scholarly journals Probabilistic Site Identification Analysis Using NUPEC Recorded Free-Field Motions

2002 ◽  
Author(s):  
J. Xu ◽  
C. Costantino ◽  
C. Hofmayer ◽  
A. Murphy ◽  
Y. Kitada
Keyword(s):  
Soil Properties ◽  
Free Field ◽  
Soil Layer ◽  
Random Variable ◽  
Response Spectra ◽  
Test Site ◽  
Linear Convolution ◽  
Site Identification ◽  
Identification Analysis

This paper describes a probabilistic site identification analysis performed by BNL, using the free-field earthquake motions recorded at the NUPEC test site. The BNL analysis was intended to provide adequate characterization of the soil properties for the test site to be used for the SSI analyses. The free-field data were provided by NUPEC. The methodology employed in the BNL probabilistic analysis of site identification includes the Monte Carlo process in conjunction with equivalent linear convolution analyses for generating a large number of site profiles for use in convolution studies from which mean estimates of response can be generated. The random variable selected to characterize the site profile is the shear wave velocity in each soil layer of the site profile. A lognormal distribution was assumed with the standard deviation determined from available site data and applicable regulatory requirements. The convolution analyses were performed using an appropriate soil degradation model and the outcrop input motions generated from the recorded in-rock motions. The BNL analysis produced results in terms of the mean, median and various fractiles of free-field soil properties at the test site, and the corresponding surface response spectra, which are presented in this paper.

Sensitivity analysis of geotechnical site conditions effect on the seismic response of a saturated inhomogeneous poroviscoelastic soil profile

2018 ◽  
Vol 15 (6) ◽  
pp. 661-677 ◽  
Author(s):  
Toufiq Ouzandja ◽  
Mohamed Hadid
Keyword(s):  
Soil Properties ◽  
Seismic Response ◽  
Pore Water ◽  
Soil Profile ◽  
Water Saturation ◽  
Free Field ◽  
Response Spectra ◽  
Response Analysis ◽  
Content Type ◽  
Linear And Nonlinear

Purpose This paper aims to present the investigation of the linear and nonlinear seismic site response of a saturated inhomogeneous poroviscoelastic soil profile for different soil properties, such as pore-water saturation, non-cohesive fines content FC, permeability k, porosity n and coefficient of uniformity Cu. Design/methodology/approach The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and is characterized by the Biot’s theory, with a shear modulus varying continuously with depth according to the Wichtmann’s model. Seismic response analysis has been evaluated through a computational model, which is based on the exact stiffness matrix method formulated in the frequency domain assuming that the incoming seismic waves consist of inclined P-SV waves. Findings Unlike the horizontal seismic response, the results indicate that the vertical one is strongly affected by the pore water saturation. Moreover, in the case of fully saturated soil profile, the same vertical response spectra are found for the two cases of soil behavior, linear and nonlinear. Originality/value This research is a detailed study of the geotechnical soil properties effect on the bi-directional seismic response of saturated inhomogeneous poroviscoelastic soil profile, which has not been treated before; the results are presented in terms of the peak acceleration ratio, as well as the free-field response spectra and the spectral ratio (V/H).

Corrigendum to: Conservation agriculture effects on soil properties and crop productivity in a semiarid region of India

Soil Research ◽  
2019 ◽  
Vol 57 (2) ◽  
pp. 200 ◽  
Author(s):  
J. Somasundaram ◽  
M. Salikram ◽  
N. K. Sinha ◽  
M. Mohanty ◽  
R. S. Chaudhary ◽  
...  
Keyword(s):  
Soil Properties ◽  
Management Practices ◽  
Crop Yields ◽  
Cropping Systems ◽  
Soil Layer ◽  
Conservation Agriculture ◽  
Semiarid Region ◽  
Reduced Tillage ◽  
Organic C ◽  
Residue Retention

Conservation agriculture (CA) including reduced or no-tillage and crop residue retention, is known to be a self–sustainable system as well as an alternative to residue burning. The present study evaluated the effect of reduced tillage coupled with residue retention under different cropping systems on soil properties and crop yields in a Vertisol of a semiarid region of central India. Two tillage systems – conventional tillage (CT) with residue removed, and reduced tillage (RT) with residue retained – and six major cropping systems of this region were examined after 3 years of experimentation. Results demonstrated that soil moisture content, mean weight diameter, percent water stable aggregates (>0.25mm) for the 0–15cm soil layer were significantly (Pmoderately labile>less labile. At the 0–15cm depth, the contributions of moderately labile, less labile and non-labile C fractions to total organic C were 39.3%, 10.3% and 50.4% respectively in RT and corresponding values for CT were 38.9%, 11.7% and 49.4%. Significant differences in different C fractions were observed between RT and CT. Soil microbial biomass C concentration was significantly higher in RT than CT at 0–15cm depth. The maize–chickpea cropping system had significantly (P–1 followed by soybean+pigeon pea (2:1) intercropping (3.50 t ha–1) and soybean–wheat cropping systems (2.97 t ha–1). Thus, CA practices could be sustainable management practices for improving soil health and crop yields of rainfed Vertisols in these semiarid regions.

CHARACTERIZATION OF LIQUEFACTION RESISTANCE OF SAND: EFFECT OF INITIAL FABRIC

2014 ◽  
Vol 08 (01) ◽  
pp. 1450001 ◽  
Author(s):  
BO LI ◽  
XIANGWU ZENG ◽  
HAO YU
Keyword(s):  
Depositional Environment ◽  
Design Method ◽  
Free Field ◽  
Recent Experience ◽  
Permeability Test ◽  
Fabric Anisotropy ◽  
Liquefaction Resistance ◽  
Liquefaction Potential ◽  
Centrifuge Tests

The micro-fabric of deposition reflects the imprints of its geologic and stress history, its depositional environment, and its weathering history. Recent experience shows that the fabric anisotropy does influence the static and dynamic behavior of granular materials. In this study, a series of centrifuge tests are conducted to investigate the effects of fabric anisotropy on the dynamic response in the free field. The results show the acceleration, pore pressure, and residual settlement is significantly affected by the fabric anisotropy of the ground, which shows the liquefaction resistance of the ground. Meanwhile, the response of acceleration is analyzed in frequency domain, which shows that the model prepared by 90° absorbs more energy than that of 0°. To verify the effects induced by the initial fabric, permeability test are conducted and related to the liquefaction potential. The results indicate the fabric anisotropy should be incorporated into the design method.

scholarly journals Characterization of tillage effects on the spatial variation of soil properties using ground-penetrating radar and electromagnetic induction

Geoderma ◽  
2013 ◽  
Vol 207-208 ◽  
pp. 310-322 ◽  
Author(s):  
François Jonard ◽  
Mohammad Mahmoudzadeh ◽  
Christian Roisin ◽  
Lutz Weihermüller ◽  
Frédéric André ◽  
...  
Keyword(s):  
Soil Properties ◽  
Spatial Variation ◽  
Ground Penetrating Radar ◽  
Electromagnetic Induction ◽  
Ground Penetrating

Characterization of the logistic and loglogistic distributions by extreme value related stability with random sample size

1987 ◽  
Vol 24 (04) ◽  
pp. 838-851 ◽  
Author(s):  
W. J. Voorn
Keyword(s):  
Positive Integer ◽  
Sample Size ◽  
Random Variable ◽  
Logistic Distribution ◽  
Size Distributions ◽  
Random Sample Size ◽  
Maximum Value ◽  
Maximum Stability ◽  
Independent Observations

Maximum stability of a distribution with respect to a positive integer random variable N is defined by the property that the type of distribution is not changed when considering the maximum value of N independent observations. The logistic distribution is proved to be the only symmetric distribution which is maximum stable with respect to each member of a sequence of positive integer random variables assuming value 1 with probability tending to 1. If a distribution is maximum stable with respect to such a sequence and minimum stable with respect to another, then it must be logistic, loglogistic or ‘backward' loglogistic. The only possible sample size distributions in these cases are geometric.

Lateral structure-foundation interaction of structures with base masses

1972 ◽  
Vol 62 (2) ◽  
pp. 453-470
Author(s):  
R. J. Scavuzzo ◽  
D. D. Raftopoulos ◽  
J. L. Bailey
Keyword(s):  
Integral Equation ◽  
Free Field ◽  
Response Spectra ◽  
Elastic Half Space ◽  
Two Dimensional ◽  
Transient Solution ◽  
Volterra Type ◽  
Seismic Motion ◽  
Lateral Structure ◽  
Inertia Forces

abstract The interaction of lateral inertia forces of an N-mass structure with a base mass and lateral seismic motion of the foundation is formulated as an integral equation of the Volterra type. Flexibility of the foundation is based on the transient solution of a two-dimensional elastic half-space. Interaction effects are evaluated by comparing the response spectra of the free-field motion to that of the foundation motion. Results show that changes in the response spectra are significant for heavy, stiff structures such as a reactor-containment vessel.

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