• Journal of the Korean Geotechnical Society
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• v.38 no.8
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• pp.75-84
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• 2022

Currently, tension ground anchors are divided into temporary and permanent based on their purpose and period of use, and their performance evaluations are presented separately. Therefore, applying the current performance evaluation's upper and lower limits to practice seems reasonable. However, because compression ground anchors have been mainly used as permanent, performance evaluation corresponding to permanent is conducted without distinction between temporary and permanent. This evaluation is a strict standard for ground anchors used as temporary, including the removal type. Because of examining the existing performance evaluation for the compression ground anchor, the lower limit can be applied without distinguishing between the temporary and permanent. However, the upper limit should be presented separately for the temporary and permanent. In applying the upper limit, it is necessary to adjust the upper limit of the anchor considering the anchored ground condition (rock or soil), the period of use, and particularly whether the load-displacement curve maintains the elastic state.

• Journal of the Korean Geotechnical Society
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• v.36 no.8
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• pp.35-47
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• 2020

For permanent anchors used for slope reinforcement, bearing capacity and durability should be secured during the period of use. However, according to recent domestic and foreign studies, phenomena such as tension fractures, damage to anchorages, deformation and damage to slope and reduction of residual load over time have been reported along the long-term behavior of the anchors. These problems are expected to increase in the future, which will inevitably lead to problems such as increasing maintenance costs and relevant facility collapse. It is necessary to improve maintenance procedures and methods of ground anchors more practically. In this study, the problems and limitations of domestic maintenance methods were analyzed by conducting a literature study, and the measurement data of load cells installed on the install ground anchors were analyzed to determine the change in the residual load with regard to the elapsed date of the anchors. Based on the results, the effect of the construction conditions of anchors and the soil compositions on the increase and decrease of load were identified.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.87-96
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• 2010

PAP method is a combined measures which consist a anchored retaining wall method with permanent ground anchors and vertical precast concrete panels, step by step on the slope surface. And soil is back filled between slope and vertical precast panels. Therefore, this method is more effective than any other ground anchor reinforcing methods of slope stability, for example cross type concrete block ground anchor or buttress concrete block ground anchor method. Because of increasing effective anchor force and green tree planting.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.27-36
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• 2004

The corrosion rate measurement procedure for the permanent ground anchors using polarization resistance measurements and electrochemical impedance spectroscopy is presented in this paper. The polarization resistance measurements were used to determine the correlation between corrosion rate in the steel and soil characteristics. The electrochemical impedance spectroscopy was used to predict the time dependent corrosion reaction and evaluate the different type of coating systems and the effect of cement grouting on the corrosion attack under various conditions. The results indicate that a low pH soil is a good indicator of a corrosive soil. The low pH soil condition (<5) in both clay and sand has a significant effect on the corrosion reaction of steel members in permanent found anchors. In the case of neutral and alkaline conditions beyond pH 6 in clay and sand, no consistent acceleration of corrosion was measured and the corrosion rate was constant regardless of variations of soil pH levels. Laboratory test data for porcelain clay indicate that the change of soil pH level has a small influence on the corrosion reaction in the steel member. The use of cement footing in the bonded length is sufficient to decrease the corrosion rate to a level close to 0.003∼0.01mm/y at the end of the given period. With epoxy and fusion bonded epoxy coating, the steel specimens remained unaffected and retained the original condition. It is suggested that epoxy and fusion bonded epoxy coating can provide effective protection against corrosion for a long time even in aggressive environment.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.538-541
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• 2007

In this study, the complex AAM permanent anchor was introduced and the design method for the complex AAM permanent anchor was showed by examining the relationship of the forces applied to the anchor, the ground failure, the loads inducing the tensile failure between the anchors, etc. In order to understand the behavioral characteristics of the complex AAM permanent anchor, the field pullout test was carried out, and the results obtained with the design method were compared with those of the field pullout test.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.195-203
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• 2001

The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.175-181
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• 2004

This study is about a section where underground water level occurs at the underground 5m depth by the excavation of the ground, as a stream is adjacent to a excavation section of High Speed Railway ${\bigcirc}{\bigcirc}$ Station construction sections and a reservoir being always full of water is located at the left side of the construction section. Therefore this test is executed for the design and construction of buoyance anchors able to permanently prevent buoyance by the underground water level at working and for the stable construction and permanent smooth maintenance of structures. In this test, bar type anchors are divided according to their length and standard to execute test-anchor test, and In spot test, 9 test-anchors test, proof test to construction process, suitability test and acceptance test are executed 4 times to 9 test-anchors by dividing anchors according to the length of permanent anchor, the outer diameter of bar and boring diameter. Standard motion characteristic centering on load transmission and break mechanism of bar-type anchors for the prevention of buoyance will be showed in the thesis.

• Journal of the Korean Geotechnical Society
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• v.37 no.8
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• pp.25-35
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• 2021

Recently, the ground anchor method is commonly applied with nail and rock bolt to secure the stability of slopes and structures in Korea. Among them, permanent anchor which is used for long-term stability should secure bearing capacity and durability during the period of use. However, according to recent studies, phenomenon such as deformation to slope and the reduction of residual tensile load over time have been reported along the long-term behavior of the anchors. These problems of reducing residual tensile load are expected to increase in the future, which will inevitably lead to problems such as increasing maintenance costs. In this study, we identified the factors that affect the tensile load of permanent anchor from a literature study on the domestic and foreign, and investigated the prior studies that analyzed previously conducted load cell monitoring data. Afterwards, using this as basic data, the load cell measurement data collected at the actual site were analyzed to identify the tensile load reduction status of anchors, and the long-term load reduction characteristics were analyzed. Finally, by aggregating the preceding results, proposed a technique to predict the long-term load reduction characteristics of permanent anchors through short-term data to around 100 days after installation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.87-98
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• 2006

This paper is an experimental result of performing the prototype of anchor tests in field to investigate the ultimate uplifting capacity of permanent anchor embedded in weathered rock. For prototype of actual anchor test in situ, four grouted anchors having various anchor lengths were installed in field and their ultimate uplift capacities were obtained by analyzing test results of load-displacement curves obtained from field uplift tests. On the other hand, creep tests, applying pull-out loading at the stage of the maximum loading during 15 minutes, were performed to investigate ultimate resisting capacity of anchor so that the values of creep rate at the ultimate loading conditions were evaluated. Dial gauges were installed on the surface of ground to measure the vertical displacement distribution from the anchor so that the failure mechanism of permanent anchor embedded in weathered rock and failure boundary of ground during application of loading were evaluated.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.123-134
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• 2013

Urban underground structures at low ground elevations (i.e. shallow substructures) unlike typical tunnel structures are subjected to low overburden and high water pressures. This often causes the underground structures to become damaged. Various conventional methods for the urban underpass structures such as dead weight increasement, round anchors, and tension piles, are significantly conservative and provok concerns about the costly, time-consuming installation process. Recently, permanent drainage system becomes to widely use for supplementing the conventional method's shortcomings, but, it is applied without the considerations for ground conditions and water table. In this study, therefore, numerical analyses are performed with various parameters such as groundwater level, wall height, and ground conditions in order to establish design guidelines for induced drainage system which is a kind of the permanent drainage method constructed at the Y-area. According to the numerical results, the induced drainage system is very effective in reducing the uplift pressure that acts on the base of underpass structures.