Buy article PDF
The purchased file will be sent to you
via email after the payment is completed.
US$ 35
|
Structural Engineering and Mechanics Volume 57, Number 1, January10 2016 , pages 1-20 DOI: https://doi.org/10.12989/sem.2016.57.1.001 |
|
|
|
Numerical analysis on stability of express railway tunnel portal |
||
Xiaojun Zhou, Hongyun Hu, Bo Jiang, Yuefeng Zhou and Yong Zhu
|
||
| Abstract | ||
| On the basis of the geological conditions of high and steep mountainous slope on which an exit portal of an express railway tunnel with a bridge-tunnel combination is to be built, the composite structure of the exit portal with a bridge abutment of the bridge-tunnel combination is presented and the stability of the slope on which the express railway portal is to be built is analyzed using three dimensional (3D) numerical simulation in the paper. Comparison of the practicability for the reinforcement of slope with in-situ bored piles and diaphragm walls are performed so as to enhance the stability of the high and steep slope. The safety factor of the slope due to rockmass excavation both inside the exit portal and beneath the bridge abutment of the bridge-tunnel combination has been also derived using strength reduction technique. The obtained results show that post tunnel portal is a preferred structure to fit high and steep slope, and the surrounding rock around the exit portal of the tunnel on the high and steep mountainous slope remains stable when rockmass is excavated both from the inside of the exit portal and underneath the bridge abutment after the slope is reinforced with both bored piles and diaphragm walls. The stability of the high and steep slope is principally dominated by the shear stress state of the rockmass at the toe of the slope; the procedure of excavating rockmass in the foundation pit of the bridge abutment does not obviously affect the slope stability. In-situ bored piles are more effective in controlling the deformation of the abutment foundation pit in comparison with diaphragm walls and are used as a preferred retaining structure to uphold the stability of slope in respect of the lesser time, easier procedure and lower cost in the construction of the exit portal with bridge-tunnel combination on the high and steep mountainous slope. The results obtained from the numerical analysis in the paper can be used to guide the structural design and construction of express railway tunnel portal with bridge-tunnel combination on high and abrupt mountainous slope under similar situations. | ||
| Key Words | ||
| tunnel portal; high and abrupt slope; slope stability; safety factor; strength reduction method; numerical simulation | ||
| Address | ||
| Xiaojun Zhou, Hongyun Hu: Key Laboratory of Transportation Tunnel Engineering of China Education Ministry, School of Civil Engineering, Southwest Jiaotong University,Chengdu 610031, China Bo Jiang, Yuefeng Zhou and Yong Zhu: The 1st Design Institute of Civil Engineering and Architecture,China Railway ErYuan Engineering Group Co. Ltd. Chengdu 610031, China | ||