• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.105-115
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• 2016

This paper describes a restoration of retaining wall, which was collapsed by rainfall. The failure causes was analyzed by field case, and then the countermeasure was suggested. The failure causes confirmed that observance of design and construction criteria was insufficient. It also was the climate condition like a rainfall and inappropriate construction management. The stability analysis for retaining wall, soil improvement and reinforced earth wall was conducted to confirm validity of the countermeasure. The analysis results showed that the suggested construction method satisfied in required safety factors. Therefore, it should be secured the stability of the structure based on the application of appropriate design method and construction management, when structure was constructed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.95-103
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• 2016

The absolute value management method is widely used in the most of the earth retaining construction, which evaluates the safety by comparing measurement result and management criteria. Therefore, the management criteria is the standard to evaluate the safety of the site, and in other words, the criteria is a direct factor of the evaluation. That means that the safety of the site can not be acquired if the management criteria is not proper, even though the measurement system is perfectly set. However, many of field technicians do not have rely on the current management criteria, and they even recognize the necessity of the revision. Therefore, in this study, the necessity of the revision was studied. Also, the optimum criteria selection and the application were performed based on the test results of earth retaining deflection and probabilistic theory. The absolute value management method was used for this study. The details are tabulated.

• Journal of the Korean Geotechnical Society
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• v.28 no.12
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• pp.99-110
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• 2012

Inclined Earth Retaining Structure Method (IER method, briefly) is developed in order to improve the existing earth retaining method. In IER method, there are three main structures, front support, back support, and head binding. Especially, back support acts the role that reduces the earth pressure acting on the front support. In this study, the stability according to the installation angle and stiffness of front or back support is analysed by model tests. By the test results, it is known that inclined back support is very effective to reduce the earth pressure acting on the front support. Especially, the effect of the stiffness and installation angle of back support is analysed.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.3
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• pp.223-234
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• 1998

In this study, an attempt is made to apply the concept of fuzzy-bayesian theory to the integrity assessment of structure system, and uncertainty states are represented in terms of fuzzy sets which define several linguistic variables such as "very good", "good", "average", "poor", "very poor", etc. Especially, the concept of fuzzy conditional probability aids to derive a new reliability analysis which includes the subjective assessment of engineers without introducing any additional correction factors. The fuzzy concept are also used as reliability indexes for the condition assessment based on the proposed models, the proposed fuzzy theory-based approach with the results of PEM and AFOSM are applied to retaining wall.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.129-138
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• 2011

Construction methods for underground structure are classified as bottom-up, up-up, and top-down methods depending on the procedure of construction related to a superstructure. In top-down construction methods, building's main structure is built from the ground level downwards by sequentially alternating ground excavation and structure construction. In the mean time, the main structure is also used as supporting structure for earth-retaining wall, which results in the increased stability of the earth-retaining wall due to the minimized deformation in adjacent structures and surrounding grounds. In addition, the method makes it easy to secure a field for construction work in the downtown area by using each floor slabs as working spaces. However top-down construction method is often avoided since an excavation under the slab has low efficiency and difficult environment for work, and high cost compared with earth anchor method. This paper proposes a combined construction method where semi-open cut is selected as excavation work, slurry as earth -retaining wall and CWS as top-down construction method. In the case study targeted for an actual construction project, the proposed method is compared with existing top-down construction method in terms of economic feasibility, construction period and work efficiency. The proposed construction method results in increased work efficiency in the transportation of earth and sand, and steel frame erection, better quality management in PHD construction, and reduced construction period.

• Journal of the Korean Geotechnical Society
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• v.33 no.10
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• pp.15-24
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• 2017

A self-supported temporary excavation method called Inclined Earth Retaining structure (IER) has been developed by improving an existing excavation method. The stability of the IER was proved with both model tests and field tests. Especially, the results of the model tests proved that the lateral displacement of a model retaining wall was significantly reduced in clay. In this study, the applicability of the IER installed in the soft clay ground is estimated by analyzing survey data collected in the construction field. The results of FE analysis show that the lateral displacement of the IER decreased by 70.9% of that of a single row, self-supported retaining wall using the same number of H-piles. Thus, using the IER method in the soft clay ground will increase the stability of the excavated ground with the effect restraining its lateral displacement. Furthermore, using Deep Cement Mixing (DCM) to the upper half embedded depth of front support is recommended as a subsidiary method of reducing the lateral displacement of IER in the soft clay ground based on FE analysis results.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.75-85
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• 2019

The lateral load from traffic depends on standard truck's axle loads and locations, loading distance from the inner wall. The method of limit state design has been adopted and used for design of roads in the Republic of Korea since 2015. The concept of equivalent height of soil accounting for traffic loading is often used for design of retaining walls to quantify the traffic loads transmitted to the inner wall faces. Due to the different characteristics of the standard design trucks between Korea and US (AASHTO), the direct use of the guidelines from AASHTO LRFD leads to incorrect estimation of traffic load effects on retaining walls. This paper presents the results of evaluation of equivalent height of soil to reflect the standard truck of the nation, based on the findings from analytical solutions using 3D finite element method. Compare to US, the standard truck loading has a structure where the axle load is concentrated so that the equivalent load height is estimated to be slightly larger than AASHTO for lower retaining wall height. It would be reasonable to present the equivalent load height in Korea more conservatively than AASHTO in terms of securing long term stability of the retaining wall structure.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.380-387
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• 2004

Recently the geosynthetics reinforced retaining wall has been widely used instead of the steel reinforced retaining wall. The geosynthetics reinforced retaining wall is a very dangerous structure if the geosynthetics lose their strength about tension or if it lose their pullout resistence, but it was known that the geosynthetics reinforced wall had a great resistence and was a very safe structure against a earthquake or a dynamic load. It can be said that most important factors in the stability of the geosynthetics reinforced wall are the horizontal length of reinforcement and the vertical distance between two reinforcements. That is to say, as the length of reinforcement is longer, the structure is more stable and as the vertical distance between two reinforcements is shorter, it is more stable. In this study, in order to get the critical condition with a safety rate of 1, various kinds of model tests about geosynthetics reinforced wall has been performed. Photos by B-shutter method has been taken during tests and from photos, which show us the failure state, the critical condition about failure has been conformed. Accordingly the equation, which says the limit of stability in geosynthetics reinforced wall., has been proposed.

• Journal of the Korean Geosynthetics Society
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• v.12 no.4
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• pp.11-19
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• 2013

Recently despite the development of analysis program and construction technologies, collapse at the many earth retaining wall construction site of the structure due to the economic and human damage has occurred. The results of geothechnical investigation studies field, it was found to differ from the results of the original design. There may be errors parameters calculated from the results of ground investigation in such a case. And it can be estimated that it is irrational to behavior analysis of the earth retaining wall were analyzed by utilizing the parameters. And in this study, parameters that affect the earth retaining wall the correlations were analyzed using elasto-plastic method. Analysis method was changed various parameters (cohesion, subgrade reaction coefficient, load condition) applied to the elasto-plastic method. And due to a change in the behavior of earth retaining wall materials were analyzed. As a result, the cohesion greatly affects the behavior of earth retaining wall materials in various parameters. For this reason, the results of the geothechnical investigation, confirmation of the actual ground is very important in the design of the earth retaining wall. And, calculating accurate and reasonable of the cohesion of the various parameters is very important.