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Underground cavities can develop below structures, leading to ground settlement and hindering the development of urban infrastructure. Soil flow protectors (SFPs) have been developed to prevent and alleviate problems due to the formation of such cavities. In this study, we performed scaled model experiments to develop a design method for an SFP with an adequate safety factor under different installation lengths of its upper and lower parts in sandy ground. The installation of the SFP reduced the average surface settlement ratio to the range of 0.44–0.72, thus demonstrating its effectiveness in reducing ground settlement. In addition, we proposed a relational equation for determining the optimal length ratio of the SFP and the settlement ratio. An analysis of the influencing factors showed that the lower part of the SFP influenced the settlement reduction, whereas the upper part influenced the stability of the SFP depending on the ground settlement ratio. Finally, we have proposed an optimal length equation for the SFP and presented a flowchart for the design method. The results of this study can serve as a design basis for the efficient construction of infrastructure.
Suwon Son; Moonbong Choi; Jaewon Yoo. Stability Analysis of Soil Flow Protector and Design Method for Estimating Optimal Length. Applied Sciences 2021, 11, 7314 .
AMA StyleSuwon Son, Moonbong Choi, Jaewon Yoo. Stability Analysis of Soil Flow Protector and Design Method for Estimating Optimal Length. Applied Sciences. 2021; 11 (16):7314.
Chicago/Turabian StyleSuwon Son; Moonbong Choi; Jaewon Yoo. 2021. "Stability Analysis of Soil Flow Protector and Design Method for Estimating Optimal Length." Applied Sciences 11, no. 16: 7314.
Porous asphalt pavement is a part of the permeable pavement system, which can be used to mitigate the negative impacts of urbanisation on the water hydrological cycle and environment. This study aims to assess the mechanical and hydrologic characteristics of porous asphalt pavements, with and without geocell composites, using a plate load test, falling weight deflectometer test, and rainfall simulation test. The corresponding results indicate that the elastic modulus of the unreinforced pavement is lower than that of the reinforced pavement. The analysis demonstrates that the use of geocell composites effectively increases the load-bearing capacity of the pavement. When the base layer is reinforced with geocells, its load-bearing capacity increases. Observation of the rainfall simulation tests on the reinforced pavement indicates that the reinforced pavement effectively handles the surface runoff.
Jaehun Ahn; Tan Nguyen; In Yoo; Jeongho Oh. Investigation of Mechanical and Hydrologic Characteristics of Porous Asphalt Pavement with a Geocell Composite. Materials 2021, 14, 3165 .
AMA StyleJaehun Ahn, Tan Nguyen, In Yoo, Jeongho Oh. Investigation of Mechanical and Hydrologic Characteristics of Porous Asphalt Pavement with a Geocell Composite. Materials. 2021; 14 (12):3165.
Chicago/Turabian StyleJaehun Ahn; Tan Nguyen; In Yoo; Jeongho Oh. 2021. "Investigation of Mechanical and Hydrologic Characteristics of Porous Asphalt Pavement with a Geocell Composite." Materials 14, no. 12: 3165.
Owing to the increasing use of permeable pavement, there is a growing need for studies that can improve its design and durability. One of the most important factors that can reduce the functionality of permeable pavement is the clogging issue. Field experiments for investigating the clogging potential are relatively expensive owing to the high-cost testing equipment and materials. Moreover, a lot of time is required for conducting real physical experiments to obtain physical properties for permeable pavement. In this paper, to overcome these limitations, we propose a three-dimensional microstructure reconstruction framework based on 3D-IDWGAN with an enhanced gradient penalty, which is an image-based computational system for clogging analysis in permeable pavement. Our proposed system first takes a two-dimensional image as an input and extracts latent features from the 2D image. Then, it generates a 3D microstructure image through the generative adversarial network part of our model with the enhanced gradient penalty. For checking the effectiveness of our system, we utilize the reconstructed 3D image combined with the numerical method for pavement microstructure analysis. Our results show improvements in the three-dimensional image generation of the microstructure, compared with other generative adversarial network methods, and the values of physical properties extracted from our model are similar to those obtained via real pavement samples.
Ludia Feri; Jaehun Ahn; Shahrullohon Lutfillohonov; JoonHo Kwon. A Three-Dimensional Microstructure Reconstruction Framework for Permeable Pavement Analysis Based on 3D-IWGAN with Enhanced Gradient Penalty. Sensors 2021, 21, 3603 .
AMA StyleLudia Feri, Jaehun Ahn, Shahrullohon Lutfillohonov, JoonHo Kwon. A Three-Dimensional Microstructure Reconstruction Framework for Permeable Pavement Analysis Based on 3D-IWGAN with Enhanced Gradient Penalty. Sensors. 2021; 21 (11):3603.
Chicago/Turabian StyleLudia Feri; Jaehun Ahn; Shahrullohon Lutfillohonov; JoonHo Kwon. 2021. "A Three-Dimensional Microstructure Reconstruction Framework for Permeable Pavement Analysis Based on 3D-IWGAN with Enhanced Gradient Penalty." Sensors 21, no. 11: 3603.
The hydrologic characteristic of a permeable friction course (PFC) pavement is dependent on the rainfall intensity, pavement geometric design, and porous asphalt properties. Herein, the hydrologic characteristic of PFC pavements of various lengths and slopes was determined via numerical analysis. A series of analyses was conducted using length values of 10, 15, 20, and 30 m and slope values of 0.5%, 2%, 4%, 6%, and 8% for the equivalent water flow path. The PFC pavements were simulated for various values of rainfall intensity, which ranged from 10 to 120 mm/h, to determine the time taken for water to flow over the PFC pavement surface. The results show that the time for water overflow decreased when the pavement length or rainfall intensity increased, and it increased when the slope increased. Finally, a series of design charts was developed to determine the time taken for water to flow over the PFC pavement surface for given rainfall intensities. Since this study was conducted based on numerical analysis, further studies are recommended to verify experimentally the results presented.
Tan Nguyen; Jaehun Ahn. Numerical Study on the Hydrologic Characteristic of Permeable Friction Course Pavement. Water 2021, 13, 843 .
AMA StyleTan Nguyen, Jaehun Ahn. Numerical Study on the Hydrologic Characteristic of Permeable Friction Course Pavement. Water. 2021; 13 (6):843.
Chicago/Turabian StyleTan Nguyen; Jaehun Ahn. 2021. "Numerical Study on the Hydrologic Characteristic of Permeable Friction Course Pavement." Water 13, no. 6: 843.
The impermeable cover in urban area has been growing due to rapid urbanization, which prevents stormwater from being naturally infiltrated into the ground. There is a higher chance of flooding in urban area covered with conventional concretes and asphalts. The permeable pavement is one of Low-Impact Development (LID) technologies that can reduce surface runoff and water pollution by allowing stormwater into pavement systems. Unlike traditional pavements, permeable pavement bases employ open-graded aggregates (OGAs) with highly uniform particle sizes. There is very little information on the engineering properties of compacted OGAs. In this study, the moduli of open-graded aggregates under various compaction energies are investigated based on the Plate Load Test (PLT) and Light-Weight Deflectometer (LWD). Artificial Neural Network (ANN) and Linear Regression (LR) models are employed for estimation of the moduli of the aggregates based on the material type and level of compaction. Overall, the moduli from PLT and LWD steeply increase until the number of roller passes reaches 4, and they gradually increase until the number of roller passes becomes 8. A set of simple linear equations are proposed to evaluate the moduli of open-graded aggregates from PLT and LWD based on the material type and the number of roller passes.
Yunje Lee; Yongjin Choi; Donghyun Ahn; Jaehun Ahn. Prediction Models Based on Regression and Artificial Neural Network for Moduli of Layers Constituted by Open-Graded Aggregates. Materials 2021, 14, 1199 .
AMA StyleYunje Lee, Yongjin Choi, Donghyun Ahn, Jaehun Ahn. Prediction Models Based on Regression and Artificial Neural Network for Moduli of Layers Constituted by Open-Graded Aggregates. Materials. 2021; 14 (5):1199.
Chicago/Turabian StyleYunje Lee; Yongjin Choi; Donghyun Ahn; Jaehun Ahn. 2021. "Prediction Models Based on Regression and Artificial Neural Network for Moduli of Layers Constituted by Open-Graded Aggregates." Materials 14, no. 5: 1199.
The importance of establishing a disaster prevention plan considering seismic performance is being highlighted to reduce damage to structures caused by earthquakes. Earthquake waves propagate from the bedrock to the ground surface through the soil. During the transmission process, they are amplified in a specific frequency range, and the degree of amplification depends mainly on the characteristics of the ground. Therefore, a seismic response analysis process is essential for enhancing the reliability of the seismic design. We propose a model for predicting seismic waves on the surface from seismic waves measured on the bedrock based on Multilayer Perceptron (MLP) and Convolutional Neural Networks (CNN) and validate the applicability of the proposed model with Spectral Acceleration (SA). Both the proposed models based on MLP and CNN successfully predicted the seismic response of the surface. The CNN-based model performed better than the MLP-based model, with a 10% smaller average error. We plan to implement the physical properties of the ground, such as shear wave velocity, to create a more versatile model in the future.
SeokGyeong Hong; Jaehun Ahn. Seismic Ground Response Analysis Based on Multilayer Perceptron and Convolution Neural Networks. Journal of the Korean Society of Hazard Mitigation 2021, 21, 231 -238.
AMA StyleSeokGyeong Hong, Jaehun Ahn. Seismic Ground Response Analysis Based on Multilayer Perceptron and Convolution Neural Networks. Journal of the Korean Society of Hazard Mitigation. 2021; 21 (1):231-238.
Chicago/Turabian StyleSeokGyeong Hong; Jaehun Ahn. 2021. "Seismic Ground Response Analysis Based on Multilayer Perceptron and Convolution Neural Networks." Journal of the Korean Society of Hazard Mitigation 21, no. 1: 231-238.
Earthquake disasters can cause enormous social and economic damage, and therefore the sustainability of infrastructure requires the mitigation of earthquake consequences. In seismic design of infrastructures, it is essential to estimate the response of the site during earthquake. Geotechnical engineers have developed quantitative methods for analyzing the seismic ground response. This study proposes a multilayer perceptron (MLP) model to evaluate the seismic response of the surface based on the seismic motion at the bedrock (or 100 m level), and compares its performance with that of a conventional model. A total of 6 sites, with 100 earthquake events at each site, were selected from the Kiban Kyoshin Network (KiK-net) and used as datasets. The acceleration response spectra were calculated from the predicted and measured (baseline) acceleration histories and compared. The proposed MLP model predicted the magnitudes of response and the natural periods where the response amplifies closely with the measured ground motions (baseline). The MLP model outperformed the conventional model for seismic ground response analysis. However, the proposed model did not perform as well for earthquakes whose response spectra exceed 2 g due to a deficiency in large earthquake measurements in the training datasets.
Jaewon Yoo; SeokGyeong Hong; Jaehun Ahn. Seismic Ground Response Prediction Based on Multilayer Perceptron. Applied Sciences 2021, 11, 2088 .
AMA StyleJaewon Yoo, SeokGyeong Hong, Jaehun Ahn. Seismic Ground Response Prediction Based on Multilayer Perceptron. Applied Sciences. 2021; 11 (5):2088.
Chicago/Turabian StyleJaewon Yoo; SeokGyeong Hong; Jaehun Ahn. 2021. "Seismic Ground Response Prediction Based on Multilayer Perceptron." Applied Sciences 11, no. 5: 2088.
Several studies in environmental engineering emphasize the importance of air quality forecasting for sustainable development around the world. In this paper, we studied a new approach for air quality forecasting in Busan metropolitan city. We proposed a convolutional Bi-Directional Long-Short Term Memory Network (Bi-LSTM) autoencoder model trained using a distributed architecture to predict the concentration of the air quality particles (PM2.5 and PM10). The proposed deep learning model can automatically learn the intrinsic correlation among the pollutants in different location. Also, the meteorological and the pollution gas information at each location are fully utilized, which is beneficial for the performance of the model. We used multiple one-dimension convolutional neural network (CNN) layers to extract the local spatial features and a stacked Bi-LSTM layer to learn the spatiotemporal correlation of air quality particles. In addition, we used a stacked deep autoencoder to encode the essential transformation patterns of the pollution gas and the meteorological data, since they are very important for providing useful information that can significantly improve the prediction of the air quality particles. Finally, in order to reduce the training time and the resource consumption, we used a distributed deep leaning approach called data parallelism, which has never been used to tackle the problem of air quality forecasting. We evaluated our approach with extensive experiments based on the data collected in Busan metropolitan city. The results reveal the superiority of our framework over ten baseline models and display how the distributed deep learning model can significantly improve the training time and even the prediction accuracy.
Axel Mengara Mengara; Younghak Kim; Younghwan Yoo; Jaehun Ahn. Distributed Deep Features Extraction Model for Air Quality Forecasting. Sustainability 2020, 12, 8014 .
AMA StyleAxel Mengara Mengara, Younghak Kim, Younghwan Yoo, Jaehun Ahn. Distributed Deep Features Extraction Model for Air Quality Forecasting. Sustainability. 2020; 12 (19):8014.
Chicago/Turabian StyleAxel Mengara Mengara; Younghak Kim; Younghwan Yoo; Jaehun Ahn. 2020. "Distributed Deep Features Extraction Model for Air Quality Forecasting." Sustainability 12, no. 19: 8014.
The p-y curve method and p-multiplier (Pm), which implies a group effect, are widely used to analyze the nonlinear behaviors of laterally loaded pile groups. Factors affecting Pm includes soil properties as well as group pile geometry and configuration. However, research on the change in Pm corresponding to soil properties has not been conducted well. In this study, in order to evaluate the effect of soil properties on the group effect in a laterally-loaded pile group installed in sandy soil, numerical analysis for a single pile and 3×3 pile group installed in loose, medium, and dense sand, was performed using the 3D numerical analysis program, Plaxis 3D. Among the factors considered in this study, the column location of the pile was the most dominant factor for Pm. The effect of the sand property change on Pm was not as significant as that of the column location of the pile. However, as the sand became denser and the friction angle increased, the group effect increased, leading to a decrease in Pm of approximately 0.1. This trend was similar to the result reported in a previous laboratory-scale experimental study.
Yongjin Choi; Jaehun Ahn. Evaluation of p-y Curves and p-multiplier of Pile Groups Corresponding to Sand Properties Change Based on 3D Numerical Analysis. Journal of the Korean Society of Hazard Mitigation 2020, 20, 207 -217.
AMA StyleYongjin Choi, Jaehun Ahn. Evaluation of p-y Curves and p-multiplier of Pile Groups Corresponding to Sand Properties Change Based on 3D Numerical Analysis. Journal of the Korean Society of Hazard Mitigation. 2020; 20 (4):207-217.
Chicago/Turabian StyleYongjin Choi; Jaehun Ahn. 2020. "Evaluation of p-y Curves and p-multiplier of Pile Groups Corresponding to Sand Properties Change Based on 3D Numerical Analysis." Journal of the Korean Society of Hazard Mitigation 20, no. 4: 207-217.
Although the permeability of open-graded friction course (OGFC) materials in the transverse direction and the reduction in permeability associated with long-term traffic loading are important issues, they have remained under researched thus far. In this study, testing equipment and procedure were developed to evaluate the permeability of an OGFC specimen along the horizontal direction and its reduction due to rutting. Horizontal permeability tests were conducted by varying the hydraulic gradient of specimens with porosities of 19.6%, 15.6%, and 10.3%. The reduction in cross-section due to traffic loading was simulated via a wheel tracking test, and the permeability was subsequently evaluated. The reliability of test methodology was successfully verified; the tendency of the relationship between discharge velocity and hydraulic gradient was in good agreement with existing research results. The reduction in cross-sectional flow area due to rutting decreased and the horizontal permeability. The test results using developed testing equipment will enable efficient OGFC design.
Jaewon Yoo; Tan Nguyen; Eungu Lee; Yunje Lee; Jaehun Ahn. Measurement of Permeability in Horizontal Direction of Open-Graded Friction Course with Rutting. Sustainability 2020, 12, 6428 .
AMA StyleJaewon Yoo, Tan Nguyen, Eungu Lee, Yunje Lee, Jaehun Ahn. Measurement of Permeability in Horizontal Direction of Open-Graded Friction Course with Rutting. Sustainability. 2020; 12 (16):6428.
Chicago/Turabian StyleJaewon Yoo; Tan Nguyen; Eungu Lee; Yunje Lee; Jaehun Ahn. 2020. "Measurement of Permeability in Horizontal Direction of Open-Graded Friction Course with Rutting." Sustainability 12, no. 16: 6428.
Settlement of a relatively small magnitude occurs in box structures supported by pile foundations. However, if cavities are generated under the box structure, ground settlement can be accelerated by surrounding soil entering the cavities. In order for the structure to maintain stability for a long period of time, sustainable development to maintain the stability of the building must be continued. Preventing rapid ground settlement can lead to long-term structural stability and prevent the occurrence of life-threatening damage, thereby helping to maintain and build a sustainable urban infrastructure. Thus, in this study, a soil flow protector (SFP) that can be easily installed on the sides of the structure was developed to mitigate the aforementioned problem. Field tests and numerical analysis were performed to investigate the effect of SFP installation on structural stability and settlement reduction. After performing field experiments, it was found that SFP installation could reduce ground settlement and ground horizontal displacement. Moreover, for a 79.9-mm settlement, the safety factor was 1.315, which remained stable even when the settlement reached 345 mm. Hence, the developed SFP can be used to reduce soft ground settlement affecting box structures supported by pile foundations.
Jaewon Yoo; Suwon Son; Sangtae Kim. Development and Performance Analysis of Soil Flow Protector to Reduce Soft Soil Settlement Caused by Cavity Formation. Sustainability 2020, 12, 3641 .
AMA StyleJaewon Yoo, Suwon Son, Sangtae Kim. Development and Performance Analysis of Soil Flow Protector to Reduce Soft Soil Settlement Caused by Cavity Formation. Sustainability. 2020; 12 (9):3641.
Chicago/Turabian StyleJaewon Yoo; Suwon Son; Sangtae Kim. 2020. "Development and Performance Analysis of Soil Flow Protector to Reduce Soft Soil Settlement Caused by Cavity Formation." Sustainability 12, no. 9: 3641.
Increase in impermeable area and frequency of intense rainfall cause flooding damages in urban areas. Permeable Interlocking Concrete Paver (PICP) system, which is a composite system comprised of soils and blocks, is considered as one of the solutions to improve the urban water environment, and its applications are increasing rapidly worldwide. It is important to evaluate the initial permeability and its reduction due to clogging. In this study, the permeability and effect of clogging were evaluated based on experimental methods developed. The equivalent permeability and its degradation of PICP systems were successfully evaluated using the prodecure developed, and the equation for equivalent permeability presented quite a good agreement with the experimental results.
ACKNOWLEDGEMENT : The authors would like to thank the Ministry of Land, Infrastructure, and Transport of Korean government for the grant from Technology Advancement Research Program (grant no. 20CTAP-C152124-02) and Basic Science Research Program (grant no. 2017R1D1A3B03034563) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education.
Jaehun Ahn; Yunje Lee. Experimental Evaluation of Equivalent Permeability for Permeable Interlocking Concrete Paver (Soil-Block) Composite System. 2020, 1 .
AMA StyleJaehun Ahn, Yunje Lee. Experimental Evaluation of Equivalent Permeability for Permeable Interlocking Concrete Paver (Soil-Block) Composite System. . 2020; ():1.
Chicago/Turabian StyleJaehun Ahn; Yunje Lee. 2020. "Experimental Evaluation of Equivalent Permeability for Permeable Interlocking Concrete Paver (Soil-Block) Composite System." , no. : 1.
It is an important task to model and predict seismic ground response; the results of ground response analysis are, in turn, used to assess liquefaction and integrity of undergound and upper structures. There has been numerious research and development on modelling of seismic ground response, but often there are quite large difference between prediction and measurement. In this study, it is attempted to train the input and output ground excitation data and make prediction based on it. To initiate this work, the deep learning network was trained for low level excitation data; the results showed reasonable match with actual measurements.
ACKNOWLEDGEMENT : The authors would like to thank the Ministry of Land, Infrastructure, and Transport of Korean government for the grant from Technology Advancement Research Program (grant no. 20CTAP-C152100-02) and Basic Science Research Program (grant no. 2017R1D1A3B03034563) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education.
Jaewon Yoo; Jaehun Ahn. Data Driven Prediction of Seismic Ground Response under Low Level Excitation. 2020, 1 .
AMA StyleJaewon Yoo, Jaehun Ahn. Data Driven Prediction of Seismic Ground Response under Low Level Excitation. . 2020; ():1.
Chicago/Turabian StyleJaewon Yoo; Jaehun Ahn. 2020. "Data Driven Prediction of Seismic Ground Response under Low Level Excitation." , no. : 1.
Open-graded aggregates (OGAs) are free-draining materials often used as the base layer of permeable pavements to allow the infiltration or drainage of stormwater. Despite their widespread use, the compaction quality of OGA base layers has not been specified properly. The currently used density-based compaction quality control (QC) has limitations; obtaining the field density and maximum dry density of OGAs by typical methods is challenging, due to their unique properties. To overcome these limitations, modulus-based compaction QC can be used as an alternative. In this study, five different OGAs were chosen and compacted into a specially built soil chamber to measure their densities. The light weight deflectometer (LWD) and the soil stiffness gauge (SSG) were used to evaluate the modulus of the compacted OGAs. The vibratory hammer compaction test was conducted to obtain the maximum dry density of the aggregates. Through these tests, the relationship between the modulus of the compacted aggregates and the relative density was obtained, and efforts to find a modulus range that ensures proper compaction were made. It was found that the LWD and SSG are valid and reliable devices for monitoring the modulus change of OGAs due to compaction.
Yongjin Choi; Donghyun Ahn; Yunje Lee; Jaehun Ahn. Compaction Quality Monitoring of Open-Graded Aggregates by Light Weight Deflectometer and Soil Stiffness Gauge. Sustainability 2020, 12, 2521 .
AMA StyleYongjin Choi, Donghyun Ahn, Yunje Lee, Jaehun Ahn. Compaction Quality Monitoring of Open-Graded Aggregates by Light Weight Deflectometer and Soil Stiffness Gauge. Sustainability. 2020; 12 (6):2521.
Chicago/Turabian StyleYongjin Choi; Donghyun Ahn; Yunje Lee; Jaehun Ahn. 2020. "Compaction Quality Monitoring of Open-Graded Aggregates by Light Weight Deflectometer and Soil Stiffness Gauge." Sustainability 12, no. 6: 2521.
Yongjin Choi; Tan Hung Nguyen; Jaehun Ahn. Resilient Modulus and Permanent Deformation of 40-mm Open-Graded Aggregates based on Repeated-Load Triaxial Tests. Journal of the Korean Society of Hazard Mitigation 2019, 19, 367 -374.
AMA StyleYongjin Choi, Tan Hung Nguyen, Jaehun Ahn. Resilient Modulus and Permanent Deformation of 40-mm Open-Graded Aggregates based on Repeated-Load Triaxial Tests. Journal of the Korean Society of Hazard Mitigation. 2019; 19 (7):367-374.
Chicago/Turabian StyleYongjin Choi; Tan Hung Nguyen; Jaehun Ahn. 2019. "Resilient Modulus and Permanent Deformation of 40-mm Open-Graded Aggregates based on Repeated-Load Triaxial Tests." Journal of the Korean Society of Hazard Mitigation 19, no. 7: 367-374.
Jaewon Yoo; Tan Hung Nguyen; Jaehun Ahn. Change in Dynamic Modulus of Porous Asphalt According to Thawing-Cycle Moisture Conditioning. Journal of Korean Society of Hazard Mitigation 2019, 19, 375 -381.
AMA StyleJaewon Yoo, Tan Hung Nguyen, Jaehun Ahn. Change in Dynamic Modulus of Porous Asphalt According to Thawing-Cycle Moisture Conditioning. Journal of Korean Society of Hazard Mitigation. 2019; 19 (7):375-381.
Chicago/Turabian StyleJaewon Yoo; Tan Hung Nguyen; Jaehun Ahn. 2019. "Change in Dynamic Modulus of Porous Asphalt According to Thawing-Cycle Moisture Conditioning." Journal of Korean Society of Hazard Mitigation 19, no. 7: 375-381.
In permeable pavement systems, open-graded aggregates are commonly used for base and subbase layers that allow water to store and drain. At each traffic load cycle, the permanent strain accumulates and is considered to be one of major distresses in permeable pavement systems. This study investigates the permanent strain of open-graded aggregate material using the multi-stage repeated-load triaxial test. For this purpose, the open-graded aggregate materials with three different gradations, from a single quarry, were used. Their nominal maximum aggregate sizes were 13, 25, and 40 mm. In the multi-stage repeated-load triaxial test, the specimen is subjected to five loading sequences and each sequence is comprised of six stress combinations. At each stress combination, the specimen is subjected to 10,000 load repetitions. Based on the test results, the material parameters of the predictive model were determined and then used to predict the permanent strains of three open-graded aggregates in other loading sequences. The test results and the predictions showed that specimen whose gradation bounded by two others happened to have the highest resistance to permanent strain. Regardless of the difference in aggregate sizes, the material parameters of the open-graded aggregates did not vary significantly. In addition, open-graded aggregate materials were more dependent on bulk stress than deviator stress.
Tan Hung Nguyen; Jaehun Ahn. Experimental evaluation of the permanent strains of open-graded aggregate materials. Road Materials and Pavement Design 2019, 22, 1667 -1678.
AMA StyleTan Hung Nguyen, Jaehun Ahn. Experimental evaluation of the permanent strains of open-graded aggregate materials. Road Materials and Pavement Design. 2019; 22 (7):1667-1678.
Chicago/Turabian StyleTan Hung Nguyen; Jaehun Ahn. 2019. "Experimental evaluation of the permanent strains of open-graded aggregate materials." Road Materials and Pavement Design 22, no. 7: 1667-1678.
Yunje Lee; Aryssa Kathreen Marcaida; Jaehun Ahn; Taehyeong Lee; Myunghwan Cha. Porosity, Permeability, and Compressive Strength after Freezing and Thawing of Permeable Polymer Concrete. Journal of Korean Society of Hazard Mitigation 2019, 19, 203 -208.
AMA StyleYunje Lee, Aryssa Kathreen Marcaida, Jaehun Ahn, Taehyeong Lee, Myunghwan Cha. Porosity, Permeability, and Compressive Strength after Freezing and Thawing of Permeable Polymer Concrete. Journal of Korean Society of Hazard Mitigation. 2019; 19 (3):203-208.
Chicago/Turabian StyleYunje Lee; Aryssa Kathreen Marcaida; Jaehun Ahn; Taehyeong Lee; Myunghwan Cha. 2019. "Porosity, Permeability, and Compressive Strength after Freezing and Thawing of Permeable Polymer Concrete." Journal of Korean Society of Hazard Mitigation 19, no. 3: 203-208.
Retaining walls are generally used for temporary installations during the excavation process of a construction project. They are also utilized to construct embankments in order to extend a railway facility. In this case, a retaining wall is installed during the construction process and contributes to the resistance of large amounts of stress, including the railway load. However, it is generally difficult to retain walls to maintain their stability. Therefore, alternative construction methods, such as the use of an inclined earth-retaining wall, have been utilized to suppress the lateral displacement. The stability is verified in advance through field tests; however, the maximum stress acting on the railway is thought to be the concentrated railway load. In this study, a two-dimensional numerical analysis was conducted by changing the railway load to a dynamic load. The analysis was applied according to the number of H-piles of the same length (10 m) when only the front wall was installed and when a back support was also applied. It was determined that the lateral displacement of the latter case is smaller than that of the former, whereas the resistance to dynamic loading of the former case is greater.
Su-Won Son; Minsu Seo; Jong-Chul Im; Jae-Won Yoo. Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction. Applied Sciences 2019, 9, 2213 .
AMA StyleSu-Won Son, Minsu Seo, Jong-Chul Im, Jae-Won Yoo. Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction. Applied Sciences. 2019; 9 (11):2213.
Chicago/Turabian StyleSu-Won Son; Minsu Seo; Jong-Chul Im; Jae-Won Yoo. 2019. "Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction." Applied Sciences 9, no. 11: 2213.
Eunku Lee; Jaehun Ahn; Hyunsuk Shin. Design Factors and Procedure for Hydrological Design of Permeable Road Systems. Journal of Korean Society of Hazard Mitigation 2019, 19, 221 -232.
AMA StyleEunku Lee, Jaehun Ahn, Hyunsuk Shin. Design Factors and Procedure for Hydrological Design of Permeable Road Systems. Journal of Korean Society of Hazard Mitigation. 2019; 19 (2):221-232.
Chicago/Turabian StyleEunku Lee; Jaehun Ahn; Hyunsuk Shin. 2019. "Design Factors and Procedure for Hydrological Design of Permeable Road Systems." Journal of Korean Society of Hazard Mitigation 19, no. 2: 221-232.