• Title/Summary/Keyword: Final Settlement

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Vibration response of saturated sand - foundation system

  • Fattah, Mohammed Y.;Al-Mosawi, Mosa J.;Al-Ameri, Abbas F.I.
    • Earthquakes and Structures
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    • v.11 no.1
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    • pp.83-107
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    • 2016
  • In this study, the response and behavior of machine foundations resting on dry and saturated sand was investigated experimentally. A physical model was manufactured to simulate steady state harmonic load applied on a footing resting on sandy soil at different operating frequencies. Total of (84) physical models were performed. The parameters that were taken into consideration include loading frequency, size of footing and different soil conditions. The footing parameters are related to the size of the rectangular footing and depth of embedment. Two sizes of rectangular steel model footing were used. The footings were tested by changing all parameters at the surface and at 50 mm depth below model surface. Meanwhile, the investigated parameters of the soil condition include dry and saturated sand for two relative densities; 30 % and 80 %. The dynamic loading was applied at different operating frequencies. The response of the footing was elaborated by measuring the amplitude of displacement using the vibration meter. The response of the soil to dynamic loading includes measuring the stresses inside soil media by using piezoelectric sensors. It was concluded that the final settlement (St) of the foundation increases with increasing the amplitude of dynamic force, operating frequency and degree of saturation. Meanwhile, it decreases with increasing the relative density of sand, modulus of elasticity and embedding inside soils. The maximum displacement amplitude exhibits its maximum value at the resonance frequency, which is found to be about 33.34 to 41.67 Hz. In general, embedment of footing in sandy soils leads to a beneficial reduction in dynamic response (displacement and excess pore water pressure) for all soil types in different percentages accompanied by an increase in soil strength.

What Is It to Be Mentally Healthy from the North Korean Refugees' Perspective?: Qualitative Research on the Changes in Mental Health Awareness among the North Korean Refugees

  • Yu, Shieun;Jang, Jungeun;Noh, Jin-Won;Kwon, Young Dae;Park, Hyunchun;Woo, Jong-Min
    • Psychiatry investigation
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    • v.15 no.11
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    • pp.1019-1029
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    • 2018
  • Objective We investigated how mental health awareness among North Korean refugees transformed depending on temporal-spatial context changes. Methods In 2013, we conducted interviews with 10 refugees (eight women) who had been in South Korea for over a year and performed a qualitative analysis of the change in mental health awareness in the differences between living in North Korea, escape (a related period of forced sojourn in a third country), and settlement in South Korea. Results We classified 39 concepts into five main categories. The first two categories (while living in North Korea) were "a mindset for the system, but not for individual mental health" and "being confined in a social environment that was indifferent to mental health." A third category appeared during escape: "focusing on survival amid continuity of intense suffering." The final two categories appeared when settling in South Korea: "recognition of mental health amid cultural shock" and "introspection and sorting oneself out." Conclusion This qualitative study enabled a better multi-dimensional understanding of the social and cultural aspects involved in improving mental health awareness among North Korean refugees in South Korea. It is desirable to integrate mental health as a part of daily life and to expand training for North Korean settlers.

Elastic solutions for shallow tunnels excavated under non-axisymmetric displacement boundary conditions on a vertical surface

  • Wang, Ling;Zou, Jin-Feng;Yang, Tao;Wang, Feng
    • Geomechanics and Engineering
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    • v.19 no.3
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    • pp.201-215
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    • 2019
  • A new approach of analyzing the displacements and stress of the surrounding rock for shallow tunnels excavated under non-axisymmetric displacement boundary conditions on a vertical surface is investigated in this study. In the proposed approach, by using a virtual image technique, the shear stress of the vertical ground surface is revised to be zero, and elastic solutions of the surrounding rock are obtained before stress revision. To revise the vertical normal stress and shear stress of horizontal ground surface generated by the combined action of the actual and image sinks, the harmonic functions and corresponding stress function solutions were adopted. Based on the Boussinesq's solutions and integral method, the horizontal normal stress of the vertical ground surface is revised to be zero. Based on the linear superposition principle, the final solution of the displacements and stress were proposed by superimposing the solutions obtained by the virtual image technique and the stress revision on the horizontal and vertical ground surfaces. Furthermore, the ground settlements and lateral displacements of the horizontal and vertical ground surfaces are derived by the proposed approach. The proposed approach was well verified by comparing with the numerical method. The discussion based on the proposed approach in the manuscript shows that smaller horizontal ground settlements will be induced by lower tunnel buried depths and smaller limb distances. The proposed approach for the displacement and stress of the surrounding rocks can provide some practical information about the surrounding rock stability analysis of shallow tunnels excavated under non-axisymmetric displacement boundary conditions on a vertical surface.

The Relationship between the Key Audit Matters and Value Relevance of Accounting Information in the Financial Industry (금융업 핵심감사사항과 회계정보 가치관련성의 관계)

  • Ma, Hee-Young;Kim, Eun-Hae
    • Asia-Pacific Journal of Business
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    • v.11 no.3
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    • pp.123-136
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    • 2020
  • Purpose - This study is to verify the impact of the documentation of key audit matters on the value relevance of accounting information in accordance with the revised accounting audit standards in 2017. Investors will be able to identify the company's significant financial risks through key audit matters and use them to make investment decisions. Design/methodology/approach - From 2011 to 2019, the final sample is 290, based on the December settlement of accounts listed on the securities market. Ohlson (1995) was used to verify the incremental link between net income and the book value as a determinant of corporate value. Findings - First, the key audit matters in the financial industry was found to have a negative (-) effect that was significant to the value relevance of accounting Information. In addition, the value of the interaction between the key audit matters and the net income is a significant (+) relationship with the share price and the value of the interaction between the key audit matters and the book value is a significant (-) relationship with the share price. This means that the key audit matters is the determining factor of corporate value, positively reflects the accounting information in net income and negatively reflects the accounting information in book value. Second, among the key audit matters, the fair value assessment of financial instruments and the adequacy of premiums reserve have a significant impact on the value relevance of accounting information. Research implications or Originality - The results of this study suggest that investors recognize key audit matters as information about the company's major financial risks and reflect them differently in the value relevance of accounting information.

Childcare teachers' perception of play support in the 2019 revised Nuri Curriculum (2019개정 누리과정의 놀이지원에 대한 보육교사의 인식)

  • Kim, Dong Rye
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.1
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    • pp.67-74
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    • 2022
  • This study was investigated the perceptions of play and play support in the 2019 revised Nuri curriculum of childcare teachers. A questionnaire survey was conducted and 259 childcare teachers form K city and J province randomly sampled were selected as final research subjects. The collected data was analyzed descriptive statistics and analysis of variance using the SPSS 24.0 program. The results are as follows: First, childcare teachers' perception of play was high, whereas the perception of the difference between laissex-faire play and play permissiveness was the lowest. perception of childcare teachers about play management in the 2019 revised Nuri curriculum was also high. The perception of play management according to the play perception level of childcare teachers were a signficant difference. And it was found that higher the childcare teacher's level of perception of play, the higher the level of perception of play management. Through this study, we intend to provide basis data for childcare teacher education that will lay the foundation for the successful settlement of the 2019 revised Nuri course play-centered.

A Study on Consolidation Characteristic of Dredged Fill Using Geotechnical Centrifuge (원심모형시험에 의한 준설지반의 압밀특성연구)

  • Kim, Hee-Chul;Kim, Heung-Seok;Lee, Song
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.45-55
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    • 2008
  • In this study, the in-situ model test has been conducted to estimate and analyze consolidation behavior of the ground by using the miniature test that reconstructs economically geotechnical behavior of in-situ full scale structure. To analyze the relation of effective stress, void ratio and coefficient of permeability at the self-weight consolidation stage, the low stress seepage consolidation test has been conducted and the involution function of constitutive equation had been obtained from the result of the curve fitted seepage consolidation test. As a result of the numerical analysis that had been conducted on the representative section using a constitute equation, final settlement was similar to those of self-weight consolidation of the centrifugal model test. But it was more or less smaller. It seems that these trends are caused by the difference between estimated values.

Investigation of three-dimensional deformation mechanisms of existing tunnels due to nearby basement excavation in soft clay

  • Wanchun Chen;Lixian Tang;Haijun Zhao;Qian Yin;Shuang Dong;Jie Liu;Zhaohan Zhu;Xiaodong Ni
    • Geomechanics and Engineering
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    • v.34 no.2
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    • pp.115-124
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    • 2023
  • By conducting three-dimensional simulation with consideration of small-strain characteristics of soil stiffness, the effects of excavation geometry and tunnel cover to diameter ratio on deformation mechanisms of an existing tunnel located either at a side of basement or directly underneath the basement were systematically studied. Field measurements were used to verify the numerical model and model parameters. For basement excavated at a side of an existing tunnel, the maximum settlement and horizontal displacement of the tunnel are always observed at the tunnel springline closer to basement and tunnel crown, respectively, regardless of basement geometry. By increasing basement length and width by five times, the maximum movements of tunnel located at the side of basement and directly underneath the basement increase by 450% and 186%, respectively. Obviously, tunnel movements are more sensitive to basement length rather than basement width. For basement excavated at a side of an existing tunnel, tunnel movements at basement centerline become stable when basement length reaches 10 He (i.e., final excavation depth). Moreover, tunnel heaves due to overlying basement excavation become stable when the normalized basement length (L/He) is larger than 8.0. As tunnel cover to diameter ratio varies from 2.5 to 3.0, the maximum heave and tensile strain of tunnel due to overlying basement excavation decrease by up to 41.0% and 44.5%, respectively. If basement length is less than 8 He, the assumption of plane strain condition of basement-tunnel interaction grossly overestimates tunnel movements, and ignores tensile strain of tunnel along its longitudinal direction. Thus, three-dimensional numerical analyses are required to obtain a reasonable estimation of tunnel responses due to adjacent and overlying basement excavations in clay.

Performance Evaluation of High Strength Lattice Girder by Structural Analyses and Field Measurements (구조해석과 현장계측에 의한 고강도 격자지보재의 성능 평가)

  • Lee, Jeo-Won;Min, Kyong-Nam;Jeong, Ji-Wook;Roh, Byoung-Kuk;Lee, Sang-Jin;Ahn, Tae-Bong;Kang, Seong-Seung
    • The Journal of Engineering Geology
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    • v.30 no.3
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    • pp.237-251
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    • 2020
  • This study examined structural analysis of supports in tunnel and displacement and underground stress of tunnel by measurement, in order to evaluate the performance of high-strength lattice girders developed as a substitute for H-profiles. According to the three-dimensional nonlinear structural analysis results of the tunnel support, the load and displacement relationship between the H-profiles and the high-strength lattice girders showed almost the same behavior, and the maximum load of the high-strength lattice girders were 1.0 to 1.2 times greater than the H-profiles. By the results of the three-dimensional tunnel cross-section analysis of the supports, the axial force was occurred largely in the lower left and right sides of the tunnel, and showed a similar trend to the field test values. In the results of the measurement of the roof settlement and rod extension, the final displacement of the steel arch rib (H-profile) and high-strength lattice girder section in tunnel was converged to a constant value without significant difference within the first management standard of 23.5 mm. According to the results of underground displacement measurement, the final change amount of the two support sections showed a slight displacement change, but converged to a constant value within the first management standard of 10 mm. By the results of measurement of shotcrete stress and steel arch rib stress, the final change amount of the two support sections showed a slight stress change, but converged to a constant value within the first management standard of 81.1 kg/㎠ and 54.2 tonf.

Effects of Various Loading Periods on the Consolidation Characteristics of Remolded Clay - With Special Reference to Gwangyang Marine Clayey Soil - (하중재하기간이 재성형 점토의 압밀특성에 미치는 영향 - 광양항 해성점토를 중심으로 -)

  • Hong, Jae-Cheol;Kim, Jin-Young;Shim, Jae-Rok;Kang, Kwon-Soo;Kim, Ju-Hyun;Baek, Won-Jin
    • Journal of the Korean Geotechnical Society
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    • v.30 no.2
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    • pp.53-64
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    • 2014
  • This study sets it's face to define effects of the various loading periods in normal consolidation area on clay's compression and long-term consolidation characteristics through a laboratory test using homogeneous remolded clay. Moreover, by carrying out a long-term consolidation test which diversifies initial consolidation applicable to effective overburden loading in the various loading period. This study intended to suggest the method predicting the final settlement on the basis of loading periods by comparing and analyzing compression curve's characteristics according to loading weight of each stage and increase in loading period when carrying out the standard consolidation test. From the test results, the study shows that as of the soft clay's compression characteristics on the basis of various loading periods, preconsolidation load has a tendency to be decreased slightly as the loading period is getting more and more longer at each step after initial consolidation load puts on the remolded clay which is caused by secondary consolidation's increase in the latter part of each phase. And those effects have an weaker influence on compression index in normal consolidation area at the same time as secondary consolidation brought out quasi-overconsolidation and stabilization of clay's structure, have an influence re-compression index is increased in overconsolidation area on the other hand.

A Comparative Assessment Between LVTS of Canada and Fedwire of America as a Wholesale Electronic Payment System (미국과 캐나다의 거액전자지급결제제도 비교연구 - 미국의 Fedwire와 캐나다의 LVTS를 중심으로 -)

  • Lee, Byeong-Ryul
    • International Commerce and Information Review
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    • v.19 no.1
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    • pp.43-63
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    • 2017
  • I focused on LVTS compare with Fedwire to advance a research effects in this paper. The Fedwire Funds Service is generally used to make large-value, time-critical payments. The Federal Reserve Banks provide the Fedwire Funds Service, a real-time gross settlement system that enables participants to initiate funds transfer that are immediate, final, and irrevocable once processed. The Fedwire Funds Service is a credit transfer service. While, The LVTS(Large Value Transfer System) is the high value electronic wire system that facilitates the transfer of irrevocable payments in canadian dollars across the country. Through LVTS, funds can be transferred between participating financial institutions virtually instantaneously in a fully collateralized environment. Thus in this article, first of all, I considered features of payment system between LVTS and Fedwire. Second, I analyzed the governing structure and legal background. Third, I focused on the operational policy and risk aversion policy. Lastly, I suggested that the payment and banking system have to assume, with good reason, more efficiently accurately and securely operation together with conclusion.

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