Causes and processing methods for quality defects of CFG piles at high compressibility soft soil site

2021 ◽  
Author(s):  
Rong Chen ◽  
Chao Yu ◽  
Dongxue Hao ◽  
Ke Wu
Keyword(s):  
Soft Soil ◽  
Processing Methods ◽  
Soil Site

Power Analysis of Sdof Structures with Tuned Inerter Dampers Subjected to Earthquake Ground Motions

2020 ◽  
Author(s):  
Wenai Shen ◽  
Zhentao Long ◽  
Heng Wang ◽  
Hongping Zhu
Keyword(s):  
Seismic Response ◽  
Output Power ◽  
Analytical Solutions ◽  
Ground Motions ◽  
Soft Soil ◽  
Response Control ◽  
Seismic Response Control ◽  
Earthquake Ground Motions ◽  
Short Period ◽  
Soil Site

Abstract Tuned inerter dampers (TID) have been demonstrated as efficient energy dissipation devices for seismic response control. However, its potential capability for energy harvesting remains largely unexplored. Here, we present a theoretical analysis of the power of a structure-TID system subjected to earthquake ground motions. The analytical solutions of the average damping power of the system are derived for considering white noise base excitations and the Kanai-Tajimi earthquake model, respectively. Comparisons of the numerical results of a Monte Carlo simulation and the theoretical predictions verify the accuracy of the analytical solutions. Besides, we uncover the influence of the TID parameters on the damping power and output power of the system. The optimal frequency ratio of the TID for maximizing its output power slightly differs from that for seismic response control, and the former varies with site conditions. In contrast, both the damping power and output power are not sensitive to the damping ratio of the TID. For short-period structures, a small inertance-to-mass ratio (µ) of the TID is beneficial to maximize its output power, while seismic response control requires a large µ. For long-period structures, the damping power and output power are not sensitive to the µ. Generally, a structure-TID system on a soft soil site absorbs more energy from a given earthquake and is capable of harvesting more energy than that on a hard soil site. This study may help develop new strategies for self-powered control and monitoring in civil structures.

SEISMIC AMPLIFICATION AT A SOFT SOIL SITE WITH LIQUEFIABLE LAYER

2000 ◽  
Vol 4 (1) ◽  
pp. 1-23 ◽  
Author(s):  
J. YANG∗ ◽  
T. SATO ◽  
X. S. LI
Keyword(s):  
Soft Soil ◽  
Seismic Amplification ◽  
Soil Site

Research on Inelastic Response Spectra for Asymmetric Plan Systems Subjected to Bi-Directional Earthquake Motions

2012 ◽  
Vol 166-169 ◽  
pp. 2332-2336
Author(s):  
Feng Wang ◽  
Hong Nan Li ◽  
Ting Hua Yi
Keyword(s):  
Soft Soil ◽  
Rotation Frequency ◽  
Response Spectra ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Inelastic Response ◽  
Surface Plasticity ◽  
Soil Site ◽  
Spectral Equation

The limitations of traditional inelastic response spectra are discussed. Considering a one-storey asymmetric plan system subjected to perpendicular bi-directional earthquake motions, the inelastic multi-dimensional strength reduction factor spectra is presented. The yield rule of the asymmetric plan system is determined by two-dimensional yield-surface plasticity function. The spectral equation is simplified by the relationship of strength reduction factors between x-direction and y-direction.The multi-dimensional spectra are analyzed based on 30 pair strong earthquake motion records for hard soil site, intermediate soil site and soft soil site. Analytic results shows that the strength reduction factor mean spectra for each soil site has its own characteristics, and the strength reduction factor spectra is affected strongly by ductility, normalized stiffness eccentricity, period and rotation frequency ratio.

scholarly journals Application of Resistivity Seismic Flat Dilatometer (RSDMT) System for Multiple Evaluation of the Soft Soil Site

2012 ◽  
Vol 28 (12) ◽  
pp. 111-122 ◽  
Author(s):  
Eun-Seok Bang ◽  
Young-Sang Kim ◽  
Sam-Gyu Park ◽  
Dong-Soo Kim
Keyword(s):  
Soft Soil ◽  
Soil Site

Surface settlements at a soft soil site due to bedrock dewatering

2009 ◽  
Vol 107 (3-4) ◽  
pp. 109-117 ◽  
Author(s):  
Debasis Roy ◽  
Keith E. Robinson
Keyword(s):  
Soft Soil ◽  
Soil Site ◽  
Surface Settlements

The site response of two rock and soil station pairs to strong and weak ground motion

1991 ◽  
Vol 81 (5) ◽  
pp. 1885-1899
Author(s):  
Robert B. Darragh ◽  
Anthony F. Shakal
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Soft Soil ◽  
Ground Acceleration ◽  
Ground Shaking ◽  
Soil Site ◽  
Rock Site ◽  
Loma Prieta ◽  
Strong Ground ◽  
Stiff Soil

Abstract The site response to strong and weak ground motion depends largely on the subsurface conditions at the soil site for the two rock-soil station pairs studied. The first station pair consists of a soft-soil site (Treasure Island) and a sandstone and shale site (Yerba Buena Island). These stations recorded strong ground shaking from the Loma Prieta mainshock and weak ground motion from four aftershocks. The range of peak ground acceleration is from approximately 0.00006 to 0.07 g at the rock site. Compared to the rock site, the strong ground motion at the soft-soil site is amplified by a factor of about 3 over a frequency range from 0.5 to 2.0 Hz. The amplification is much higher for weak motion and suggests a dependence on signal amplitude. For example, near 1 Hz, the site response shows an increasing amplification as magnitude (and the peak velocity at the rock site) decreases. For events of local magnitude 7.0, 4.3, 4.1, 3.5, and 3.3, the maximum soil-site amplifications are 4, 12, 17, 19, and 25, respectively. A second station pair consisting of a stiff-soil site (Gilroy #2) and a sandstone site (Gilroy #1) was also studied with contrasting results. These two stations recorded strong ground shaking from the 1979 Coyote Lake, 1984 Morgan Hill, and 1989 Loma Prieta mainshocks. Weak ground motion was recorded at these stations after the Loma Prieta mainshock. The range of peak ground acceleration is from 0.006 to 0.43 g at the rock site. Unlike the results for the soft-soil study above, the estimated stiff-soil site responses are not significantly different for strong and weak motion from 0.5 to 2.0 Hz. Near 0.7 Hz, the stiff-soil site responses range from 2.5 to 4.5 for strong ground shaking from three mainshocks and from 1.5 to 4.0 for weak ground shaking from thirteen aftershocks.

scholarly journals The Study of Soft Soil Seismic Subsidence Based On 3D Model

2021 ◽  
Author(s):  
Ping li ◽  
Junru Gu ◽  
Yingci Liu ◽  
Yuying Li
Keyword(s):  
Ground Motion ◽  
Soft Soil ◽  
Low Frequency ◽  
High Sensitivity ◽  
Simulation Method ◽  
High Amplitude ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Dynamic Finite Element Analysis ◽  
Soil Site

Abstract Soft soils are characterized by high sensitivity, low strength, and susceptibility to seismic subsidence. In this study, nonlinear dynamic finite element analysis was performed by OpenSees numerical simulation method to evaluate seismic subsidence response of soft soil site to input ground motions. Higher peak acceleration of ground motion enhanced degree of uneven seismic subsidence, depth of seismic depression, and damage to horizontal surface. Frequency characteristics of a ground motion are another factor influencing seismic subsidence of soft soil. Similar predominant frequency of a ground motion to natural frequency of soil site, high number of low frequency contents, and high amplitude of a ground motion promoted a more severe seismic subsidence of soft soil. The findings of this study expand current understanding on seismic subsidence of soft soil.

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