• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.127-132
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• 2002

While the pavement design is based on mechanical property such dynamic elastic modulus, the quality of highway subgrade during construction is controled by the optimum moisture content(OMC) and maximum dry density(${\gamma}$$\_$dmax/). However, since the quality control based on the OMC and maximum dry density does not consider the mechanical characteristics, there is a conceptional gap between design and PMS(pavement management system). Therefore, it is necessary to develope a new qualify control system using mechanical property for highway construction in more rational way. To achieve this goal, it is planned to perform various laboratory tests to collect mechanical properties of subgrade soil samples from several highway construction sites and to propose the relationship between dry unit weight (or OMC) and mechanical parameters. In this paper, the experimental data so far obtained are presented and analyzed. In addition, further research plan is presented and discussed.

• Journal of the Korean Geosynthetics Society
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• v.6 no.3
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• pp.1-7
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• 2007

The property of weathered soil cannot but have a possibility of having a limit when its precise approaching due to the various weathering environment, and the peculiarity of its conduct affected by the weathering degree and effect factors. Especially most domestic or international researches are concentrated on the sedimentary soil, trying to analyze the mechanical behavior of weathered soil from the viewpoint of sedimentary soil. Therefore, it's difficult to judge if those results meet the actual conduct of weathered soil. This study suggested a way of weathering degree changing experiment as an early stage in an experiment of artificially changing weathering degree. In order to find out the property of strength change by the change of weathering degree, indoor mechanical experiment was made using soil sample after freezing and thawing. Under the weathering degree, characteristic change is watched by country rock and region of weathered granite soil.

• Asian Journal of Turfgrass Science
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• v.10 no.1
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• pp.31-40
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• 1996

The mechanical expresion provides for the use of Soil property reserves and permanent protec-tion or improvement of soil resources in accordance with measurable standards. If the functions I (initial soil property), E (soil erosion), R (soil renewal), and M. (minimum allowable value) are assumed to be integrable in region A, erosion tolerance over a region is leaded to ${\int}_A{\int}I(m, cl, re, ch, b)dA-{\int}_A{\int}{\{\int}_{to}^{\infty}[E(w, re, c, re, ch, b, t)-R(m, ch, re, b, t)]dt}\dA{\geqq}{\int}_A{\int}M_i(m, cl, re, ch, b)dA$ were variable factors are m=parent material of soil, cl=climate, re=relief or topography, ch=soil characteristics, r=rain or water, w=wind, b=biota, and t=time.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.4
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• pp.4805-4811
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• 1978

This paper deals with the correlations between the results of the physical property tests and the mechanical property tests for estimating the mechanical indexes by the physical property test results. The soil samples were taken at changweon area, Gyeon-gsangnam-do, where the structures would be placed on the alluvial clay foundation. The outcomes of the study are as follows: 1. Judging from casagrande's plasticity chart, it is considered that the almost all soil samples belong to inorganic silty clay with medium plasticity (clay 14∼62%, silt 36∼73%, sand 1∼29%). The specific gravities are between 2.61 and 2.72, the wet unit weights 1.53g/㎤ and 1.93g/㎤, the liquid limits 28% and 51%, the plastic limits 15% and 31%, the plastic indexes 7% and 27%, the natural moisture contents 33% and 64%. 2. The unconfined compression strengths are between 0.07kg/$\textrm{cm}^2$ and 0.77kg/$\textrm{cm}^2$, the cohesions 0.04kg/$\textrm{cm}^2$ and 0.37kg/$\textrm{cm}^2$, the internal friction angles 0$^{\circ}$ and 9$^{\circ}$. 3. The consolidation tests show that the initial void ratios are between 0.68 and 1.68, the precompression loads 0.27kg/$\textrm{cm}^2$ and 1.15kg/$\textrm{cm}^2$, the compression indexes 0.12 and 0.59. 4. The correlations between the results of the physical property tests and the mechanical property tests for the soil samples are presented as follows: rt=0.011 (203-wn), Cc=0.025 (LL-27.2), Cc=0.46 (e0-0.58), Cc=0.013 (wn-23.2), C=0.021+qu/2.08, qu=2.268rt-3.635

• Geomechanics and Engineering
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• v.29 no.1
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• pp.1-11
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• 2022

A semi-analytical solution to responses of overconsolidated (OC) unsaturated soils surrounding an expanding spherical cavity under constant suction condition is presented. To capture the elastoplastic hydro-mechanical property of OC unsaturated soils, the unified hardening (UH) model for OC unsaturated soil is adopted in corporation with a soil-water characteristic curve (SWCC) and two suction yield surfaces. Taking the specific volume, radial stress, tangential stress and degree of saturation as the four basic unknowns, the problem investigated is formulated by solving a set of first-order ordinary differential equations with the help of an auxiliary variable and an iterative algorithm. The present solution is validated by comparing with available solution based on the modified Cam Clay (MCC) model. Parametric studies reveal that the hydraulic and mechanical responses of spherical cavity expanding in unsaturated soils are not only coupled, but also affected by suction and overconsolidation ratio (OCR) significantly. More importantly, whether hydraulic yield will occur or not depends only on the initial relationship between suction yield stress and suction. The presented solution can be used for calibration of some insitu tests in OC unsaturated soil.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.4 s.152
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• pp.607-614
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• 2006

This study was carried out to suggest the optimal spinning process condition which provides a proper range of tenacity and biodegradability as textile fibers. The effects of the melt spinning speed and heat treatment on the mechanical property and biodegradability of polylactic acid fiber were investigated. Polylactic acid(PLA) was spun in a high spinning speed of $2000{\sim}4000m/min$. Each specimen was heat-treated at $100^{\circ}C$ during 30min. Mechanical properties such as breaking stress and the degree of crystallinity were evaluated using WAXS. Biodegradability was estimated from the decrease of breaking stress, weight loss, and the degree of crystallinity after soil burial. Experimental results revealed that heat treated specimens showed higher breaking stress than untreated specimens, but the increase was not so high as was expected from the remarkable change of crystallinity by heat treatment. It was concluded that breaking stress was more influenced by spinning speed than heat treatment. In the soil burial test, however biodegradability calculated from weight loss was more influenced by heat treatment than spinning speed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.89-98
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• 2010

Recently, many researches on bottom ash which is produced in the burning process of power plant are actively performed for its utilization for soil-subbase materials. In this paper, bottom ashes from 5 different power plants are prepared and several tests including compaction, CBR, and tri-axial compression are carried out for mixed bottom ash and weathered soil considering 3 replacement ratio of 30%, 50%, and 70%. Through the tests, CBR result over 20 are evaluated without plastic property, which shows availability of subbase material. With higher increase in replacement ratio of bottom ash, CBR of mixed soil increases due to the higher mechanical performance of bottom ash. However, replacement effects of bottom ash on friction angle and cohesion are evaluated to be little since bottom ash plays a little role in rearrangement of mixed soil. Bottom ash with a good mechanical property is evaluated to have reasonable bearing capacity which shows a good property for subbase materials.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.42-47
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• 2010

Recently, many techniques have been developed for the inspection of pipelines using guided waves. However, few researches have been made on the application of those techniques for buried underground pipes. Guided wave motions in the buried pipes are somewhat different from those of on-ground pipes which have traction-free (air) boundary condition on outer pipe walls and thus are strongly affected by the mechanical property of the surrounding soils. Therefore, it should be investigated the effect of soil properties on the guided wave behavior in buried pipe. On the other hand, the mechanical property of soil is largely depending on its moisture conditions nevertheless of other influential factors such as void ratio. In this study, the effect of moisture conditions in soils on mode attenuation of guided waves in the buried pipe is investigated. To this end, numerical study is performed to characterize mode attenuation behavior in buried pipes and the effective mode which is suitable for long range inspection is identified.

• Geomechanics and Engineering
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• v.36 no.4
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• pp.381-390
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• 2024

The introduction of bio-based materials has been recommended in the geotechnical engineering field to reduce environmental pollutants such as heavy metals and greenhouse gases. However, bio-treated soil methods face limitations in field application due to short research periods and insufficient verification of engineering performance, especially when compared to conventional materials like cement. Therefore, this study aimed to develop a machine learning model for predicting the unconfined compressive strength, a representative soil property, of biopolymer-based soil treatment (BPST). Four machine learning algorithms were compared to determine a suitable model, including linear regression (LR), support vector regression (SVR), random forest (RF), and neural network (NN). Except for LR, the SVR, RF, and NN algorithms exhibited high predictive performance with an R² value of 0.98 or higher. The permutation feature importance technique was used to identify the main factors affecting the strength enhancement of BPST. The results indicated that the unconfined compressive strength of BPST is affected by mean particle size, followed by biopolymer content and water content. With a reliable prediction model, the proposed model can present guidelines prior to laboratory testing and field application, thereby saving a significant amount of time and money.

• Journal of the Korean Professional Engineers Association
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• v.15 no.1
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• pp.7-13
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• 1982

The program of safety performance of synthetic resin pipe which is used to the pipe Line for cable protection as an underground Communication is recognized importance gradually. For investigating of these, The Mechanical experiments by each type was carried out From the results, This study compared experimental data with theorical data against soil pressure and traffic pressure which went through laying pipe, and presumed the reasonable laying conditions after calculating total pressure by each laying depth, also grasped material Property of laying pipe and knew impact effect, relation of thickness against strain.