• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.345-349
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• 2019

In Korea, the mountainous area occupies more than 70% of the whole country, cutting of earth slope that cuts a part of the ground surface is widely used when building infrastructures such as road, railroad, and industrial complex construction. In recent years, regulations on environmental damage have become more strict, and various methods have been developed and applied. Among them, Concrete-Panel Retaining Wall technique is actively applied. Concrete-Panel Retaining Wall is a method to resist horizontal earth pressure by forming a wall by attaching a precast retaining wall to the front of the support material and increasing the shear strength of the disk through reinforcement of the support material. Soil nailing, earth bolt, and ground anchor are used as support material. Among them, ground anchor is a more aggressive reinforcement type that introduces tensile load in advance to the steel wire, and a large concentrated load acts on the front panel. This concentrated load is a factor that creates cracks in the concrete panel and reduces the durability of the retaining wall itself. In this study, steel pipe sleeves and reinforcements were purchased at the anchorage of the panel to prevent cracks, and by applying bumpy shear keys to the end of the panel, the weakness of the individual behavior of the existing grout anchors was improved. The problem of degraded landscape by exposure to front concrete of retaining wall and protrusion of anchorage was solved by the production of natural stone patterns and the construction of sections that do not protrude the anchorage. In order to verify the effectiveness of anti-crack sleeves and reinforcements used in the null, indoor testing and three-dimensional numerical analysis have been performed, and the use of steel pipe sleeves and reinforcements has demonstrated the overall strength increase and crack suppression effect of panels.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.381-393
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• 2021

Physical, mechanical, hydraulic, and geophysical tests were applied to validate methods of inspecting the effectiveness of grouting on an agricultural reservoir dam. Data obtained from series of in situ and laboratory tests considered four stages: before grouting; during grouting; immediately after grouting; and after aging the grouting for 28 days. The results of SPT and triaxial tests, including the unit weight, compressive strength, friction angle, cohesion, and N-value, indicated the extent of ground improvement with respect to grout injection. However, they sometimes contained errors caused by ground heterogeneity. Hydraulic conductivity obtained from in situ variable head permeability testing is most suitable for identifying the effectiveness of grouting because the impermeability of the ground increased immediately after grouting. Electric resistivity surveying is useful for finding a saturated zone and a seepage pathway, and multichannel analysis of surface waves (MASW) is suitable for analyzing the effectiveness of grouting, as elastic velocity increases distinctly after grouting injection. MASW also allows calculation from the P- and S- wave velocities of dynamic properties (e.g., dynamic elastic modulus and dynamic Poisson's ratio), which can be used in the seismic design of dam structures.

• Journal of the Korean Geotechnical Society
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• v.26 no.6
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• pp.5-19
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• 2010

The purpose of this study is to figure out the effect of pressurized grouting on the pullout resistance and the group effect of the compression ground anchor by performing pilot-scale chamber tests and field tests. The laboratory tests are carried out for 3-types of soils which are abundant in the Korean peninsular. Experimental results showed that the enlargement of anchor diameters estimated from the cavity expansion theory matches reasonable well with that obtained from experiments. Moreover, the required injection time as a function of the coefficient of permeability of each soil type was proposed. A series of in-situ anchor pullout tests were also performed to experimentally figure out the effect of pressurized grouting on the pullout resistance. Experimental results also showed that the effect of the pressurized grouting is more prominent in a softer ground with smaller SPT-N value in all of the following three aspects: increase in anchor diameter; pullout resistance; and surface roughness. The pressurized grouting effect in comparison with gravitational grouting was found to be almost nil if the SPT-N value is more than 50. Based on experimental results, a new equation to estimate the pullout resistance as a function of the SPT-N value was proposed. And based on in-situ group anchor pullout tests results, a new group effect equation was proposed which might be applicable to decomposed residual soils which are abundant in the Korean peninsular.

• The Journal of Engineering Geology
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• v.32 no.1
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• pp.173-191
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• 2022

In this study, the shear wave velocity of the ground was measured using Flat TDR, and the precision analysis of the measured value and the verification of field applicability were performed. The shear wave velocity measurement value was derived in the field using the piezo-stack combined in the Flat TDR. analyzed. As a result of the experiment, the average value of the change in shear wave speed at the time of grout material injection was 10.15 m/s at the beginning of age, and the average value of the change in shear wave speed after the 7th to 14th days was 65.99 m/s, showing a tendency to increase with age. Also, it was found that dry density and shear wave speed increased as the water content increased on the dry side, and that the dry density and shear wave rate decreased as the water content increased on the wet side as the water content increased. The shear modulus value derived from the field test was confirmed to be a minimum of 17.36 MPa and a maximum of 28.13 MPa, confirming a measurement value similar to the reference value. Through this, it can be seen that the measured value of the shear modulus using Flat TDR is reliable data, and it can be determined that the compaction management of the site can be effectively managed in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.313-319
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• 2009

In this study, field pull-out test and 3-D FEM analysis have been performed for examining and reflecting the behavior of steel pipe nailing installed foldable wedge. Field pull-out test was performed under various conditions. As a result, the steel pipe nailing installed foldable wedge has an effect of pull-out resistance increased about 30% in comparison with non-wedge type steel pipe nailing. Through back analysis in 3-D FEM for behavior of non-wedge type steel pipe nailing, friction characteristics between nail to soil was analyzed and obtained first consistent with field pull-out behavior. Then, the frictional characteristic was used for analyzing the behavior of the steel pipe nailing installed foldable wedge. The result was compared with the test results. Consequently, friction coefficient (${\mu}$) of about 1.2 between grout to soil leads to good agreement with analysis results and test results. And a limited pull-out resistance, $$T_L{\sim_=}32$$ tonf is similar to field pull-out test result which is improved about 33% in comparison with non-wedge type steel pipe nailing's $$T_L{\sim_=}24$$ tonf.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.541-554
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• 2023

The utilization of underground spaces in relation to tunnels and energy/waste storage is on the rise. To ensure the stability of underground spaces, it is crucial to reinforce rock fractures and discontinuities. Discontinuities, such as joints, can weaken the strength of the rock and lead to groundwater inflow into underground spaces. In order to enhance the strength and stability of the area around these discontinuities, rock grouting techniques are employed. However, during rock grouting, it is impossible to visually confirm whether the grouting material is being smoothly injected as intended. Without proper injection, the expected increases in strength, durability, and degree of consolidation may not be achieved. Therefore, it is necessary to predict in advance whether the grouting material is being injected as designed. In this study, we aimed to assess the injection performance based on injection variables such as the water/cement mixture ratio, injection pressure, and injection flow using UDEC (Universal Distinct Element Code) numerical program. Additionally, numerical results were validated by the lab experiment. The results of this study are expected to help optimize variables such as injection material properties, injection time, and pump pressure in the grouting design in the field.

• Journal of the Korean GEO-environmental Society
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• v.25 no.4
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• pp.29-35
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• 2024

This is an analytical study to confirm the passive resistance effect before post-tensioning of steel bar anchors. When using a steel bar as a permanent anchor, if displacement occurs within the slope even before the head load is applied, the displacement is suppressed by the passive resistance caused by the interaction between the steel bar, grout, and surrounding soil. Accordingly, the shape of the failure surface and changes in the safety factor were examined using limit equilibrium analysis and finite element analysis targeting sites where steel bar anchors were actually applied. It was found that the safety factor of the slope reinforced with steel bar anchors is 2.02 using finite element analysis, which is about 5.9% smaller than 2.14 using limit equilibrium analysis. Also, the location of the failure surface was found to be deeper compared to the unreinforced slope. Likewise, the factor of safety has a 153% and 163% increase using finite element method and limit equilibrium analysis, respectively. In addition, the maximum displacement occurs in the lower unreinforced section within the slope, and the displacement is found to be reduced by 42 to 83% at the location where the steel bar anchors are installed.

• Korean Journal of Veterinary Service
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• v.24 no.3
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• pp.223-241
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• 2001

From September 1996 to September 1999, 419 Korean-native calves with diseases under 6-month old collected from Kyonggi, Chungcheong, Chonlla and Kyongsang were examined by clinical, microbiological, parasitic, hematologic and histopathological mean. Among them, 124 cases were tested about the neutralization antibodies against infectious bovine rhinotracheitis virus(IBRV), Parainfluenza-3 virus(PI-3V), bovine uiral diarrhea virus(BVDV), bovine ephemeral fever virus(BEFV). In calf diseases in the survey, enteric diseases(72.8%) were most frequently involved and the following orders were taken by respiratory(17.4%) and reproductive (5.0%) disorders. In the causative pathogens associated with calf diseases and motality, 48.4% was induced by bacteria origin and also 35.6% by viral agents. Calf mortality was up to 76.3% in the cae of bacterial diseases and 55.7% in viral diseases. In bacterial diseases, frequent disorders were composed of colibacillosis(52.7%), salmonellosis(13.8%), pasteurellosis(12.8%) and campylobacteriosis(3.9%) and their mortalities showed 73.8% in colibacillosis, 73.0% in pasteurellosis, 67.9% in salmonellosis and 50.0% in campylobacteriosis (50.0%). Among the outbreaks of viral diseases, there were BVD(22.8%), bovine rotavirus infection(20.8%), bovine coronavirus infection(16.8%), bovine respiratory syncytial virus infection(15.4%), IBR(15.4%). Akabane disease(4.7%) and Chuzan diseases(3.4%). Interesting results through this studies were obtained the first isolate to Chuzan virus and Ainovirus in Korea which could be promised the development for diagnostic method and vaccines soon. Calf mortality to Akabane and Chuzan diseases was 100%. Main parasitic diseases were occupied by coccidiosis and babesiosis and their mortality of babesiosis was 20.0%. Other diseases were abomasal impaction(6.7%) and toxicosis(4.5%). The mortality of abomasal impaction was 89.3%. In some causes with malformations(1.9%) were confirmed as anasarca, derodidymus, polymelia, humerus hypoplasia, and tracheal collapse. Calf diseases had mostly been occurred in one month old grout (52.5%) and its prevalence was 25.1% in two to three month old group and 22.4% in four to six month old group. In calf mortality by age, there were 37.9% in one month old group, 18.1% in two and three month old group, and 13.8% in four to six month old group, respectively. The older the age of calf, the less the prevalence of calf enteric diseases. Respiratory diseases in calves to be tested frequently occurred in one to two month old group (41.4%). In one month old calves, the prevalence of enteric disease was 80.0%(p<0.05) and that of reproductive and respiratory disease was 9.5% and 8.2%, respectively. In two month old and four to six month old, enteric disease was 65.7% and 63.8% and respiratory disease was 28.6% and 26.6%. Seasonal prevalence and mortality of Korean-native calf diseases were not a significant difference. Prevalence of calf diseases in summer(31.5%) frequently occurred to compare that in winter(20.3%). Abortion and malformation in calves frequently occurred in spring. Hematological values in 84 calves with clinical signs showed mild to marked leukocytosis. Also, there was slight increase in hematocrit, platelet, mean corpuscular volume and mean plasma volume, but all of those were included the higher level to normal ranges. Calves with respiratory signs showed slightly erythrocytosis. One hundred seventy three calves without clinical signs were not significant different to ill cases in hematological values, but number of platelets was in higher normal range. In 125 calves, 84.8% was taken the antibody to IBRV, but 72% with the antibody had recorded the titer level lower than log$_2$5. The neutralizing antibody levels of higher than $log_{2}5$ to PI-3V and BVD virus were 60.8% and 67.2% cases, respectively. There were the cases of 57.6% had the neutralizing antibody level lower than log$_2$5 to BEFV.

• Applied Microscopy
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• v.25 no.4
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• pp.83-103
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• 1995

This experiment was carried out to investigate the effects of telluric acid on the histological and fine structural changes in the rat liver. Fischer 344 rats($150{\sim}200gm$) were used in this study as control and experimental groups. Telluric acid(5 mg/100 gm of body weight) suspensed in olive oil was given intraperitoneally to the animals of the experimental group and only olive oil to those of the control group. At the intervals of 3, 6 and 12 hours, 1, 2, 3, 5, 10, 20, 30 and 60 days after administration, the animals were sacrificed, and livers were obtained from the rats. For light microscopic examination of the liver, sections($5{\mu}m$) were stained with hematoxylineosin(H-E). For electron microscopic examination of the liver, sections were stained with uranyl acetate and lead citrate, finally examined with Zeiss EM 109 electron microscopes. The results obtained were as follows. 1. In the control group, round nucleus. well developed mitochondria, Golgi apparatus, rough endoplasmic reticulum(RER) and numerous glycogen particles were observed in the cytoplasm of the hepatocyte. In the cytoplasmic membranes of the hepatocyte, sinusoidal surface had numerous microvilli and cellular surface is combinated adjacent hepatocyte with desmosomes. The RER cisterns were dilated and zymogen granules were fewer than those of the dark cells. Kupffer cells with irregular nuclear membrane were observed. Fat storing cell and collagenous fiber bundle were observed in the Disse space. 2. Kupffer cell, inflammatory cells in the connective tissue of hepatic triad and lysosome were increased in the 3, 6, and 12 hour experimental group comparing with that of the control group. 3. In the 1 day experimental group, infiltration of inflammatory cells in interlobular connective tissue, dilatation of sinusoidal capillary and increasing of Kupffer cell were observed. Atropic change of hepatocyte and aggregation of glycogen particles in the cytoplasm of hepatocyte were observed. In this group, desmosome near bile canaliculi and collagenous fiber bundle in the Disse space were increased comparing with that of the 12 hours experimental group. In the 2 days experimental group, desmosome, lysosome, peroxisome and collagenous fiber bundle were increased comparing with that of the 1 day experimental group. Furthermore, lamellated bodies were also seen in the cytoplasm of the hepatocyte. 4. In 3 and 5 days experimental groups, transformations of hepatic cell cord and degeneration of the hepatocyte were markedly inclosed comparing with the all experimental groups. And damaged RER and mitochondria. collagenous fiber bundle were also inclosed comparing with that of the 2 days experimental group. Autophagosome and fat storing cells with large lipid droplets were also observed comparing with that of the 2 days experimental group. Tight junction and desmosome between the hepatocytes were separated. These degenerating changes were severe through the all experimental groups. 5. In the 10 and 20 days experimental groups, arrangement of hepatic cell cords and cell organelles of hepatocytes were similar to those of the control group. However, aggregation of glycogen particles, dilatation of sinusoidal capillary and infiltration of inflammatory cells remained. 6. In the 30 days experimental group, the tissue findings were similar to those of the control grout. But lamellated bodies in some hepatocytes and lysosome were remained in the cytoplasms of the Kupffer cells. In the 60 days experimental group, these all changes were recovered as the control group. In conclusion, telluric acid would directly induce the degenerative and necrotic changes on the hepatic tissue. However, these changes were perfectly recoverd in the 60 days experimental group as the control group.

• Journal of Sasang Constitutional Medicine
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• v.19 no.2
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• pp.40-52
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• 2007

1. Objectives and Methods The purpose of this study was to objectify the diagnosis of Sasang Constitution. 63 Male Juvenile's and 151 Female Juvenile's sentences were analyzed into 73 factors like Pitch, APQ, Shimmer, Octave and Energy, etc. Juvenile's sentences were classified into 6 categories: total Male Juvenile group, under 12 years old Male Juvenile grout, over 13 years old Male Juvenile group, total Female Juvenile group, under 12 years old Female Juvenile group and over 13 years old Female Juvenile group. 2. Results 1) In Total Male Juvenile group, there were no significant differences among constitutional groups in APQ and Octave segment. Taeumin's Center freq.(3) was significantly high compared with Soyangin group. Soeumin's Center freq.(5) was significantly high compared with Soyangin and Taeumin groups. Taeumin's Octave3 Shimmer was significantly high compared with Soeumin group. Soeumin's Octave6 Shimmer was significantly high compared with Taeumin group. Solyangin's D# Tot E was significantly high compared with Taeumin group. 2) In Under 12 years old Male Juvenile group, there were on significantly among constitutional groups in Pitch, APQ, Octave and Energy segment. Taeumin's Octave3 Shimmer and G Shimmer(1) were significantly high compared with Soeumin group. 3) In Over 13 years old Male Juvenile group, there were no signigicant differences among constitutional groups in Pitch, APQ and Shimmer segment. Soyangin's and Soeumin's Octave6 were significantly high compared with Taeumin group. Soyangin's $0k{\sim}2k$ Total Sum, $0k{\sim}2k$ Dev., $2k{\sim}4k$ Total Sum, $2k{\sim}4k$ Dev., A Dev.(1), D# Dev.(1) and G# Dev.(1) were significantly high compared with Taeumin group. Soyangin's and Soeumin's G# Tot E were significantly high compared with Taeumin group. 4) In Total Female Juvenile group, there were no significant differences among constitutional groups in Pitch and APQ segment. Soeumin's Octave4 Shimmer was significantly high compared with Soyangin group. Soyangin's Octave6 was significantly high compared with Soeumin group. Solyangin's 2k-4k Total Sum and B Tot E were significantly high compared with Soeumin group. 5) In Under 12 years old Female Juvenile group, there were no significant differences among constitutional groups in APQ and Energy segment. Soeumin's and Taeumin's Center Pitch and Pitch were significantly high compared with Soyangin group. Soyangin's Center freq.(1) and Center freq.(7) were significantly high compared with Soeumin and Taeeunin groups. Soyangin's and Taeumin's B Shimmer(1) and F# Shimmer(1) were significantly high compared with Soeumin group. Soeumin's D Shimmer(1) was significantly high compared with Soyangin group. Taeumin's and Soeumin's G# Shimmer(1) were significantly high compared with Soyangin group. Soyangin's and Taeumin's Octave2 were significantly high compared with Soeumin group. 6) In Over 13 years old Female Juvenile group, there were no significant differences among constitutional groups in Pitch, APQ and Octave segment. Soeumin's Octave4 Shimmer was significantly high compared with Soyangin group. Soyangin's B Dev.(1) and F Dev.(1) were significantly high compared with Soeumin group. 3. Conclusions In juvenile groups, some sound factors are regarded as useful. PSSC are thought to be the objertive way to diagnose the Consitution and more participants are needed to get more efficiencies using PSSC.