Comparative Study of Seismic Ground Motion Parameters in Deep-Cut and High-Fill Engineering before and after Ground Leveling

2017 ◽  
Vol 872 ◽  
pp. 109-113
Author(s):  
Su Ting Mi ◽  
Xin Qiu Meng ◽  
Xiao Bo Huang
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Response Analysis ◽  
Peak Acceleration ◽  
Ground Motion Parameters ◽  
Seismic Ground Motion ◽  
Characteristic Period ◽  
Geological Conditions ◽  
Before And After ◽  
Motion Parameters

Because of lack of flat land, more and more deep-cut and high-fill engineering are being carried out in mountainous areas. The original geological formations are greatly changed by ground leveling. Therefore, it is very important to analyze the seismic parameters before and after ground leveling. In this paper, the seismic motion parameters before and after ground leveling of deep-cut and high-fill engineering are compared by the establishment of seismic response analysis model in different geological conditions. The results show that the peak acceleration and the characteristic period of the response spectrum are lower than those before excavation; But the results change when filling on the foundation of bedrock or the foundation where original cover soil layers have already existed. The peak acceleration and characteristic period of acceleration response spectrum increase more than those ground motion parameters before filling in this site. Besides, when filling in the bedrock site, the peak acceleration magnification tended to decrease, with the increase of the filling thickness, and the characteristic period tended to increase. Therefore, seismic ground motion parameters after ground leveling can be lower than those before ground leveling in excavation area, conversely, ground motion parameters are higher in fill area.

scholarly journals Research on seismic ground motion parameters applicable to the safety of rectangular shallow tunnel

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110726
Author(s):  
Dong An ◽  
Zheng Chen ◽  
Guangyao Cui
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Mean Square ◽  
Analysis Method ◽  
Ground Motion Parameters ◽  
Evaluation Result ◽  
Seismic Ground Motion ◽  
Intensity Index ◽  
Lining Structure ◽  
Motion Parameters

The objective of this paper is to optimize the selection of seismic ground motion intensity indexes in the seismic fortification of urban shallow-buried rectangular tunnels. This paper takes a shallow-buried rectangular tunnel in a city as the research object, uses ABAQUS to establish a finite-infinite element coupling model, and selects 70 typical seismic ground motions for dynamic calculation. Using dynamic time history analysis method to study the seismic response of tunnel lining structure in terms of internal force, minimum safety factor and strain energy, and analyze their correlation with 15 seismic ground motion parameters. Selecting the seismic ground motion parameters with strong correlation, good effectiveness, and high credibility for safety evaluation. The research results show that: Peak acceleration (PGA) has a weak correlation with the seismic response of tunnel lining structures, and PGA as an independent seismic ground motion intensity index has greater uncertainty in the seismic fortification of tunnels; Peak displacement (PGD), Root-mean-square velocity (RMSV), Root-mean-square displacement (RMSD), and Specific energy density (SED) can be used as independent seismic ground motion intensity index, The linear regression model is used to evaluate the safety of the lining structure, and finally the evaluation result is verified by the incremental dynamic analysis method (IDA), which shows that the evaluation result is accurate. The research results can provide reference for the preliminary design of seismic fortification of rectangular shallow tunnels.

scholarly journals Study on the influence of seafloor soft soil layer on seismic ground motion

2020 ◽  
Author(s):  
Jingyan Lan ◽  
Juan Liu ◽  
Xing Song
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Sea Water ◽  
Response Spectrum ◽  
Soft Soil ◽  
Free Field ◽  
Soil Layer ◽  
Response Analysis ◽  
Peak Acceleration ◽  
Seismic Response Analysis

Abstract. In the complex medium system of sea area, the overlying sea water and the surface soft soil have a significant impact on the seafloor ground motion, which brings great seismic risk to the safety of offshore engineering structures. In this paper, four sets of typical free field models are constructed and established, which are land model, land model with surface soft soil, sea model and sea model with surface soft soil. The dynamic finite difference method is used to carry out two-dimensional seismic response analysis of typical free field based on the input forms about P and SV wave. By comparing the seismic response analysis results of four groups of calculation models, the effects of overlying seawater and soft soil on peak acceleration and acceleration response spectrum are studied. The results show that when SV wave is input, the peak acceleration and response spectrum of the surface of soft soil on the surface and the seabed surface can be amplified, while the overlying sea water can significantly reduce the ground motion. When P wave is used, the effect of overlying seawater and soft soil on peak acceleration and response spectrum of surface and seabed can be ignored. The peak acceleration decreases first and then increases from the bottom to the surface, and the difference of peak acceleration calculated by four free field models is not obvious. The results show that the overlying sea water and the surface soft soil layer have little effect on the peak acceleration of ground motion below the surface.

scholarly journals Study on the influence of the seafloor soft soil layer on seismic ground motion

2021 ◽  
Vol 21 (2) ◽  
pp. 577-585
Author(s):  
Jingyan Lan ◽  
Juan Liu ◽  
Xing Song
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Response Spectrum ◽  
Soft Soil ◽  
Free Field ◽  
Soil Layer ◽  
P Wave ◽  
Response Analysis ◽  
Peak Acceleration ◽  
Seismic Response Analysis

Abstract. In the complex medium system of the sea area, the overlying seawater and the surface soft soil have a significant impact on the seafloor ground motion, which brings great seismic risk to the safety of offshore-engineering structures. In this paper, four sets of typical free-field models are constructed and established, comprising a land model, land model with surface soft soil, sea model and sea model with surface soft soil. The dynamic finite-difference method is used to carry out two-dimensional seismic response analysis of a typical free field based on the input forms of P and SV waves. By comparing the seismic response analysis results of four groups of calculation models, the effects of overlying seawater and soft soil on the peak acceleration and acceleration response spectrum are studied. The results show that when an SV wave is input, the peak acceleration and response spectrum of the surface of soft soil on the surface and the seabed surface can be amplified, while the overlying seawater can significantly reduce the ground motion. When the P wave is used, the effect of overlying seawater and soft soil on the peak acceleration and response spectrum of the surface and seabed can be ignored. The peak acceleration decreases first and then increases from the bottom to the surface, and the difference of peak acceleration calculated by four free-field models is not obvious. The results show that the overlying seawater and the surface soft soil layer have little effect on the peak acceleration of ground motion below the surface.

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