• Journal of the Korean GEO-environmental Society
• /
• v.7 no.1
• /
• pp.5-18
• /
• 2006

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete. Finally, a regression formula for calculating settlement reduction coefficients is proposed in this study by using numerical analysis results and applicability of the proposed method is identified by a series of parametric study about settlement reduction coefficients.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.8
• /
• pp.1136-1142
• /
• 2012

With concern for new renewable energy sources rising, the offshore wind turbine energy market is growing. In order to install offshore wind turbines safely in a harsh environment, jack-up rigs need to be used. Recently, a WTIV(Wind Turbine Installation Vessel), which has a self-propelling system, was developed to replace traditional jack-up rigs. Since the jack-up rig works at 60 meters of depth in offshore and the seafloor is composed mostly of soft clay and sand, it is necessary to conduct a stability examination for ground subsidence before using it. This study conducts an improved numerical analysis of the effect of jack-up rig loading on the soft ground by using FLAC3D considering consolidation theory. This includes analyzing the amount of subsidence when applying different cases of surchargings. It can be concluded that the mid-loading method has an advantage as regards clay layers and the pre-loading method has an advantage as regards sand layers.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1999.12a
• /
• pp.301-313
• /
• 1999

Recently, the rabid development of information technology has brought enormous changes in education. Consolidation of communications and multimedia technologies are enabling the new educational paradigm such as distance learning and virtual education. Furthermore, many studies in the education engineering field report that teaching using multimedia technologies more enhances students' performance than the traditional instructor-teaching method. However, little research regarding the education using multimedia has been done in the MIS filed. None of multimedia-related studies could be found in the top-ranked MIS journals published in Korea for the last five years, and only a few studies were found even worldwide. In this regard, the purpose of this study is to investigate which features of multimedia software are most important to enhance the teaching results of students. From the previous research, we found out the specific features of the educational multimedia software which are considered to affect the students'performance, and defined the research variables related to those educational software features. And, based on the constructivism and motivation theory of the education engineering field a theoretical research model and research hypotheses were developed. Perceived usefulness of the class and a student's perceived interests in the class were used as surrogate variables to measure teaching performance. Total 277 students participated separately in one of the two multimedia classes which have continued for three weeks. One was C programming language class and the other was multimedia CD-title development class. Each student listened for the multimedia session of the class using multimedia software and, at the end of the multimedia session, answered the survey questionnaire. The results of the study show that motivation to the class and the contents of education were statistically significant to the students'performance in the class. That implies, not only in the traditional instructor-teaching method but also in the multimedia class, that the contents of education itself and student's motivation to the class are most important to raise instructional results.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.1
• /
• pp.116-127
• /
• 1996

This paper dealt with FEM analysis of foundation improved with pack drain. The theory on pack drain was scrutinized and observed values in the field were compared with numerical results. Work site of Kwangyang container pier was selected as a ease study in which measurement of settlement and pore water pressure was accurately carried out. Biot's consolidation equation was selected as governing One, coupled with modified Camclay model as constitutive one. Christian and Boehmer's numerical technique was adopted. Behavior of foundation with pack drain is not simple but very complicated. Discontinuity resulted from rigidity difference between adjacent materials, smear effect and complicated boundary conditions should be considered in the behavior analysis of foundation behavior. The results of numerical analysis were influenced by smear zone. In relevant to this effect, finite element analysis was carried out using the reduced horizontal coefficient of permeability in the smear zone; The numerical results were compared with observed values in surface settlement. including pore water pressure. However only lateral di5plaoement by numerical ana1Ysis was shown since its measurement was not performed in the field. The predication of settlement to be developed later can be effectively employed for the obtimization of construction. The predication of residual settlement using the data measured in the field was made by Hoshino, Asaoka and hyperbolic method. Among them, the hyperbolic method proved best one. Settlements accorded well between numsrical and observed values while pore pressure showed a slight difference. Lateral displacement showed largest values at constant distance from ground surface. The validation of foundation analysis improved with pack drain by computer program employed in this study selecting modified Cam-clay model was satisfactorily secured.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.119-128
• /
• 1993

Effective machine capacity is affected by the physical and geometrical conditions of the fields. In the small and scattered farmland structure field efficiency is greatly influenced by plot geometry. In this paper, a method for estimating field efficiency and effective machine capacity was developed . The developed method was applied to Korean paddy cultivation. Various time elements related to farm operations for small and scattered plots are discussed in this paper . Available working time is divided into two parts, viz. the preparation time for machine operation and actual working time. Two kinds of machine efficiencies, namely , Machine Efficiency 1, applicable on a single large plot or set of well consolidated plots ; and Machine Efficiency 2, applicable on small and scattered multiple plots, are considered. Based assumptions made and steps followed to construct the model are discussed. Effective capacity of each machine based on different plot geometries are calculated y the model. Machine efficiency on a single plot increases with increase in the dimension of longer side of the plot . Low speed, low theoretical capacity machines have higher machine efficiency which is only slightly influenced by plot geometry. As plot geometry is improved , the machine efficiency of high speed, high capacity machines increases rapidly. The effects of short side length and plot size on machine efficiency on a single plot depend on the type of farm operation. For a particular plot shape, as plot size increases, machine efficiency on multiple plots increases rapidly. The effects of consolidation on machine efficiency is highly significant if the plot size is small and/or machine size is large.

• Journal of Korean Medical classics
• /
• v.12 no.1
• /
• pp.113-138
• /
• 1999

Distension of hydrops is the pathosis that the hydration is retented in abdomen and that is caused by disturbance of hydrometabolism. Most of hydrops belongs to Consolidation. In part of OhRyungJinAek-Byeul of Youngchu"靈樞 五癃津液別", the general explanation of hydrops is briefed. But there was nothing about pathogenesis, pathology, symptoms and the method of treatment. The part SuChang of Youngchu "靈樞 水脹" divided it by Superficial-swelling, Hidden-swelling, Ovarian-hydrops, Stony-uterin-mass and explained it to cure by Category of pathology. So, the books JeByeongWonHuRon"諸病源候論" ChonGeumYoBang"千金要方", WoiDaeBiYo"外臺秘要", TaePyeungSeongHyeBang"太平聖惠方", BoJeBang"普濟方", EuiHakGangMok"醫學綱目", DongEuiBoGam"東醫寶鑑" etc. published later, show the method of treatments and medications with quotation the original text of this part. And it is convinced that more profound research of this part is inevitable to understand the correct meaning of hydrops that explained by many of ancient medical scholars, and to apply it to clinical medicine. There is an explanation on Distension hydrops in the prologue of this part. And t six kinds of disease in this part is simila to edema, so it is called SuChang"水脹", pathology of Edema. Superficial-swellin Hidden-Swelling is reported in the fir chapter, differential diagnosis of Ovarian-hydrops, Stony-uterin-mass is rep in the second chapter, and treatment Superficial swelling. Hidden Swelling reported in the third chapter. Briefly looking over that chapter, Distension of hydrops is recognized as stay of hydration at the abdomen as a result of disturbance of hydrometabolism and it says about symtoms, pathogenesis, pathology, differential diagnosis, treatment of Hydrops Superficial-swelling Hidden-swelling Ovarian-hydrops Stony-uterinmass. And it says about a few things that Superficial-swelling, Hidden-swelling could be differentiated by colors of skin and distension of abdomen, and Ovarian-hydrops, Stony-ulerin-mass could be differentiated that it occurs which sex and whether mensturation occurs or not, and treatment of Superficial-swelling, Hidden-swelling, Ovarian-hydrops.

• Geotechnical Engineering
• /
• v.3 no.2
• /
• pp.29-40
• /
• 1987

This paper aims at investigating the characteristics of soil deformation by finite element method (FEM) coupling the cap model with the multi.purpose program developed by authors for the analysis of foundation displacement. The cap model as the constitutive equation has proved to be very useful to a partially saturated roils as well as rocks with high accuracy. As described in the Previous Paper (Park et al 1987) , there exist some difficulties in the determination of soil parameters in order to use the cap model at Present. However the authors have been studying to seek the method for the determination of the soil parameters from the laboratory results of conventional cylindrical triaxial test. Though the computer program advocated by foreign scholars has been kept secret, authors accomplished in performing the FEM analysis by the algorithm and program developed by authors for the cap model. Good results are obtained compared with those published already by Desai(1981) The main conclusions analyzed are as follows: 1. The cap model can be coupled with the multi.purpose computer program of authors bases on the Biot's consolidation theory without loss of generality. 2. Big difference appears in the settlement of center of the embankment between the cap modes and the modified Cam clay model in undrained conditions. The more study on which is more accurate should be performed in this respect.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.4
• /
• pp.21-32
• /
• 2011

A series of in-situ and laboratory tests were performed for the clayey soils of Busan area in order to develop the methods to evaluate the compressibility using CPT and DMT results. The laboratory tests show that the clayey layers of Busan areas are normally consolidated, and their compression indices are turned out to be 0.5~1.3. From the analysis of test results, correlation factors between the cone resistance and constrained modulus (${\alpha}_m$ and ${\alpha}_n$) are observed to decrease with increasing plasticity index, and the correlation factor between the dilatometer modulus and constrained modulus $(R_M)$ increases with $1/I_D$. Based on these relationships, the methods evaluating the constrained modulus from CPT and DMT results are suggested. It is shown that the prediction method by CPT underestimates the constrained modulus of improved ground, whereas the prediction method by DMT is suitable for evaluating the constrained modulus of improved and unimproved ground.

• Journal of the Korean GEO-environmental Society
• /
• v.3 no.1
• /
• pp.67-77
• /
• 2002

Volume change of the dredged soils is composed of the volume loss of soil particle flowing over an outflow weir with water and settlement due to both the self-weight consolidation in reclaimed layer and the desiccation at the surface of reclaimed layer. In order to estimate the amount of soil particles flowing over an outflow weir with water, the evaluation procedure of loss ratio of the dredged soils is proposed in the present study based on the Marsal's modified breakage theory and the results of hydrometer analyses. To verify a validity of the proposed procedure, evaluated loss ratio is compared with results from the other existing methods. The model test results and those of field test were compared and analyzed. Also, the variation of soil loss ratio was examined through the model test in the lab.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.03a
• /
• pp.1046-1053
• /
• 2006

In the large scale recent reclaiming works performed within the wide spatial boundary, evaluation of long-term consolidation settlement and residual settlement of the whole construction area is sometimes made with the results of the limited ground investigation and measurement. Then the reliability of evaluation has limitations due to the spatial uncertainty. Additionally, in case of large scale deep excavation works such as urban subway construction, there are a lot of hazardous elements to threaten the safety of underground pipes or adjacent structures. Therefore it is necessary to introduce a damage prediction system of adjacent structures and others. For the more accurate analysis of monitoring information in the wide spatial boundary works and large scale urban deep excavations, it is necessary to perform statistical and spatial analysis considering the geographical spatial effect of ground and monitoring information in stead of using diagrammatization method based on a time-series data expression that is traditionally used. And also it is necessary that enormous ground information and measurement data, digital maps are accumulated in a database, and they are controlled in a integrating system. On the abovementioned point of view, we developed Geomonitor 2.0, an Internet based real time monitoring program with a new concept by adding GIS and geo-statistical analysis method to the existing real time integrated measurement system that is already developed and under useful use. The new program enables the spatial analysis and database of monitoring data and ground information, and helps the construction- related persons make a quick and accurate decision for the economical and safe construction.