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CONTENTS
Volume 7, Number 6, December 2014
 

Abstract
This study includes determination of liquefaction potential in Erzincan city center. Erzincan Province is situated within first-degree earthquake zone on earthquake map of Turkey. In this context, the earthquake scenarios were produced using the empirical expressions. Liquefaction potential for different earthquake magnitudes (6.0, 6.5, 7.0) were determined. Liquefaction potential was investigated using Standard Penetration Test (SPT). Liquefaction potential analyses are determined in two steps: geotechnical investigations and calculations. In the first steps, boreholes were drilled to obtain disturbed and undisturbed soil samples and SPT values were obtained. Laboratory tests were made to identify geotechnical properties of soil samples. In the second step, liquefaction potential analyses were examined using two methods, namely Seed and Idriss (1971), Iwasaki et al. (1981). The liquefaction potential broadly classified into three categories, namely non-liquefiable, marginally liquefiable and liquefiable regions. Additionally, the liquefaction potential index classified into four categories, namely non-liquefiable, low, high and very high liquefiable regions. In order to liquefaction analysis complete within a short time, MATLAB program were prepared. Following the analyses, liquefaction potential index is investigated by Iwasaki et al. (1982) methods. At the final stage of this study, liquefaction potential maps and liquefaction potential index maps of the all study area by using IDW (inverse distance weighted) interpolation method in Geostatistical Analyst Module of ArcGIS 10.0 Software were prepared for different earthquake magnitudes and different depths. The results of soil liquefaction potential were evaluated in ArcGIS to map the distributions of drillings with liquefaction potential. The maps showed that there is a spatial variability in the results obtained which made it difficult to clearly separate between regional areas of high or low potential to liquefy. However, this study indicates that the presence of ground water and sandy-silty soils increases the liquefaction potential with the seismic features of the region.

Key Words
liquefaction; liquefaction potential; liquefaction potential index; earthquake; geostatistical analysis; standard penetration test

Address
(1) Esra Subaşı Duman:
Civil Engineering Department, Turgut Ozal University, Ankara, 06010, Turkey;
(2) Sabriye Banu Ikizler, Zekai Angın:
Civil Engineering Department, Karadeniz Technical University, Trabzon, 61080, Turkey;
(3) Gökhan Demir:
Civil Engineering Department, 19 Mayıs University, Samsun, 55139, Turkey.

Abstract
To complement the method of field-scale seismic ground motion simulations by buried blast techniques, the application and evaluation of the capability of a numerical modeling platform to simulate buried explosion-induced ground motion at a real soil site is presented in this paper. Upon a layout of the experimental setup at a level site wherein multiple charges that were buried over a large-diameter circle and detonated in a planned sequence, the formulation of a numerical model of the soil and the explosives using the finite element code LS-DYNA is developed for the evaluation of the resulting ground motion and surface subsidence. With a compact elastoplastic cap model calibrated for the loess soils on the basis of the site and laboratory test program, numerical solutions are obtained by explicit time integration for various dynamic aspects and their relation with the field blast experiment. Quantitative comparison of the computed ground acceleration time histories at different locations and induced spatial subsidence on the surface afterwards is given for further engineering insights in regard to the capabilities and limitations of both the numerical and experimental approaches.

Key Words
buried explosion; field tests; numerical method; earthquakes; ground motion; ground subsidence

Address
(1) Zhi-Chao Zhang, Han-Long Liu, Yu-Min Chen:
College of Civil and Transportation Engineering, Hohai University, Nanjing, China;
(2) Ronald Y.S. Pak:
Department of Civil, Environmental & Architectural Engineering, University of Colorado, Boulder, CO, USA.

Abstract
Biopolymers, polymers produced by living organisms, are used in various fields (e.g., medical, food, cosmetic, medicine) due to their beneficial properties. Recently, biopolymers have been used for control of soil erosion, stabilization of aggregate, and to enhance drilling. However, the inter-particle behavior of such polymers on soil behavior are poorly understood. In this study, an artificial biopolymer (β-1,3/1,6-glucan) was used as an engineered soil additive for Korean residual soil (i.e., hwangtoh). The geotechnical behavior of the Korean residual soil, after treatment with β-1,3/1,6-glucan, were measured through a series of laboratory approaches and then analyzed. As the biopolymer content in soil increased, so did its compactibility, Atterberg limits, plasticity index, swelling index, and shear modulus. However, the treatment had no effect on the compressional stiffness of the residual soil, and the polymer induced bio-clogging of the soil

Key Words
beta-1,3/1,6-glucan; biopolymer; Korean residual soil; geotechnical behavior; elastic wave

Address
(1) Ilhan Chang:
SOC Research Institute, Korea Institute of Civil Engineering and Building Technology (KICT), 283 Goyangdae-ro, Ilsanseo-gu, Goyang 411-712, Republic of Korea;
(2) Gye-Chun Cho:
Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.

Abstract
In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has become popular as a ground improvement technique for sandy soil. However, this technique was not applied to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work. Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate. Change in the permeability was measured before and after biocementation. The test results showed that the pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found that the biocementation can be considered as an effective method for reducing permeability of organic soil. The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray (EDX) analysis.

Key Words
bacillus pasteurii; organic soil; biocementation; pH distribution; calcimeter test; permeability of organic soil; scanning electron microscope; -energy-dispersive x-ray-

Address
(1) Waleed S. Sidik, Hanifi Canakci, Fatih Celik:
Department of Civil Engineering, Gaziantep University, Gaziantep, Turkey;
(2) Ibrahim H. Kilic:
Department of Biology, Gaziantep University, Gaziantep, Turkey;
(3) Waleed S. Sidik:
Department of Civil Engineering, Kirkuk University, Kirkuk, Iraq.

Abstract
In discrete element modeling, 2D software has been widely used in order to gain further insights into the fundamental mechanisms with less computational time. The porosities used in 2D DEM studies should be determined with appropriate approaches based on 3D laboratory porosities. This paper summarizes the main approaches for converting porosities from 3D to 2D for DEM studies and theoretical evaluations show that none of the current approaches can be widely used in dealing with soil mechanical problems. Therefore, a parabolic equation and a criterion have been suggested for the determination of 2D porosities in this paper. Moreover, a case study has been used to validate that the 2D porosity obtained from the above suggestion to be rational with both the realistic contact force distribution in the specimen and the good agreement of the DEM simulation results of direct shear tests with the corresponding experimental data. Therefore, the parabolic equation and the criterion are suggested for the determination of 2D porosities in a wide range of polydisperse particle systems, especially in dealing with soil mechanical problems.

Key Words
discrete element method (DEM); 2D porosity; criterion; soil mechanics; Particle Flow Code (PFC)

Address
(1) Zhijie Wang, Felix Jacobs, Martin Ziegler:
Institute of Geotechnical Engineering, RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany;
(2) Axel Ruiken:
Wayss & Freytag Spezialtiefbau GmbH, Wiesenstr. 21 A II, 40549 Dusseldorf, Germany (formerly at RWTH Aachen University, Germany).

Abstract
This paper investigates nonlinear response of 51 laterally loaded rigid piles in sand. Measured response of each pile test was used to deduce input parameters of modulus of subgrade reaction and the gradient of the linear limiting force profile using elastic-plastic solutions. Normalised load - displacement and/or moment - rotation curves and in some cases bending moment and displacement distributions with depth are provided for all the pile tests, to show the effect of load eccentricity on the nonlinear pile response and pile capacity. The values of modulus of subgrade reaction and the gradient of the linear limiting force profile may be used in the design of laterally loaded rigid piles in sand.

Key Words
piles; lateral loading; shear modulus; modulus of subgrade reaction; ultimate soil resistance

Address
(1) Hongyu Qin:
School of Engineering, Griffith University, Gold Coast, QLD 4222, Australia;
(2) Wei Dong Guo:
School of Civil, Mining and Environmental Engineering, University of Wollongong, NSW 2522, Australia.


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