• Geotechnical Engineering
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• v.10 no.3
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• pp.33-40
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• 1994

The effects of smear and well resistance should be taken into account for the design of sand drains. Practically, simple design, which employs the method using 112 reduced diameter of drains or assuming the coefficient of consolidation in horizontal direction equals to that in vertical direction, based on the theory neglecting these effects, has been used. In this study, the reliability of existing simple design methods as well as the influences of smear and well resistance was investigated with the equations proposed by Hansbo and Onoue. It is shown that the consolidation time is chiefly governed by the effect of smear for drains with highly permeable sands. For general soil condition and placing type of sand drain, consolidation time is underestimated for simple design wi어. 1/2 reduced diameter of drains, and it is overestimated for that with the assumption that the coefficient of consolidation in horizontal direction equals to that in vertical direction. Through the investigations on different reduced diameter, it was shown that simple design with 1/4 reduced diameter of drains yielded the reliable results with errors less than 6%.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2004.04a
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• pp.219-229
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• 2004

In this article a comprehensive review of the Rock Mass Rating and Q-rockmass classification systems is made with reference to their scope with in the constraints of underground mining operations. The modifications suggested by KIGAM for both the RMR and Q for the calculation of a safe unsupported span were tested for Daesung and Pyunghae underground limestone mines. Even though the suggested modifications were site specific, the additional parameters considered in the above classification systems are very significant for a design of stable underground openings, considering any general mining conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.607-619
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• 2009

In case that there is not an influence of river influx because the foundation is a good rock and the mountain topography, we present the design case for the reasonable underpass foundation form, bearing capacity and drainage process considering the topography and the ground condition.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.99-118
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• 2018

Recently, the limit state design method in the design of the structure is in global trend, but it is limited to a few structures in Korea. Since the introduction of the limit state design method has recently been attempted for tunnels, which are the main underground structures, it is surely necessary to understand the latest limit state design method. Therefore, based on the recently published AASHTO LRFD Road Tunnel Design and Construction Guide Specification (2017), structural load factors and load combinations were reviewed, and various factors which should be applied for the review of structures have been analyzed. In this study, utility tunnel section and subway tunnel sections used in Korea were analyzed by the limit state design method, and we have analyzed the direction of application of limit state design method through studying the tendency of member force by various influential factors such as ground conditions, load modifier and joint stiffness.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.19-30
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• 2000

The major design parameters of the anchored sheet-pile wall include the determination of required penetration depth, the force acting on the anchor, and the maximum bending moment in the piling. Blum solved the fixed earth supported wall using the equivalent beam method, assuming that the wall can be separated into upper and lower parts of the point of contraflexure. Design charts help designer by simplifying the design procedure. But they have some difficulties under some Geotechnical and geometrical conditions. For example, the conventional design charts can compute design parameters only when the ground water table exists above the dredge line. In this paper, the design charts which can be used for the ground water table existing under the dredge line are presented. And simplified formulae are developed by regression analysis. It is found that simplified formulae are not only very useful for the practice of design but also they can evaluate the result of numerical methods or design charts.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.95-104
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• 2002

In this study, a reliability-based design (RBD) procedure for determining design values fur anchored sheet pile wall is proposed considering overturning about the anchor point as the major failure mode. In this design procedure, the depth of embedment of the sheet pile wall is logically chosen in accordance with degrees of uncertainties of design input parameters using approximate probabilistic computation methods. These methods have been successfully used in the geotechnical engineering requiring neither understandings of complex probabilistic theories nor efforts to prepare more data. It was investigated that the design results by the proposed method were compatible with those by commonly used deterministic design methods. Additionally, in an effort to investigate the effects of changes in the degree of uncertainties of major design variables on the design results of the sheet pile wall, a sensitivity analysis was peformed.

• Geomechanics and Engineering
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• v.12 no.1
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• pp.139-160
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• 2017

The bearing mechanism of tunnel-type anchorage (TTA) for suspension bridges is studied. Model tests are conducted using different shapes of plug bodies, which are circular column shape and circular truncated cone shape. The results show that the plug body of the latter shape possesses much larger bearing capacity, namely 4.48 times at elastic deformation stage and 4.54 times at failure stage compared to the former shape. Numerical simulation is then conducted to understand the mechanical and structural responses of plug body and surrounding rock mass. The mechanical parameters of the surrounding rock mass are firstly back-analyzed based on the monitoring data. The calculation laws of deformation and equivalent plastic strain show that the numerical simulation results are rational and provide subsequent mechanism analysis with an established basis. Afterwards, the bearing mechanism of TTA is studied. It is concluded that the plug body of circular truncated cone shape is able to take advantage of the material strength of the surrounding rock mass, which greatly enhances its bearing capacity. The ultimate bearing capacity of TTA, therefore, is concluded to be determined by the material strength of surrounding rock mass. Finally, recommendations for TTA design are proposed and discussed.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.142-152
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• 2007

Geotechnical information database, foundation of underground geographic information system in 2nd NGIS plan, had been developing by Ministry of Construction and Transportation since 2000. This database contains not only soil condition, such as depth, type and color of layer, and ground water level, but also engineering properties used for foundation design and construction, for instance, standard penetration test, compression test. But, it is difficult to apply this database for analyzing and designing geotechnical works, because report document is only offered. In this paper, we have developed web-based geospatial information system for the effective uses. First, underground cross-section model is generated by location, layer, and engineering properties of geotechnical information database at the realtime process. Second, earth volume, bearing capacity, and settlement is calculated and potentials of soft ground, liquefaction are evaluated through pre-defined empirical formula. This process is operated by web-based client. We wish to strengthen the application capacity through this system in construction planning and design works.

• Journal of the Korean Geosynthetics Society
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• v.12 no.3
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• pp.75-79
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• 2013

The frost depth is one of important factors in the design of structures such as roadways, buried pipeline, and foundations. A frost indicator with methylene blue solution has several advantages with respect to installation cost, maintenance, and simple measurement. However, as a geotechnical engineering aspect, the accuracy of the frost indicator has not been proved yet. This paper presents experimental and field investigations of the accuracy of the frost indicator and contour maps of maximum frost depth. The contour maps of maximum frost depth can be applied to design geo-infrastructure in South Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1251-1258
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• 2006

Field evaluation of new scour countermeasure using geobag and aggregate is performed to prepare for the basis of design and construction standard in Korea. Polyester non-woven geotextile is determined as a geobag material and tire cord is used to sew up the geobag which contain aggregate. Hwasang-gyo(bridge) is selected as a pilot test site through office review and field investigation. According to the design flood of Hwasang-gyo(bridge), the size and volume of geobag are calculated and construction area and required number of geobags are computed by considering the specification of the pier and foundation of the bridge. After construction, scour depth around geobag construction area is measured and the stability of geobag is ascertained by using pole and digital camera.