Effect of random thickness variations on the seismic response of a soft soil layer: applications to Mexico City

1991 ◽  
Vol 28 (4) ◽  
pp. A202
Keyword(s):  
Seismic Response ◽  
Mexico City ◽  
Soft Soil ◽  
Soil Layer ◽  
Thickness Variations

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.

Evaluation of floor acceleration demands from the 2017 Mexico City code seismic provisions using a continuous elastic model and records of instrumented buildings

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 213-237
Author(s):  
Miguel A Jaimes ◽  
Adrián D García-Soto
Keyword(s):  
Mexico City ◽  
Seismic Design ◽  
Soft Soil ◽  
Response Spectra ◽  
Elastic Model ◽  
Ground Acceleration ◽  
Nonstructural Components ◽  
Floor Response Spectra ◽  
Instrumented Buildings ◽  
Floor Acceleration

This study presents an evaluation of floor acceleration demands for the design of rigid and flexible acceleration-sensitive nonstructural components in buildings, calculated using the most recent Mexico City seismic design provisions, released in 2017. This evaluation includes two approaches: (1) a simplified continuous elastic model and (2) using recordings from 10 instrumented buildings located in Mexico City. The study found that peak floor elastic acceleration demands imposed on rigid nonstructural components into buildings situated in Mexico City might reach values of 4.8 and 6.4 times the peak ground acceleration at rock and soft sites, respectively. The peak elastic acceleration demands imposed on flexible nonstructural components in all floors, estimated using floor response spectra, might be four times larger than the maximum acceleration of the floor at the point of support of the component for buildings located in rock and soft soil. Comparison of results from the two approaches with the current seismic design provisions revealed that the peak acceleration demands and floor response spectra computed with the current 2017 Mexico City seismic design provisions are, in general, adequate.

scholarly journals CONCERNING THE EXTRACTION OF A SLACK SOIL LAYER FROM COMPRESSIBLE THICKNESS OF FOUNDATION STRATUM OF FINITE WIDTH FOUNDATIONS

2019 ◽  
Vol 7 (4) ◽  
pp. 49-56
Author(s):  
Zaven Ter-Martirosyan ◽  
Armen Ter-martirosyan ◽  
Valery DEMYANENKO
Keyword(s):  
Analytical Solutions ◽  
Soft Soil ◽  
Soil Layer ◽  
Horizontal Displacement ◽  
Creep Model ◽  
Shear Stresses ◽  
Finite Width ◽  
Relative Depth ◽  
Weak Layer ◽  
Horizontal Displacements

The paper provides a quantitative assessment of the deflected mode of foundation stratum of finite width foundation, in the compressible thickness of which there is a slack clay soil layer. A number of criteria for assessing the possibility or impossibility of extruding a slack layer depending on its strength and rheological properties, as well as the relative thickness of the layer to its length (h/l) and the relative depth of the layer (h/d) have been given. Closed analytical solutions are given to determine the rate of Foundation precipitation depending on the rate of extrusion of the weak layer, including taking into account the damped and undamped creep. The analytical solutions in the article are supported by the graphical part made with the help of the Mathcad program. Plots of changes in shear stresses in the layer along the x axis at different distances from the axis and at different values 0, contours of horizontal displacement velocities in the weak layer at different distances from the x axis, plots of horizontal displacement velocities in the middle of the weak layer and plots of horizontal displacement velocities in the weak layer at different distances from the x axis are given. As a calculation model for describing the creep of a slack layer, rheological ones of the soil using power and hyperbolic functions and their modifications have been considered. In addition, most modern rheological models that take into account soil hardening during creep have been considered. Based on these models, the problem is solved by means analytical and numerical methods using the Mathcad PC and the PLAXIS PC according to the Soft Soil Creep model. The graphical part shows the isofields of horizontal displacements for 300 days and 600 days and the corresponding contours of horizontal displacements.

scholarly journals Dynamic Analysis and Structure Soil Interaction of Retaining Wall Using ETABS

2018 ◽  
Vol 7 (3.10) ◽  
pp. 50
Author(s):  
T Subramani ◽  
E Narendra Kumar
Keyword(s):  
Dynamic Analysis ◽  
Seismic Response ◽  
Retaining Wall ◽  
Soil Layer ◽  
Complex Problem ◽  
Dynamic Conditions ◽  
The Past ◽  
Dynamic Traits

Retaining systems are widely used international for serving numerous functions in structures and infrastructures. The seismic response of forms of walls that assist a single soil layer has been examined with the aid of some of researchers in the past. The design of preserving partitions in seismic areas poses a complex problem. The conventional layout method usually contains calculation of an element of safety in opposition to sliding, overturning and bearing ability failure. Retaining partitions have suffered damages under beyond earthquakes. Typically the analyses do not bear in mind the retained soil’s interplay with the wall, which takes location at some point of dynamic conditions. The situations of separation of wall (at some point of interactions) over again trade the dynamic traits of the assumed wall-soil interplay that needs to be addressed. Our study conducts the retaining wall beneath static in addition to seismic situations about above components.  

Model Test of Bearing Capacity of WasteTire Assembly Foundation on Soft Soil Layer

2021 ◽  
Vol 69 (7) ◽  
pp. 263-269
Author(s):  
Me ti ◽  
Tri Harianto ◽  
Abdul Rachman Djamaluddin ◽  
Achmad Bakri Muhiddin
Keyword(s):  
Bearing Capacity ◽  
Model Test ◽  
Soft Soil ◽  
Soil Layer

The ground effects of the Skopje July 26, 1963 earthquake

1969 ◽  
Vol 59 (1) ◽  
pp. 1-22
Author(s):  
Apostol Poceski
Keyword(s):  
Resonant Frequency ◽  
Seismic Response ◽  
Abrupt Change ◽  
Soil Layer ◽  
Soil Amplification ◽  
Damage Distribution ◽  
Predominant Period ◽  
Clear Explanation ◽  
Ground Effects

Abstract Damage distribution in Skopje can be explained in terms of the seismic response of surficial soils. There exists a generally good correlation between the distribution of damage, the thickness of the surficial soil layer, and the predominant periods of microtremors. The most heavily damaged region is covered with about 20 to 30 meters of alluvium, and the predominant period of this alluvium is about 0.36 seconds. The alluvium in this heavily damaged region probably was shaken near its resonant frequency, and soil amplification may have reached three. The greatest destruction was recorded along a belt which is defined by an abrupt change of the thickness of the alluvium. However, heavy destruction was also recorded on the shallow alluvium side, and no clear explanation exists for this.

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