• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1358-1365
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• 2010

A case study deals with Squeezing behavior under tunneling. Squeezing stands for large time-dependent convergence during tunnel excavation. Squeezing can occur in both rock and soil as long as the particular combination of induced stresses and material properties pushes some zone around the tunnel beyond the limiting shear stress at which creep starts. Under squeezing rock conditions, If the support installation is delayed the rock mass moves into the tunnel and a stress redistribution takes place around it. On the contrary, if deformation is restrained, squeezing will lead to long-term load build-up of rock support. This paper shows analysis case mutually with monitoring and numerical analysis result of squeezing behavior of Pinglin tunnel in Taiwan.

• 한국치위생학회지
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• 제10권4호
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• pp.577-584
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• 2010

Objectives : The purpose of this study was to examine the relationship of toothpaste-squeezing methods to the amount of toothpaste used among adults. Methods : The subjects in this study were 227 freshmen in a local college. After the intent of a survey was explained by this researcher, how much dentifrice they used was checked to ensure statistical objectivity, and then a survey was conducted. The collected data were analyzed with a SPSS WIN 13.0 program. Results : The findings of the study were as follows:1. As for connections between the way of squeezing and the amount used, the usual amount used, the amount used by horizontal squeezing and the amount used by pea-sized squeezing were respectively 1.12g, 0.66g and 0.46g. The amount used by horizontal squeezing and pea-sized squeezing was less than the usual amount used by 0.46g(41%) and 0.66g(59%) respectively.2. Gender, residential area, educational experiences and daily mean toothbrushing frequency made no differences to the amount of toothpaste used.3. The students who normally used a larger amount of toothpaste used a greater amount of toothpaste as well when they utilized horizontal squeezing and pea-sized squeezing, and the larger amount used by horizontal squeezing led to the greater amount used by pea-sized squeezing. Conclusions : As there were large disparities in the amount of toothpaste used according to the squeezing methods, systematic research efforts should be directed into setting the standard for the recommended amount of toothpaste used for adults and into squeezing method so that they could brush their teeth in an effective manner by using the minimum amount of toothpaste.

• Geomechanics and Engineering
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• 제30권1호
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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.

• 터널과지하공간
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• 제13권4호
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• pp.245-259
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• 2003

Refering to the articles "Squeezing rocks in tunnels(Barla, 1995)" and "Tunnelling under squeezing rock conditions(Barla 2002)" this article deals with technologies for design, stability analysis and construction of the tunnel being driven in the squeezing rock mass. The definition of this type of behavior was proposed by ISRM(1994). The identification and quantification of squeezing is given according to both the empirical and semi-empirical methods available to anticipate the potential of squeezing problems in tunnelling. Based on the experiences and lessons learned in recent years, the state of the art in modem construction methods was reported, when dealing with squeezing rock masses by either conventional or mechanical excavation methods. The closed-form solutions available for the analysis of the rock mass response during tunnel excavation are described in terms of the ground characteristic line and with reference to some elasto-plastic models for the given rock mass. Finally numerical methods were used for the simulation of different models and for design analysis of complex excavation and support systems, including three-dimensional conditions in order to quantify the influence of the advancing tunnel face to the deformation behavior of the tunnel.

• Reproductive and Developmental Biology
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• 제30권3호
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• pp.207-212
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• 2006

본 연구는 물리적 탈핵 방법인 aspiration 방법과 squeezing 방법을 사용해 핵이식된 소 체세포 복제란의 발달능을 조사하였다. 두 방법에 의해 탈핵된 수핵란에 한우 귀피부 세포를 융합하여 체외에서 $7{\sim}8$일간 배양하여 발육능을 검사하였다. 배양 7일째 배반포 발달율은 aspiration 방법($31.9{\pm}13.4%$)과 squeezing 방법($33.6{\pm}15.7%$) 간에 차이가 없었다. 또한 배양 8일째 배반포 발달율도 squeezing 방법($35.3{\pm}15.1%$)과 aspiration 방법($37.8{\pm}10.4%$) 간에 차이가 없는 것으로 나타났다. 배양 7일째 배반포의 평균 세포수에 있어 각 처리 간에 차이가 없는 것으로 조사되었으며(aspiration: $110.3{\pm}39.2$, squeezing $103.7{\pm}42.8$), 세포자연사의 비율에 있어서도 역시 유의적인 차이가 없는 것으로 조사되었다(aspiration: $2.8{\pm}2.6%$, squeezing: $4.3{\pm}4.4%$). 본 연구의 결과는 물리적 탈핵 방법인 aspiration 방법과 squeezing 방법 모두 소 체세포 복제수정란의 생산을 위한 유용한 방법임을 보여준다.

• 한국응급구조학회지
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• 제21권1호
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• pp.99-109
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• 2017

Purpose: There is no recommended bag-squeezing technique for emergency medical providers to maintain correct tidal volume during mechanical ventilation. This study compared the tidal volume of two different bag-squeezing techniques during mechanical ventilation. Methods: The subjects were 38 paramedic students who were trained in airway management techniques. Two different bag-squeezing techniques were used with a bag valve mask on an intubated manikin: a conventional technique and a finger-marked, in which the bag is squeezed until the thumb and the middle finger come into contact. Hand size and grip strength were measured and analyzed statistically. Results: The mean tidal volumes for the finger-marked were significantly higher than those for the conventional technique ($542.6{\pm}35.92mL$ versus $338.0{\pm}111.15 mL$, p<.001). There was a correlation between the two techniques (Pearson $x^2=1.160$, p<.001). The subject's characteristics, including sex, hand size, and grip strength, showed no correlation with tidal volume. Conclusion: A finger-marked bag-squeezing technique provides adequate and correct tidal volumes during mechanical ventilation.

• Geomechanics and Engineering
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• 제18권2호
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• pp.215-224
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• 2019

Excavation of long tunnels by shielded TBMs is a safe, fast, and efficient method of tunneling that mitigates many risks related to ground conditions. However, long-distance tunneling in great depth through adverse geological conditions brings about limitations in the application of TBMs. Among various harsh geological conditions, squeezing ground as a consequence of tunnel wall and face convergence could lead to cluttered blocking, shield jamming and in some cases failure in the support system. These issues or a combination of them could seriously hinder the performance of TBMs. The technique of excavation has a strong influence on the tunnel response when it is excavated under squeezing conditions. The Golab water conveyance tunnel was excavated by a double-shield TBM. This tunnel passes mainly through metamorphic weak rocks with up to 650 m overburden. These metamorphic rocks (Shales, Slates, Phyllites and Schists) together with some fault zones are incapable of sustaining high tangential stresses. Prediction of the convergence, estimation of the creeping effects and presenting strategies to overcome the squeezing ground are regarded as challenging tasks for the tunneling engineer. In this paper, the squeezing potential of the rock mass is investigated in specific regions by dint of numerical and analytical methods. Subsequently, several operational solutions which were conducted to counteract the challenges are explained in detail.

• 한국학교보건학회지
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• 제22권1호
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• pp.67-72
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• 2009

Purpose: The purpose of this study was to examine the relationship between the toothpaste squeezing methods and the amount of toothpaste that the daycare teachers apply for the children in order to prevent the overuse of fluoride-containing toothpaste among children, and to understand their educational experiences on oral health and their awareness of the right amount of toothpaste used. Methods: The subjects in this study were 87 teachers at 16 different daycare centers in the city of Sokcho, Gangwon Province. They were interviewed to find out whether they had ever received oral health education and whether they were cognizant of the right amount of toothpaste to be used. And a transverse technique and a pea-sized squeezing technique were selected to look for connections between their toothpaste squeezing methods and the amount of toothpaste used by them. Results: 89.7 percent of the daycare teachers investigated taught to preschoolers how to do toothbrushing after they took meals and had a snack. 36.8 percent of the daycare teachers had children squeeze toothpaste on their own. The amount of toothpaste applied by the daycare teachers at a time was 0.58ｇ. When they utilized two other squeezing methods, transverse technique and pea-sized squeezing technique, they used each 0.38 g (p<0.005) and 0.38 g (p=0.405) of toothpaste. Conclusion: To prevent children from being overly exposed to fluoride-containing toothpaste, daycare teachers should learn about the right amount of toothpaste to be used when oral health education is provided, and the transverse technique should be recommended to ensure the use of the proper amount of toothpaste.

• Korea-Australia Rheology Journal
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• 제11권3호
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• pp.233-240
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• 1999

In order to understand the flow behavior of Electrorheological (ER) fluid, dynamic simulation has been intensively performed for the last decade. When the shear flow is applied, it is easy to carry out the simulation with relatively small number of particles because of the periodic boundary condition. For the squeezing flow, however, it is not easy to apply the periodic boundary condition, and the number of particles needs to be increased to simulate the ER system more realistically. For this reason, the simulation of ER fluid under squeezing flow has been mostly performed with some representative chains or with the approximation that severely restricts the flow geometry to reduce the computational load. In this study, Message Passing Interface (MPI), which is one of the most widely-used parallel processing techniques, has been employed in a dynamic simulation of ER fluid under squeezing flow. As the number of particles used in the simulation could be increased significantly, full domain between the electrodes has been covered. The numerical treatment or the approximation used to reduce the computational load has been evaluated for its validity, and was found to be quite effective. As the number of particles is increased, the fluctuation of the normal stress becomes diminished and the prediction in general was found to be qualitatively In good agreement with the experimental results.

• 대한조선학회논문집
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• 제44권6호
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• pp.666-674
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• 2007

It is very important to estimate static squeezing pressure distributions for lining material of sterntube after bearing at dry dock stage since the maximum squeezing pressure value can be one of the significant characteristics representing coming navigation performances of the propulsion system. Moderate oil film pressure between lining material and propulsion shaft is also essential for safe ship service. In this paper, Hertz contact theory is explained to derive static squeezing pressure. Reynolds equation simplified from Navier-Stokes equation is centrally differentiated to numerically obtain dynamic oil film pressures. New shaft alignment technology of nonlinear elastic multi-support bearing elements is also used in order to obtain external forces acting on lining material of bearing. For 300K DWT class VLCC with synthetic bush of sterntube after bearing, static squeezing pressures are calculated using derived external forces and Hertz contact theory. Optimum partial slope of the after bush is presented by parametric shaft alignment analyses. Dynamic oil film pressures are comparatively evaluated for partially bored and unbored after bush. Finally it is proved that the partial slope can drastically reduce oil film pressure during engine running.