• Journal of Bio-Environment Control
• /
• v.10 no.3
• /
• pp.148-154
• /
• 2001

The uplift capacity of a pile for improving the wind resistance of the 1-2 W type plastic film pipe on greenhouses was tested using the plane and corrugated piles with various shapes and diameters. First, the resistant uplift capacity was measured by using the uplift loading on plane piles. As the uplift loading on plane piles increased, the resistant uplift capacity also increased until the loading was reached to ultimate uplift capacity. After ultimate uplift capacity was appeared the uplift displacement, the uplift capacity was decreased gradually. Secondly, the resistant uplift capacity was measured by using the uplift loading on corrugated piles. After the uplift capacity was reached the uplift displacement, the uplift capacity was continually increased or decreased. In general, the ultimate uplift capacity was independent of pile shapes, pile diameter length, and embedded pipe depth. However, the ultimate uplift capacity of a corrugated pile was twice more than that of a plane pile without regard to its diameter and embedded depth. The ultimate uplift capacity per unit pile area was increasing in deeper embedded depth. However, the longer a pile diameter was, the less ultimate uplift capacity. The uplift capacity of a plane pile, used in conjunction with the design wind velocity (26.9m.s$^{-1}$ ) of the project area, was unsatisfiable without regard to diameters and embedded depths of piles, while most of corrugated piles were well appeared uplift capacity under various experimental conditions.

• Journal of The Geomorphological Association of Korea
• /
• v.26 no.2
• /
• pp.55-67
• /
• 2019

This study tries to reveal and compare uplift rates in the southern coast of the Korean Peninsula, based on absolute ages from coastal terrace on the coast. The uplift rate in the East Coast from previous study ranges from 0.258 to 0.357 m/ka with a median rate of 0.262 m/ka and shows an increase trend from north to south. Median uplift rate of 0.082 m/ka with minimum and maximum rates of 0.053 m/ka and 0.127 m/ka, respectively, is calculated in the South Coast from previous and this studies. The uplift rate in the West Coast from 3 absolute ages in this study is 0.082~0.112 m/ka with a median rate of 0.090 m/ka. Based on these uplift rates in the southern coast of the Korean Peninsula, it can be concluded that since MIS 5, the East Coast has experienced 3 to 4 times faster uplift rate than the West and South Coasts. However, this study suggests that more discussion on whether these uplift rates are long-term tectonic movement associated with tilted warping movement since the Tertiary or short-term tectonic movement associated with isostatic rebound due to sea level change since the Last Interglacial is needed.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.6
• /
• pp.1-6
• /
• 2008

Anchors have been commonly used to as foundation systems of the structures that require the uplift resistance. Recently anchors have been used in ocean sediment for mooring systems to stabilizeoffshore structures. In the saturated clayey soil however suction developed between the soil and andchor and affects the uplift capacity of anchor. To estimate the uplift capacity of the andchor accurately, the failure mechanisms of the andchor by the uplift force should also be correctly assumed. The uplift capacity is usually expressed in terms of breakout factors with respect to embedment ratio. In this paper, a two-dimensional plane strain numerical investigation into the vertical uplift capacity of a plate andchor in a clayey soil is described. The breakout factor against their corresponding values of embedment ratio was calculated and plotted along a single curve. The modes of failure mechanism at shallow and deep andchors are also presented.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.10
• /
• pp.864-869
• /
• 2009

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

• Geomechanics and Engineering
• /
• v.7 no.2
• /
• pp.165-181
• /
• 2014

In the past decade, different types of underreamed ground anchors have been developed for substructures requiring uplift resistance. This article introduces a new type of umbrella-shaped anchor. The uplift behavior of this ground anchor in clay is studied through a series of laboratory and field uplift tests. The test results show that the umbrella-shaped anchor has higher uplift capacity than conventional anchors. The failure mode of the umbrella-shaped anchor in a large embedment depth can be characterized by an arc failure surface and the dimension of the plastic zone depends on the anchor diameter. The anchor diameter and embedment depth have significant influence on the uplift behavior. A finite element model is established to simulate the pullout of the ground anchor. A parametric study using this model is conducted to study the effects of the elastic modulus, cohesion, and friction angle of soils on the load-displacement relationship of the ground anchor. It is found that the larger the elastic modulus and the shear strength parameters, the higher the uplift capacity of the ground anchor. It is suggested that in engineering design, the soil with stiffer modulus and higher shear strength should be selected as the bearing stratum of this type of anchor.

• Geomechanics and Engineering
• /
• v.9 no.6
• /
• pp.757-774
• /
• 2015

Reinforcing soils with the geosynthetics have been shown to be an effective method for improving the uplift capacity of granular soils. The pull-out resistance of the reinforcing elements is one of the most notable factors in increasing the uplift capacity. In this paper, a new reinforcing element including the elements (anchors) attached to the ordinary geogrid for increasing the pull-out resistance of the reinforcement, is used. Thus, the reinforcement consists of the geogrid and anchors with the cylindrical plastic elements attached to it, namely grid-anchors. A three-dimensional numerical study, employing the commercial finite difference software FLAC-3D, was performed to investigate the uplift capacity of the pipelines buried in sand reinforced with this system. The models were used to investigate the effect of the pipe diameter, burial depth, soil density, number of the reinforcement layers, width of the reinforcement layer, and the stiffness of geogrid and anchors on the uplift resistance of the sandy soils. The outcomes reveal that, due to a developed longer failure surface, inclusion of grid-anchor system in a soil deposit outstandingly increases the uplift capacity. Compared to the multilayer reinforcement, the single layer reinforcement was more effective in enhancing the uplift capacity. Moreover, the efficiency of the reinforcement layer inclusion for uplift resistance in loose sand is higher than dense sand. Besides, the efficiency of reinforcement layer inclusion for uplift resistance in lower embedment ratios is higher. In addition, by increasing the pipe diameter, the efficiency of the reinforcement layer inclusion will be lower. Results demonstrate that, for the pipes with an outer diameter of 50 mm, the grid-anchor system of reinforcing can increase the uplift capacity 2.18 times greater than that for an ordinary geogrid and 3.20 times greater than that for non-reinforced sand.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.125-128
• /
• 2002

The uplift capacity and displacement of an earth anchor for improving the wind resistance of the 1-2W type plastic film pipe on greenhouse was tested using the steel circular vertical earth anchor with various diameters and embedded depths (L) in dry sand. The diameter (B) of the model anchor is 90mm, 120mm, 150mm, respectively. The model tests were performed embedded depth ratios (L/B) ranging from $1{\sim}3$ in loose density. In the case of diameter 90mm, as the uplift loading increased, the uplift capacity also increased until the loading was reached to ultimate uplift capacity. After that, the uplift capacity was continually increased or decreased until the experiment was finished. In general, the ultimate uplift capacity was different depending upon the anchor diameter and embedded depth ratios.

• Geomechanics and Engineering
• /
• v.5 no.3
• /
• pp.187-194
• /
• 2013

The most soil anchor works have been concerned with the uplift problem on embedded in non-reinforced soils under pullout test. Symmetrical anchor plates are a foundation system that can be resisting tensile load with the support of around soil in which symmetrical anchor plate is embedded. Engineers and authors proved that the uplift response can be improved by grouping the symmetrical anchor plates, increasing the unit weight, embedment ratio and the size of symmetrical anchor plates. Innovation of geosynthetics in the field of geotechnical engineering as reinforcement materials found to be possible solution in symmetrical anchor plate responses. Unfortunately the importance of reinforcement in submergence has received very little attention by researchers. In this paper, provision of tensile reinforcement under embedded conditions has been studied through uplift experiments on symmetrical anchor plates by few researchers. From the test results it has been showed that the provision of geogrid reinforcement system enhances the uplift response substantially under uplift test although other results are such as increase the ultimate uplift response of symmetrical anchor plate embedded using geosynthetic and Grid Fixed Reinforced (GFR) and symmetrical anchor plate improvement is very dependent on geosynthetic layer length and increases significantly until the amount of beyond that further increase in the layer length does not show a significant contribution in the anchor response.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.2
• /
• pp.45-52
• /
• 2016

The object of this paper was to evaulate modified proposed design equation in model test result in order to estimate uplift-resistance of timber pile of reclaimed land greenhouse foundation. Uplift resistance result of model test was increased to according to increased of contact area. Uplift-resistance result of field test tend to lineary increased to according to increased of embedment depth and contact area. Results of field uplift-resistance was evaluate compare with modified proposed design equation results of model test and Effective stress method. As the Effective stress method tend to underestimate, modified proposed design equation results of model test tend to similar type. As the contact area increase, difference between field uplift-resistance results and modified proposed design equation results of model test was considered uplift-speed.

• Geotechnical Engineering
• /
• v.11 no.2
• /
• pp.19-28
• /
• 1995

Based on the various test data acquired in the field, the large pressure chamber and the small pressure chamber, uplift behaviors and method of determining the ultimate uplift capacity of pile driven in small pressure chamber were studied. After uplift pile experienced 2 or 3 sudden slip due to increase of uplift load, complete pullout failure was occurred. Thus, it appears that the ultimate uplift capacity could be identified as the load at displacement where first slip occurs. The ultimate uplift capacity might be determined in every test and the disturbance after first uplift test could be recovered by adding one blow of the drop hammer, which had to depend on the model pile capacity.