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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
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Journal DOI :
Korean Geotechical Society
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Volume & Issues
Volume 25, Issue 12 - Dec 2009
Volume 25, Issue 11 - Nov 2009
Volume 25, Issue 10 - Oct 2009
Volume 25, Issue 9 - Sep 2009
Volume 25, Issue 8 - Aug 2009
Volume 25, Issue 7 - Jul 2009
Volume 25, Issue 6 - Jun 2009
Volume 25, Issue 5 - May 2009
Volume 25, Issue 4 - Apr 2009
Volume 25, Issue 2 - Feb 2009
Volume 25, Issue 1 - Jan 2009
Selecting the target year
A Study on Application of HWAW Method to the Non-horizontally Layered Soil Structure
Bang, Eun-Seok ; Park, Heon-Joon ; Park, Hyung-Choon ; Kim, Dong-Soo ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 5~17
In HWAW method, experimental dispersion curve is obtained through time-frequency analysis, and inversion procedure is based on the forward modeling which considers full wavefield. Therefore, it enables us to use relatively short testing setup and has advantage for two dimensional subsurface imaging compared with another surface wave methods. Numerical study was performed to verify that the HWAW method can be applied to non-horizontally layerd soil structure. The experimental dispersion curves obtained from HWAW method agreed with the theoretical dispersion curves based on full wavefield. Experimental dispersion curves are mainly more affected by the region between two receivers than by the region from source to the first receiver. Fluctuation phenomena of dispersion curve can be reduced by adequate receiver spacing setup. From numerical study, it was thought that reliable Vs distribution map can be constructed by HWAW method and finally subsurface imaging was tried in the real field.
Characteristics of Collapsed Retaining Walls Using Elasto-plastic Method and Finite Element Method
Jeong, Sang-Seom ; Kim, Young-Ho ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 19~29
In this study, a numerical analysis was performed to predict the sequential behavior of anchored retaining wall where the failure accident took place, and verified accuracy of prediction through the comparisons between prediction and field measurement. The emphasis was given to the wall behaviors and the variation of sliding surface based on the two different methods of elasto-plastic and finite element (shear strength reduction technique). Through the comparison study, it is shown that the bending moment and the soil pressure at construction stages produce quite similar results in both the elasto-plastic and finite element method. However, predicted wall deflections using elasto-plastic method show underestimate results compared with measured deflections. This demonstrates that the elasto-plastic method does not clearly consider the influence of soil-wall-reinforcement interaction, so that the tension force (anchor force and earth pressure) on the wall is overestimated. Based on the results obtained, it is found that finite element method using shear strength reduction method can be effectively used to perform the back calculation analysis in the anchored retaining wall, whereas elasto-plastic method can be applicable to the preliminary design of retaining wall with suitable safety factor.
Fast Consolidation Test Using Seepage Forces : Method and Validation
Lee, Kang-Il ; Kim, Tae-Hyung ; Znidarcic, Dobroslav ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 31~38
A continuous, fast, and convenient experimental method, replacing recent tests such as standard oedometer or self weight consolidation test, is needed for the determination of the consolidation behavior of unformed soft soils. This study introduced the seepage induced fast consolidation test using the flow pump technique. It can obtain the consolidation characteristics of unformed soft soils conveniently and fast. The seepage induced consolidation test apparatus consists of a modified triaxial cell, differential pressure transducer, flow pump, and displacement transducer. The test continuously proceeds with starting seepage forces induced consolidation, loading consolidation, and permeability test on the same sample. In addition, this test result was compared with the standard oedometer test result to make this method valid. From this study it was found that this method is a convenient and time saving effective method for obtaining data required for calculation of consolidation settlement of unformed soft soils.
Characteristics of Shear Behavior for Coarse Grained Materials Based on Large Scale Direct Shear Test (III) - Final Comprehensive Analysis -
Lee, Dae-Soo ; Kim, Kyoung-Yul ; Hong, Sung-Yun ; Oh, Gi-Dae ; Jeong, Sang-Seom ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 39~54
Large scale direct shear tests were carried out to analyze the shear behavior of crushed rocks at local representative quarries. Shear strength for each specimen was derived and the effects on shear behavior induced by the variation of factors such as particle size, water immersion, density, uniformity coefficient, and particle breakage were evaluated and quantitatively compared with previous studies. The opportunity was also taken to identify stress-dilatancy relation of crushed rocks following the energy-based theory and friction coefficients at critical state as well as peak friction angles and dilation angles were estimated. As a result of tests it was found that uniaxial compressive strength and particle breakage of the parent rocks have crucial effect on internal friction angles; in addition, dilatancy at the failure showed strong relationship as well.
A Study on Development and Application of New Borehole Roughness and Verticality Measurement System (BKS-LRFS) for Drilled Shafts
Park, Bong-Geun ; Nam, Moon-S. ; Choi, Yong-Kyu ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 55~68
A new borehole roughness and verticality measurement system (BKS-LRPS) for rock socketed drilled shafts were developed and verified its field application. The stability of BKS-LRPS was verified for several field conditions, which included the effect of measuring unit shaking, the application of water/air calibration factors, and the resistance of high water pressure inside piles. Also, effective measurement distances for various conditions of turbidity were defined in the field by measuring borehole roughness and vertical alignment for 6 drilled shafts. Vertical alignments for all drilled shafts could be measured by BKS-LRPS. However, borehole roughness was not able to be measured due to high turbidity caused by RCD drilling processing. Based on the BKS-LRPS field verification, BKS-LRPS is the first borehole roughness and verticality measurement system applying both in the water and air.
Analysis of Laterally Loaded Pile-Bent Structure with Varying Cross-sectional Area
Jeong, Sang-Seom ; Sung, Chul-Gyu ; Ko, Jun-Young ; Kim, Soo-Il ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 69~75
The load distribution and deformation of pile-bent structures are investigated using a numerical study. A numerical analysis that takes into account the effects of varying cross-sectional area was performed for different pier diameters, loading steps, and soil conditions. Through the comparison study, it is shown that the location of maximum bending moment is almost the same per each loading step, regardless of varying cross-sections. However, the member force (i.e., stress of pile material) has the largest value at the ground surface when the cross-section is changed. Based on the results obtained, it is found that the location of maximum member force influences highly the behavior of pile-bent structure with varying cross-sections for repair works.
The Behavior and Capacity of Lateral Loaded Rigid Pile Characteristics in Multi-layered Soil Conditions
Kyung, Doo-Hyun ; Kang, Beong-Joon ; Hong, Jung-Moo ; Lee, Jun-Hwan ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 77~90
In this study, experimental analysis was performed about lateral load capacity and behavior of laterally loaded-bored rigid piles in muti-layered soil conditions. Lateral pile load tests were performed for muti-layerd soils consisting of different relative density. Ultimated lateral load capacities were measured from lateral load-displacement curves and compared with estimated values using theoretical methods. Bending moments and unit lateral capacity distribution of surrounding piles were measured from attached strain gauges and earth pressure sensors on the pile. It was found that ultimated lateral load capacities were different from the muti-layered soil conditions, and measured values were lower than estimated values. The bending moment distributions of the pile were similar all the time. Unit lateral capacity distributions were a little different from muti-layered soil conditions, but basically similar to the distribution proposed by Prasad and Chari (1999).
Analysis on the Rainfall Triggered Slope Failure with a Variation of Soil Layer Thickness: Flume Tests
SaGong, Myung ; Yoo, Jea-Ho ; Lee, Sung-Jin ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 91~103
Slope failure depends upon the climatic features related to related rainfall, structural geology and geomorphological features as well as the variation of the mechanical behaviors of soil constituting a slope. In this paper, among many variables, effects of soil layer thickness on the slope failure process, and variations of matric suction and volumetric water content were observed. When the soil layer is relatively thick, the descending wetting front decreases matric suction and the observed matric suction reaches to "0" value. When the wetting front reaches to the impermeable boundary, the bottom surface of steel soil box, ascending wetting front was observed. This observation can be postulated to be the effects of various sizes of pores. When macro size pores exist, the capillary effects can be reduced and infilling of pore will be limited. The partially filled pores would be filled with water during the ascending of the wetting front, which bounces from the impermeable boundary. This assumption has been assured from the observation of variation of the volumetric water contents at different depth. When the soil layer is thick (thickness = 20 cm), for granular material, erosion is a cause triggering the slope failure. It has been found that the initiation of erosion occurs when the top soil is fully saturated. Meanwhile, when the soil layer is shallow (thickness = 10 cm), slope slides as en mass. The slope failure for this condition occurs when the wetting front reaches to the interface between the soil layer and steel soil box. As the wetting front approaches to the bottom of soil layer, reduction of shear resistance along the boundary and increase of the unit weight due to the infiltration occur and these produce complex effects on the slope failure processes.
Characteristics of Friction Angles between the Nak-dong River Sand and Construction Materials by Direct Shear Test
Kim, Young-Su ; Kim, Dae-Man ;
Journal of the Korean Geotechnical Society, volume 25, issue 4, 2009, Pages 105~112
In this study, a series of direct shear tests were performed to investigate the characteristics of friction angles for sands and interface friction angle between sands and construction materials with respect to different relative density of the Nak-dong River sands and shearing velocity. The result of the test shows that friction angles of sands are always higher than interface friction angle between sands and construction materials. As the shearing velocity get faster, the friction angles of sand became higher. With respect to the density of sand by reducing void ratio, friction angles increase linearly, and relevant equations were proposed to calculate the friction angle by changing void ratio and relative density of sand. The interface roughness of construction materials was also an important factor in interface friction angle.