• Journal of the Korean Geosynthetics Society
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• v.8 no.4
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• pp.19-25
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• 2009

In this study, field pull-out tests were performed for steel pipe nailing installed foldable wedge and non-wedge type steel pipe nailing under the same test conditions. This is to evaluate pull-out resistance improvement effect of steel pipe nailing installed foldable wedge. Evaluating for field pull-out characteristics of steel pipe nailing installed foldable wedge was performed through analysis of ultimate pull-out resistance ($T_L$), ultimate unit skin friction ($q_s$, $u_{max}$), tensile normal stiffness ($K_{\beta}$), tension of nail. As a result, the steel pipe nailing installed foldable wedge have an effect of pull-out resistance increased about 30% in comparison with non-wedge type steel pipe nailing.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.33-43
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• 2006

Driving tests using model plastic piles with different hammer cushion materials were performed in order to evaluate the efficiency of energy transfer ratio from the hammer, degree of vibration of the surrounding ground and noise due to impacting. A small pile driving analyzer (PDA) was composed using straingages and Hopkinson bar which is measuring force signal and pile-head velocity. The hammer cushion (cap block) materials used for the model driving tests were commercial Micarta, plywood, polyurethane, rubber (SBR) and silicone rubber. The highest energy transfer ratio was obtained from Micarta in the same soil and driving conditions. Micarta was followed by polyurethane, plywood, rubber and silicone in descending order. The more efficient energy transfdr ratio of the hammer cushion materials became, the bigger average noisy (sound) level was found. In addition, Micarta and polyurethane provided bigger bearing capacities than other materials compared in the same soil and driving conditions in which the static loading tests were performed at the end of driving.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1140-1147
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• 2010

To find the soil plug of steel piles shaped by jet grouting, 4 blocks of cement milk with cube of 1.2m were made. 4 open-ended steel piles on the blocks were rested. The inner end part of 2 the piles was not reinforced. Cement milk 65%(SIG-1) and 100%(RJP-1) were filled into the block and height of 4.2 times of inner the pile diameter respectively. And the other the piles were welded 2 steel ring. The filling of the cement milk was an equal method as before(SIG-2 and RJP-2). Also the strain gauges were installed and the static pile load tests were done at the piles all. As a result, list in great order for effect of soil plug was (1)SIG-1, (2)SIG-2, (3)RJP-1, (4)RJP-2. This is because of strength and filling height of cement milk. And the higher the strength is, the greater the confining coefficient is.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.6 no.2
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• pp.9-14
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• 2010

The ground source heat pump system is increasingly being considered as an alternative to traditional heating and cooling systems to reduce the emission of ground house gases. In this paper, A series of numerical analysis for energy piles has been performed focusing on heat transfer efficiency, performance and thermal stress. Results of numerical analyses for the W-shape type shows more efficient heat exchange transfer than the coil type. From results of the thermo-mechanical analysis, it is shown that the concentration of thermal stress occurs around the circulating pipe and the interfaces between different materials. The largest deformation caused by thermal stress is observed in the energy pile.

• Geotechnical Engineering
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• v.5 no.4
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• pp.27-36
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• 1989

Load tests are executed on instrumented model piles to evaluate the magnitudes of soil plugging resistances mobilized at open-end pile tips. The plugging resistances are calculated by some existing methods, which are compared with observation. A couple of the methods are found to give good results. A new computational method to predict the plugging resistance is proposed in this paper, which also gives fairly close prodiction to the measurement, and is much simpler than the other computational methods.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.20 no.3
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• pp.60-66
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• 2016

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.41-48
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• 2012

In this study the negative skin friction test of foundation pile was performed in order to monitor the negative skin frictional force acting on the steel pipe pile installed in soft soil. The monitored frictional stresses obtained from the long-term loading test. Through the long-term frictional stress monitoring test, the economical period for the construction of the superstructure was determined. The following conclusion were derived from this study: (1) In soft soil, negative skin friction increases with the increase in the rate of settlement. (2) In the friction relationship graph, the period where there is no frictional strain increase is verified and the time for the construction of the superstructure is determined. (3) The pile loading test was performed and the negative skin friction was compared with the test results. It was determined that the negative skin friction after driving was larger than the negative skin friction obtained from the loading test. 15 days after the construction, the monitored value was similar with the theoretical data. (4) It was determined that even during the occurrence of negative skin friction an economical construction management can be performed using the long-term monitoring method of negative skin friction.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.35-43
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• 2020

Currently, cofferdams of circular cross section are widely applied as temporary facilities for the installation of bridge foundations in river/sea bridge construction in Korea. Existing caisson, sheet pile, and cell type cofferdam are widely used, but these methods take a lot of time and cost for installation and dismantling. In the case of the existing sheet pile construction method, attention is needed to secure internal and external stability because of the damage to the sheet pile due to ground penetration and difficulty in connecting element members. In this study, penetration design of circular steel pipes using suction pressure was performed on the soft ground of the west coast, and it was confirmed that penetration construction using suction pressure was possible through field tests. It was confirmed that applying the ground analysis results using the cone penetration test (CPT) to the design rather than the standard penetration test (N value) results more similar to the field test results. In addition, it was confirmed that local failure of the inside of the cofferdam was induced when a suction pressure higher than the upper limit suction pressure was applied in the silty sand.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.107-116
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• 2000

Dynamic and static load tests are conducted in four construction sites by using steel pipe piles(SPP) and concrete piles to compare differences of load bearing mechanism. Steel pipe piles are instrumented with electric strain gages and are subject to dynamic load tests during driving. The damage of strain gages attached is checked simultaneously. Static load test is also conducted on the same piles after two to seven days' elapse. Then load-settlement behavior and shaft and/or tip resistances are measured. As a result, the allowable bearing capacity calculated by the Davisson's offset method of CAPWAP analysis shows 2~33% larger than that of static load test. The average value of allowable bearing capacity of static load test is closer to the allowable capacity obtained at the safety factor of 2.5 applied on ultimate bearing capacity than to the one obtained from the Davisson's offset method. The analysis of strain gage readings shows that unit skin friction increases with depth. Furthermore, the friction mobilized around the 1~2m above the pile tip considerably contributes to the total shaft resistance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.904-908
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• 2008

As the various industrial production machinery has come into being by development of industrial technology, the productivity of the basic industrial production machinery has improved and the international competitiveness of the one of Korea has strengthened. However, at the same time, noise from various industrial production machinery disturbs the quiet environment. There are 35 kinds of the noise emission machinery defined in the noise and vibration control act according to the horse power and the number of machinery. These were classified in 1992 through investigation from 1990 to 1991, and the characteristic of the noise emission machinery may be different from the past one. So we need to investigate the characteristics of the noise emitted by machinery to control it rightly. Also we need to investigate the new noise emission machinery which has come into being recently. In this survey, we measured sound intensity of 32 noise emission machinery to calculate the sound power levels of those and investigated the characteristic of the sound power level of those according to the frequency. From the survey, we found that the forging machine, concrete pipe and pile making machine, sawing machine, etc. are the noisy machinery. And the automatic packing machine, sewing machine, centrifuge, etc. are the silent machinery. Also the generator, the concrete pipe and pile making machine, the printing machine, etc. emit the low frequency noise, and the molding machine, the stone cutter, the metal cutter, etc. emit the high frequency noise. Lastly, we intented to propose the proper guide line of classifying noise emission machinery.