Seismic Stability of Circular Tunnels in Anisotropic Granular Soil with Surcharge Loading Based on the Modified Pseudodynamic Approach

This study evaluated the stability of circular tunnels constructed in anisotropic granular soil in the presence of surcharges on the ground surface and seismic loads. The stability problem was solved using the lower bound limit analysis method in conjunction with the finite-element technique. In add...

Full description

Saved in:
Bibliographic Details
Published in:International journal of geomechanics 2024-05, Vol.24 (5)
Main Authors: Gowtham, G., Sahoo, Jagdish Prasad
Format: Article
Language:English
Subjects:
Acceleration
Anisotropy
Coefficients
Depth
Earthquake loads
Limit analysis
Lower bounds
Normal stress
P-waves
Parameters
Pressure
Seismic stability
Seismic waves
Soil
Soils
Stability
Stability analysis
Stress distribution
Surface stability
Tunnel construction
Tunnel linings
Tunnels
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study evaluated the stability of circular tunnels constructed in anisotropic granular soil in the presence of surcharges on the ground surface and seismic loads. The stability problem was solved using the lower bound limit analysis method in conjunction with the finite-element technique. In addition, the modified pseudodynamic technique was employed, which permits seismic accelerations to vary with depth and time, including the impact of amplitude and phase differences between shear and primary waves. The forces exerted by the soil on the tunnel lining vary over the perimeter. Therefore, the ultimate support pressure should at least be equal to the maximum normal stress from the earth surrounding the tunnel. It was discovered that parameters such as the tunnel cover depth, tunnel diameter, magnitude of surcharge, soil friction angle and its degree of anisotropy, seismic acceleration coefficients, period, and frequency of seismic waves determine the support pressure’s magnitude and location. The influence of surcharge diminished beyond a certain cover depth and diameter ratio for given soil and seismic wave parameter magnitudes. This study showed that the maximum normal stress was 8.5 times greater than the uniform stress distribution. Furthermore, the support pressure was found to be a maximum of about 45.5% higher for a tunnel cover depth-to-diameter ratio of 3 than for 1%, 34% higher for anisotropy than for isotropic case, 25% higher in the presence of ground surcharge than its absence, and 60% higher for the horizontal acceleration coefficient of 0.3 compared to the static case.
ISSN:1532-3641
1943-5622
DOI:10.1061/IJGNAI.GMENG-9293