• Geomechanics and Engineering
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• v.20 no.5
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• pp.421-432
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• 2020

Cutting of rocks is very common encountered in tunneling and mining during underground excavations. A deep understanding of rock-tool interaction can promote industrial applications significantly. In this paper, a distinct element method based approach, PFC^3D, is adopted to simulate the rock cutting under different operation conditions (cutting velocity, depth of cut and rake angle) and with various tool geometries (tip angle, tip wear and tip shape). Simulation results showed that the cutting force and accumulated number of cracks increase with increasing cutting velocity, cut depth, tip angle and pick abrasion. The number of cracks and cutting force decrease with increasing negative rake angle and increase with increasing positive rake angle. The numerical approach can offer a better insight into the rock-tool interaction during the rock cutting process. The proposed numerical method can be used to assess the rock cuttability, to estimate the cutting performance, and to design the cutter head.

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.53-65
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• 2004

This paper presents the prediction of deep excavation-induced ground surface movements using artificial neural network(ANN) technique, which is of prime importance in the damage assessment of adjacent buildings. A finite element model, which can realistically replicate deep excavation-induced ground movements, was employed to perform a parametric study on deep excavations with emphasis on ground movements. The result of the finite element analysis formed a basis for the Artificial Neural Network(ANN) system development. It was shown that the developed ANN system can be effective for a first-order prediction of ground movements associated with deep-excavation.

• Journal of the Korean Ceramic Society
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• v.45 no.6
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• pp.350-357
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• 2008

The use of shotcrete-sprayed concrete for the support of underground excavations was pioneered by the civil engineering. Now, for the nuclear wastes disposal plant in our country, watertightness of shotcrete is one of the very important properties. This study evaluated the watertightness of shotcrete using cement mineral accelerator with watertightness materials for the long-term watertightness. In this study, for improvement of watertightness of shotcrete, it used two types of obtainable at a store. Watertightness tests of shotcrete were performed the water absorption coefficient, permeability, porosity and hydrates variation. In a shotcrete containing watertightness materials, watertightness of shotcrete was improved about $15%{\sim}65%$ rather than plain shotcrete.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.606-611
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• 2009

MiStrut is a new method to establish structural stability in designing braced excavations by making a rigid connection between top-level steel beams and soldier beams. MiStrut has a function of working as a strut as well as supporting cover plates of top-level steel beams. The structural mechanism of MiStrut is supposed to reduce flexural deformation of soldier beams, which may lead to reduced lateral earth pressures behind excavation. In this research, for verification of the performance of MiStrut, shear-wave velocities of subsurface soil before and after excavation was compared. The rigid connection of main girder beams with soldir beams reduced shear-wave velocity by 67% and lateral earth pressures by 90%, which indicates that MiStrut is effective development in reducing lateral earth pressures on braced excavation.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.451-458
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• 2002

This paper presents the prediction of deep excavation-induced ground surface movements using artificial neural network, which is of prime importance in the perspective of damage assessment of adjacent buildings. A finite element model, which can realistically replicate deep-excavation-induced ground movements was employed and validated against available large-scale model test results. The validated model was then used to perform a parametric study on deep excavations with emphasis on ground movements. Using the result of the finite element analysis, Artificial Neural Network(ANN) system is formed, which can be used in the prediction of deep exacavation-induced ground surface displacements. The developed ANN system can be effecting used for a first-order prediction of ground movements associated with deep-excavation.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.147-179
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• 2002

The important role of observational method in geotechnical engineering are emphasized together with the direction of future development, concerning successful application of the technique on the site investigation, design and feed back at various construction stages. Case histories on the application of feed back are introduced in order to achieve the most economical and reliable construction for tunnel, rock slope and deep excavations through feed back system at design and construction stages. Also the limitations and advantages of the observational method and the role of feed back system are discussed for construction of tunnel, rock slope and deep excavation in hard ground such as layered ground conditions including weathered, soft and hard rocks.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1614-1622
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• 2008

A series of three-dimensional numerical modelling have been conducted to clarify the behaviour of multi-pressurised soil nails with high strength steel pipes. In this study, the soil non-linearity, the soil-nail interaction and staged construction are considered. It has been found that pressurised soil nails can reduce lateral ground movement by 14-21% compared to general soil nails with very low pressure. In addition, ground settlement was reduced when using multi-pressurised soil nails. The pressurised soil nail may result in an increase in the surcharge loading on the ground surface.

• Journal of the Korea Institute of Building Construction
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• v.7 no.3
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• pp.131-137
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• 2007

To predict deep excavation wall movements is important in the urban areas considering the cost and the safety in construction. Failing to estimate deep excavation wall movements in advance causes too many problems in the projects. The purpose of this study is to propose the forecast model of deep excavation wall movements using artificial neural networks. The data of the Deep Excavation Wall Movements which were done form Long research is used of Artificial neural networks training and apply the real construction work measured data to the Artificial neural networks model. Applying the artificial neural networks to forecast the deep excavation wall movements can significantly contribute to identifying and preventing the accident in the overall construction work.

• Geomechanics and Engineering
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• v.6 no.3
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• pp.213-233
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• 2014

The present paper is dealing with the investigation of the stress field around the infinitely long cylindrical cavity, of a circular cross section, contained in the transversally isotropic elastic continuum. Investigation is based upon the determination of the stress function that satisfies the biharmonic equation, for the given boundary conditions and for rotationaly symmetric loading. The solution of the partial differential equation of the problem is given in the form of infinite series of Bessel's functions. Determination of the stress-strain field around cavities is a common requirement for estimation of safety of underground rock excavations.

• KOMUNHWA
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• no.59
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• pp.3-34
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• 2002

The researches on the prehistoric sites in Jeonnam Province started in 1970s. During 1980s and 1990s, excavations increased and their results also became larger than before. For example, the paleolithic sites were excavated along the Yeongsan River basin