재하조건(載荷條件)이 선행하중(先行荷重)에 미치는 영향(影響)

지인택 ( Chee In Taeg ),강예묵 ( Kang Yea Mook ),윤현정 ( Yoon Hyun Jung ) 한국농공학회 1985 韓國農工學會誌 : 전원과 자원 Vol.27 No.3

The Paper was made to search the mostly proper loading condition in the consolidation tests. The consolidation tests have been carried out with dia. 6cm × ht. 2cm specimens after the Kaolin-Clay sedimented artificially had been precompressed in 4kg/㎠. The results were summarized as follows 1. The structual stable arrengement of soil particles with dia. 6cm × ht. 2cm specimens was appeared to more than increment duration of preload was 24 hours. 2. The preconsolidation load was showed highly in order of increment ratio of preload, 0.5, 1, respectively and the instantaneous load, 0.4kg/㎠. 3. At the relationship between load increment ratio and preconsolidation load, the latter gradually decreased in regular of former, 0.5, 1.0, 2.0. The coefficient of secondary consolidation was increased with the increment of the consolidation load, made a point of the inflection near consolidation load, 0.4-0.8kg/㎠. 4. At load increment duration of 30min, 90min, the preconsolidation load was 0.4kg/㎠. Above the load increment duration of 12hr, preconsolidation load was constant in 0.38kg/㎠. The coefficient of secondary consolidation was increased with the increment of compression index.

점성토(粘性土)의 시간의존적(時間依存的) 응력(應力) - 변형(變形) 특성(特性)에 관한 연구(硏究)

지인택 ( Chee In Taeg ),강예묵 ( Kang Yea Mook ) 한국농공학회 1988 韓國農工學會誌 : 전원과 자원 Vol.30 No.4

This paper was carried out to investigate the existence of a unique stress- strain behavior by obtaining some factors influencing the time dependent stress- strain behavior of clay. The results obtained from this study were summarized as follows ; 1. The relationship between stress ratro and strain in normally consolidated clay was in- dependent on pre-shear consolidation pressure. Therefore, shear strain could be expressed as a function with stress ratio. 2. The constitutive equation of shear strain on Modified Carn Clay Model coincided better with the observed value than Cam Clay Model. 3. The relationships between deviator stress and shear strain, between pore water pressure and shear strain were unified by the mean equivalent pressure. 4. The shear strain contour in norrnally consolidated clay was increased linearly through origin, but that in overconsolidated clay was not in accordance with the result of the former. 5. Because the effective stress path of normally consolidated clay was unified by the mean equivalent pressure, state boundary surface in (e,p,q) space was transformed into two dimensional surface. But it was considered to be suitable that the unified stress- strain in overconsolidated clay be expressed by a function with overconsolidation ratio. 6. The deviator for constant strain was increased linearly with increment of strain rate (ε) on semi-log scale, but pore water pressure was decreased. 7. The behavior of stress relaxation was transformed from linear to curvilinear with increment of strain rate before stress relaxation test, and pore water pressure was increased in total range. 8. The strain of creep was increased linearly with increment of time on semi-log scale. The greater the strain rate before creep test became, the greater the increment of strain of creep became. And the pore water pressure during creep test was increased generally with increment of time on semi-log scale. 9. The phenomena of stress relaxation and creep of clay were influenced greatly with strain rate before stress relaxation and creep test. Therefore, it is considered that the strain rates (ε) before stress relaxation and creep test should be dealed with a new factor in constitution equation of soil.

한계상태(限界狀態) 공극수압(空隙水壓) 계수(係數)에 의(依)한 비배수(非排水) 전단강도(剪斷强度)의 예측(豫測)

지인택 ( Chee In Taeg ),강예묵 ( Kang Yea Mook ) 한국농공학회 1987 韓國農工學會誌 : 전원과 자원 Vol.29 No.1

The paper was carried out to predict the characteristics of undrained strength by critical-state pore pressure parameter (□_o) The results were summarized as follows: 1. One of the critical-state theory used in the prediction of strains is the Cam Clay Model assumed that soil is elasto-plastic. The Cam Clay Model could be easily utilized to analyze and predict the deformation of soil due to structures with the some fundamental soil parameters measured in standard laboratory test. 2. Critical-state pore pressure provides a simple analytical representation of undrained stress-strain behavior, since it is independent of overconsolidation (OCR), intial stress state (K_o),and level of shear to failure. 3. The advantage of using the critical-state pore pressure (□_o) against Skempton’s pore pressure parameter (A_f) and Henkel’s pore pressure parameter (a) is that □_o is constant in a range of OCR valus while A_f and a are variable with OCR. In this study, Skempton’s pore pressure parameter was rearranged, as a function of OCR using critical-state pore pressure parameter. 4. Modified Cam Clay Model was better than Cam Caly Model for the prediction of undrained strength in normally consolidated range. 5. The variation of undrained strength in overconsolidated range was greater with OCR in Kaolin clay than in Marine clay. 6. Pore pressure in overconsolidated range was varied slightly greater in Marine clay than in Kaolin clay, but reverse was true in normally consolidated range. 7. The proposed critical state pore pressure perameter can describe the pore pressure as a function of strain.

불포화된 실트질 모래의 액상화 거동

이달원 ( Lee Dal Won ),지인택 ( Chee In Taeg ) 한국농공학회 2006 한국농공학회 학술대회초록집 Vol.2006 No.-

This study was carried out to investigate the liquefaction behaviour with matric suction, of unsaturated silty sand. The unsaturated soil tests were conducted using a modified triaxial cell and specimens were prepared using the moisture tamping method. The axis translation technique was used to create the desired matric suctions in the samples. Undrained triaxial compression tests were carried out at matric suction of 0, 2, 5, 10 and 25 kPa. The samples were sheared undrained to axial strains of about 20% to obtain steady state conditions. The results show that liquefaction of silty sand only occurs at matric suction of 0 kPa and 2 kPa. The results also show that at matric suctions of 5, 10 and 25 kPa, the resistance to liquefaction increases. As the suction increases, the undrained effective stress path approaches the drained stress path.

지진계수(地震係數)를 고려(考慮)한 제방(堤防)의 사면안정(斜面安定)에 관(關)한 연구(硏究)

강예묵 ( Kang Yea Mook ),지인택 ( Chee In Taeg ),이달원 ( Lee Dal Won ) 한국농공학회 1991 韓國農工學會誌 : 전원과 자원 Vol.33 No.4

This study was performed to investigate the minimum safety factor of embankment in consideration of seismic coefficient by the psuedo-static analysis The variables were cohesion, the internal friction angle, angle of slope, height of seepage, height of embankment, depth of replacement The results obtained were compared with those by Fellenius method, simplified Bishop method and Janbu method. The results were summarized as follows: 1. The increasing rate of the minimum safety factor with the increasing of cohesion appeared larger in Fellenius method and Bishop method than in Janbu method. And that with the increasing of the internal friction angle appeared the lowest value in Janbu method. The minimum safety factor was influenced larger on the internal friction angle than on cohesion. 2. The variation of the minimum safety factor with the height of seepage at 0m and 5 m was nearly similar to Fellenius method, Bishop method and Janbu method. On the other hand, it was decreased suddenly at 25 m. 3. The minimum safety factor with the height of embankment was decreased remarkably under 10 m with the increasing of seismic coefficient. But, it was decreased slowly more than 10 m. As the height of embankment was low, the influence of cohesion appeared larger. 4. In heigher case of the depth of replacement, the phenomenon of reduction of the minimum safety factor appeared remarkably with seismic coefficient increased. And in lower case of the depth of replacement, the minimum safety factor was similar in Fellenius method and Bishop mehtod. But it appeared larger in Bishop method and Janbu method than in Fellenius method with the depth of replacement increased. 5. As the cohesion and the internal friction angle were large, the phenomenon of reduction of the minimum safety factor with the increasing of seismic coefficient appeared remarkably. Also, the influence of seismic coefficient in minimum safety factor appeared larger with the soil parameter increased. 6. When the seismic coefficient was considerated, investigation of the structural body on the slope stability appeared profitably in Fellenius method and Janbu method than in Bishop method.

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.

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.

荷重增加率이 二次壓密에 미치는 影響

池仁澤,姜乂默 충남대학교 농업과학연구소 1983 農業技術硏究報告 Vol.10 No.1

This study was conducted to investigate the influence of load increment ratio on the secondary consolidation for the marine clay at Asan bay by the hyperbola method. The results were summarized as follow : 1. Calculated secondary consolidation by the hyperbola method was slightly less than the value of Casagrande's log t method, but the difference was very little, and the secondary consolidation could be easily calculated by the hyperbola method even if load increment ratio was small. 2. The secondary consolidation ratio was increased with the decrement of load increment ratio, and the creep phenomenon of the settlement curve occurred under the condition of small load increment ratio seemed to be caused by the secondary consolidation. 3. The secondary consolidation ratio occurred during the primary consolidation was irregular in the overconsolidated range, but it was increased with the decrement of load increment ratio in the normally consolidated range. 4. The coefficient of secondary consolidation was increased with the increment of the consolidation load, made a point of the inflection near preconsolidation. And the coefficient of secondary consolidation was decreased from consolidation load 2kg/㎠, showed independent of load increment ratio. 5. The coefficient of secondary consolidation was showed in proportion to compression index.

절취사면에서의 파괴형태에 따른 안정해석방법

강예묵,지인택,김용성,김지훈 충남대학교 농업과학연구소 1998 농업과학연구 Vol.25 No.1

This study was carried out to investigate the problem of analysis method of circular sliding, which uses a high rate to work out a countermeasure for landslides. The results of this study were summarized as follows : 1. As a result of the analysis of sliding surface along the soil layers in forty model slopes, the boundary layer in weathered soil and weathered rock indicated a very high possibility of sliding than in other places. 2. Because most landslides in Korea occur along the discontinuity face at the boundary of soil layers, below 2m. from land surface, it is a good method for safe design to work the countermeasure for these kinds of landslides in cutting slopes. 3. When the inclination of slopes is fixed and the length of slopes is changed, the cercular sliding slopes were more safe as the soil layers are more shallow and the length of sloped are shorter, but the safety ratio of infinite sliding slopes was same as the other even though their length of slopes was different. 4. As a result of the analysis by cercular sliding analysis method and infinite sliding analysis method with some condition that the inclination of slopes was 30˚ degree, because most landslides in Korea occur at this condition, these methods indicated different results to each other as well as cercular sliding analysis method showed too much safety ratio than infinite sliding analysis method.

버팀대로 보강된 널말뚝의 안정해석

김지훈,강예묵,지인택 충남대학교 농업과학연구소 1997 농업과학연구 Vol.24 No.2

The results obtained by elasto-plastic analysis method about the displacement, deformation and stability on the soft ground excavation using sheet pile were summarized as follows ; 1. In the case of strut 1 step, the maximum wall displacement value in the first and the second excavation was small, but it increase remarkably after the third excavation and when the excavation depth was 8m, the point of maximum wall displacement was shown 0.75H~0.8H. 2. The value of safety factor(Fs) was increased with increasing of the penetration depth of sheet pile, cohesion and internal friction angle of ground. Safety factor was mostly effected by penetration depth of sheet pile and more effected by cohesion than internal friction angle of ground. 3. Since the deformation of sheet pile of this ground from the results of analysis and measurement increased remarkabaly after 6m excavation depth, it was desirable that the point of strut installation was GL-6m. 4. Safe excavation depth on ground by analysis considered penetration depth, cohesion and internal friction was shown at the table 3.