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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
Journal Basic Information
Journal DOI :
Korean Geotechical Society
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Volume & Issues
Volume 22, Issue 12 - Dec 2006
Volume 22, Issue 11 - Nov 2006
Volume 22, Issue 10 - Oct 2006
Volume 22, Issue 9 - Sep 2006
Volume 22, Issue 8 - Aug 2006
Volume 22, Issue 7 - Jul 2006
Volume 22, Issue 6 - Jun 2006
Volume 22, Issue 5 - May 2006
Volume 22, Issue 4 - Apr 2006
Volume 22, Issue 3 - Mar 2006
Volume 22, Issue 2 - Feb 2006
Volume 22, Issue 1 - Jan 2006
Selecting the target year
A Study of the Bottom Ash as Environmentally Grouting Materials
Doh, Young-Gon ; Kwon, Hyuk-Doo ; Lee, Song ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 5~11
The purpose of this study was to examine the proper mixing ratio of ordinary portland cement and Bottom Ash to recycle the Bottom Ash, which is an industrial waste. After the evaluation, the compressive strength and durability were assessed using the mixture of completely weathered soil (Hwangto), weathered granite soil, and Bentonite. Then environmental friendliness of this mixed material was examined through heavy metal leaching method. It was found out that proper mixing ratio is 6:4, and that the 6% mixture quantity of completely weathered soil (Hwangto), weathered granite soil, and Bentonite is the most effective for compressive strength and durability It was also found out through heavy metal leaching method that the Bottom Ash could be below the standard of the Clean Water Law.
The Effect of Remedial Works to Control the Leakage Problem in Earth Fill Dam by Compaction Grouting
Chun, Byung-Sik ; Lee, Yong-Jae ; Chung, Ha-Ik ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 13~23
The sinkhole and leakage in dam core were detected at one of earth fill dams in Korea. The damage areas in the core of the dam were repaired by compaction grouting method. This study is to evaluate compaction grouting activity by in-situ and laboratory experiments before, during and after the remedial work. The intensive site investigation and geophysical survey were conducted during and after the compaction grouting work. The compaction grouting work was carried out for the damaged dam core between June 16 and August 24, 2000. The leakage reduction generally occurred in the core of the dam after the remedial work. The use of compaction grouting was considered the proper countermeasures for repairing the damaged dam. It shows that the loose or voided zones have been properly filled and the leakage has been reduced by about 96% of that before the treatment of the remedial work performed at dam core by compaction grouting.
Compressive Behaviors of Reinforced Lightweight Soil Using Waste Fishing Net
Kim, Yun-Tae ; Kim, Hong-Joo ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 25~35
This paper investigates the mechanical characteristics of reinforced lightweight soil (RLS) using waste fishing net. RLS used in this experiment consists of dredged soil taken from construction site of Busan New Port, cement, air foam and waste fishing net. Several series of laboratory tests were performed to compare behavior characteristics between RLS and unreinforced lightweight soil, in which the reinforced effect by waste fishing net on RLS was evaluated. The experimental results of RLS indicated that the stress-strain relationship and the unconfined compressive strength are strongly influenced by the content of waste fishing net. Compressive strength of RLS Increased with the increase in curing time and generally increased by adding waste fishing net, but the amount of increase in compressive strength was not proportional to the content of waste fishing net. In this test, the maximum increase in compressive strength was obtained at 0.25% content of waste fishing net. On the other hand, water content of RLS rapidly decreased up to 7 days of curing time and converged to constant value.
Implementation of Bender Element to In-situ Measurement of Stiffness of Soft Clays
Mok, Young-Jin ; Jung, Jae-Woo ; Han, Man-Jin ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 37~45
Bender elements, composed of thin piezo-ceramics and elastic shims, have been used to measure shear wave velocities of specimens in laboratories. In a preliminary stage of their field applications, an in-house research of optimizing suitable bender elements and their geometrical arrangement has been carried out in a barrel of kaolinite-water mixture. Two types of measurement configuration, similar to cross-hole and in-hole seismic testing, have been implemented. prototype instrumented rods were penetrated into a soft clay layer in the west coast and excellent shear waves were recorded. Development of penetration device (mandrel) and associated instrumented rods are in progress for deeper investigation.
Characteristics of Shear Wave Velocity as Stress-induced and Inherent Anisotropies
Lee, Chang-Ho ; Yoon, Hyung-Koo ; Truong, Hung-Quang ; Cho, Tae-Hyeon ; Lee, Jong-Sub ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 47~54
Shear wave velocity of uncemented soil can be expressed as the function of effective stresses when capillary phenomena are negligible. However, the terms of effective stresses are divided into the direction of wave propagation and polarization because stress states are generally anisotropy. The shear wave velocities are affected by
exponents that are experimentally determined. The
exponents are controlled by contact effects of particulate materials (sizes, shapes, and structures of particles) and the
parameters are changed by contact behaviors among particles, material properties of particles, and type of packing (i.e., void ratio and coordination number). In this study, consolidation tests are performed by using clay, mica and sand specimens. Shear wave velocities are measured during consolidation tests to investigate the stress-induced and inherent anisotropies by using bender elements. Results show the shear wave velocity depends on the stress-induced anisotropy for round particles. Furthermore, the shear wave velocity is dependent on particle alignment under the constant evvective stress. This study suggests that the shear wave velocity and the shear modulus should be carefully estimated and used for the design and construction of geotechnical structures.
Prediction of the Damage Zone Induced by Rock Blasting Using a Radial Crack Model
Sim, Young-Jong ; Cho, Gye-Chun ; Kim, Hong-Taek ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 55~64
It is very Important to predict the damage zone of a rock mass induced by blasting for the excavation of an underground cavity such as a tunnel, as the damage zones incur mechanical and hydraulic instability of the rock mass potentially. Complicated blasting processes that can hinder the proper characterization of the damage zone can be effectively represented by two loading mechanisms. The first mechanism is the dynamic impulsive load-generating stress waves that radiate outwards immediately after detonation. This load creates a crushed annulus along with cracks around the blasthole. The second is the gas pressure that remains for an extended time after detonation. As the gas pressure reopens some arrested cracks and extends these, it contributes to the final structure of the damage zone induced by the blasting. This paper presents a simple method to evaluate the damage zone induced by gas pressure during rock blasting. The damage zone is characterized by analyzing crack propagations from the blasthole. To do this, a model of a blasthole with a number of radial cracks that are equal in length in a homogeneous infinite elastic plane is considered. In this model, crack propagation is simulated through the use of only two conditions: a crack propagation criterion and the mass conservation of the gas. The results show that the stress intensity factor of a crack decreases as the crack propagates from the blasthole, which determines the crack length. In addition, it was found that the blasthole pressure continues to decrease during crack propagation.
Relations of Safety Factor and Reliability for Pile Load Capacity
Kim, Dae-Ho ; Kim, Min-Ki ; Hwang, Sung-Uk ; Park, Young-Hwan ; Lee, Jun-Hwan ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 65~73
Reliability between safety factor and reliability index for driven and bored pile load capacity was analyzed in this study. 0.1B, Chin, De Beer, and Davisson's methods were used for determining pile load capacity by using load-settlement curve from pile load test. Each method defines ultimate yield and allowable pile load capacities. LCPC method using CPT results was performed for comparing results of pile load test. Based on FOSM analysis using load factors, it is obtained that reliability indices for ultimate pile load capacity were higher than those of yield and allowable condition. Present safety factor 2 for yield and allowable load capacities is not enough to satisfy target reliability index
. However, it is sufficient for ultimate pile load capacity using safety factor 3.
Excess Pore Pressure Induced by Cone Penetration in OC Clay
Kim, Tai-Jun ; Kim, Sang-In ; Lee, Woo-Jin ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 75~87
A series of calibration chamber tests are performed to investigate the spatial distribution of the excess porewater pressure due to piezocone penetration into overconsolidated clays. It was observed that the excess porewater pressure increases monotonically from the piezocone surface to the outer boundary of the shear zone and then decreases logarithmically, approaching zero at the outer boundary of the plastic zone. It was also found that the size of the shear zone decreases from approximately 2.2 to 1.5 times the cone radius with increasing OCR, while the plastic radius is about 11 times the piezocone radius, regardless of the OCR. Based on the modified Cam clay model and the cylindrical cavity expansion theory, the expressions to predict the Initial porewater pressure at the piezocone were developed, considering the effects of the strain rate and stress anisotropy. The method of predicting the spatial distribution of excess porewater pressure proposed in this study was verified by comparing it with the porewater pressure measured in overconsolidated specimens in the calibration chamber.
A Study on Optimal Reinforcing Type of Precast Retaining Wall Reinforced by Micropiles
Kim, Hong-Taek ; Park, Jun-Yong ; Yoo, Chan-Ho ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 89~99
The PCRW (Precast Concrete Retaining Wall) has many advantages compared with cast in place concrete retaining wall : shorter construction period, excellency of quality and minimum interference with the adjacent structure and traffics. However, shallow foundation type of PCRW, which has comparatively better ground condition, has some disadvantages such as difficulty in transportation and higher cost due to the size of PCRW being expanded by resisting only with self-weight if there is no other supplementary reinforcement. The presented study, in order to complement such disadvantages of PCRW, have applied the micropile method. The micropile method has advantages like low-cost and high-efficiency and does not require huge space, because it can be executed with small size equipment. However, the mechanical behavior characteristics of the PCRW reinforced by micropile, which is installed to improve the reinforcement effect, is not yet clearly identified and there is no suggested standard as to the length, diameter, install angle and install position of micropiles. Hence, this method is yet being designed depend on engineer's experience. In this study, various laboratory model tests as to sliding and overturning were performed in order to identify and present the optimum type of reinforcement and reinforcement effect of the PCRW reinforced by micropiles. In addition, it also executed numerical analysis for the purpose of verifying the optimum type of reinforcement for micropiles based on the results of laboratory model tests. The optimum reinforcement type of micropiles was estimated by model test and numerical analysis. The length of micropiles is 0.4 times wall height and the diameter is 0.04 times wall length.
A Study on the Probabilistic Stability Analysis of Slopes
Kim, Ki-Young ; Cho, Sung-Eun ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 101~111
Slope stability analysis is a geotechnical engineering problem characterized by many sources of uncertainty. Some of them are connected to the variability of soil properties involved in the analysis. In this paper, a numerical procedure of probabilistic analysis of slope stability is presented based on Spencer's method of slices. The deterministic analysis is extended to a probabilistic approach that accounts fur the uncertainties and spatial variation of the soil parameters. The procedure is based on the first-order reliability method to compute the Hasofer-Lind reliability index and Monte-Carlo Simulation. A probabilistic stability assessment was performed to obtain the variation of failure probability with the variation of soil parameters in homogeneous and layered slopes as an example. The examples give insight into the application of uncertainty treatment to the slope stability and show the impact of the spatial variability of soil properties on the outcome of a probabilistic assessment.
Determination of True Resistance from Load Transfer Test Performed on a PHC Pile
Kim, Sung-Ryul ; Chung, Sung-Gyo ; Dzung, N.T. ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 113~122
Although a number of static pile load tests have been performed in this country, re-consideration on the interpretation and loading method is needed, because of their less usefulness in practice. For this study, a static loading testing was performed for a long instrumented PHC pile, which was installed in sand layer overlying thick soft clay. The shaft resistance of the pile had been monitored for a long time after installation, and then the static load testing was performed by the quick load test, unlike the recent Korean practice. Using the measured data, the elastic modulus of pile, residual stress and true resistance on the pile were determined. In the event, it was found that the residual stress on the pile, which remained prior to the static loading, significantly affects the shaft and toe resistances. Also, it was realized that the setup effect for the long pile is significant.
Analysis of Failure Behavior of Piles Embedded in Liquefied Soil Deposits
Cho, Chong-Suck ; Han, Jin-Tae ; Hwang, Jae-Ik ; Park, Young-Ho ; Kim, Myoung-Mo ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 123~131
Liquefaction-induced lateral spreading has been the most extensive damage to pile foundations during earthquakes. Several cases of pile failures were reported despite the fact that a large margin of safety factor was employed in their design. In this study, 1-g shaking table tests were performed in order to analyze the failure behavior of piles embedded in liquefied soil deposits by buckling instability. As a result, it can be concluded that the pile subjected to excessive axial loads
can fail easily by buckling instability during liquefaction. When lateral spreading took place in sloping grounds, it was found that lateral loading due to lateral spreading increased lateral deflection of pile and reduced the buckling load. In addition, from the buckling shape of pile, difference between Euler's buckling and pile buckling vat observed. In the case of pile buckling, hinge formed at the middle point of the pile, not at the bottom. And in sloping grounds, location of hinge formation got lower compared with level ground because of the soil movements.
Permeability Characteristics of Pusan Clay from Laboratory Tests
Chung, Sung-Gyo ; Jang, Woo-Young ; Ninjgarav, E. ; Kim, Sung-Ryul ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 133~142
Pusan clay, which is distributed in the Nakdong River estuary, is unusually soft and thick compared with other clays in the world. Because the consolidation settlement of the clay was significantly underestimated in several recent reclamation projects, it has been emphasized particularly on the need of studying the permeability characteristics. This study carries out vertical and horizontal permeability tests on undisturbed and consolidated samples from two sites of the area. The results of the study show the peculiar permeability anisotropy and the relationships with other indexes on Pusan clay and also comparison with those of other world clays.
Stabilizing Capability of Oyster Shell Binder for Soft Ground Treatment
Yoon, Gil-Lim ; Kim, Byung-Tak ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 143~149
An experimental study was carried out to investigate the stabilizing capability of oyster shell binder, which was developed using waste oyster shell inducing environmental pollutions by piling up out at the open or the temporary reclamation. The purpose of this paper is to compare stabilinzing capability of oyster shell binder and cement binder with treated soils. For this, a series of compressive laboratory tests were peformed to evaluate strength characteristics of treated soils by both oyster shell binder and cement binder with varing water content of dredged soils, different mixing rates of binder and curing days. Based on test results, eco-friendly binder manufactured by oyster shells showed more stabilizing capacity than cement binder and is estimated as good resource materials for soft soil improvements.
The Influence of Stress-induced Densification and Centrifuge Model Preparation Method for Soil Liquefaction
Park, Sung-Sik ;
Journal of the Korean Geotechnical Society, volume 22, issue 11, 2006, Pages 151~158
Centrifuge tests have shown that a uniformly placed sand layer will first initiate liquefaction near the surface and that liquefaction will progress downward during shaking. This appears to be in conflict with the overburden stress effect on soil liquefaction (i.e.,
effect) observed in laboratory testing. This discrepancy can be explained by stress-induced densification at depth which overcomes the effect of confining stress on liquefaction resistance. Stress densification occurs in centrifuge model tests but its effect has generally not been considered when preparing or evaluating centrifuge models. A new centrifuge model preparation method is proposed by considering stress-induced densification upon spin-up. The proposed method can be used to explore
effects. The method is supported in this study by numerical predictions.