scholarly journals Liquefaction susceptibility based on dissipated energy

1996 ◽  
Vol 29 (2) ◽  
pp. 83-91 ◽  
Author(s):  
R. O. Davis ◽  
J. B. Berrill
Keyword(s):  
Pore Pressure ◽  
Earthquake Engineering ◽  
Epicentral Distance ◽  
Response Spectrum ◽  
Soil Layer ◽  
Pressure Increase ◽  
Dissipated Energy ◽  
Engineering Practice ◽  
Energy Calculation ◽  
Liquefaction Susceptibility

This paper presents a novel approach to characterization of liquefaction susceptibility for deposits of saturated cohesionless soils. The method we propose is based on an assumed relationship between pore pressure increase and dissipated energy density within the soil layer. Use of dissipated energy is not new. What makes the present work different is our approach to the energy calculation. Earlier analyses used simple attenuation models based on earthquake magnitude and epicentral distance to determine the dissipated energy and hence the pore pressure increase within a sand deposit. In this work, instead of magnitude and distance, we will use the response spectrum for surface motion at the site as input information. This permits us to carry out liquefaction susceptibility analyses which are more closely aligned with other types of analyses such as structural response. In particular, we can employ code-prescribed spectral loads exactly as are used by structural designers. This leads to an analysis of liquefaction which is consistent with other earthquake engineering practice in New Zealand.

Drift Spectrum vs. Modal Analysis of Structural Response to Near-Fault Ground Motions

2001 ◽  
Vol 17 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Anil K. Chopra ◽  
Chatpan Chintanapakdee
Keyword(s):  
Earthquake Engineering ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Engineering Practice ◽  
Drift Spectrum ◽  
Combination Rules ◽  
Near Fault ◽  
Far Fault

A new measure of earthquake demand, the drift spectrum has been developed as an adjunct to the response spectrum, a central concept in earthquake engineering, in calculating the internal deformations of a structure due to near-fault ground motions with pronounced coherent pulses in the velocity and displacement histories. Compared in this paper are certain aspects of the elastic structural response to near-fault and far-fault ground motions. It is demonstrated that (1) the difference between drift and response spectra are not unique to near-fault ground motions; these differences simply reflect higher-mode response, which is larger due to near-fault ground motions; (2) response spectrum analysis (RSA) using existing modal combination rules can provide an estimate of structural response that is accurate to a useful degree; (3) these modal combination rules are similarly accurate for near-fault and far-fault ground motions although the underlying assumptions are not satisfied by near-fault excitations; and (4) RSA is preferable over the drift spectrum in computing structural response because it represents standard engineering practice and is applicable to a wide variety of structures.

Design Ground Motion Library: An Interactive Tool for Selecting Earthquake Ground Motions

2015 ◽  
Vol 31 (2) ◽  
pp. 617-635 ◽  
Author(s):  
Gang Wang ◽  
Robert Youngs ◽  
Maurice Power ◽  
Zhihua Li
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Response Spectrum ◽  
Time History ◽  
Earthquake Ground Motion ◽  
Engineering Practice ◽  
Period Range ◽  
Engineering Research ◽  
Interactive Tool ◽  
Design Response Spectrum

The Design Ground Motion Library (DGML) is an interactive tool for selecting earthquake ground motion time histories based on contemporary knowledge and engineering practice. It was created from a ground motion database that consists of 3,182 records from shallow crustal earthquakes in active tectonic regions rotated to fault-normal and fault-parallel directions. The DGML enables users to construct design response spectra based on Next-Generation Attenuation (NGA) relationships, including conditional mean spectra, code spectra, and user-specified spectra. It has the broad capability of searching for time history record sets in the database on the basis of the similarity of a record's response spectral shape to a design response spectrum over a user-defined period range. Selection criteria considering other ground motion characteristics and user needs are also provided. The DGML has been adapted for online application by the Pacific Earthquake Engineering Research Center (PEER) and incorporated as a beta version on the PEER database website.

Present State of Seismic Design and Analysis Regulations in Chile

1989 ◽  
Vol 5 (4) ◽  
pp. 661-674
Author(s):  
Ernesto F. Cruz
Keyword(s):  
Seismic Design ◽  
Earthquake Engineering ◽  
Response Spectrum ◽  
Soil Conditions ◽  
Engineering Practice ◽  
Seismic Design Code ◽  
Standard Response ◽  
Building Characteristics ◽  
Basic Ideas ◽  
Three Degree Of Freedom

A summary of the different provisions existing in Chile is given. The codes related to earthquake engineering practice are divided into two major groups: the first defining the loads and actions, and the other dealing with materials behavior, resistance, and detailing requirements. The overall characteristics of these codes are discussed. Special emphasis is given to the seismic design code provisions that define the level of earthquake action to expect, depending on building characteristics and site soil conditions. No seismic risk map is included in the code. Two different analysis procedures are allowed: an equivalent lateral forces procedure where torsion is considered through an amplification of the static torsion in the building; and the standard response spectrum analysis method with a three degree of freedom per story model of the building. The maximum responses of the different modes are combined using a special combination rule. Additional restrictions are imposed to torsional effects, and to overall building deformations. Finally, the basic ideas being discussed in the revision that is actually being done to the code are presented.

Calculation of Static Safety Coefficient about Loess Cave

2011 ◽  
Vol 189-193 ◽  
pp. 2366-2370
Author(s):  
Jun Hong Li
Keyword(s):  
Finite Element ◽  
Yield Criterion ◽  
Soil Layer ◽  
Engineering Application ◽  
Static Stability ◽  
Strength Reduction ◽  
Engineering Practice ◽  
Stability Calculation ◽  
Safety Coefficient ◽  
The Stability

For the loess cave characteristics, such as the thin coverage soil layer at the hole top, the poor self-stabilizing capacity, the large disturbance deformation after excavation and the easy collapse, thus in this paper, the loess cave safety factor is obtained by the method of strength reduction. And the stability calculation analysis is much more perfect. The Northwest Area Lishi loess cave is used in this paper, and the idea of strength reduction finite element method is applied, based on the Drucker-Prager yield criterion, the loess cave static stability analysis is made by the software of ANSYS.The results show that the actual situation can be reflected by the method of finite element strength subtraction. And the obtained loess cave stability coefficient is much closer to the actual steady state, thus showing the certain advantages of stability analysis.The method is also adopted in this paper. And its feasibility can be applied to the engineering practice, also a theoretical basis of reference is provided for engineering application.

Utilization of Classification Techniques for the Determination of Liquefaction Susceptibility of Soils

2016 ◽  
pp. 124-160 ◽  
Author(s):  
J. Jagan ◽  
Prabhakar Gundlapalli ◽  
Pijush Samui
Keyword(s):  
Support Vector Machine ◽  
Earthquake Engineering ◽  
Relevance Vector Machine ◽  
Least Square ◽  
Support Vector ◽  
Ground Acceleration ◽  
Geotechnical Earthquake Engineering ◽  
Liquefaction Susceptibility ◽  
Input Variables

The determination of liquefaction susceptibility of soil is a paramount project in geotechnical earthquake engineering. This chapter adopts Support Vector Machine (SVM), Relevance Vector Machine (RVM) and Least Square Support Vector Machine (LSSVM) for determination of liquefaction susceptibility based on Cone Penetration Test (CPT) from Chi-Chi earthquake. Input variables of SVM, RVM and LSSVM are Cone Resistance (qc) and Peak Ground Acceleration (amax/g). SVM, RVM and LSSVM have been used as classification tools. The developed SVM, RVM and LSSVM give equations for determination of liquefaction susceptibility of soil. The comparison between the developed models has been carried out. The results show that SVM, RVM and LSSVM are the robust models for determination of liquefaction susceptibility of soil.

scholarly journals Experiment and Analysis of Submarine Landslide Model Caused by Elevated Pore Pressure

2019 ◽  
Vol 7 (5) ◽  
pp. 146 ◽  
Author(s):  
Tao Liu ◽  
Yueyue Lu ◽  
Lei Zhou ◽  
Xiuqing Yang ◽  
Lei Guo
Keyword(s):  
Pore Pressure ◽  
Soil Layer ◽  
Initial Crack ◽  
Excess Pore Pressure ◽  
Deep Soil ◽  
Hydrate Decomposition ◽  
Dynamic Relationship ◽  
Geological Conditions ◽  
Shear Slip ◽  
Excess Pore

Hydrate decomposition is an important potential cause of marine geological disasters. It is of great significance to understand the dynamic relationship between hydrate reservoir system and the overlying seabed damage caused by its decomposition. The purpose of this study is to understand the instability and destruction mechanisms of a hydrated seabed using physical simulations and to discuss the effects of different geological conditions on seabed stability. By applying pressurized gas to the low permeability silt layer, the excess pore pressure caused by the decomposition of hydrate is simulated and the physical appearance process of the overlying seabed damage is monitored. According to the test results, two conclusions were drawn in this study: (1) Under the action of excess pore pressure caused by hydrate decomposition, typical phenomena of overlying seabed damage include pockmark deformation and shear–slip failure. In shallower or steeper strata, shear-slip failure occurs in the slope. The existence of initial crack in the stratum is the main trigger cause. In thicker formations or gentler slopes, the surface of the seabed has a collapse deformation feature. The occurrence of cracks in the deep soil layer is the main failure mechanism. (2) It was determined that the thickness and slope of the seabed, among other factors, affect the type and extent of seabed damage.

scholarly journals A method of calculating the bearing capacity of sand pile composite foundations in a mucky soil layer considering consolidation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yongtao Zhang ◽  
Yuqing Liu ◽  
Huiwu Luo ◽  
Peishuai Chen ◽  
Dejie Li ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Water Content ◽  
Effective Stress ◽  
Void Ratio ◽  
Soil Layer ◽  
Composite Foundation ◽  
Engineering Practice ◽  
Application Process ◽  
Sand Pile ◽  
Cavity Expansion Theory

AbstractIn engineering practice, the measured bearing capacity of a sand pile composite foundation in a mucky soil layer is much larger than the design value. Based on the sand pile construction and the load application process, a method of calculating the bearing capacity of the foundation based on the effective stress was proposed. Cavity diameter expansion in sand pile construction was simplified into a planar problem, and the cavity expansion theory was used to establish the expression of the rate of displacement and the horizontal stress increase. Based on the e–p curve and the calculation of the degree of consolidation, the relationships between the horizontal and vertical effective stress and the void ratio were obtained. According to the close relationship between the bearing capacity of the foundation in a mucky soil layer and the water content, an expression describing the relationships between the bearing capacity of the foundation, effective stress, void ratio, and water content was established. For the temporary engineering foundation treatment project, which needs a high bearing capacity but allows large foundation deformation, the design of sand pile composite foundations uses these relationships to take the consolidation effect of mucky soil into consideration, thereby reducing the replacement rate and lowering the construction cost.

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