직접전단시험(直接剪斷試驗)에 의한 화강토(花崗土)의 전단특성(剪斷特性)에 관(關)한 연구(硏究)

이달원,강예묵,조성섭,Lee, Dal Won,Kang, Yea Mook,Cho, Seong Seup 충남대학교 농업과학연구소 1986 Korean Journal of Agricultural Science Vol.13 No.2

공학적(工學的) 성질(性質)이 복잡(複雜)한 화강암질풍화토(花崗岩質風化土)를 함수비(含水比) 및 밀도(密度)와 변형속도(變形速度) 등(等)을 달리하여 수침시(水浸時)와 비수침시(非水浸時)에 대한 전단시험(剪斷試驗)을 하고, 이들간의 상호관계(相互關係)가 전단강도(剪斷强度)에 미치는 영향(影響)을 비교(比較) 분석(分析)하여 다음과 같은 결론(結論)을 얻었다. 1. 함수비(含水比)가 증가(增加)하면 전단강도(剪斷强度)는 감소(減少)하여, A 시료(試料)는 함수비(含水比) 5~10%에서, B 시료(試料)는 함수비(含水比) 15~20%에서, 강도(强度)의 감소율(減少率)이 크게 나타났다. 2. 점착력(粘着力)과 내부마찰각(內部摩擦角)은 함수비(含水比)가 증가(增加)함에 따라서 감소(減少)하고 건조밀도(乾燥密度)가 증가(增加)함에 따라 증가(增加)하였다. 3. 수직응력(垂直應力)이 증가(增加)함에 따라 전단강도(剪斷强度)는 증가(增加)하였고, 체적변화(體積變化)는 대체(大體)로 감소(減少)(압축(壓縮))하는 경향(傾向)을 나타내었다. 또 변형속도(變形速度)가 증가(增加)할수록 전단강도(剪斷强度)는 대체(大體)로 증가(增加)하는 경향(傾向)을 나타내었다. 4. A시료(試料)는 밀도(密度)가 증가(增加)할수록 진행성파괴형태(進行性破壞形態)를 보이고 체적(體積)은 감소(減少)(압축(壓縮))하였으며, B시료(試料)는 초기(初期)에 파괴(破壞)되고 체적(體積)은 증가(增加)(팽창(膨脹))하는 경향(傾向)을 나타내었다. 5. 수침시(水浸時)의 전단강도(剪斷强度)는 비수침시(非水浸時)에 비(比)해서 감소(減少)하였고, 관계식(關係式)은 A시료(試料)에서는 ${\tau}_f=0.1009+1.026{{\tau}_f}^*$이고, B시료(試料)에서는 ${\tau}_f=0.1586+0.8005{{\tau}_f}^*$로 나타낼 수 있었다. 6. 내부마찰각(內部摩擦角)은 직접전단시험(直接剪斷試驗)에서 더 크게 나타났고, 유효응력경로(有效應力經路)는 거의 유사(類似)하게 나타났다. This paper describes the observed behavior in the direct shear test on decomposed granite soil having the complicate engineering properties at various different levels of factors. The objectives of this study were to investigate the characteristics of the decomposed granite soil under controlled various moisture content, dry density, strain rate and soaking which give influence to the shear strength. The results were summarized as follows; 1. The shear strength was decreased remarkably with the increasing of moisture contents of A and B soil were 5-10% and 15-20% respectively. 2. Cohesion and angle of internal friction were decreased with the increasing of moisture content and increased with the increasing of dry density. 3. The shear strength was increased with the increasing of normal stress and volume change was decreased on the whole. The shear strength was generally increased with the increasing of the strain rate. 4. As dry density increases, A-soil shows the progressive failure and the decrease of volume change while B-soil shows the initial failure and the increase of volume change. 5. The relationships between the soaked and unsoaked specimens were as follows ; ${\tau}_f=0.1009+1.026{{\tau}_f}^*$ (A-soil), ${\tau}_f=0.1586+0.8005{{\tau}_f}^*$ (B-soil) 6. Angle of internal friction of the direct shear test shows larger value than that of the triaxial compression test. All effective stress path was nearly similar.

사면(斜面)의 안정해석(安定解析)에 관한 연구(硏究)

강예묵 ( Kang Yea Mook ),조성섭 ( Cho Seong Seup ),지인택 ( Chee In Taeg ) 한국농공학회 1989 韓國農工學會誌 : 전원과 자원 Vol.31 No.1

The paper compared the Bishop methed to the Fellenius method in the analysis of slope stability. Laboratory model test was carried out in the case of seepage flow considered. The results obtained from this study were summarized as follows; 1. The slice pieces of 10 were enough to analysis the slope stability. 2. The safety factor by the Fellenius method was lower than the Bishop method by the 96 to 97% in the case of no seepage flow and by the 95 to 96% in the case of seepage flow considered. 3. Besides the parameter of soil and slope, the safety factor of slope was influenced by the height of slope. This phenomena was distinct in the height of height less than 10 meters. 4. In the case of clay, there was no difference in the safety factor of slope between Fellenius and Bishop method. The safety factors of slope with the seepage flow considered were lower than those with no see-page flow. 5. The influence of cohesion on the safety factor was more significant in the Bishop method than in the Fellenius method. 6. The slope failure of model test of A and B soil samples with high permeability coefficient was taken place slightly in vicinity of toe by the concentration of stress and gradually increased. 7. Under condition of same slope height, the shapper the slope, the shorter the radius and the center of critical circle appered downward and finally failure of slope occured inside the slope.

포화점성토(飽和粘性土)의 비배수(非排水) CREEP 성질(性質)에 의한 공극수압(空隙水壓)의 거동(擧動)

강예묵 ( Kang Yea Mook ),조성섭 ( Cho Seong Seup ),지인택 ( Chee In Taeg ) 한국농공학회 1988 韓國農工學會誌 : 전원과 자원 Vol.30 No.3

This study was carried out to present a rheology model which is able to treat time-dependent properties of clay. The results were summarized as follow ; 1. The slope (a(ε₁)) of deviator stress in strain rate test was independent on axial strain, and pore water pressure was decreased with increment of strain rate. 2. The pore water pressure in a stress relaxation condition was not changed when the strain rate before stress relaxation was 0.05%/min., but it was increased with increment of time when the strain rate before stress relaxation was 0.2%/min 3. The greater the stress condition (q/q_max) and the strain rate before creep test became, the greater the increment rate of axial strain in creep test became. 4. SEKIGUCHI's constitutive equation was slightly overpredicted while empirical equation proposed in the study was well coincided with measured values. 5. The constitutive equation induced by a strain function could be dealed with a behavior of the pore water pressure increased with increment of elapsed time after primary consolidation.

直接剪斷試驗에 의한 花崗土의 剪斷特性에 關한 研究

李達遠(Dal Won Lee),姜乂默(Yea Mook Kang),趙成燮(Seong Seup Cho) 충남대학교 농업과학연구소 1986 農業技術硏究報告 Vol.13 No.2

不飽和 花崗岩質風化土의 剪斷强度 特性

趙成燮,姜乂默,池仁澤 충남대학교 농업과학연구소 1985 農業技術硏究報告 Vol.12 No.1

In order to investigate the strength characteristics of weathered granite soils in unsaturated state, the five physically different weathered granite soils and the common soil(sandy loam) were examined. The disturbed and the undisturbed material were prepared for triaxial compression test. The following conclusions were drawn from the study; 1. Dry density of the undisturbed soil samples was lower than maximum dry density determined from the compaction test and it showed the higher value at the well graded soil. 2. The failure strength of the samples decreased with the increase of moisture content of the soil and these results were highly pronounced at the common soil sample having a brood cohesive property. 3. On weathered granite soils, the cohesion was lower measured and the internal friction angle highly, the decrease rate of internal friction angle with increase of moisture content of the soil was more significant than that of cohesion 4. The modulus of deformation of the samples decreased with increase of moisture content of the soil and these phenomena were highly pronounced at the weathered granite soils than common soil. 5. The failure strength of the samples increased with increase of confining pressure and effect confining pressure on failure strength was highly significant at the lower moisture content of soil.

粘性土의 應力-變形 推定에 關한 硏究

趙成燮,姜乂默,鄭成圭,尹鉉晶 충남대학교 농업과학연구소 1992 농업과학연구 Vol.19 No.1

The paper describes the comparison between observed and predicted stress-strain characteristics of marine silty clay in Dangjin district. For prediction, the hyperbolic model which is applied the parameters acquiring by physical and triaxial compression test was adopted, and the obtained results were summarized as follows: 1. The Young's modulus were increased with decreasing of moisture contents and increasing of dry density. 2. The most affective factor to hyperbolic model is lateral stress and dry density. and than cohesion and internal friction angle. 3. The comparision between the statistical and hyperbolic values of maximum deviator stress have few accordance. and the statisticals is lower than the hyperbolics. 4. Without. much labor and tiresome procedures, effective computer program was made and applied, but technical procedure for prevents test errors of parameter calculation is importants.

人工輕量粗骨材를 使用한 無細骨材 輕量콘크리트의 物理·力學的 特性

金成完,閔正基,趙成燮,成瓚鏞 충남대학교 농업과학연구소 1996 농업과학연구 Vol.23 No.1

The normal cement concrete is widely used material to build the construction recently, but is has a fault to increase the dead load on account of its unit weight is large compared with strength. So, many engineers are continuously searching for new materials of construction to provide greater performance at lower density. Many studies were carried out on the lightweight aggregate concrete in foreign country in the latter half of the 19th century, therefore lightweight aggregate concrete has been used successfully for many years for structural members. The main purpose of the work described in this paper were to establish its physical and mechanical properties of no-fines lightweight concrete using synthetic lightweight coarse aggregates. Test results are summarized as follows ; The water-cement ratio was shown less than 33% in use synthetic lightweight coarse aggregates, unit weights of synthetic lightweight concrete was shown less than 1,800kg/㎡ and compressive strength was higher than 200kg/㎠. And the pulse velocity was more than 3,000m/sec. The relationship of compressive strength between unit weight and pulse velocity was shown to be approximately linear.

起泡劑가 모르터의 特性에 미치는 影響

金成完,姜信業,趙成燮,成瓚鏞 충남대학교 농업과학연구소 1984 農業技術硏究報告 Vol.11 No.1

To study the effect of foaming agent on the characteristic of mortar, the tests of water-cement ratio and bulk density of mortar were done under the different mixing ratio with G. U and J foaming agents. The results obtained were summarized as follows: 1 . At the mixing ratio of 1 : 4 and 0.5% of foaming agent, the highest water-cement ratio was 90% by G, 88.3% by U and 70% by J foaming agent, respectively, being lower than 91.6% of that of cement mortar. 2. At the mixing ratio of 1 : 3 and 3.0% of foaming agent, the water-cement ratio was decreased up to 22.0% by G and 24.1% by U foaming agent, respectively, but it gradually was increased in richer and poorer mixing ratio. At the mixing ratio of 1 : 4 and 3.0% of foaming agent, the water-cement ratio was decreased up to 53.1% by J foaming agent, but. it gradually was increased in richer mixing ratio. 3 . At the mixing ratio of 1 : 1 and 0.5% of foaming agent, the highest bulk density was 1.981 g/㎤ by G, 1.863 g/㎤ by U and 1.149 g/㎤ by J foaming agent, respectively, being lower than 2.048 g/㎤ of that of cement mortar. 4. At the mixing ratio of 1 : 2 and 3.0% of foaming agent, the bulk density was decreased up to 20 7% by G, 23.7% by U and 56.5% by J foaming agent, respectively, but it gradually was increased in richer and poorer mixing ratio, 5. The water-cement ratio and bulk density were decreased in more addition of foaming agent, respectively, multiple regression equations of water cement ratio and bulk density were computed depending on a function of mixing ratios and addition of foaming agents.

FEM에 의한 필댐의 應力解析

姜乂默,趙成燮,梁海鎭 충남대학교 농업과학연구소 1992 농업과학연구 Vol.19 No.1

The embankment material of Andong Dam was the decomposed granite soil, and FEM analysis with settlement and stress characteristics were studied in this thesis. and also the results were as follows: 1. The vertical settlement of dam quite nearly coincides with the calculated one by FEM. A maximum value of the measured and the calculated is 40cm and 42cm, respectively, at the EL. 130m. 2. The measured settlement values of the central parts in elevation are nearly the same as those of the calculated, and the settlement values in order of magnitude are in core, filter, random and rock. 3. Horizontal deformation of max. 21cm in downstream is larger than that of max. 17cm in upstream, which is highly influenced by the water pressure of reservoir water level and the earth pressure of coffer dam in upstream. 4. Reverse arching effect of vertical stress in streamflow section are caused by the difference of stiffness, because stiffness is larger in core zone than in filter zone. 5. Load transfer ratio which is the ratio of principal stress of core zone and filter zone is 1.06, which clearly showes the reverse arching effect in vertical stress.

經量콘크리트의 製造와 그 性質에 關한 硏究

金成完,姜信業,趙成燮,成瓚鏞 충남대학교 농업과학연구소 1983 農業技術硏究報告 Vol.10 No.2

To study the effect of foaming agent on the production and property of light weight concrete, the tests of compressive, tensile, bending strengths and absorption rates of mortar were done under the different mixing ratio with J, A and D foaming agents. The results obtained were summarized as follows : 1. The strengths were decreased in richer mixing ratio and more addition of foaming agent. The decrease of strengths was the greatest at the level of 0.75% of foaming agent. The decreasing rate of strengths was in order of J, A and D foaming agent. 2. At the mixing ratio of 1 : 1, σ_28 and 0.75% of foaming agent, the compressive strength was decreased up to 34.9% by D, 47.8% by A and 86,8% by J foaming agent, respectively, the tensile strength was decreased up to 14.8% by D, 20.2% by A and 77.9% by J foaming agent, respectively, bending strength was decreased up to 19.9% by D, 35.0% by A and 79.1% by J foaming agent, respectively. The decrease of compressive strength was more severe than that of tensile and bending strengths. 3. The absorption rates were increased in poorer mixing ratio and more addition of foaming agent. The absorption rate was significantly higher at the early stage of immersed water. The absorption rate was in order of J, A and D foaming agent. 4. The decrease of strengths was inevitable in cement-mortar with foaming agent, but the cement mortar with foaming agent has such the properties of the light-weight, lnsulation, Keeping-warmth, sound proof and fire-proof that if could be utilized to the constructions which need low strengths.