Cement系固化材에 依한 軟弱粘土의 性質改良

趙誠正,高山昌照 충북대학교 농업과학기술연구소 1994 農業科學硏究 Vol.11 No.2

The frail clay that liguid index was 1 and over became in liquid phase by kneading with water. Excavating the frail ground that the level of water table was high, there were various problems in construction works. This study was conducted to investigate in laboratory test the revelation of strength of the improved soils adding the hardening material of cement system (CEM) on frail clay. The amounts of hardening material of cement system used in this test were 40, 85, 100, 120 and 160 kgf/m2, and the ratio of water to hardening material of cement system(W/CEM ratio) were 0.4, 0.8, 1.2 and 1.6. The main results summarized were as follows ; 1. The strength of improved soil was influenced by the amount of CEM and W/CEM ratio. In case of more addition of CEM the strength of improved soil was high, adversely more W/CEM ratio, the increase of strength was low. Considering the revelation of strength and the embankment of improved ground in field, low W/CEM ratio was profitable. W/CEM ratio was determined from construction property obtainning the uniform improved soil. 2. The strength of improved soil was increased in type of hyperbola, in accordance with the longer period. Although the design was performed by the curing period of 28-day, the increase of strength was recognized in the curing period of 90 dyas and over. 3. The transformation coefficient was increased in proportion to compressive strength. The equations (2) (3) were recognized between both sides. Poisson's ratio was to the extent of 0.02-0.1. 4. The linear relations same as equations (4) - (9) were recognized on each of compressive strength-tensile strength, compressive strength-bending strength and tensile strength-bending strength. 5. The ratio of tensile strength to compressive strength was 1/4-1/5, whereas the ratio of bending strength to compressive strength was to the extent of 1/2-1/3.

石灰含量 및 遲延다짐이 石灰混合土의 壓縮强度에 미치는 影響

趙誠正 忠北大學校 1986 論文集 Vol.31 No.-

휴대기기에서의 기울임 기반 사진 감상 UI

조성정,최창규,성영훈,이광현,김연배(Yeunbae Kim),Murray-Smith 한국HCI학회 2007 한국HCI학회 학술대회 Vol.2007 No.2

석탄혼합토의 Consistency 및 다짐특성에 관한 연구

조성정 충북대학교 농업과학기술연구소 1987 農業科學硏究 Vol.5 No.1

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흙의 粒度分捕가 石灰混合土의 强度特性에 미치는 影響

조성정,강예묵,Cho, Seong-Jeong,Kang, Yea-Mook 한국농공학회 1985 한국농공학회논문집 Vol.27 No.2

The characteristics of compaction and unconfined compressive strength were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to obtain the most effective distribution of grain size and the optimum lime content for soil stabilization. In addition, unconfined compressive strength and durability tested by adding of sodium metasilicate, sodium sulfate, sodium carbonate, sodium gydroxide and magnesium oxide to lime-soil mixture mixed with 8 percent lime to adjusted soil having the mixing percentage of 60 percent of cohesive black clay and 40 percent of sand by weight to get the effect and the optimum content of chemicals. The results obtained were as follows; 1.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay and the less was the maximum drt density. 2. In the soil having more fine grain size the unconfined compressive strength was larger in the earlier stage of curing period, in accordance with the longer period, the mixing percentages of sand to clay showing the maximum unconfined compressive strength, on the basis of 28-day strength, were 60% : 40% (black clay) and 40% : 60% (brown clay) respectively. 3. The reason why the soil adjusted with black clay was remarkably bigger in the unconfined compressive strength than ones adjusted with brown clay for all specimen of lime-soil mixture was the difference in the kind of clay, the amount of chemical compositions the value of pH. Black clay was mainly composed of halloysite that reacted with lime satisfactorily, whereas the main composition of brown clay was kaolinite that was less effect in the enhance of unconfined compressive strength. Also the difference of unconfined compressive strength was because black clay was larger in the amount of composition of calcium oxide and magnesium oxide in the value of pH affecting directly on the unconfined compressive strength of lime-soil mixture than brown clay. 4. In the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40%, on the standard of 7-day strength, the effect of chemical was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium hydroxide and sodium metasilicate. 5. The optimum amount of chemical being applicable to the maximum unconfined compressive strength of lime-chemical-soil mixture was 1 percent by weight for air dry soil in the case of adding sodium carbonated and 0.75 percent on sodium hydroxide, the unconfined compressive strength was increased continuously with increase of the amount of chemical up to 2 percent of chemical content is the lime-chemical-soil mixture added sodium metasilicate, sodium sulfate and magnesium oxide. 6. It was considered that the chemical played and accelerant role of early revelation of strength because the rate of increase of unconfined compressive strength of all of lime-chemical-soil mixtures was largest on the 7-day cured specimen. 7. The effect of test on freezing and thawing after adding suitable amount of chemical on the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40% was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium metasilicate and sodium hydroxide.

Rammer의 重量이 다짐효果에 미치는 影響

趙誠正,閔興基 충북대학교 농업과학기술연구소 1987 農業科學硏究 Vol.5 No.1

This study was conducted to investigate the effect of soil compaction, the changes of optimum soil moisture content and maximum dry density in accordance with each weight of 3 rammers and soil types. The results obtained were as follows; 1.According to a change in soil consistency, the increasing ratio of maximum dry density to the change of optimum soil moisture content by rammer weight was appeared in the following order: Rammer II> Rammer III> Rammer I in A and B samples, but in C and D samples: Rammer III> Rammer II> Hammer I. 2.In accordance with rammer weight, the lighter the rammer weight in A and B samples and the heavier the rammer weight in C and D samples, the larger was the increasing ratio of maximum dry density in each sample. That is, it was desirable to compact with lighter equipment in purely cohesive soil, whereas compacting with heavier equipment was good in cohesionless soil. 3.By rammer weight, the larger soil moisture content, the larger was the decreasing ratio of optimum soil moisture content. 4.In the relationship between compacting energy and optimum soil moisture content and maximum dry density, the lighter the rammer weight, the larger was the increasing ratio of maximum dry density and the decreasing ratio of optimum soil moisture content. The lighter the rammer weight, the larger was the effect of soil compaction and the less was optimum soil moisture content in case of over certain compacting energy, but in case of below the compacting energy, the heavier the rammer weight, the larger was the effect of soil compaction and the less was optimum soil moisture content. 5.In case of standard compacting energy, the heavier the rammer weight, the larger was maximum dry density and the less was optimum soil moisture content.

점질토의 논에서 암거배수의 효과에 관한 연구

조성정 忠北大學 1979 論文集 - 忠北大學校 Vol.17 No.-

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석회혼합토의 강도특성에 관한 연구

조성정 한국농공학회 1980 한국농공학회논문집 Vol.22 No.3

This study was conducted to obtain the most effective distribution of grain size and the optimum lime content for lime-soil stabilization. To achieve the aim, the change of consistency, the characteristics of compaction and unconfined compressive strength were tested by adding of 0, 4, 6, 8, 10 and 12 percent lime by weight for all soils adjusted by given ratios of sand to clay. The results obtained were as follows; 1. There was a tendency that the plasticity index of lime-soil mixture was decreased by increasing the amount of lime, whereas the liquid limit was varied irregularly and the plastic limit was increased. 2. With the addition of more lime, the optimum moisture content of lime-soil mixture was increased, and the maximum dry density was decreased. 3. The optimum lime content of lime-soil mixture was varied from soil to soil, and the less amount of small grain size, the less value of optimum lime content. 4. The optimum distribution of grain size for lime-soil mixture was in the soil, having the ratio of about 60 percent of cohesive clay and about 40 percent of sand by weight. 5. In the soil having fine grain size, the effect of curing appeared for long periods of time, whereas the increasing rate of unconfined compressive strength was great on the soil of coarse grain size in the earlier stage of curing period.

200番체 通過率이 다짐效果에 미치는 影響

趙誠正,閔興基 충북대학교 농업과학기술연구소 1991 農業科學硏究 Vol.9 No.2

This study was conducted to investigate on the influence of the passing percent of No. 200 sieve on the compaction effect of adjusted soil sample, compared with the effect of natural soil sample, decreasing the passing percent of No. 200 sieve of natural soil sample. The results obtained were as follows ; 1.In the case of the passing percent of No. 200 sieve was much too small (A soil sample : 23%) or too large (B soil sample), though the passing percent of No. 200 sieve was decreased, the influence affecting the change of maximum dry density did not appear, but the optimum moisture content was decreased. 2.There Was a tendeney that the optimum moisture content was increased conversely, whereas the maximum dry density of adjusted soil sample was decreased.

石灰混合土의 Consistency 및 다짐特性에 關한 硏究

趙誠正 충북대학교 농업과학기술연구소 1987 農業科學硏究 Vol.5 No.1

The characteristics of consistency and compaction were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to research the change of physical properties of lime-soil mixtures in soil stabilization. The results obtained were as follows; 1.There was a tendency that the change of liquid limit of lime-soil mixture was varied irregularly by the amount of lime, but was decreased by increasing the amount of lime. The plastic limit was increased, but its rate of increase was small over 8 percent of lime content, whereas the plastic index was decreased by increasing the amount of lime. 2.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay contained, the more was the value of optimum moisture content of lime-soil mixture and the less was the maximum dry density.