• Geomechanics and Engineering
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• v.29 no.6
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• pp.697-706
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• 2022

In order to explore the stable anchoring conditions of coal side under the mining disturbance of soft section coal pillar in Wangcun Coal Mine of Chenghe Mining Area, the distribution model of the anchoring support pressure at the coal pillar side was established, using the strain-softening characteristics of the coal to study the distribution law of anchoring coal side support pressure. The analytical solution for the reinforcement anchorage stress in the coal pillar side was derived with the inelastic state mechanical model. The results show that the deformation angle of the roadway side and roof increases with the roof subsidence due to the mining influence at the adjacent working face, the plastic deformation zone extends to the depth of the coal side, and the increase of anchorage stress can effectively control the roof subsidence and further deterioration of plastic zone. The roadway height and the peak support pressure have a certain influence on the anchorage stress, the required anchorage stress of the coal side rises with the roadway height and the peak support pressure. The required anchorage stress of the coal pillar side decreases as the cohesion between the coal seam and the roof and floor and the anchor length increases. Then, applied the research result to Wangcun coal mine in Chenghe mining area, the design of anchor cable reinforcement support was proposed for the section of coal pillars side that has been anchored and deformed, which achieved great results and effectively controlled the convergence and deformation of the side, providing a safety guarantee for the roadway excavation and mining.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.335-340
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• 2001

Recently in abroad, structural synthetic fiber developed, has been studied extensively as a substitute for steel fiber due to its properties such as corrosion-resistance, low density, good pumping, and in-place safety, etc. In this study, we conducted pull-out test, for seven different geometries of structural synthetic fibers and obtained optimum geometry for structural synthetic fiber which fully utilizes matrix anchoring without revealing fiber fracturing. According to pull-out test results, it was found that crimped type structural synthetic fiber give significant improvement in the interface toughness(roll-out enemy) and pull-out load.

• Geomechanics and Engineering
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• v.16 no.3
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• pp.321-329
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• 2018

Classic braced walls use struts and wales to minimize ground movements induced by deep excavation. However, the installation of struts and wales is a time-consuming process and confines the work space. To secure a work space around the retaining structure, an anchoring system works in conjunction with a braced wall. However, anchoring cannot perform well when the shear strength of soil is low. In such a case, innovative retaining systems are required in excavation. This study proposes an innovative earth-retaining wall that uses in situ soil confined in dual sheet piles as a structural component. A numerical study was conducted to evaluate the stability of the proposed structure in cohesionless dry soil and establish a design chart. The displacement and factor of safety of the structural member were monitored and evaluated. According to the results, an increase in the clearance distance increases the depth of safe excavation. For a conservative design to secure the stability of the earth-retaining structure in cohesionless dry soil, the clearance distance should exceed 2 m, and the embedded depth should exceed 40% of the wall height. The results suggest that the proposed method can be used for 14 m of excavation without any internal support structure. The design chart can be used for the preliminary design of an earth-retaining structure using in situ soil with dual steel sheet piles in cohesionless dry soil.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.55-62
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• 2014

During five years (Year 2009~2013), Total victims of 72 %(81,560 people) and those 50.6 %(1,258 people) of death accident occurs in small scale construction site which operate 2 million USD less construction budget. Especially, falling death accident account for 785 people, in the share of 33.2 %(261 people) death disaster takes due to defect of original cause materials. The major safety issues in small scale work place take place while scaffold installation, disassembling, work-plate improper installation or non-professional skills of workers. Furthermore, labor subcontract systems make small construction site shortage of resources. Those workers regard work-plate as unnecessary and consumables supplies. Because of that most of workers use unsafe workplace in most construction site. Therefore, in order to prevent falling accident occurring in small scale work site, government should organize related regulations such as "Work site safety construction method" and then expands education support, financial aid, and sourcing safety supplies for work plate which offer broad variety experiences. Also, introduce certificate solutions for various work plates to improve safety function such as anchoring type method and anti sliding function.

• Journal of Navigation and Port Research
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• v.39 no.3
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• pp.233-239
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• 2015

Recently, Due to variable marine accident occurred, problems relating to marine accidents have been raised. Of these accidents, designated anchorage of Korea coastal port, spcially open-sea anchorage, occurred dragging anchor and accidents are likely, due to failure to obtain a valid ship's holding power so that it is the situation unsatisfactory that ensuring the safety of the anchored ship and anchorage systematic safety management stadars for the efficent operation of the anchorage. also in case of open-sea anchorage vulnerable to external force of certain conditions due to geographical location and topographical characteristics of the port, accidents are likely dragging anchor by typoon or suddenly strong wind and secondary accidents are concerned. This paper shows standard of limit external force to ensure the safety anchorage each of ship's size through review marine accidents on Pohang port, also it is determined to be used as a basic reference for anchoring safety and efficient anchorage management.

• Advances in concrete construction
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• v.3 no.2
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• pp.113-126
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• 2015

Holed-Incrementally Prestressed Concrete (H-IPC) girders are designed using the following new design concepts. At first, web openings reduce the self-weight of the girder, and also diffuse prestressing tendon anchorages. The reduced end anchoring forces decrease the web thickness of the end sections. Additionally, precast technology help to improve the quality of concrete and to reduce the construction period at the site. For experimentally verification, two 50 m full-scale H-IPC girders are manufactured with different concrete strength of 55 MPa and 80 MPa. The safety, stiffness, ductility, serviceability and crack development of H-IPC girder are measured and compared with each other for different strengths. Both girders show enough strength to carry live load and good stiffness to satisfy the design criteria. The experimental result shows the advantages of using high strength concrete and adopting precast girder. The test data can be used as a criterion for safety control and maintenance of the H-IPC girder.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.302-309
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• 2019

This study introduces the navigational environment database(DB) compiling water depth, sediment type and marine managed areas (MMAs) in coastal waters of South Korea. The water depth and sediment data were constructed by combining their sparse points of electronic navigation chart and survey data with high spatial resolution using the inverse distance weighting and natural neighbor interpolation method included in ArcGIS. The MMAs were integrated based on all shapefiles provided by several government agencies using ArcGIS because the areas should be used in an emergency case of ship. To test the validity of the constructed DB, we conducted a test application for grounding and anchoring zones using a ship accident case. The result revealed each area of possible grounding candidates and anchorages is calculated and displayed properly, excluding obstacle places.

• Journal of Gastric Cancer
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• v.18 no.1
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• pp.37-47
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• 2018

Purpose: The endoscopic management of a fully covered self-expandable metal stent (SEMS) has been suggested for the primary treatment of patients with anastomotic leaks after total gastrectomy. Embedded stents due to tissue ingrowth and migration are the main obstacles in endoscopic stent management. Materials and Methods: The effectiveness and safety of endoscopic management were evaluated for anastomotic leaks when using a benign fully covered SEMS with an anchoring thread and thick silicone covering the membrane to prevent stent embedding and migration. We retrospectively reviewed the data of 14 consecutive patients with gastric cancer and anastomotic leaks after total gastrectomy treated from January 2009 to December 2016. Results: The technical success rate of endoscopic stent replacement was 100%, and the rate of complete leaks closure was 85.7% (n=12). The mean size of leaks was 13.1 mm (range, 3-30 mm). The time interval from operation to stent replacement was 10.7 days (range, 3-35 days) and the interval from stent replacement to extraction was 32.3 days (range, 18-49 days). The complication rate was 14.1%, and included a single jejunal ulcer and delayed stricture at the site of leakage. No embedded stent or migration occurred. Two patients died due to progression of pneumonia and septic shock 2 weeks after stent replacement. Conclusions: A benign fully covered SEMS with an anchoring thread and thick membrane is an effective and safe stent in patients with anastomotic leaks after total gastrectomy. The novelty of this stent is that it provides complete prevention of stent migration and embedding, compared with conventional fully covered SEMS.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.724-731
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• 2006

The purpose of this study is to estimate a landslide using the SLOPILE program from the slope reinforced by slope stability systems such as soil nailing and pile. To do this, cutting slope located at Donghae-Highway in Kwangwon-Do was considered. The behavior of slope was monitored for a long term by using instrumentation according to the reinforcement stages. The sequence of reinforcement stages was followed as pile installation, boring, soil nailing installation, anchoring and embankment. The result from this case study shows that the safety factor of slope depends on the reinforcement stage more or less.

• Structural Engineering and Mechanics
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• v.90 no.6
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• pp.531-542
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• 2024

This study proposes a ground anchor using electromagnetic induction and utilizes an extended structure using hinges and links and mounting and sensing using electromagnets. The aim is to secure the anchor force, excluding grout, and to secure various sensing capabilities, including ground behavior. We propose a design based on the drilling diameter of 150 mm, and the materials used were STS304 and Aluminum 6061-T6. Computerized analysis was performed to confirm structural safety and functional implementation. The pull-out experiment was conducted by simulating the bedrock environment on a model earthwork as an experiment to check whether anchor force was generated by the insertion and tension of the anchor. The environmental pollution of grout, the difficulty of removing strands, and the inability to check whether the anchor is seated, which were pointed out as disadvantages of the existing ground anchor, were solved. Therefore, this study suggest that it can be effectively utilized as a secure and monitored anchoring solution in eco-friendly construction practices, including the installation of landslide prevention barriers.