• Proceedings of the Korean Geotechical Society Conference
• /
• 1997.10a
• /
• pp.373-382
• /
• 1997

• Proceedings of the Korean Geotechical Society Conference
• /
• 1998.10a
• /
• pp.167-174
• /
• 1998

• Proceedings of the Korean Geotechical Society Conference
• /
• 1996.03a
• /
• pp.145-154
• /
• 1996

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.153-160
• /
• 2003

While the interests on the environmental problem during the construction are increasing, the use of low noise-vibration auger-drilled pilling is increasing to solve noise and vibration problem in pilling. Therefore, in Korea, SIP(Soil-Cement Injected Precast Pile) method is mainly used as auger-drilled pilling. However, there is no proper design criteria compatible with the ground condition of Korea, so which is most wanted. To improve and supplement this situation, direct shear tests between SIP pile skin interface and soil were executed on various conditions. Through the analysis of test results, skin resistance characteristics of SIP were investigated thoroughly. Also, the nonlinear unit skin resistance capacity model with SM, SC soil were suggested.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.583-588
• /
• 2002

As environmental problem in course of construction has been a matter of interest, noise and vibration in the process of piling are considered as a serious problem. For this reason, the use of SIP method inserting pile as soon as boring and cement grouting is rapidly increasing for preventing vibration and noise. But a resonable bearing capacity formula for SIP method does not exit and even the standard specification for domestic condition isn't formed, though the lateral friction between cement paste and the ground does an important role and boring depth largely influences to the design bearing capacity, applying the SIP method . Therefore, the lateral friction was analyzed after the direct shear test worked with the lateral face of SIP and the soil.

• Korean Journal of Oriental Medicine
• /
• v.16 no.3
• /
• pp.135-140
• /
• 2010

The usefulness of constitutional diagnoses based on skin measurements has been established in oriental medicine. According to Sasang constitutional medicine, humans can be distinguished based on properties of skin's friction, thickness and elasticity. To quantify and standardize skin diagnosis, the present study designed an equipment for measuring skin elasticity of hand. But there were some noises in measuring skin elasticity such as measurement method, environment, operator and conditions of patient. So we considered a six sigma project for reducing the measurement errors. The project was followed to discipline process of five macro phases: Define, Measure, Analyze, Improve and Control(DMAIC). So, we could find the major factors which should be controled for stabilizing measurement system and we revised the SOP(Standard Operating Procedure) of the skin elasticity measurement.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.11
• /
• pp.107-117
• /
• 2020

Open-ended steel pipe piles have outside frictional force and inside frictional resistance in which blocked soil acts on the inside of the steel pipe during installation. It is expected that the ultimate load will change depending on the inside and outside resistance. And, if the ground on which the piles were constructed is clay soil, it is predicted that it will have effect on the negative skin friction caused by the ground settlement. Therefore, in this study, the behavior according to the inside and outside resistance characteristics of steel pipe piles was analyzed numerically, and the frictional force distribution, axial load and settlements before and after the occurrence of ground settlement were calculated. As a result of the analysis, the inside frictional resistance had less influence than the outside frictional resistance. However, inside frictional resistance is considered to be one of the important factors considering the effect on the overall pile behavior, and both resistance factors need to be considered in the design process.

• Journal of the Korean Geotechnical Society
• /
• v.33 no.1
• /
• pp.31-38
• /
• 2017

Skin friction of prebored and precast pile may be one of the most critical factors affecting the bearing capacity and settlement. Special attention was given to the interface behavior of pile-cement milk-surrounding soil when the load is acting on the prebored and precast pile. The cases of single pile were analyzed through a three-dimensional finite element approach and pile loading tests. A series of numerical analyses of the interface of pile-cement milk-soil was conducted with the proposed t-z curve and field measurements. It is shown that the use of cement milk around the pile increases the skin friction and reduces the pile settlement. It is also known that the suggested t-z curve between the cement milk and the soil, enhances the accuracy of the numerical analysis results.

• Tunnel and Underground Space
• /
• v.12 no.4
• /
• pp.277-283
• /
• 2002

This experimental study concerns the characteristics of a helical flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one is rotating. The pressure losses and skin friction coefficients have been measured for the fully developed flow of Non-Newtonian fluid, aqueous solution of sodium carbomethyl cellulose (CMC) and bentonite with inner cylinder rotational speed of 0~400 prm. Also, the visualization of helical flows has been performed to observe the unstable waves. The results of present study reveal the relation of the Reynolds number Re and Rossby number Ro with respect to the skin friction coefficients. In somehow, they show the existence of flow instability mechanism. The pressure losses increase as the rotational speed increases, but the gradient of pressure losses decreases as the Reynolds number increases in the regime of transition and turbulence. And the increase of flow disturbance by Taylor vortex in a concentric annulus with rotating inner cylinder results in the decrease of the critical Reynolds number with the increase of skin friction coefficient.

• The Journal of Engineering Geology
• /
• v.30 no.1
• /
• pp.59-69
• /
• 2020

Pull-out load tests were performed on a CPR (Compaction grouting compound Pile with Reinforce) test pile, with skin friction being evaluated by the yield load and allowable bearing capacity after analyzing load-displacement curves and load-settlement curves. Results of the CPR test piles analyzed from the load-displacement curves show that the yield load and allowable bearing capacity of the large-diameter CPR test pile were about 1.4 times larger than that of the small-diameter pile. Results of the load-settlement curves reveal that the allowable bearing capacity of the CPR test pile with diameter of D500 was 1.2~2.1 times greater than that of the pile with diameter of D400. However, the allowable bearing capacity calculated using Fuller's analysis differed substantially from that determined using the P (Pull-out load) - S (Settlement) and log P - log S curves. Therefore, calculation of the allowable bearing capacity using Fuller's analysis is shown to be inappropriate.