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.

Soil Liquefaction Evaluation of Offshore Site Based on In Situ Shear Wave Velocity Measurements

2013 ◽  
Vol 405-408 ◽  
pp. 470-473
Author(s):  
Sheng Jie Di ◽  
Ming Yuan Wang ◽  
Zhi Gang Shan ◽  
Hai Bo Jia
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Wind Farm ◽  
Soil Liquefaction ◽  
Offshore Wind ◽  
Velocity Measurements ◽  
Liquefaction Resistance ◽  
Liquefaction Potential

A procedure for evaluating liquefaction resistance of soils based on the shear wave velocity measurements is outlined in the paper. The procedure follows the general formal of the Seed-Idriss simplified procedure. In addition, it was developed following suggestions from industry, researchers, and practitioners. The procedure correctly predicts moderate to high liquefaction potential for over 95% of the liquefaction case histories. The case study for the site of offshore wind farm in Jiangsu province is provided to illustrate the application of the proposed procedure. The feature of the soils and the shear wave velocity in-situ tested in site are discussed and the liquefaction potential of the layer is evaluated. The application shows that the layers of the non-cohesive soils in the depths 3-11m may be liquefiable according to the procedure.

Penetration Testing of Liquefaction Potential of Ashes due to Seismic Load

2016 ◽  
Vol 837 ◽  
pp. 140-145
Author(s):  
Ivan Slavik
Keyword(s):  
Sandy Soils ◽  
Unit Weight ◽  
Seismic Load ◽  
High Porosity ◽  
Liquefaction Resistance ◽  
Liquefaction Potential ◽  
Penetration Testing ◽  
Lake City ◽  
Penetration Tests ◽  
Cpt Test

Geomaterials with typical low unit weight and high porosity are significantly prone to liquefaction as a result of dynamic – seismic load. Investigation of geomaterials that are prone to liquefaction due to seismic load can use certain SPT and CPT penetration tests. The method of investigating liquefaction caused by seismic activity was developed based on numerous penetration tests of sandy or silty–sandy soils and was elaborated in detail at the Workshop on Evaluation of Liquefaction Resistance of Soil, NCEER, Salk Lake City, USA, 1996. In the present paper, the results of penetration CPT test conducted at the ash impoundment in Zemianske Kostoľany are analyzed using methodology NCEER.

Prediction of liquefaction potential and pore water pressure beneath machine foundations

2014 ◽  
Vol 4 (3) ◽  
Author(s):  
Mohammed Fattah ◽  
Mohammed Al-Neami ◽  
Nora Jajjawi
Keyword(s):  
Pore Water ◽  
Sandy Soil ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Liquefaction ◽  
Elastic Model ◽  
Liquefaction Resistance ◽  
Overburden Pressure ◽  
Liquefaction Potential ◽  
Frequency Changes

AbstractThe present research is concerned with predicting liquefaction potential and pore water pressure under the dynamic loading on fully saturated sandy soil using the finite element method by QUAKE/W computer program. As a case study, machine foundations on fully saturated sandy soil in different cases of soil densification (loose, medium and dense sand) are analyzed. Harmonic loading is used in a parametric study to investigate the effect of several parameters including: the amplitude frequency of the dynamic load. The equivalent linear elastic model is adopted to model the soil behaviour and eight node isoparametric elements are used to model the soil. Emphasis was made on zones at which liquefaction takes place, the pore water pressure and vertical displacements develop during liquefaction. The results showed that liquefaction and deformation develop fast with the increase of loading amplitude and frequency. Liquefaction zones increase with the increase of load frequency and amplitude. Tracing the propagation of liquefaction zones, one can notice that, liquefaction occurs first near the loading end and then develops faraway. The soil overburden pressure affects the soil liquefaction resistance at large depths. The liquefaction resistance and time for initial liquefaction increase with increasing depths. When the frequency changes from 5 to 10 rad/sec. (approximately from static to dynamic), the response in displacement and pore water pressure is very pronounced. This can be attributed to inertia effects. Further increase of frequency leads to smaller effect on displacement and pore water pressure. When the frequency is low; 5, 10 and 25 rad/sec., the oscillation of the displacement ends within the period of load application 60 sec., while when ω = 50 rad/sec., oscillation continues after this period.

The Characterization of Stratigraphic Play in Middle Baong Sand for Hydrocarbon Prospecting in Offshore North Sumatera Basin

2021 ◽  
Author(s):  
A. Nurhasan
Keyword(s):  
Depositional Environment ◽  
Hydrocarbon Exploration ◽  
Ratio Distribution ◽  
Basin Floor ◽  
Distinct Character ◽  
Net To Gross ◽  
And Migration ◽  
Sand Bodies ◽  
Malacca Strait

Pertamina EP is operating a small block in Offshore North Sumatera Basin where a couple of the fields are producing gas and condensate from the Belumai Carbonate. However, the wells production is depleting and several delineation wells are unable to find additional reserves, it is important to find a new play within the block. Few discoveries in the Middle Baong Sand (MBS) reservoir suggested a promising stratigraphic play to be explored, but it requires more detailed characterization of the reservoir extent. The Malacca strait-sourced MBS consists of several deposited sand packages during a mega sequence. The term MBS might represent a deltaic environment from a transgressive system tract of some marine shore bar or a basin floor fan. Each system has a distinct character (thickness, net to gross ratio, distribution) that must be evaluated before proposing an exploration well. The depositional environment and reservoir distribution are interpreted and modeled using regional 2D seismic and high-quality 3D seismic. Paleo-bathymetric interpretation from well samples shows a good correlation with the palinspastic reconstruction. The result shows that the Pertamia EP working area is located in the shore bar depositional environment. Seismic attributes are used to delineate reservoir distribution within the working block and well logs are used to constrain prospective sand bodies and water zones identification. Furthermore, source rock maturation and migration path and hydrocarbon occurrence from the discovery wells have been evaluated for hydrocarbon prospecting and risking. This study suggests a promising lead for hydrocarbon exploration in the study area and opens up a new opportunity for an underexplored play.

THE GEOCHEMICAL CHARACTERIZATION OF AUSTRALIAN CRUDE OILS

1972 ◽  
Vol 12 (1) ◽  
pp. 125
Author(s):  
T.G. Powell ◽  
D.M. McKirdy
Keyword(s):  
Organic Matter ◽  
Organic Material ◽  
Depositional Environment ◽  
Land Plant ◽  
Crude Oils ◽  
Geochemical Characterization ◽  
Marine Organic Matter ◽  
Show Evidence ◽  
Lower Palaeozoic

Australian oils are generally light by world standards. They have API gravities greater than 35°, low sulphur and asphalt contents, and are of paraffinic or naphthenic base. The geochemical similarity of oils from the Bowen-Surat Basin, with the notable exception of the Conloi crude, is most marked in the fraction boiling above 250 °C. Oils from the Cooper, Gippsland and Otway Basins are probably derived from terrestrial organic material, but differ in their degree of maturation as indicated by n-alkane patterns. Samples from the Perth Basin exhibit a similar variation in maturity. In the Carnarvon Basin, the Windalia crude differs from those in deeper reservoirs in containing a higher proportion of oxygen-bearing, nitrogen-bearing, and sulphur-bearing compounds, another sign of a less mature oil. The East Mereenie oil displays an odd-even predominance in its n-alkane distribution which is characteristic of some Lower Palaeozoic crudes. A Papuan Basin condensate is the only available sample produced from a limestone reservoir. This probably accounts for its higher sulphur content. Two seeps obtained from the Papuan Highlands are inspissated residues which may have suffered microbiological alteration.A major control of the composition of Australian crude oils appears to be the depositional environment of the source rock. Most of the oils show evidence of having been generated, at least in part, from terrestrial (as opposed to marine) organic matter. The location of all but one of the reservoirs within sequences dominated by the sandstone - shale association is consistent with the likely contribution of land plant detritus to their source environment. Likewise, low sulphur and asphalt values reflect the scarcity of favourable carbonate-evaporite source and reservoir situations in Australia.

Characterization of Ground Response and Liquefaction for Kathmandu City Based on 2015 Earthquake Using Total Stress and Effective Stress Approach

2020 ◽  
Vol 11 (2) ◽  
pp. 1-25
Author(s):  
Shiv Shankar Kumar ◽  
Pradeep Acharya ◽  
Pradeep Kumar Dammala ◽  
Murali Krishna Adapa
Keyword(s):  
Peak Ground Acceleration ◽  
Seismic Vulnerability ◽  
Ground Motions ◽  
Total Stress ◽  
Ground Response ◽  
Ground Acceleration ◽  
Liquefaction Potential ◽  
Potential Index ◽  
Semi Empirical

This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.

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