• Geomechanics and Engineering
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• v.13 no.4
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• pp.641-651
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• 2017

Ground improvement with use of geosynthetic products is globally accepted now. The present paper discusses the improvement in bearing capacity of square footing placed at surface of cohesionless soil reinforced with geocell. Mohr-Coulomb failure criterion has been used in the observations. To study effects of geocell with respect to planar geogrid, model tests were conducted on planar reinforcement also. A comparative study of unreinforced soil and soil reinforced with plane geogrid and geocell has also been made. Numerical analysis results obtained by PLaxis have been compared with those obtained from model tests and were found to be in good agreement. A parametric study revealed the role of length of reinforcement, spacing between layers, placement of reinforcement from top surface etc. on bearing capacity. A design example given in paper illustrates the savings in cost of construction of footing on reinforced sand. The study shows that there is improvement in bearing capacity with respect to unreinforced soil which is of the order of 86%. Similarly settlement reduction is 13.07% for single layer of geocell which for double layers of geocell is 693% and 86.48% respectively. The cost reduction in case of reinforced soil is 35% as compared to unreinforced soil.

• Geomechanics and Engineering
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• v.8 no.5
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• pp.687-706
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• 2015

Methods commonly used to evaluate the improvement of lime-treated expansive soil include swelling characteristics and unconfined compressive strength. In the field, lime-treated expansive soils are in compacted unsaturated state. Soil water characteristic curves (SWCCs) represent a key parameter to interpret and describe the behavior of unsaturated expansive soil. This paper investigates the use of SWCC as a technique to evaluate improvements acquired by expansive soil after lime treatment. Three different lime contents were considered 2%, 4% and 6% by dry weight of clay. Series of tests were performed to determine the SWCC for the different lime content under curing periods of 7 and 28 day. Correlations between key features of the soil water characteristic curves of lime treated expansive soils and basic engineering behavior such as swelling characteristics and unconfined compression strength were established. Test results revealed that initial slope ($S_1$), saturated water content ($w_{sat}$), and air entry value (AEV) play an important role in reflecting improvement in engineering behavior achieved by lime treatment.

• Korean journal of applied entomology
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• v.21 no.1 s.50
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• pp.15-18
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• 1982

The integrated soil improvement practice reduced neck blast incidence by ranging from 6.3 to 59.5 percent compared to control plot. However, effect of integrated soil improvement practice in reducing neck blast incidence was greater in Tongil type cultivars. On the contrary, mean value of plant height of eleven rice cultivars was taller by 6.4cm in the integrated soil improvement plot with 2.3 more tillers than that of control plot. As a result, yield increase of milled rice by metric tons per hectare was 24.1 percent in the integrated soil improvement plot.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1008-1013
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• 2006

Ground anchor method is widely used in the large scale deep excavation of urban area to support a retained wall. Excavation using the ground anchor as a supporting system near a building have many difficulties due to the limitation of construction space. This method can not be applied to the site with the insufficient space from the retained wall to the boundary line. In this case, soil improvement at the anchor bond zone can be used to secure the frictional resistance of ground anchor within the boundary. Through this method, the bond length of anchor can be shortened considerably. This paper deals with the case study on the ground excavation adjacent to a building. The object field is Yongsan Park Tower Construction Site. In this site, the enlarged anchor with soil improvement was applied to solve the problem due to the limitation of construction space. According to the results of field test and monitoring, the anchor with soil improvement is very effective to secure the frictional resistance at the anchor bond zone.

• 기술발표회
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• s.2006
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• pp.185-192
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• 2006

In this study the case of ground improvement by CGS as injection method were analyzed in order to find out effect of behavior of sandy soil and the application of this method as ground improvement. The study were analyzed N value after CGS work of sandy soil by many sites test. Considering that increase of N value, CGS can be considered as an effective method to increase the bear capacity as well as constrain the settlement of soft ground From the results of this study, N value after CGS work of sandy soil were closed to N value of ground and relative density(Dr), improvement ratio(As) of grouting and the study will be done continuously for finding out relation of them

• Geomechanics and Engineering
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• v.6 no.5
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• pp.419-436
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• 2014

Soil improvement by preloading with PVD in combination with vacuum is helpful when a considerable load is required to meet the desired rate of settlement in a relative short time. To facilitate the vacuum propagation, vertical drains are usually employed in conjunction. This ground improvement method is more and more applied in the Mekong delta of Vietnam to meet the needs of fast infrastructure development. This paper reports on a pilot test that was carried out to investigate the effect of ground improvement by vacuum and PVD on the rate of consolidation at the site of Saigon International Terminals Vietnam (SITV) in Ba Ria-Vung Tau Province, Viet Nam. Three main aspects of the test will be presented, and namely, instrumentation and field monitoring program, calculation of consolidation settlement and back-analysis of soil properties to see the difference before and after ground improvement.

• Structural Engineering and Mechanics
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• v.10 no.4
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• pp.299-312
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• 2000

The response of an embedded body to dynamic loads is greatly influenced by the reactions of the soil to the motion of the body. The properties of the soil surrounding embedded bodies (e.g., piles) may be different than those of the far-field for a variety of reasons. It may be weakened or strengthened according to the method of installation of piles, or altered due to applying one of the soil strengthening technique (e.g., electrokinetic treatment of soil, El Naggar et al. 1998). In all these cases, the shear strength of the soils and its shear modulus vary gradually in the radial direction, resulting in a radially inhomogeneous soil layer. This paper describes an analysis to compute vertical and torsional dynamic soil reactions of a radially inhomogeneous soil layer with a circular hole. These soil reactions could then be used to model the soil resistance in the analysis of the pile vibration under dynamic loads. The soil layer is considered to have a piecewise, radial variation for the complex shear modulus. The model is developed for soil layers improved using the electrokinetic technique but can be used for other situations where the soil properties vary gradually in the radial direction (strengthened or weakened). The soil reactions (impedance functions) are evaluated over a wide range of parameters and compared with those obtained from other solutions. A parametric study was performed to examine the effect of different soil improvement parameters on vertical and torsional impedance functions of the soil. The effect of the increase in the shear modulus and the width of the improved zone is investigated.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.105-110
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• 1994

Field experiment was carried out to obtain the basic information on the soil improvement with different improved methods on job's tears yield and soil properties in the newly-reclaimed land from 1985 to 1988. Job's tears yield, soil properties and annual changes of soil were investigated and analyzed. Soil bulk density and hardness of topsoil decreased from 1st year to 3rd year, but those increased in 4th year. Soil pH of topsoil had no differences in different soil depths and cultivated years. Average yield of job's tears in the integrated improvement plot was 2.16ton/ha. That was increased by 49% than the control plot. Crop yield was greatest in order of integrated improvement>subsoiling>phosphate>lime>compost>control plot. Correlation coefficients of job's tears yield with soil pH and organic matter content were higher significantly. Also those of subsoil were higher than topsoil. Ratios of annual changes of soil bulk density and hardness showed significant highly with job's tears yield. Also that soil pH was significant at 5 % level in the topsoil.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.35-44
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• 2013

This paper presents the slope wall technique using soil improvement material for reinforced soil slope through laboratory scale model tests, and verifies the experimental results comparing with numerical analysis. In additional, case study in field has performed to investigate the deformation of reinforced soil slope for 6 months. As a result of laboratory scale model test, numerical analysis, and case study, the reinforcement effect of the slope wall technique using soil improvement material is sufficient to be constructed as reinforced soil slope. The technique shows the stable ratio (0.4%) of horizontal to vertical deformation in the surface loading.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.527-532
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• 2010

Soil-cement has been broadly used for eco friendly pavement, slope protection and soft soil improvement since it used for the increase of soil strength with cement. Recently, additional agents are mixed with existing soil-cement so as to improve specific properties or functions such as strength, color and permeability of it. This study aims at figuring out the physical and mechanical properties of a soil-cement mixed with crashed oyster shell and loess. The study is specially focused on the applicability of oyster shell as an alternative material for sands. To have his objective achieved a series of uniaxial compression tests were conducted. As a result, it appears that usage of oyster shell may have effect on strength improvement of mixed soils.