• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.63-71
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• 1989

Four series of reinforced concrete beams were tested to determine their shear cracking strengths and ultimate shear capacities. All beams were singly reinforced without shear reinforcement. The concrete strength was the prime variable which was varied from 247 to $708kg/cm^2$(8500 to 10000 psi). Within each series the shear span-to-depth ratio was varied from 2 to 5, while concrete strength was held constant. Test results indicate that the effect of concrete strength on shear capacities is varied as the shear span-to-depth ratio is changed. Furthermore, the current shear design provisions do not provide a consistency with respect to estimating shear capacities of reinforced concrete beams. By introducing the shear failure mode index, a new equation is proposed to predict ultimate shear strengths of reinforced concrete beams without web reinforcement.

• Journal of the Korean GEO-environmental Society
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• v.17 no.12
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• pp.55-64
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• 2016

In this paper bearing capacity and safety margin of shallow foundation on weathered soil ground against shear failure by using current design method of allowable stress design (ASD), load resistance factor design (LRFD) based on reliability analysis and partial safety factor design (PSFD) in Eurocode were estimated and compared to each other. Results of the plate loading test used in construction and design were collected and analysis of probability statistics on soil parameters affecting the bearing capacity of shallow foundation was performed to quantify the uncertainty of them and to investigate the resistance bias factor and covalence of ultimate bearing capacity. For the typical sections of shallow foundation in domestic field as examples, reliability index was obtained by reliability analysis (FORM) and the sensitivity analysis on soil parameters of probability variables was performed to investigate the effect of probability variable on shear failure. From stability analysis for these sections by ASD, LRFD with the target reiability index corresponding to the safety factor used in ASD and PSDF, safety margins were estimated respectively and compared.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.83-91
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• 2020

In this study, the characteristics of support behavior according to the change of ground condition of the cast-in-place pile and the large Caisson foundation, which are increasingly used as foundations of large structures and bridges. the allowable bearing capacity calculated using the yield load analysis method was analyzed to calculate similar allowable bearing capacity for each method. In addition, the allowable bearing capacity calculated by the ultimate load analysis method was found to have a large difference in bearing capacity for each method. Through this point, it can be usefully used as an empirical formula for evaluating the settlement characteristics of piles in future design and construction. In addition, as a result of examining the ground force distribution during sedimentation of large caissons, the section of the weathered rock layer showed almost constant ground force distribution as ground forces decreased after yield occurred at the base corner. And in the bed rock layer section, the foundation's center was transformed into a ground force in the form of a convex downward due to an increase in the ground resistance of the central part. Using these results, the theory previously presented by Fang (1991) and Kőgler (1936) was proved.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.261-268
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• 2000

In this study the bearing capacity of the eccentrically loaded shallow footing is estimated by means of the upper bound method of limit analysis. In the case of applying the upper bound, the results depend on the failure mechanism. So the failure surface is correctly studied through the model test using sand. New method is proposed to estimate the bearing capacity of the eccentrically loaded shallow footing by means of the upper bound method to apply the failure mechanism based on the model test. The propriety of new method is verified by the results of various methods. And the influences of the variables eccentricity, embedment depth, variations of contact width factor by model test using sand are also studied in this paper

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.5-16
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• 2008

This study investigated the existing theoretical backgrounds in order to examine the stability control method of lateral flow caused by the Plasticity of soils when unsymmetrical surcharge works on polluted soils and then compared and analyzed the results measured through model tests. Ultimate bearing power of ML and $ML_{p1}$ and $ML_{p2}$ obtained at surcharge(q)-settlement$(S_v)$ curve showed similar trends to ultimate bearing power obtained from control chart of deflection $(S_v-Y_m)$ by Tominaga.Hashimoto, that of $S_v-(Y_m/S_v)$ by Matsuo.Kawamura and that of $(q/Y_m)-q$ by Shibata.Sekiguchi and so it is considered that it has no problem in actual applicability. ${S_v-(Y_m/S_v)}$ of control chart of $ML_{p1}$ by Matsuo.Kawamura showed smaller value than ultimate bearing capacity value from surcharge-settlement curve $(q-S_v)$. Expression of ML of fracture baseline at stability control charge by Matsuo Kawamura is ${S_v=3.21exp}\{-0.48(Y_m/S_v)\}$ and expression of $ML_{p1}$ is ${S_v=3.26exp}\{-0.96(Y_m/S_v)\}$ and expression of $ML_{p2}$ is ${S_v=6.33exp}\{-0.45(Y_m/S_v)\}$.

• Journal of the Daesoon Academy of Sciences
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• v.42
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• pp.109-141
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• 2022

As many perhaps already know, in East Asian thought there are two aspects of all things such as light and darkness coexist and are called Yin-Yang (陰陽). The initial concept of Yin-Yang was just a simple expression meant to depict natural phenomena, but it gradually became the central concept in explanations of creation and the changes that undergo all things in the universe. The study of the ordering principle of nature that was known as Myeongli (命理) also examined the interrelation between the sky and the earth and divided the two into Ten Celestial Stems (天干 cheongan) and the Twelve Earth Branches (地支 jiji) based on Yin-Yang theory. This thesis analyzed contents of the relationship between Ten Celestial Stems and the Twelve Earth Branches in terms of the patterns of Mutual Aid (相助 sangjo) and Mutual Contention (相剋 sanggeuk) through a literature review and exploration of their common features and differences. Different categorized phenomena under the pattern of Mutual Aid include Tonggeun (通根 root downward) and Tugan (透干 appearance of the upward). Tonggeun means that signs in the Celestial Stems took root in their counterparts of the Earthly Branches. In the Celestial Stems, there is also Tonggeuncheo (通根處 a place to root downward) which in relation to the Earthly Branches show that the same five phases become Samhap (三合 combined three ways to gain power) and Banghap (方合 gathering in the same season). The methods of seeing Tonggeunryeok (通根力 power of a downward root) are as follows: First, it is seen by the places where Tonggeun takes hold. Ilgan (日干 the Celestial Stem of a birthday) is ordered as month (月 wol) > day (日 il) > hour (時 shi) > year (年 nyeon), and other Celestial Stems appear ordered as month > sitting > close place. Second, it can be seen by the characteristics of Earthly Branches that Tonggeun has taken hold. The Earthly Branches are ordered as Rokwangji (祿旺支 vigorous land) and Jangsaengji (長生支 newborn land) > Yeogi (餘氣 remaining energy) > Myogo (墓庫 storage and burial grounds). Tugan is the concept that the main agent was changed to Tonggeun, which means that the spirit of the Earthly Branches is manifested in the Celestial Stems. And the five phases hidden in the Earthly Branches will be able to play their roles as they are revealed. There are also the phenomena of Gaedu (蓋頭 the heavenly destroying the earthly) and Jeolgak (截脚 the earthly destroying the heavenly) which are concepts that convey that the Heavenly Stems and Earthly Branches can mutually destroy one another. There are different opinions on Gaedu because some adopt viewpoints of just focusing on the Celestial Stems and considering it only in terms the Celestial Stems destroying the Earthly Branches. But, the vast majority of scholars think that the Celestial Stems weakens the role of the roots by destroying the Earthly Branches. Jeolgak, the reverse concept of Gaedu, weakens the spirit of the Celestial Stems as the Earthly Branches destroy them, and this is associated with the strong possibility that one is fated to experience disharmony.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.99-107
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• 2013

In order to investigation Lateral bearing capacity of bored-precast pile, we carried out the analysis of the relationship between Lateral load and horizontal displacement using the result of horizontal pile load test. The six piles injected cement milk of 50%, 70% and 100% of the embedded length of pile were used in the horizontal pile load test. The horizontal displacement, yielding load and horizontal bearing capacity are mainly affected by The injecting ratio of cement milk (injected length of cement milk/embedded length of pile). As the injecting ratio of cement milt is increased, the starting point of horizontal displacement in piles become close to the ground surface and the amount of horizontal displacement is decreased. Also, the horizontal bearing capacity and yielding load are highly increased with increasing the ration of cement milk. The horizontal bearing capacity and yielding load of bored pile with 1 of cement milk ratio are about two or three times those of pile with 0.5 of cement milk ratio.

• Journal of the Korean GEO-environmental Society
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• v.5 no.3
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• pp.31-39
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• 2004

The bored pile is widely used as a low noise and vibration piling method in Korea. However, there is design tendency to minimize the friction capacity of the bored pile because of uncertainty and the quality control specification is not set up. This research analysed the strength characteristics of cement paste after the uniaxial compression test with various condition. Test results show that the compressive strength of cement paste with w/c=0.83 was up to $156.0kgf/cm^2$, and the lower w/c ratio and the longer age, the strength of cement paste increased. Also the higher soil mixing ratio, the strength of soil cement decreased, and too high soil mixing ratio caused the malfuction of soil cement. Also this research analysed the 188 dynamic pile test results which were performed before and after hardening of cement paste. Analysis result showed that the average ultimate unit friction capacity was $9.1tf/m^2$ and this result surpassed the common design criteria of the bored pile.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.145-153
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• 2004

Based on the previous studies proposed by many researchers about the evaluation method of replacement depth, a modified formula which incorporates the effect factors such as embanked height and load, replacement depth, cohesive force of original ground and unit weight of embankment etc, was suggested in this study. The new proposed formula was applied in the three construction sites of Kwangyang-Bay Area (Yeocheon, Youlchon, and Kwangyang) constructed by the compulsion replacement method. The application of the new method was investigated through these case studies in domestics. A modified bearing capacity parameter was estimated form the relationship of modified embankment loading and ultimate bearing capacity resulted from the site investigation, and the replacement depth was predicted by using this parameter. In addition, through the relationship analyses between each effect factors to the replacement depth in two areas, Yeocheon and Youlchon, an empirical prediction method which can evaluate the replacement depth in adjoining area was proposed. The predicted value obtained by new method is approximately similar to the measured replacement depth in Kwangyang area.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.119-130
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• 2008

Uncertainties in physical and engineering parameters for the design of shallow foundations arise from various aspects such as inherent variability and measurement error. This paper aims at investigating and reducing uncertainty from deterministic method by using the reliability-based design of shallow foundations accounting for the variation of various design parameters. A probability distribution type and statistics of random variables such as unit weight, cohesion, infernal friction angle and Young's modulus in geotechnical engineering are suggested to calculate the ultimate bearing capacities and immediate settlements of foundations. Reliability index and probability of failure are estimated based on the distribution types of random variables. Widths of foundation are calculated at target reliability index and probability of failure. It is found that application and analysis of the best-fit distribution type for each random variables are more effective than adoption of the normal distribution type in optimizing the reliability-based design of shallow foundations.