• Journal of the Korean Institute of Rural Architecture
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• v.2 no.2
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• pp.115-126
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• 2000

Retaining walls are used to prevent excessive movement of retained soils. Typical retaining walls include gravity, reinforced concrete, reinforced earth and tie-back. However, from a practical viewpoint there are still drawbacks among these often constructed retaining walls. New types of retaining walls constructed with precast concrete blocks are proposed. This type of retaining wall is incorporates each blocks interconnected with adjacent block by connecting unit to build up a flexible retaining-wall system. This paper focus to behavior characteristics includes deformation and distribution of lateral earth pressure by loading tests and FEM analysis. For model tests, a 1/10 scale reduce models are manufactured include unevenness part, drainage hole and connecting unit and steel wire used to connect each blocks with adjacent block. To simulate the real retaining walls closely, uneven parts are interconnected each other and the construction type of blocks and wall front inclination are varied to investigate the relative displacement of individual block and the location of maximum deformation of wall as increasing surcharging. Additionally, PENTAGON3D, which solve the geotechnical and other problem, used for verifying and comparing with model tests.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.449-456
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• 1999

The concrete wall is the most useful of retaining structure which can obtain the engineering stability, but has problems that is not friendly with nature environment in a fine view, such as poor rear drainage, and shrinkage crack by temperature difference, etc. Because of this problems, the research for a segmental crib retaining wall has been performed. A segmental crib retaining wall is quickly and easily erected because is possible to be erected as the individual members, and is not sensitive to differential settlement and earthquakes. Also, it shows effective drainage and has a friendly advantage with nature environment because of being able to be planted with vines and shrubs in retaining walls The design of crib retaining walls has traditionally been based on classical soil mechanics theories. These theories, originally derived by Rankine(1857) and Coulomb(1776), assume that the wall acts as a rigid body. This assumption results in failure being predicted by either monolithic overturning or base sliding mechanisms. However, the wall consists of individual members which have been created a three dimensional grid. This grid confines an fill mass which becomes part of the wall. The filled wall resists the earth pressure with the same mechanism of classical gravity walls. Because of the flexibility of the individual segment, it allows relative movement between the individual members within the wall. The three dimensional flexible grid leads to stress redistribution when the wall is subjected to external or fill loads. Due to the flexibility and the stress redistribution, the failure of segmental crib wall consists of not only overturing and base sliding but the local deformation and the failure between the segmental members. It has been researched in the field that due to this flexibility and load redistribution, serviceability failure of segmental crib walls is unlikely to be due to overturning or base sliding. Therefore, in this study, the relative displacement appearance of retaining wall due to variation of inclination is measured to examine this behavior characteristics. Also, the behavior characteristics of retaining walls by surcharge load, and location of acting point of retaining wall rear, and the displacement characteristics and deflections are estimated about the existence and nonexistence of Rear Stretcher performing an role in transmitting earth pressure of Header and Stretcher organizing retaining walls. This research focuses on the characteristics due to the behavior of retaining walls. This research focuses on the characteristics due to the behavior of retaining walls.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.45-53
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• 2011

Recently reinforced retaining walls secure their position as a stabilized method of construction replacing concrete retaining walls gradually. However, in the event of using extensible reinforcement, a bulging phenomenon can be happened in the front of reinforced retaining walls. Bulging of reinforced retaining walls means a phenomenon that, in the height of an arbitrary block, the upper part and the lower part of the block don't secure a relative position in design. Therefore, it is judged that it has the necessity to be examined in design since reinforcement needs metamorphosis to some degree to display tensile force. Therefore, the study examined about how extensibility of reinforcement had an effect on movement of reinforced retaining walls through a small-scale model test with aluminum rods. The study used Changhoji(traditional korean paper made from mulberry bark) as inextensible reinforcement and membrane as extensible reinforcement. As the result of the test, rigidity of reinforcement had a lot of effects on displacement of reinforced retaining walls and generally occurrence point of the maximum horizontal displacement had a tendency transferring to the upper part of walls according to rigidity of reinforcement was increased.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.195-205
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• 2021

Time effect on the deformation and strength characteristics of geogrid reinforced sand retaining wall has become an important issue in geotechnical and transportation engineering. Three physical model tests on geogrid reinforced sand retaining walls performed under various loading conditions were simulated to study their rate-dependent behaviors, using the presented nonlinear finite element method (FEM) analysis procedure. This FEM was based on the dynamic relaxation method and return mapping scheme, in which the combined effects of the rate-dependent behaviors of both the backfill soil and the geosynthetic reinforcement have been included. The rate-dependent behaviors of sands and geogrids should be attributed to the viscous property of materials, which can be described by the unified three-component elasto-viscoplastic constitutive model. By comparing the FEM simulations and the test results, it can be found that the present FEM was able to be successfully extended to the boundary value problems of geosynthetic reinforced soil retaining walls. The deformation and strength characteristics of the geogrid reinforced sand retaining walls can be well reproduced. Loading rate effect, the trends of jump in footing pressure upon the step-changes in the loading rate, occurred not only on sands and geogrids but also on geogrid reinforced sands retaining walls. The lateral earth pressure distributions against the back of retaining wall, the local tensile force in the geogrid arranged in the retaining wall and the local stresses beneath the footing under various loading conditions can also be predicted well in the FEM simulations.

• Structural Engineering and Mechanics
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• v.57 no.4
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• pp.763-783
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• 2016

A methodology based on Teaching Learning-Based Optimization (TLBO) algorithm is proposed for optimum design of reinforced concrete retaining walls. The objective function is to minimize total material cost including concrete and steel per unit length of the retaining walls. The requirements of the American Concrete Institute (ACI 318-05-Building code requirements for structural concrete) are considered for reinforced concrete (RC) design. During the optimization process, totally twenty-nine design constraints composed from stability, flexural moment capacity, shear strength capacity and RC design requirements such as minimum and maximum reinforcement ratio, development length of reinforcement are checked. Comparing to other nature-inspired algorithm, TLBO is a simple algorithm without parameters entered by users and self-adjusting ranges without intervention of users. In numerical examples, a retaining wall taken from the documented researches is optimized and the several effects (backfill slope angle, internal friction angle of retaining soil and surcharge load) on the optimum results are also investigated in the study. As a conclusion, TLBO based methods are feasible.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1224-1239
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• 2008

The earth retaining walls using stabilizing piles can be applied to shallow excavation works without any stiffener. But, It demends a variety of installed composite stiffener on the earth retaining walls when it is installed as deep excavation works. Because, it causes an excessive displacement of walls. This research tried to overcome the problems created by the above issues and intended to apply the composite stiffener. The model test, focused on the effect of installed composite stiffener, measured the bending stress with stabilizing piles and walls, the settlement of earth surface, the displacement of walls for a step excavation and an increase in strip load. With the test results and soil deformation analysis, the reinforcement effect(relating to control displacement and earth presure) was analyzed in a qualitative and quantitative manner. It is expected to overcome a deep excavation works.

• Geomechanics and Engineering
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• v.34 no.3
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• pp.329-339
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• 2023

The objective of this study is to develop a Stability Evaluation System for retaining walls to assess their safety in real-time during excavation. A ground investigation is typically conducted before construction to gather information about the soil properties and predict wall stability. However, these properties may not accurately reflect the actual ground being excavated. To address this issue, the study employed a differential evolution algorithm to estimate the soil parameters of the actual ground. The estimated results were then used as input for an artificial neural network to evaluate the stability of the retaining walls. The study achieved an average accuracy of over 90% in predicting differential settlement, wall displacement, anchor force, and structural stability of the retaining walls. If implemented at actual excavation sites, this approach would enable real-time prediction of wall stability and facilitate effective safety management. Overall, the developed Stability Evaluation System offers a promising solution for ensuring the stability of retaining walls during construction. By incorporating real-time soil parameter analysis, it enhances the accuracy of stability predictions and contributes to proactive safety management in excavation projects.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.329-336
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• 2001

The numbers of geogrid-reinforced walls are widely used in Korea. This papers present the results of two failure case histories of geogrid-reinforced segmental retaining walls. The geological background of the construction sites, detailed construction sequences, and the amount of rainfall were examined. The failure of these reinforced walls are caused by the improper drainage system and foundation treatment, too sharpened curvature of corner work, and too high height of wall.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.81-89
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• 2011

This paper introduces a recently developed thinning-out timber framed earth retaining wall system. Timber framed retaining walls are usually designed by using design code of gravity type retaining wall but internal stability of timber framed earth retaining walls is often neglected. In this study, it is recommended to use the design code for segmental retaining walls by National Concrete Masonry Association (NCMA, 1997) to check internal stability of timber framed earth retaining wall. Based on the several shear test results for 3 types of timber frames, a simple design chart including internal stability is suggested.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.32-47
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• 2005

This study was carried out to investigate and propose a green-wall system with evergreen plants for urban greening of Tongyeong City. To achieve these goals, the requirements and possibilities for wall greening were investigated and evaluated considering the location, topography, and climate of Tongyeong City. Existing walls were analyzed and then a suitable green wall system is proposed. Tongyeong City and its 151 islands covers the central and the southern parts of the Goseong peninsula. Most of the land is covered with hills and mountains; $43.9\%$ of the land area has a slope greater than $15\%$ and most hills and mountains near the urban area have a slope of more than $30\%$. As a result of the topographical properties, concrete retaining walls can often be seen along the streets in urbanized areas. These retaining walls are not only unattractive, but they also create environmental problems, and thus should be replaced with native evergreen plants. Options for replacing the retaining walls include evergreen vine-plants such as Hedaa spp. and Euonymus radicans, but native evergreen shrubs such as Pittosporum tobira, Nandina domestica, Raphiolepis umbellata, Ilex cornuta, flex crenata, Fatsia japonic, and Aucuba japonica may be a more attractive option. Current wall conditions are unsuitable for planting vines, therefore, a reservoir-drainage-type plant box filled with a light artificial substrate is required for greening these concrete retaining walls. These might be irrigated in the dry season and fertilized annually by an appropriate system. These plant boxes could be attached along the entire walls. An experiment investigating effects of substrates and bark-chip mulching on the growth of Hedera spp. showed that the mixture of cerasoil and field soil(v/v, 4:6) was superior to field soil alone and to the mixture of perlite small grain, large grain, and field soil(v/v/v, 2:2:6). Bark-chip mulching tended to increase the growth of Hedera spp..