• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.507-534
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• 2015

The present work investigates the behavior of the embankment models resting on soft soil reinforced with ordinary and stone columns encased with geogrid. Model tests were performed with different spacing distances between stone columns and two lengths to diameter ratios (L/d) of the stone columns, in addition to different embankment heights. A total number of 42 model tests were carried out on a soil with undrianed shear strength $${\sim_\sim}10kPa$$. The models consist of stone columns embankment at s/d equal to 2.5, 3 and 4 with L/d ratio equal 5 and 8. Three embankment heights; 200 mm, 250 mm and 300 mm were tested for both tests of ordinary (OSC) and geogrid encased stone columns (ESC). Three earth pressure cells were used to measure directly the vertical effective stress on column at the top of the middle stone column under the center line of embankment and on the edge stone column for all models while the third cell was placed at the base of embankment between two columns to measure the vertical effective stress in soft soil directly. The performance of stone columns embankments relies upon the ability of the granular embankment material to arch over the 'gaps' between the stone columns spacing. The results showed that the ratio of the embankment height to the clear spacing between columns (h/s-d) is a key parameter. It is found that (h/s-d)<1.2 and 1.4 for OSC and ESC, respectively; (h is the embankment height, s is the spacing between columns and d is the diameter of stone columns), no effect of arching is pronounced, the settlement at the surface of the embankment is very large, and the stress acting on the subsoil is virtually unmodified from the nominal overburden stress. When $(h/s-d){\geq}2.2$ for OSC and ESC respectively, full arching will occur and minimum stress on subsoil between stone columns will act, so the range of critical embankment height will be 1.2 (h/sd) to 2.2 (h/s-d) for both OSC and ESC models.

• Geomechanics and Engineering
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• v.18 no.3
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• pp.329-337
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• 2019

This paper presents an experimental investigation about visualization of bulging development of geosynthetic-encased stone column (GESC) based on the digital image correlation (DIC) technique and transparent soil. Visual model tests on GESC and ordinary stone column (OSC) were carried out. In order to delete the warping effect resulting from transparent soil and experiment setup, a modification for experiment results was performed. The bulging development process of the GESC and the displacement field of the surrounding soil were measured. By comparing with the existing experimental and theoretical results, it demonstrates that the model test system developed for studying the continuous bulging development of GESC is suitable. The current test results show that the bulging depth of GESC ranges from 1.05 to 1.40 times the diameter of GESC. The influence depth of GESC bulging on surrounding soil displacement is 0~3 the times diameter of GESC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3232-3236
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• 2012

Consolidation and remedies for slope stability were considered for the slope with additional embankment. Transferred stresses due to additional embankment were assessed by the derived formula based on elasticity theory. Available remedies for slope stability with additional embankment including JSP method, stone column method and EPS method were studied. Caution needed for using JSP method is high pressure which can result in heaving of adjacent soils. Shortages of used case and noise of construction of stone column method are also considered for the safe remedy for slope stability.

• Journal of architectural history
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• v.23 no.5
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• pp.37-45
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• 2014

It was identified by the excavation that architecture remains were confirmed buddhist temple consist of ruins of main building of a temple, auditorium site, ruins of stone pagoda, embankment, pedestrian Facilities and drainage etc. in the Gwangmyeong-dong site. The site has been held temple arrangement with 1 main building of a temple, twin Pagodas from the Unified Silla period to Goryeo dynasty. The temple constructed after that was destroyed the architecture in the Unified Silla period. It seems that aristocrat or royalty power of within group of the nearby remains of city which was constructed in the Unified Silla period build and visit the temple. Considering there are excavations, it assumes that the temple had been constructed during the last days of the Unified Silla, was closed up during the mid-Goryeo Dynasty.

• Geomechanics and Engineering
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• v.22 no.4
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• pp.305-318
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• 2020

Stone columns are widely used to treat soft clay ground. Optimizing the design of stone columns based on cost-effectiveness is always an attractive subject in the practice of ground treatment. In this paper, the design of stone columns is optimized using the concept of robust geotechnical design. Standard deviation of failure probability, which is a system response of concern of the stone column-reinforced foundation, is used as a measure of the design robustness due to the uncertainty in the coefficient of variation (COV) of the noise factors in practice. The failure probability of a stone column-reinforced foundation can be readily determined using Monte Carlo simulation (MCS) based on the settlements of the stone column-reinforced foundation, which are evaluated by a deterministic method. A framework based on the concept of robust geotechnical design is proposed for determining the most preferred design of stone columns considering multiple objectives including safety, cost and design robustness. This framework is illustrated with an example, a stone column-reinforced foundation under embankment loading. Based on the outcome of this study, the most preferred design of stone columns is obtained.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.97-102
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• 2000

This paper presents the design, construction and performance of ground treatment to support road embankment on refuse landfill. Long-term settlement of refuse landfill is analysised by Sower and Yen/scanlon. As a results of site test, predicting settlement excess the allowable settlement and ultimate bearing capacity is not satisfied. The effectiveness of DDR(Deep Dynamic Replacement) is monitered by field tests (SPT, PBT, PMT) before, during and after construction of the stone columns. The ultimate bearing capacity for reinforced landfill by stone columns obtained from the in-situ test results has been compared with the existing theories. In municipal wastes landfill, settlement after treatment using stone column is satisfied to allowable residual settlement. Therefore, long-term stability can be gain in these cases.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.417-439
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• 2017

The stone columns are increasingly being used as a soil improvement method for supporting a wide variety of structures (such as road embankment, buildings, storage tanks etc.) especially built on soft soil. Soil improvement by the stone column method overcomes the settlement problem and low stability. Nevertheless, stone column in very soft soils may not be functional due to insufficient lateral confinement. The required lateral confinement can be overcome by encasing the stone column with a suitable geosynthetic. Encasement of stone columns with geogrid is one of the ideal forms of improving the performance of stone columns. This paper presents the results of a series of experimental tests and numerical analysis to investigate the behavior of stone columns with and without geogrid encasement in soft clay deposits. A total of six small scale laboratory tests were carried out using circular footing with diameters of 0.05 m and 0.1 m. In addition, a well-known available software program called PLAXIS was used to numerical analysis, which was validated by the experimental tests. After good validation, detailed of parametric studies were performed. Different parameters such as bearing capacity of stone columns with and without geogrid encasement, stiffness of geogrid encasement, depth of encasement from ground level, diameter of stone columns, internal friction angle of crushed stone and lateral bulging of stone columns were analyzed. As a result of this study, stone column method can be used in the improvement of soft ground and clear development in the bearing capacity of the stone column occurs due to geogrid encasement. Moreover, the bearing capacity is effected from the diameter of the stone column, the angle of internal friction, rigidity of the encasement, and depth of encasement. Lateral bulging is minimized by geogrid encasement and effected from geogrid rigidity, depth of encasement and diameter of the stone column.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.3 s.116
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• pp.12-22
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• 2006

The purpose of this study is to evaluate visual preferences of the methods for river embankment based on seasonal changes and to reveal the relationship between visual preference and effective factors, which are the physical and esthetic elements inside the river. For this research seven river embankment methods including concrete block, concrete wall, gabion, and vegetated concrete block were selected in Dongchon of Gwangyang. Twenty-eight pictures by the four pictures of each embankment method based on seasonal changes, the winter and summer of the first and second years after construction were used for a photo-questionnaire by 49 participants. In the analysis of the relationship between visual preference and effective factors, the independent variables included eight factors: form of the material, harmony with the surroundings, the cleanness of river floor, the green area of embankment methods, the water area in river floor, the stone and sand area in river floor, the planting area in river floor, and the area of embankment itself. The result of this study are as follows. First, visual preference in summer was higher than in winter, and the summer landscape of the second you scored the highest value for visual preference. Second, similarly to the way the vegetated concrete block produced a green effect, cobblestone and gabion embankments made of natural materials scored higher than others, whereas the concrete retaining wall scored the lowest of all methods because of it's artificiality. Third, the seven independent variables, except form of the material, are proved statistically significant at the 5% level. The water area in river floor, harmony with the surroundings, the planting area in river floor, and the cleanness of the river floor were revealed as more effective factors influencing visual preference. The research results suggest that the riverscape has to be controlled in terms of seasonal change and embankment methods. Natural materials and green effects in embankment methods are more important for increasing landscape preference, and the landscape factors inside a river should also be considered important variables. It is recommended that advanced study on other factors affecting visual preference of the riverscape be carried out to support this research.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.85-95
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• 2016

PBT (Plate Bearing Test) is a commonly used compaction estimation used to provide basal support for embankments. This study presents the results from experimental evaluations PBT, LWDT (Light Drop Weight Tester) test and Geogauge test with embankment materials which consist in sandy soil, crushed stone and rock. The results of this study indicate that the regression analyze results (r) from test results between Young's modulus and $k_{30}$, $E_v$ are 0.385 and 0.111~0.496, estimated very lack of correlation. The Geogauge is frequency vibration from machine to underground. Geogauge can not measure to accuracy test results when it is used on ground of the rock or crushed stone. The regression analyze results (r) from $E_v$ and Dynamic modulus are 0.502~0.847, different estimated by calculate method, as it were, when calculate $E_v$, least square method are appeared more accuracy than gradient of secant.

• Journal of architectural history
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• v.27 no.6
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• pp.31-40
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• 2018

This paper is to clarify on the characteristics of the Haeeumwonji and the Main Palace of the Goryo Dynasty. The architectural techniques and construction methods such as embankment, stylobate, stairway, foundation stone, and pave are similar to those of the Haeeumwonji and the Main Palace of the Goryo Dynasty. In order to express the hierarchy of the area and building, the materials, techniques, and forms of the embankment, stylobate, stairway, foundation stone and pave were used differently. The paving of the floor of the main building and area is also an active expression of the hierarchy and status of the building area and the building through the use of building materials, techniques and forms. This result confirms the support of Goryeo royal family and the upper class for the construction of Haeeumwonji, which is recorded in the historical documents. And it also shows that the architectural techniques and processing method of the same period were shared in the capital and provinces, which is an important clue that proves that the capital-centered architectural technology has spread to the provinces. It is expected that additional research will be needed on the characteristics of the period of 12th century architecture technique in which Haeeumwonji was built.