• Title/Summary/Keyword: clay foundation

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A study on the Upper Risen Architecture of Japan (일본(日本)의 고상식(高床式) 건축(建築)에 관(關)한 연구(硏究))

  • Lee, Byeong-Gun
    • Journal of architectural history
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    • v.12 no.3
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    • pp.19-38
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    • 2003
  • The purpose of this study is to analyze the architectural character of the upper risen architecture(高床式 建築) in Japan. There are few upper risen architecture and architectural remains in Korea. Until now most of Korean researcher recognized that the upper risen architecture is southern regions' form. But there are a few numbers of upper risen buildings in northern regions of Korea and China. Therefore we need to compare northern and southern regions' upper risen architecture. The scope of this study is architectural remains, sites and present buildings about upper risen architecture in Japan. The period of this study is from third to eighth century. The method of this study is the analyses of site plan(the ratio of front and side length) and construction about Japanese Architecture. And then this study compare Japanese with other countries in Korean and Chinese upper risen architecture. Results of the study are below. 1. In Japan, upper risen architecture was introduced into southern regions(southern China and southeast Asia) with rice farming culture. 2. After introduced upper risen architecture, they were influenced many architectural technique of Korean and Chinese. 3. There were many technical improvement(such as foundation stone standing method, high technical wooden frame structure and adaptable triangle frame wall at moisture) the Japanese upper risen architecture in Nara Period(奈良時代). 4. As the results, I found out that there were many similarity Korea and Japan in upper risen architecture. I think that we will try continuous to study another regions' upper risen architecture in order to define conclusion.

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Centrifuge Model Experiments for Lateral Soil Movements of Piled Bridge Abutments. (교대말뚝기초의 측방유동에 관한 원심모형실험)

  • Choi, Dong-Hyurk;Jeong, Gil-Soo;Park, Byung-Soo;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.25 no.B
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    • pp.63-71
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    • 2005
  • This paper is an experimental result of investigating lateral soil movements at piled bridge abutments by using the centrifuge model facility. Three different centrifuge model experiments, changing the methods of ground improvement at bridge abutment on the soft clayey soil (no improvement, preconsolidation and plastic board drains (PBD), sand compaction pile (SCP) + PBD), were carried out to figure out which method is the most appropriate for resisting against the lateral soil movements. In the centrifuge modelling, construction process in field was reconstructed as close as possible. Displacements of abutment model, ground movement, vertical earth pressure, cone resistance after soil improvement and distribution of water content were monitored during and after centrifuge model tests. As results of centrifuge model experiments, preconsolidation method with PBD was found to be the most effective against the lateral soil movement by analyzing results about displacements of abutment model, ground movement and cone resistance. Increase of shear strength by preconsolidation method resulted in increasing the resistance against lateral soil movement effectively although SCP could mobilize the resistance against lateral soil movement. It was also found that installment with PBD beneath the backfill of bridge abutment induced effective drainage of excess pore water pressure during the consolidation by embanking at the back of the abutment and resulted in increasing the shear strength of clay soil foundation and eventually increasing the resistance of lateral soil movement against piles of bridge abutment.

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Numerical Analysis on the Size Effect of a Footing (기초의 크기효과에 관한 수치해석)

  • Lee, Seung-Hyun;Han, Jin-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.778-784
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    • 2015
  • Finite element analyses were conducted to investigate the size effect on the bearing capacity and settlement of shallow foundations, and the results were compared with those of theoretical equations. The calculated bearing capacity of the plate by numerical analysis and the theoretical equation was similar. Numerical analyses showed that the ultimate bearing capacity of strip footing on sand was affected by the size effect, whereas the ultimate bearing capacity of strip footing on clay was not affected by the size effect. Numerical analyses showed that the square footing was unaffected by the size effect regardless of the type of foundation soil. In contrast to theoretical equations, settlement of the footing was affected by the size effect and was proportional to the footing width.

Cap Model을 이용한 기초식반의 수동해석(I) -범용프로그램의 검증과 수치계산례-

  • 박병기;정진섭
    • Geotechnical Engineering
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    • v.3 no.2
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    • pp.29-40
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    • 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.

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Soil Physical and Hydraulic Properties over Terrace Adjacent Four Major Rivers

  • Lee, Kyo Suk;Lee, Jae Bong;Lee, Myoung Yun;Joo, Ri Na;Lee, Dong Sung;Chung, Doug Young
    • Korean Journal of Soil Science and Fertilizer
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    • v.49 no.3
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    • pp.235-241
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    • 2016
  • The soil does not only serve as a medium for plant growth but also for engineering construction purposes. It is very weak in tension, very strong in compression and fails only by shearing. The behaviour of the soil under any form of loading and the interactions of the earth materials during and after any engineering construction work has a major influence on the success, economy and the safety of the work. Soils and their management have therefore become a broad social concern. A limitless variety of soil materials are encountered in both agronomy and engineering problems, varying from hard, dense, large pieces of rock through gravel, sand, silt and clay to organic deposits of soft compressible peat. All these materials may occur over a range of physical properties, such as water contents, texture, bulk density and strength of soils. Therefore, to deal properly with soils and soil materials in any case requires knowledge and understanding of these physical properties. The desired value of bulk density varies with the degree of stability required in construction. Bulk density is also used as an indicator of problems of root penetration,soil aeration and also water infiltration. This property is also used in foundation engineering problems. While not conforming to standard test procedures, this work attempts to add to the basic information on such important soil parameters as water content, bulk density.

Analytical study on resisting moment of concrete pole installed in sloped ground (콘크리트 전주의 경사지 저항 모멘트에 관한 해석 연구)

  • Shin, Dong-Geun;Lee, Seung-Ryun;Yi, Gyu-Sei;Yoon, Ki-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.4
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    • pp.842-847
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    • 2007
  • In this study, for the purpose of estimating the resisting moment of sloped ground based on level ground fall down safety equation in design specification, compute it depends on penetration depth of concrete pile applying modulus of foundation about the angle of internal friction, cohesion, unit weight of soil, classes of the ground, sandy or clay soil, and verify established study using L-Pile Plus13.8. Also, select four cases that characteristics of soil depending on the soil grade is considered and compute the 12m length concrete pile's resisting moment of the ground those angle is changing from $0^{\circ}{\sim}35^{\circ},\;step\;5^{\circ}$. In the result, identify that the resisting moment of ground decreases depending on ground slope. Thus, increasing of penetration depth is required.

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Optimised neural network prediction of interface bond strength for GFRP tendon reinforced cemented soil

  • Zhang, Genbao;Chen, Changfu;Zhang, Yuhao;Zhao, Hongchao;Wang, Yufei;Wang, Xiangyu
    • Geomechanics and Engineering
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    • v.28 no.6
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    • pp.599-611
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    • 2022
  • Tendon reinforced cemented soil is applied extensively in foundation stabilisation and improvement, especially in areas with soft clay. To solve the deterioration problem led by steel corrosion, the glass fiber-reinforced polymer (GFRP) tendon is introduced to substitute the traditional steel tendon. The interface bond strength between the cemented soil matrix and GFRP tendon demonstrates the outstanding mechanical property of this composite. However, the lack of research between the influence factors and bond strength hinders the application. To evaluate these factors, back propagation neural network (BPNN) is applied to predict the relationship between them and bond strength. Since adjusting BPNN parameters is time-consuming and laborious, the particle swarm optimisation (PSO) algorithm is proposed. This study evaluated the influence of water content, cement content, curing time, and slip distance on the bond performance of GFRP tendon-reinforced cemented soils (GTRCS). The results showed that the ultimate and residual bond strengths were both in positive proportion to cement content and negative to water content. The sample cured for 28 days with 30% water content and 50% cement content had the largest ultimate strength (3879.40 kPa). The PSO-BPNN model was tuned with 3 neurons in the input layer, 10 in the hidden layer, and 1 in the output layer. It showed outstanding performance on a large database comprising 405 testing results. Its higher correlation coefficient (0.908) and lower root-mean-square error (239.11 kPa) were obtained compared to multiple linear regression (MLR) and logistic regression (LR). In addition, a sensitivity analysis was applied to acquire the ranking of the input variables. The results illustrated that the cement content performed the strongest influence on bond strength, followed by the water content and slip displacement.

Effect of nonlinear soil-structure interaction on the seismic performance of 3D isolated transformers when scaling the response spectra using the improved wavelet method

  • Mohammad Mahmoudi;Abbas Ghasemi;Shahriar Tavousi Tafreshi
    • Structural Engineering and Mechanics
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    • v.91 no.5
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    • pp.469-486
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    • 2024
  • Electric transformers are major components of electrical systems, and damage to them caused by earthquakes can result in significant financial loss. The current study modeled a three-dimensional (3D) isolated electrical transformer under horizontal and vertical records from different earthquakes. Instead of using fixed coefficients, an improved wavelet method has been used to create the greatest compatibility between the response spectra and the target spectrum. This method has primarily been used for dynamic analysis of isolated structures with spring-damper devices because it has shown greater accuracy in predicting the response of such structures. The effect of the nonlinear soil-structure interaction on the probability of transformer failure also has been investigated. Soil and structure interaction modeling was carried out using a beam on a nonlinear Winkler foundation. The effect of the nonlinear soil-structure interaction during dynamic analysis of transformers revealed that the greatest increase in the probability of transformer failure was in the fixed-base condition when the structure was located on soft soil. This intensified the response of the structure and increased the probability of transformer failure by up to 27% for far-field and up to 95% for near-field ground motions. A comparison of the results indicates that the use of 3D isolation systems in transformers in areas with soft clay that are subject to near-field ground motions can strongly reduce the probability of failure and improve the seismic performance of the transformer.

A Study on the Design & Construction Method of Traditional Landscape Space through the 『Imwongyeongjeji』 「Seomyongji」 and the 'Standard Specification for Repairing Cultural Heritages' (『임원경제지』 「섬용지」와 문화재수리 표준시방서를 통해 본 전통조경공간 설계 시공방법)

  • Lee, Jung-Han
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.37 no.4
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    • pp.1-10
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    • 2019
  • The purpose of this study is to examine the design & construction methods of the traditional landscape space of the past and the repair and maintenance of cultural heritages to maintain it today. To this end, the method of narrative description, process extraction and construction related to traditional landscaping were compared to each other based on the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages'. The results are as follows; First, to analyze at the description methods of the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages' and related processes in the field of traditional landscaping. 『Imwongyeongjeji』 「Seomyongji」 was an encyclopedia of the overall construction method of the living space, describing the location, effect, and advantages and disadvantages of each component and presenting quantitative figures to institutionalize the construction of traditional landscaping spaces. 'Standard Specification for Repairing Cultural Heritages' presented the entire process of repairing cultural heritages, and it is becoming a kind of guide for reference at the site. Among them, foundation construction, roof construction, landscape construction, and fence construction were drawn as items that could be applied to traditional landscaping areas. Second, the traditional landscape space construction method was divided into the processes of foundation construction, roof construction, landscaping construction, and fence construction. Foundation construction is a way of repeating the process of land-tramping. During the construction of the roof, the tile-roofed building was built on top of the rafters and roofed with tiles. And thatched roof was made to a number of rice straws bundles to cover the roof one after the other. Instead of tiles, the stone roof was made of thin and wide stones, and the wooden boards were used for the single roof and the bark roof were constructed with many layers of dried corrugations. Landscape construction mainly consists of the Paving technique through tramping rubble and the construction of terraced flower by planting stone, plants, and shrubs on the top. According to the building materials, the wall construction was derived from the earth-stacked earthen wall, stone walls using stone and clay, marble walls made of tile patterns, and the construction of a board wall using a wood board as a wall. Third, comparing the construction methods of the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages', 『Imwongyeongjeji』 「Seomyongji」 focuses on standardizing the construction methods to create a new traditional space. There is a difference in the setting of the scope of the 『Imwongyeongjeji』 「Seomyongji」 and the construction because 'Standard Specification for Repairing Cultural Heritages' provides the overall construction procedure considering the diversity of the cultural heritages. In addition, the traditional landscape space used to be a residential space in the past, but today, the maintenance process of the already established facilities as designated cultural heritages has been carried out, and construction methods have been added to create viewing conditions. In terms of the succession of traditional knowledge, some similar methods were found in the repair of cultural assets today, and some cases were also confirmed in the reconstruction of traditional technologies such as application of some materials or mix, separation of added facilities and introduction of efficient construction methods.

Settlement Instrumentation of Greenhouse Foundation in Reclaimed Land (간척지 온실 기초의 침하량 검토)

  • Choi, Man Kwon;Yun, Sung Wook;Yu, In Ho;Lee, Jong-Won;Lee, Si Young;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.24 no.2
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    • pp.85-92
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    • 2015
  • This study examined the settlement of a 1-2W type greenhouse using a timber pile, which was recently established on Gyehwa-do reclaimed land, in order to obtain base data for the construction of a greenhouse on reclaimed land. The results of this study are as follows. foundation and timber pile increased over time, irrespective of the interior and exterior of the upon investigation of the ground, it was confirmed that there was no soft rock stratum (bedrock), and that a sedimentary stratum existed under the fill deposit, which is estimated to have been reclaimed during the site renovation. It was also found that a weathered zone was located under the fill deposit and sedimentary stratum, and that the soil texture of the entire ground floor consisted of clay mixed with sand, silty clay, and granite gneiss, in that order, regardless of boreholes. In addition, the underground water level was 0.3m below ground, regardless of boreholes. Despite a slight difference, the settlement of the greenhouse or measurement sites (channels). With regard to the pillar inside the greenhouse, except in the case of CH-2, the data at a site located on the side wall of the greenhouse (wind barrier side) indicated vibrations of relatively larger amplitude. Moreover, the settlement showed a significant increase during a certain period, which was subsequently somewhat reversed. Based on these phenomena, it was verified that the settlement range of each site in the interior and exterior of the greenhouse was between 1.0 and 7.5mm at this time, except in the case of CH-1. The results of the regression analysis indicated good correlation, with the coefficient of determination by site ranging between 0.6362 and 0.9340. Furthermore, the coefficient of determination ranged between 0.6046 and 0.8822 on the exterior of the greenhouse, which is lower than inside the greenhouse, but still indicates significant correlation.