studied the detailed excavation process of the tunnel by the double-side drift method. The numerical simulation results showed that the primary support arch cover method is effective in settlement control, plastic zone distribution, and supporting structure safety.…”

Support System for Tunnelling in Squeezing Ground of Qingling‐Daba Mountainous Area: A Case Study from Soft Rock Tunnels

“…e railway/highway tunnels are considered one of the most efficient and environment-friendly ways to improve the transportation infrastructures and have been developing rapidly all over the world in recent decades [1][2][3][4]. In reality, determining the viable support system is a key factor affecting the cost and safety of underground works.…”