• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.37-46
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• 2016

Rotary pile consists a single or multiple helix plate and it is installed into the ground using the rotation of the helix plate. Rotary pile in soft ground is able to be supported by pile shaft and helix plate. When the pile is installed into hard layer relatively, the end bearing capacity is possible to be increased by the lower helix plate. In this paper, small-size rotary piles were manufactured with using steel pipe which is reduced to 1/5 size of the rotary pile on the construction field. Pile load test was carried out on the foundation soil which was formed by weathered soft soil. The bearing capacity of small-scale piles depends on the number of helix plate, the length of plate diameter, and an interval of plates, respectively. The bearing capacity of pile increases about 40% with 3 helix plate and it is also confirmed that the bearing capacity is improved about 10% as the increment of plate interval.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.31-39
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• 2014

The helical pile is a manufactured steel pile consisting of one or more helix-shaped bearing plates affixed to a central shaft. This pile is installed by rotating the shaft into the ground to support structural loads. The advantages of helical piles are no need for boring or grout process, and ability to install with relatively light devices. The bearing capacity of the helical pile is exerted by integrating the bearing capacity of each helix plate attached to the steel shaft. In this paper, to estimate the bearing capacity of moderate-size helical piles, 6 types of helical piles were constructed with different shaft diameter, plate configuration and the penetration depth. A series of field loading tests was performed to evaluate the effect of helical pile configuration on the bearing capacity of helical pile, constructed in two different shaft diameters (i.e. 73 mm and 114 mm). In the same way, the diameter of bearing plate was also changed from 400mm to 250mm with one or three plates. As well, the penetration depth was varied from 3m to 6m to analyze the relation between the penetration depth and the bearing capacity. As a result, not only the increase of the shaft diameter, but also the number or diameter of helix bearing plates enhances the bearing capacity. Especially the configuration of the helix plate is more critical than the shaft diameter.

• Geomechanics and Engineering
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• v.31 no.5
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• pp.505-518
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• 2022

This study introduces soil resistance multipliers at locations encompassed by the zone of influence of the helix plate to consider the added lateral resistance provided to the helical pile. The zone of influence of a helix plate is a function of its diameter and serves as a boundary condition for the modified soil resistance springs. The concept is based on implementing p-multipliers as a reduction factor for piles in group action. The application of modified p-y springs in the analysis of helical piles allows for better characterization and understanding of the lateral behavior of helical piles, which will help further the development of design methods. To execute the proposed method, a finite difference program, HPCap (Helical Pile Capacity), was developed by the authors using Matlab. The program computes the deflection, shear force, bending moment, and soil resistance of the helical pile and allows the user to freely input the value of the zone of influence and Ω (a coefficient that affects the value of the p-multiplier). Results from ten full-scale lateral load tests on helical piles embedded at depths of 3.0 m with varying shaft diameters, shaft thicknesses, and helix configurations were analyzed to determine the zone of influence and the magnitude of the p-multipliers. The analysis determined that the value of the p-multipliers is influenced by the ratio between the pile embedment length and the shaft diameter (D_p), the effective helix diameter (D_h-D_p), and the zone of influence. Furthermore, the zone of influence is recommended to be 1.75 times the helix diameter (D_h). Using the numerical analysis method presented in this study, the predicted deflections of the various helical pile cases showed good agreement with the observed field test results.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.77-85
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• 2014

The helical pile has become popular with some constructional advantages because relatively compact equipment is needed for installing helical piles. However, field loading tests for estimating the bearing capacity of helical piles have drawbacks that the required dead load should be as much as the operation load, and reaction piles or anchors are required. In this paper, the bi-directional load test without necessity of reaction piles and loading frames was applied to the helical pile, and the load-settlement curves of the helical piles were measured. The bi-directional load test was performed in two separate stages with the aid of a special hydraulic cylinder whose diameter is equal to that of the pile shaft. In the first stage, the hydraulic cylinder is assembled immediately above the bottom helix plate, and the end bearing capacity of the helical pile is measured. In the second stage, the hydraulic cylinder is assembled above the top helix plate, and the skin friction of the helical pile is measured. The pile loading-test program was carried out for the two different helical piles with the shaft diameter of 89 mm and 114 mm, respectively. However, the configuration of helix plates is identical with three helix plates of 450-, 350-, 200- mm diameter. Results of the bi-directional load test were verified by the conventional static pile loading test. As a result, the bearing capacity estimated by the bi-directional load test is in good agreement with the result of the conventional pile loading test.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.3
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• pp.30-39
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• 1986

The burr worsens the accuracy of a workpiece and decreases a lot of pro- ductivity because it takes so much time and efforts to remove it. In this paper, the height, thickness and size of a drilling burr were derived from the drilling variables of drill diameter, chisel edge angle, web rate =($\Frac{2{\times}\;web\;thickness}{drill\;dia}$) and yielding stress of the workpiece as wel as feed, point angle and helix angle. The theoretical and experimental values of drilling thrust, torque and burr size of the testpiece were analyzed with the method of numerical analysis in a standard drilling condition. The order of choosing the drilling variables for the purpose of controlling the burr size was dealt in this paper with burr forming ratio. The results are as follows: (1) The drill diameter forms 42 percents feed 25 percents point angle 23 percents and web rate, chisel edge angle and gelix angle 5 percents of the partial differential slope of drilling thrust within the usual available ranges of drilling variables. (2) The drill diameter forms 55 percents feed 26 percents web rate 9 percents and chisel edge angle, point angle and helix angle 10 percents of the par- tial differential slope of drilling torque in the usual available ranges of drilling variables. (3) About 70 percents of the burr size can be controlled by feed, 29 percents by web rate in the case of a fixed diameter. It is recommended drilling10 variables to be chosen in the order of feed, web rate, drill diameter, point angle, chisel edge angle and helix angle so as to control the burr size effectively.

• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.41-47
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• 2014

Various prediction methods for the bearing capacity of helical piles have been introduced with consideration of both the steel shaft and the helix plates attached to the shaft. In this paper, three representative methods, that is, individual bearing method, cylindrical shear method, and torque correlation method are discussed and compared to each other. The prediction methods were verified by comparing with a series of loading test results performed on moderate-size helical piles from the companion paper. As a result, the measured bearing capacity is greater than the bearing capacity predicted by the cylindrical shear method, but smaller than that of the individual bearing method. In addition, the bearing capacity predicted by the torque correlation method is in good agreement with the measured bearing capacity.

• Korean Journal of Cleft Lip And Palate
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• v.2 no.1_2
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• pp.29-41
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• 1999

Cleft lip and palate is the most frequent congenital facial deformity of the orofacial area. Successful management of patients with cleft lip / palate requires a multidiciplinary approach from birth to adult stage. Coordinated treatment by the cleft palate team is an essential requirement to obtain optimum treatment results. One of the negative effect of the early surgical interventions of lip and palate is a significant incidence of maxillary growth restriction that produces secondary deformities of the jaws and malocclusion that includes congenital missing of lateral incisor, malformed teeth, rotation or ectopic position of upper anterior teeth, and it has been thought due to the resistance of palatal scar tissue. In Orthodontic treatment for cleft lip / palate patients, expansion of upper dental arch or palatal suture is often needed to correct posterior and/or anterior cross bite and align upper teeth. Various appliances such as hyrax, quad-helix, fan-type expansion screw and jointed-fan type expander can be used for palatal expansion. In the orthodontic treatment of the cleft lip / palate patient, we must consider patient age and severity of palatal constriction for proper appliance selection, and must pay special attention to maintain the treatment results.

• BMB Reports
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• v.40 no.5
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• pp.697-707
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• 2007

Cytochrome $cbb_3$ oxidase is a member of the heme-copper oxidase superfamily that catalyses the reduction of molecular oxygen to the water and conserves the liberated energy in the form of a proton gradient. Comparison of the amino acid sequences of subunit I from different classes of heme-copper oxidases showed that transmembrane helix VIII and the loop between transmembrane helices IX and X contain five highly conserved polar residues; Ser333, Ser340, Thr350, Asn390 and Thr394. To determine the relationship between these conserved amino acids and the activity and assembly of the $cbb_3$ oxidase in Rhodobacter capsulatus, each of these five conserved amino acids was substituted for alanine by site-directed mutagenesis. The effects of these mutations on catalytic activity were determined using a NADI plate assay and by measurements of the rate of oxygen consumption. The consequence of these mutations for the structural integrity of the $cbb_3$ oxidase was determined by SDS-PAGE analysis of chromatophore membranes followed by TMBZ staining. The results indicate that the Asn390Ala mutation led to a complete loss of enzyme activity and that the Ser333Ala mutation decreased the activity significantly. The remaining mutants cause a partial loss of catalytic activity. All of the mutant enzymes, except Asn390Ala, were apparently correctly assembled and stable in the membrane of the R. capsulatus.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.343-348
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• 1990

E. coli LE392, transformed with CDDP-treated pBR322 DNA, was plated on ampicillin containing media. The number of colonies formed on ampicillin containing agar plate was reduced to undetectable level after treat the DNA with 13.3 ${\mu}M$ CDDP. The CDDP-treated pBR322 DNA was susceptible to sing1e strand DNA specific S1 nuclease and it's migration Pattern in agarose gel electrophoresis was changed. These results suggest that CDDP adduction to pBR322 DNA resulted in denaturation of the double helix and changes in it's conformation which ultimately leads In the inactivation of the ampicillin resistant sere.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.1-11
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• 2017

In this study, 1/6 small-scale model tests of helical piles were conducted to evaluate their installation time and ultimate capacities. Model sand layers were constructed using sand pluviating method to produce uniform soil relative density. For installation of different helical piles varying locations (vertical center-to-center spacings of 50 mm and 150 mm) of helix plates, two different rotation speeds of 15 rpm and 30 rpm were implemented. Cone penetration equipment was installed within the hallow section of the helical pile to increase ultimate capacity of helical pile and to evaluate soil properties of plugged soils and soils below pile tip after installation of the piles. Based on the test results, the most fasted installation was possible under the condition of "rotation speed of 30 rpm and center-to-center spacing of 50 mm", and the highest ultimate capacity was mobilized under the condition of "rotation speed of 30 rpm and center-to-center spacing of 150 mm with cone penetration implementation."