• Journal of the Korea Construction Safety Engineering Association
• /
• s.51
• /
• pp.30-43
• /
• 2010

Yehliu is located at Wanli of Taipei Country with a long cape. Because the rock layer of nearby seashore contains limestone subject to sea erosion, weathering and earth movements, Yehliu is full of seawater-eroded holes as well as numerous rocks in the shape of mushroom, candle, ginger, and chessboard. All these make this 1,700-meter-long cape a geology park with rich ecological resources and a prosperous fishing village. It indicates how the geological features formed by the foundation orogeny and collapsed due to the marine erosion over thousands of years.

• Geomechanics and Engineering
• /
• v.31 no.6
• /
• pp.599-614
• /
• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• Economic and Environmental Geology
• /
• v.31 no.4
• /
• pp.311-324
• /
• 1998

Paleomagnetic study is carried out to investigate the possibility of remagnetization by dikes in the Cretaceous Gyeongsang Basin. We selected a site for a contact test as a preliminary study, and collected 41 core samples (7 from andesitic dike, 17 from sedimentary rock on the left side of dike and 17 from sedimentary rock on the right side). Magnetite was responsible for the remagnetization based on microscopic observation and demagnetization analysis. Although the increasement of magnetic susceptibility appears on both sides about 100 cm from the dike, the increment of NRM intensity was obtained from the specimens on the left side only. This is interpreted that the size of magnetite newly formed is dominated by superparamagnetic grains in the right side, but by larger than single-domain grains in the left. Reversed polarity component remagnetized by intrusion of dike was also found only for core samples from 116 cm left side of dike but abscent from right side indicating the remagnetization by the dike depends on the geometric shape and width of the dike, which is supported by field observations. The content of epidote is well correlated with remagnetization, and indicates the hydrothermal alteration/metameorphism was activated by the intrusion. We concluded that the above evidences in this study further support thermally-activated chemical origin of the remagnetization with meager contribution of contact metamorphism, and that any significant evidence of regional-scaled remagnetization was not found in the study area.

• Wind and Structures
• /
• v.30 no.2
• /
• pp.119-131
• /
• 2020

A butterfly web girder is a box-shaped girder with discretely distributed side openings along the spanwise direction. Until now, there have been few studies related to the aerodynamic performance of the butterfly web bridge. The objective of the current study was to clarify the effects of the side openings on the aerodynamic performance of the girder. Two butterfly web girders with side ratios B/D = 3.24 and 5, where B is the girder width and D is the depth, were examined through a series of wind tunnel tests. A comparison of the results for butterfly web girders and conventional box girders of the same shape confirmed that the side openings stabilized the vortex-induced vibration and galloping when B/D = 3.24, whereas the vortex-induced vibration and torsional flutter were stabilized when B/D = 5. The change in the flow field due to the side openings contributed to the stabilization against the vibration. These findings not only confirmed the good aerodynamic performance of the butterfly web bridge but also provided a new method to stabilize the box girder against aerodynamic instabilities via discretely distributed side openings.

• Journal of the Korean earth science society
• /
• v.30 no.2
• /
• pp.165-175
• /
• 2009

The East Sea including the area of this study is identified as a typical back-arc sea located in the backside of the Circum-Pacific volcanic and earthquake belt. Previous studies reported that the East Sea has begun to open by tensile force and formed its current shape. In this study, we investigate the regional tectonic structure of the East Sea using ship-borne gravity, magnetic, and satellite gravity data. The result of three-dimensional depth inversion shows that Moho depth of the study area is approximately 13-25km and inversely proportional to the thickness of the crust. In addition, as approaching to the center of the Ulleung Basin (UB), the thickness of the crust of the UB becomes thinner due to the extension caused by tensile force which had opened the East Sea.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2008.10a
• /
• pp.149-154
• /
• 2008

We analyzed the Coulomb stress transfer near a small-scale reverse fault. For the modeling we used the geometry of a Quaternary fault in Gyeongju area, Eupcheon fault. For an assumed reverse faulting slip of 10cm, the resulting values of the Coulomb stress change are relatively higher (>2 bar) near the edges (both downward and lateral) of the fault, and diminish slightly upward and downward. The equivalents are negative in the zone immediately below and above the fault, exhibiting a "T" shape of low stress zone in the vertical profile of the fault. This study demonstrates the possible ranges and directions the aftershock energy would propagates after a reverse faulting.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.9
• /
• pp.87-98
• /
• 2011

In this study, the magnitude and phase variation of dynamic earth pressure acting on a pile in liquefiable soils were analyzed using a series of 1g shaking table tests. In the case of a pile in dry sand, the value of the dynamic earth pressure was the highest near the surface due to the inertia force of the upper load on the pile and it decreased as the depth of the pile got lower. On the other hand, for a pile in liquefiable sand, the magnitude and shape of the dynamic earth pressure were similar to those of the excess pore pressure and was largely affected by the deformation of soils. Furthermore, the inertia force of the upper load and the dynamic earth pressure acted in opposite directions in cases of dry sand and saturated sand where low excess pore pressure had developed. However, after liquefaction, those force components near surface acted unfavorably in the same direction. Finally, the Westergaard’s solution was modified and proposed as a method to evaluate the magnitude of dynamic earth pressure acting on a pile during liquefaction.

• Journal of Korean Medical classics
• /
• v.27 no.2
• /
• pp.49-67
• /
• 2014

Subject : The Association between Extraordinary Organs(奇恒之腑) and Eight Extra Meridians(奇經 八脈). Objectives : This study research some special aspects of Extraordinary Organs and Eight Extra Meridians which differentiated from ordinary Organs and Meridians, and the association between Extraordinary Organs and Eight Extra Meridians. Methods : First, researched classification standard and physiological characteristics of Extraordinary Organs through studying various chapters of HuangdiNeijing. Second, researched The Association between Extraordinary Organs and Eight Extra Meridians through studying on the origin of Eight Extra Meridians in HuangdiNeijing. Third, from accompanying researching the subject of Cheon-gye(天癸) and human body shape, draw synthetic hypothesis on the relationship among ordinary Meridians and Organs, muscles and skins of body shape, Extraordinary Organs and Eight Extra Meridians. Results & Conclusions : The following conclusions could be drawn. 1. Extraordinary Organs afford background for shaping human body. This is same as the properties of the earth which afford background for shaping all creations. The physiological characteristics of Extraordinary Organs is intermediation and regulation between Ki(氣) of Five Viscera & six Bowels and shape of muscles & skins in human body. 2. The origin of Eight Extra Meridians could be found in HuangdiNeijing. The collateral Meridians of the Uterus and Epiglottis Meridian are specifically formulated to supplying for the Uterus or Epiglottis. From this we can draw The Association between Extraordinary Organs and Eight Extra Meridians, that is Eight Extra Meridians are specifically formulated to supplying for Extraordinary Organs. 3. The Cheon-gye(天癸) is doing significant function in Eight Extra Meridians supplying for Extraordinary Organs. Cheon-gye concerned to growth, secondary sexual characters, generative function, aging process. Theses are all concerned with the changing of human body shape. Cheon-gye urge to change the body shape with following the human life cycle. 4. Human body has vertical symmetry because preserve its shape from the gravitational force. Eight Extra Meridians place at the middle or flank axis of human body, thus do physiological function that assistant human body have vertical symmetry shape. The purpose of shaping vertical symmetry is securing space what the inner Twelve Regular Meridians and Five Viscera & six Bowels create there own physical changes. On the other hand the inner changes need deviation between left and right because of mobility and circulation of force. But human body change the shape in the process of growth, reproduction, aging. Eight Extra Meridians play role at time of these processing, thus they deeply concerned to human's life cycle and reproduction. 5. Eight Extra Meridians and Extraordinary Organs were named 'Extra' because of some special aspects which differentiated from ordinary Meridians and Organs. All they play role to have vertical symmetry shape of human body and maintain the shape, thus they deeply concerned to the change of human life cycle. These shaping maintaining and the change of human life cycle are very special aspects of human body. So they needed to differently cognize separate to the ordinary changes of Five Viscera & six Bowels and Twelve Meridians at inner space.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.11 no.2
• /
• pp.189-198
• /
• 2009

Recently the concern about the construction of underground structures such as oil and food storage caverns is increasing in Korea and abroad. The stability of those underground caverns is greatly influenced by shape factor and the size of excavation area as well as the joint conditions. In this study, therefore, the effect of the shape factor of an underground cavern on its stability was analyzed in terms of safety factor. To this end, four different shape factors of a cavern excavated in good rock conditions were investigated and sensitivity analyses were performed based on overburden, lateral earth pressure coefficient, joint spacing, properties, and orientation. The stability of a cavern is evaluated in terms of safety factor estimated numerically based on the shear strength reduction technique. In future, this study is expected to be helpful in designing and evaluating the stability of caverns excavated in discontinuous rock masses.

• Journal of the Korean Society of Earth Science Education
• /
• v.5 no.2
• /
• pp.197-203
• /
• 2012

The main purpose of this research is to search the effect of different types of advance organizers in elementary science classes, to the students in acquiring scientific concepts and its retentions. In order to proceed with the research, We have chosen 93 students of three different classes of fifth graders, studying in M elementary school in U metropolitan city. We have randomly chosen two classes as an experimental group and one class as a comparative group. In the first experimental group (Group1), advance organizer was put in a form of a sentence., and the second experimental group (Group2), advance organizer was put in a form of a picture. For the comparative group, We have not put any advance organizer, and the method of class was proceeded as it was before. The result of this research are as follows. Firstly, the result of 'One-way analysis of variance' on scientific concept grade, right after the experiment on three groups, has shown a meaningful difference that, the shape of advance organizer does affect the acquisition of elementary school students' scientific concept. Secondly, even though Group1, who was given with a sentence as an advance organizer, got higher scientific concept scores after the experiment than that of comparative group, However, there was not a meaningful difference between Group1 and comparative group. Thirdly, Group2, who was given with a picture as an advance organizer, has shown a meaningful difference from comparative group. Judging from the facts above, utilizing an advance organizer of a picture in elementary science class, will be very affective on students' acquiring scientific concept.