• The Journal of Engineering Geology
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• v.28 no.3
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• pp.431-441
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• 2018

To set up the future research and development direction for Auger bit, this study analyzed publicized patent trends of Deep Cement Mixing method (DCM) in Korea, USA, Japan, and Europe. DCM method was firstly classified into wing shapes and the number of rods according to the technical scope, and secondly, classified into 8 types according to type of screw and rotation axial. A total of 2,815 patents were searched and 448 validated patents were selected through de-duplication and filtering. As a result of the analysis of the portfolio through the number of patents and growth stages, it was selected as the core technology that auger is deemed to have high growth potential and if there is a patent similar to core technology through a patent barrier analysis, the basic data is suggested to develop the design around and differentiated technologies.

• Resources Recycling
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• v.27 no.5
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• pp.38-48
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• 2018

Deep cement mixing method (DCM) is used to improve the quality of various ground type and its technical development proceeding based on performance improvements of solidification materials and mixing techniques with ground soil. In this study, it was possible to improve silty clay ground soil had 1 to 3 MPa compressive strength using solidification material that composed mainly circulating fluidized bed combustion (CFBC) power plant fly ash and reduce standard deviation of strengths from over 1.0 MPa to 0.322 MPa using improved auger bits in field test to forming more uniform bulbs than in case of using existing auger bit.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.998-1004
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• 2005

U.J.S.(Ultra Jetting System) is a new ground improvement method registered as a Utility Model No.0205798, which has fundamentally improved the existing jetting method of J.S.P.(Jumbo Special Pattern System). In this study, the uniaxial compressive strengths of improved soil-grout structures by U.J.S. and J.S.P. which have been conducted on the construction site are compared. Also, the differences between the U.J.S. and J.S.P. are analyzed by considering the role of the auger bit, the injection distance measured from the axis of boring tubes, and angle of injection measured from the horizontal. The specimens of soil-grout structures are taken from the improved soils by using the U.J.S. and J.S.P. The uniaxial tests for the samples are conducted after the curing period of 28 days. The uniaxial compressive strengths and the coefficients of elasticity of surface and distance from the axis of boring. This study shows that the mean strength of the improved structure by J.S.P. is 1.9 times greater than by J.S.P.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.57-64
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• 2007

This study proposes a method to estimate drilling torque during ground boring with an aid of electrical energy required for rotating a boring-auger. Ground boring is commonly used in geotechnical engineering such as preboring precast pile installation, soil-cement grouting, ground exploration and so forth. In order to understand the correlation between required electrical energy to rotate the boring auger and the drilling torque, a small laboratory apparatus was designed and a pilot study was performed. The apparatus rotates common drill bits of $D=5{\sim}25mm$ in CBR specimens. The velocity of a bit is 19 RPM and predefined using a reduction gear which connects a main rotation axis to a 25 Watts AC electrical motor shaft. In the middle of drilling the motor current increments and the drilling torque were measured and the correlation between the current and the torque was obtained through linear square fits. Based on the correlation the acquired motor current during drilling was applied to predict the drilling torque in consequent testing and the prediction results were compared to the measured torque. The comparison leads a conclusion that the motor current during drilling using electrical power may be a good indicator to estimate/determine strength characteristics of the ground.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.29-34
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• 2008

A large diameter sampler was developed to take undisturbed samples from not only soft ground but also sandy and weathered ground. The large diameter sampler which was developed in Korea Institute of Construction Technology(KICT-type large diameter sampler) was manufactured based on the principle of triple core barrel sampling. A specially designed cutting device was used to cut and contain various kinds of samples in the sampler during a sampling and retrieval procedure. By adjusting the stiffness of the spring located at the top of the sampler, the distance between the cutting shoe and auger can be controlled in accordance with the ground condition. In order to investigate the applicability of the developed sampler and compare the quality of the samples taken by the sampler with that by the traditional thin-walled tube sampler, samples were taken at various sites according to the ground condition. And a series of laboratory tests such as the unconfined compress ion test, triaxial compression test, oedometer test, large diameter Rowe cell consolidation test (D: 150 mm) were performed. The test results showed that the samples by the KICT-type large diameter sampler show higher quality than the samples by the thin-walled tube sampler. And the validity and applicability of the developed KICT-type large diameter sampler was confirmed accordingly.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.129-139
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• 2018

The Discrete Element Method (DEM) has been widely used in granular material researches. Especially, if material has a large deformation, such as ground, it can be a useful method to analyze. In this study, to simulate ground formations, DEM was used. The main purpose of DEM analysis was to investigate the numerical model which can predict the TBM performance by simulating excavating procedure. The selected EPB TBM has a 7.73 m of diameter and six spokes. And two pre-defined excavation conditions with the different rotation speeds per minute (RPM) of the cutterhead was applied. In the modeled cutterhead, the open ratio of cutterhead was 21.31% and number of cutters (including disc cutter and cutter bit) was 219. From the results, reaction forces and resistant torques at the cutterhead face and cutting tools, were measured and compared. Additionally the muck discharge rate and accumulated muck discharge by the screw auger were evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.493-499
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• 2023

Recently, with the development of construction machinery, low-vibration construction machine such as Tricone-Bits, which can drill both soil and rock layers and minimize vibration, is being used frequently. However, although many studies have been conducted on the prediction of vibration values for earth augers and pile drivers, the reality is that studies on the effects of vibration on low-vibration drilling equipment are lacking. In this paper, ground vibration values for Tricone-Bits were measured, and a vibration distance damping formula was proposed using this. In addition, after predicting the vibration of the earth auger and pile driver using the previously proposed vibration distance damping formula, the degree of vibration damping for the Tricone-Bits was evaluated by comparing and analyzing it. As a result, the Tricone-Bits showed a vibration reduction effect of 97% and 93% compared to these machine and It will help with management and prediction of the ground vibration effects evaluation on the low-vibration equipment such as Tricone-Bits.