• Geomechanics and Engineering
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• v.30 no.1
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• pp.11-26
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• 2022

One of the most important issues in tunneling, is the squeezing phenomenon. Squeezing can occur during excavation or after the construction of tunnels, which in both cases could lead to significant damages. Therefore, it is important to predict the squeezing and consider it in the early design stage of tunnel construction. Different empirical, semi-empirical and theoretical-analytical methods have been presented to determine the squeezing. Therefore, it is necessary to examine the ability of each of these methods and identify the best method among them. In this study, squeezing in a part of the Alborz service tunnel in Iran was estimated through a number of empirical, semi- empirical and theoretical-analytical methods. Among these methods, the most robust model was used to obtain a database including 300 data for training and 33 data for testing in order to develop a machine learning (ML) method. To this end, three ML models of Gaussian process regression (GPR), artificial neural network (ANN) and support vector regression (SVR) were trained and tested to propose a robust model to predict the squeezing phenomenon. A comparative analysis between the conventional and the ML methods utilized in this study showed that, the GPR model is the most robust model in the prediction of squeezing phenomenon. The sensitivity analysis of the input parameters using the mutual information test (MIT) method showed that, the most sensitive parameter on the squeezing phenomenon is the tangential strain (ε_θ^α) parameter with a sensitivity score of 2.18. Finally, the GPR model was recommended to predict the squeezing phenomenon in tunneling projects. This work's significance is that it can provide a good estimation of the squeezing phenomenon in tunneling projects, based on which geotechnical engineers can take the necessary actions to deal with it in the pre-construction designs.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.537-550
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• 2021

There are various technical problems need to be solved in the construction process of pre-setting an isolation wall into a double lane in the outburst prone mine. This study presents a methodology that pre-setting an isolation wall into a double lane without a coal pillar. This requires the excavation of two small section roadways to dig a wide section roadway, followed by construction of the separation wall. During this process the connecting lane is reserved. In order to ensure the stability of the separation wall, the required bearing capacity of the isolation wall is 4.66 MN/m and the deformation of the isolation wall is approximately 25 cm. To reduce the difficulty of implementing support the roadway is driven by 5 m/d. After the construction of the separation wall, the left side coal wall is brushed 1.5 m to make the width of the gas roadway reach 2.5 m and the roadway support utilizes anchor rod, ladder beam, anchor cable beam and net configuration. During construction, the concrete pump and removable self-propelled hydraulic wall mold are used to pump and pour the concrete of the isolation wall. In the process of mining, the stress distribution of coal body and isolation wall is detected and measured on site. The results demonstrate that the deformation of the surrounding rock of roadway and separation of roof in the roadway is small. The stress of the bolt and anchor cable is within equipment tolerance validating their selection. The roadway is well supported and the intended goal is achieved. The methodology can be used for reference for similar mine gas control.

• Journal of Korea Entertainment Industry Association
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• v.13 no.3
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• pp.279-290
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• 2019

The purpose of this study is to analyze the relationship between the family relationship and the awareness of child abuse of parents with elementary and middle school children. This study also examines the mediating effect of parenting stress between the family relationship and awareness of child abuse. For this purpose, a questionnaire survey was conducted to school parents living in A metropolitan area and the 389 data were used for analysis. As a result of the analysis, their child abuse awareness showed that family relationship effected their awareness of child abuse positively and on parenting stress negatively. In addition, the partial mediating effect of parenting stress was proved between the family relationship and child abuse awareness. The results of this analysis signify that the family relationship is the important independent variable and parenting stress is the main mediating variable between the two variables. According to these analysis results, this study suggested that it is necessary to enhance family relations enhancement programs, child abuse prevention manual, and various parenting support services and strengthen the function of Health Family Support Center as a delivery system of family welfare services.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.356-366
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• 2023

Support, retention, and stability of dentures are key factors in the use of complete dentures in edentulous patients. With the development of digital dentistry, attempts are being made to replace traditional treatment methods. Also, struggle to reduce the number of patient visits and to manufacture high-quality digitally fabricated dentures are ongoing. In this case, a digital denture was restored using a tray capable of obtaining centric relation through gothic arch tracing and a facial scan. By replacing the traditional complete denture restoration method, the number of patient visits was reduced and esthetic results with satisfactory denture support, retention, and stability were obtained.

• Geomechanics and Engineering
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• v.36 no.1
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• pp.27-37
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• 2024

The roof-filling body system stability plays a key role in gob-side entry retained (GER). Taking the GER of the 1103 belt transportation roadway in Heilong Coal Mine as engineering background, stability analysis of roof-filling body system was conducted based on the cusp catastrophe theory. Theoretical results showed that the current design parameters of 1103 belt transportation roadway could ensure the roof-filling body system stable during the resistance-increasing support stage of the filling body and the stable support stage of the filling body. Moreover, a verified global numerical model in FLAC3D was established to analyze the failure characteristics including surrounding rock deformation, stress distribution, and plastic zone. Numerical simulation indicated that the width-height ratio of the filling body had a great influence on the stability of the roof-filling body system. When the width-height ratio was greater than 0.62, with the decrease of the width-height ratio, the peak stress of the filling body gradually decreased; when the width-height ratio was greater than 0.92, as the distance to the roadway increased, the roof stress increased and then decreased. The theoretical analysis and numerical simulation findings in this study provide a new research method to analyze the stability of the roof-filling body system in GER.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.143-153
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• 2002

Convergence Confinement Method (CCM) makes a more simple judgement in a ground-support reaction than numerical method. Also this method is good for the applicability of construction feedback and the analysis of field measurement. However, there has been little research with respect to the application of CCM in tunnel construction. One of the problems in CCM is a decision of the time to support installation. To decide a reasonable supporting installation time, support characteristic curve and displacement characteristic curve considering construction stage are proposed. In addition, to predict displacement distribution ratio and load distribution ratio, the time dependent support reaction curve is used. Finally, through a comparison of the result between CCM and numerical analysis, the trust of this study is proved and the practical application is proposed to control resonable tunnel construction management.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1869-1886
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• 2018

This paper proposes a MIDI- and audio-based music genre classification method for Korean traditional music. There are many traditional instruments in Korea, and most of the traditional songs played using the instruments have similar patterns and rhythms. Although music information processing such as music genre classification and audio melody extraction have been studied, most studies have focused on pop, jazz, rock, and other universal genres. There are few studies on Korean traditional music because of the lack of datasets. This paper analyzes raw audio and MIDI phrases in Korean traditional music, performed using Korean traditional musical instruments. The classified samples and MIDI, based on our classification system, will be used to construct a database or to implement our Kontakt-based instrument library. Thus, we can construct a management system for a Korean traditional music library using this classification system. Appropriate feature sets for raw audio and MIDI phrases are proposed and the classification results-based on machine learning algorithms such as support vector machine, multi-layer perception, decision tree, and random forest-are outlined in this paper.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.964-968
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• 2010

Ground anchor, commonly referred to as tiebacks or tie-down, is essentially steel elements secured in the ground by cement grout. They are used to provide either lateral or vertical support for various engineered structures, and are effective in all types of soil and rock. However, ground anchor can not be used in soft clay because anchor resistance would not be guaranteed. In this paper, conceptual introduction of the Smart Anchor is presented. The Smart Anchor is a kind of friction type anchor, the load is diffused and applied to the various parts of the distributed bond length, having less impact on the grout strength, and being able to secure necessary anchoring force in relatively soft grounds. This study shows a numerical study of predicting the load transfer of The Smart Anchor in soft clay. A beam-column analysis was performed by a elastic-plastic P-y curves in soft clay.

• Geomechanics and Engineering
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• v.16 no.1
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• pp.59-69
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• 2018

This study focused on the mechanical and hydraulic characteristics of underwater tunnels based on Mohr-Coulomb (M-C), Hoek-Brown (H-B) and generalized H-B failure criteria. An improved approach for calculating stress, displacement and plastic radius of the circular tunnel considering hydraulic-mechanical coupling was developed. The innovation of this study was that the radius-incremental-approach was reconstructed (i.e., the whole plastic zone is divided into a finite number of concentric annuli by radius), stress and displacement of each annulus were determined in terms of numerical method and Terzaghi's effective stress principle. The validation of the proposed approach was conducted by comparing with the results in Brown and Bray (1982) and Park and Kim (2006). In addition, the Rp-pin curve (plastic radius-internal supporting pressure curve) was obtained using the numerical iterative method, and the plastic radius of the deep-buried tunnel could be obtained by interpolation method in terms of the known value of internal supporting pressure pin. Combining with the theories in Carranza and Fairhurst (2000), the improved technique for assessing the reliability of the tunnel support was proposed.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.3
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• pp.131-142
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• 1997

As a study on a traditional garden with historical value, the objective of this study is to comprehensively understand the internal meanings of the garden in a designer's personal perspective. Tasanchodangwon was designed Chung Yakyong who is a scholar of Practical Learning in late Chosun Dynasty. Considering the features of him and basic approach of this study, the internal eanings of the Tasanchodangwon was approached with the focus on the view of nature of him, and through general review of physical components of the garden. Additionally the meanings of the garden were also reviewed in his personal situation. The result of the study may be summarized as followings. First, according to the view of nature of Chung Yakyong, his intention to enrich life practically by building separate structures for education for his residence, creating lake by having water supply, and creating vegetable garden relates with the view of nature in Primary confucianistic perspective. In addition, the place served as a ground to support Chung Yakyong's attitude to become a man of virtue, Second, his preference to enjoyu tea culture allowed an opportunity for him to accept circumstance positively and discover the self. Components related to farming reflects his Practical Learning. The man-made rock mountain in the pond is a specific technique for Yi-Jing. And third, literatures authored by Chung Yakyong show that internal meaning of Tasanchodangwon is to pursue an utopia. This is closely related to solving his conflicts felt in reality. In short, Tasanchodangwon is a form reflecting the spiritual world of Chung Yakyong, and through interaction with his life, served as a ground to culture his mind.