Study on the Surface Settlement of an Overlying Soft Soil Layer under the Action of an Earthquake at a Subway Tunnel Engineering Site

In order to study the surface settlement characteristics of an overlying soft soil layer in a subway tunnel under seismic loading, the ABAQUS finite-element analysis software was utilized. Taking the construction of Dalian Metro Line 5, which is located in seismic intensity zone Ⅶ and has an overlyi...

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Bibliographic Details
Published in:Sustainability 2023-06, Vol.15 (12), p.9484
Main Authors: Wang, Qiongyi, Zou, Liang, Niu, Yungang, Ma, Fenghai, Lu, Shasha, Fu, Zhideyi
Format: Article
Language:English
Subjects:
Analysis
China
Construction
Construction sites
Design and construction
Dimensional analysis
Earthquake construction
Earthquake intensity
Earthquake loads
Earthquakes
Finite element method
Friction
Internal friction
Light rail transit
Lithology
Mechanical properties
Modulus of elasticity
Parameter sensitivity
Poisson's ratio
Railroad tunnels
Railroads
Seismic activity
Seismic engineering
Seismic waves
Sensitivity analysis
Silty soils
Simulation
Soil layers
Soil settlement
Soils
Subway tunnels
Subways
Sustainability
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Summary:In order to study the surface settlement characteristics of an overlying soft soil layer in a subway tunnel under seismic loading, the ABAQUS finite-element analysis software was utilized. Taking the construction of Dalian Metro Line 5, which is located in seismic intensity zone Ⅶ and has an overlying soft soil layer, as the engineering background, El-Centro and Kobe waves representing class Ⅱ site seismic waves, as well as an artificial seismic wave with an exceedance probability of 10%, were inputted into the analysis. The settlement characteristics of the ground surface at the construction site of the subway tunnel under the three different seismic waves were investigated, and their behaviors were theoretically analyzed. Then, the surface settlement law with respect to the tunnel roof was studied based on El-Centro wave and soft soil parameters, and a sensitivity analysis of soft soil parameters of surface settlement of the tunnel roof was carried out by the orthogonal test method. The results show that under earthquake action, the settlement of the strata within a certain range of the tunnel roof was significantly greater than that of the surrounding strata, forming a settlement trough with a width of about 8 to 20 m. The width of the settlement trough under the El-Centro wave was the largest, about 19.6 m, surpassing that of the artificially synthesized seismic waves with a probability of 10%, which was about 15.6 m, while the width of the settlement trough under the Kobe wave was the smallest, about 8.5 m. The ground surface within a range of about 20 m above the tunnel roof was most strongly affected by the seismic waves and the special lithology of the overlying soft soil layer, and the settlement was the largest. The settlement law of the settlement trough in the overlying strata of the tunnel conformed to the Peck formula. Increasing the elastic modulus of the silty soil can reduce the settlement of the ground surface above the tunnel roof; increasing the Poisson’s ratio of the silty soil will increase the settlement of the ground surface above the tunnel roof; increasing the cohesive force of the silty soil to 20 kPa will basically stabilize the settlement of the ground surface above the tunnel roof; and increasing the internal friction angle of the silty soil will basically not change the settlement of the ground surface above the tunnel roof. The sensitivities of the soft soil parameters to the settlement of the ground surface above the tunnel
ISSN:2071-1050
2071-1050
DOI:10.3390/su15129484