• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.38-48
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• 2005

For the development of Scramjet engine technology, intake designing processes are investigated. The basic geometry is determined by the inviuld relation such as shock wave relations and geometric relations. Furthermore, bleed duct is installed for preventing boundary layer development and shock wave impingement. Performance of the designed intake is validated by numerical analysis. As a result, double- wedge intake showed better characteristics in total pressure recovery than single-wedge intake.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.379-380
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• 2006

In this study we dealt with the relationship between the initial clamping force and the sliding distance in the wedge type rail clamp. The sliding distance is determined by the wedge angle and the initial clamping force. In order to derive the relation formula between the wedge angle and the sliding distance, we ad opt 5-kinds of the wedge angle, such as 2, 4, 6, 8, $10^{\circ}$. And then we analyze the effect of the initial clamping force on the sliding distance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.1042-1045
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• 2005

The wedge type rail clamp has the operating mechanism: First, the jaw pad clamps a rail with small clamping force. Next as the wind speed increases, the clamping force of the Jaw pad Is Increased by the wedge. The initial clamping force of a jaw pad was determined by the clamping angle of a locker. In this study, we carried out the finite element analysis to evaluate the relationship between the clamping angle of a locker and the clamping force of a jaw pad with respect to the design wind speed, such as 2, 4, 6, 8, and 10m/s, we adopted the wedge type rail clamp fur 50tons class container crane with the wedge angle of $10^{\circ}$.

• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.19-27
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• 2013

Recently, the natural and man-made slope collapses occur frequently because of sudden heavy rains. So, a variety of slope reinforcement methods have been developed and applied to failure slopes. Soil nailing method usage has been increased because of its workability and economic aspects. This method has been applied in combination with other slope stability methods. Soil nailing method is a kind of combinational structure of steel bar and cement grouting. This method uses skin friction between adjacent ground and cement grouting to stabilize the slope. In this study, End-expanded soil nailing method was developed. This method consists of steel bar and anchor body attached at the tip of the nail. During construction, the anchor body at steel bar tip is settled to the ground through the expanding action. In this study, field pull-out tests were performed for un-grouting soil nailing and grouting soil nailing. From the test results, a wedge force of End-expanded soil nailing method was analyzed. And the behavior characteristics of End-expanded soil nailing were studied.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.1-11
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• 2001

The geological characteristics of Korea are that we can encounter the rock layer only after 10m of excavation, methods to presume the rock pressure distribution of the rock layer is urgently needed. When using the existing empiric science of Terzaghi-Peck, Tschebotarioff to measure the rock pressure of the rock layer, underestimate the real strength because of the cohesion is ignored. Therefore calculating the horizontal sliding force of wedge block, which includes the dips and shear strength of discontinuities and surcharge load etc., think to be to getting a closer rock stress of the real rock pressure acting upon the earth structure in rock mass. This research use Coulomb soil pressure theory assuming that the backfill soil will yield wedge failure when it has cohesion, applying Prakash-Saran(l963), and then it uses equilibrium of force and shear strength $\tau$=c+$\sigma$tan $\Phi$ of the cliscontinuities. Analyzing shear strength and dips of cliscontinuities using calculated theory according to the status of discontinuities aperture, we were able to find out that because the cohesion and friction angle of the rock layer itself is large enough, how the dip directions and dips facing the excavation face is the only factor deciding whether or not the rock stress is applied. The evaluated theory of this research should be strictly estimated, so that the many parameters such as c, $\Phi$value, types and structures of rock class, excessive lateral pressure, dynamic load, earthquake, needed later when calculating shear strength of discontinuities and especially the ground water effect acting on rock layer should be coumpted with many measuring data achieve at the insite to study the application.

• Journal of the Korean Geotechnical Society
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• v.34 no.3
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• pp.67-75
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• 2018

In this study, we developed a micropile equipped with ground fixing wedge device which is able to ensure the bearing capacity early before grouting by expanding the tip and exerting the tip surface friction while compressing and expanding the tip of the micropile during loading. The purpose of this study is to verify the applicability of the developed micropile to the ground with various kinds of strength and to compare its characteristics with those of the simple tip expansion micropile. A new test system including a model soil box which can measure the tip resistance and the tip skin friction separately was devised. The loading test was carried out according to the changes of the ground strength and the tip cross section using the devised test systems. As a result of the test, it was found that the developed micropile increased the tip skin friction due to the wedge horizontal force as the soil strength increased and could be applied more effectively to the ground with the strength not lower than the strength of the weathered rock. In addition, it was found that additional bearing capacity could be obtained due to the tip cross section expansion and the wedge horizontal force exertion even in the ground with the strength below the weathered rock strength.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.2 s.21
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• pp.17-24
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• 2006

A ground anchor system is used as a load carrying element for soil structure stability The conventional systems with ground anchors bring about the anchorage loss of wedges when anchors are installed for the support of soil structures. Hence we developed the new type of anchor system using both the spacing apparatus and spring (length 60mm, diameter 6mm). In this system, we can directly check the condition of wedges and PS strands and modify the problems with the slip and anchorage of wedges under construction. For demonstrating the superiority of this system, we carried out a series of both laboratory and field test. Consequently, we can obtain satisfactory result (18.99% reduction to the loss of conventional systems). Moreover, the replacement of wedges is easy and simple when retensioning of strands.

• Journal of the Korean Society for Railway
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• v.19 no.6
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• pp.765-776
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• 2016

In this study, a standard section of a railway bridge abutment wall was designed to satisfy the external stability condition in accordance with the design criteria; this design was used to compare and analyze the active earth pressure and to calculate various types of earth pressure acting on the virtual back (wall, plane) according to the frictional angle of the backfill materials. Also, the external stability, member force and construction cost were analyzed according to the frictional angle of the backfill materials using various theories of earth pressure such as Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge. As for the results, it was found that lateral earth pressure at the virtual back plane was higher than at the virtual back wall, and that these values decreased with the increase of the frictional angle of the backfill materials. The increasing of the frictional angle of the backfill materials decreased the active earth pressure (according to Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge results), and the member force as well as the construction cost were reduced.

• Tribology and Lubricants
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• v.34 no.2
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• pp.55-59
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• 2018

This paper proposes a new type of electro-mechanical wedge brake for commercial vehicles. The brake operates on a novel mechanism for self-boosting braking friction forces using eccentric shafts, and involves wedges that are inserted between the rampbridge and traverse; this self-boosting mechanism is explained herein. A dynamic analysis using ADAMS was conducted, and the findings are reported. The constraint and contact conditions are explained to verify the precision of the dynamic analysis. The dynamic analysis shows that in the proposed mechanism, the self-boosting effect occurs as desired. However, it is also noted that the system has a limitation in terms of the production of unlimited braking forces that can jam the roller inside the wedges. After demonstrating the self-boosting effect, dynamic analyses are performed for several values of the wedge angles and friction coefficients between the brake pads and disks. Conventionally, a lower wedge angle has been suggested owing to its provision of a larger clamping force for given friction coefficients. However, it is noted that lower wedge angles can lead to a higher probability of occurrence of undesirable high braking forces, which can jam the roller into the wedge; thus, a larger wedge angle is preferable for avoiding the undesirable jamming phenomena. These analysis results are presented and discussed herein.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.103-112
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• 2012

The most of original horizontal bearing capacity theory of the pile is not efficiently to consider interaction between soil and pile because it is only to consider the earth pressure theory and separately the ground form pile. In recent, in order to improve the pile technology, it is necessary to confirm the real behaviour characteristics of pile under lateral load. Hence, to evaluate the behaviour characteristics of the single and group pile under lateral loads using the strain wedge model that could consider the interaction between soil and piles. Primarily, laboratory scale down model tests was carried out to predict the behaviour characteristics on real size piles using the strain wedge model. The comparative analyses between model test and numerical analysis for the evaluation of whole behaviour were conducted.