• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.279-290
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• 2010

Technical countermeasures against debris flow should be established upon the risk level of the target location. Risk of debris flow should consider the hazard imposed by debris flow and vulnerability of the facilities to debris flow. In this research, we have defined the target location for risk evaluation and suggested scoring method of hazard of debris flow and vulnerability of road to debris flow. By defining risk rank into 6 categories in terms of possibility of damage during rainfall and using the risk scores of 46 debris flow cases, we have suggested risk ranking matrix. The method can be used in ranking the drainage basin adjacent to road by simply determining the hazard with vulnerability score and can be used for planning the debris flow countermeasures.

• Journal of Korean Society of Forest Science
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• v.105 no.4
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• pp.449-455
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• 2016

This study was conducted to provide the basic policy information for systematic forest road planning and maintenance management by surveying two different administrator groups. The survey results showed that the high priorities of forest road planning were silviculture, disaster prevention, and timber harvesting, and main forest road type was preferred for future use. Also 92.9% of the respondents expressed difficulties due to insufficient manpower and budget. The expected damage types due to forest road construction were threat-to-life by slope failure and dispute on crossing private land. The current main maintenance tasks on forest roads included drainage and road surface maintenance works. Main forest road facilities that should be needed after the construction were installation of additional drainage structures, and slope revegetation and stabilization.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.223-232
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• 2021

In general, stormwater flows to the road surface, especially in urban areas, and it is discharged through the drainage grate inlets on roads. The appropriate evaluation of the road drainage capacity is essential not only in the design of roads and inlets but also in the design of sewer systems. However, the method of road surface flow analysis that reflects the topographical and hydraulic conditions might not be fully developed. Therefore, the enhanced method of road surface flow analysis should be presented by investigating the existing analysis method such as the flow analysis module (uniform; varied) and the flow travel time (critical; fixed). In this study, the algorithm based on varied and uniform flow analysis was developed to analyze the flow pattern of road surface. The numerical analysis applied the uniform and varied flow analysis module and travel time as parameters were conducted to estimate the characteristics of rainfall-runoff in various road conditions using the developed algorithm. The width of the road (two-lane (6 m)) and the slope of the road (longitudinal slope of road 1 - 10%, transverse slope of road 2%, and transverse slope of gutter 2 - 10%) was considered. In addition, the flow of the road surface is collected from the gutter along the road slope and drained through the gutter in the downstream part, and the width of the gutter was selected to be 0.5 m. The simulation results were revealed that the runoff characteristics were affected by the road slope conditions, and it was found that the varied flow analysis module adequately reflected the gutter flow which is changed along the downstream caused by collecting of road surface flow at the gutter. The varied flow analysis module simulated 11.80% longer flow travel time on average (max. 23.66%) and 4.73% larger total road surface discharge on average (max. 9.50%) than the uniform flow analysis module. In order to accurately estimate the amount of runoff from the road, it was appropriate to perform flow analysis by applying the critical duration and the varied flow analysis module. The developed algorithm was expected to be able to be used in the design of road drainage because it was accurately simulated the runoff characteristics on the road surface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1D
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• pp.83-90
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• 2011

A need still exists that the unsaturated condition is to be considered when evaluating the infiltration and drainage capacity for compacted geomaterials in road foundation or embankments. For this reason, numerical analysis were used to analyze the time-dependent unsaturated infiltration and drainage condition depending on various geomaterial types. Therefore, laboratory data from the soil-water characteristic curve tests on geomaterials were adopted from previous studies. In addition, the unsaturated permeability was estimated using SWCC. Then the infiltration and drainage performance of unsaturated compacted soils were evaluated under various conditions based on the proposed method. The results demonstrated that the effect of initial suction and SWCC path on each material could be substantial and the proper application on analysis is very important to enhance the prediction on each capacity.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.75-83
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• 2013

PURPOSES: In this study, flood mitigation effect of drainage asphalt concrete pavement were analyzed by a SWMM 5.0 program in order to evaluate the low impact development (LID) based on the drainage asphalt concrete pavements. METHODS: In order to determine the porosity parameters of drainage asphalt concretes, the specimen mixtures were manufactured using the conditions presented in the previous study. The numerical simulation was conducted using the SWMM 5.0 program considering the flood mitigation effect of drainage asphalt concrete pavements. The effect of flood reduction can be observed when drainage asphalt concrete pavements were applied to Mokgamcheon watershed. The flood mitigation effect analysis of Mokgamcheon watershed as well as continuous simulation of subwatershed runoff were performed through this study. RESULTS : The analysis of drainage asphalt concrete pavements was carried out for evaluating the effect on runoff, resulting in: the peak flow decreases up to 1.26~9.53% after drainage asphalt concrete pavements applied in the SWMM 5.0 program furthermore, the discharge decreases up to 0.55~4.11%. CONCLUSIONS: As a result, the reduced peak flow and discharge were found through the SWMM 5.0 program. It can be concluded that the flood is effectively reduced when the drainage asphalt concrete pavements are used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.177-184
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• 2006

This study is to develop a distributed urban flood runoff model that simulates the road runoff and to test the applicability of the model by applying to Pyeongtaek city of $12.2km^2$. To generate the runoff along the runoff, agree burned DEM (Digital Elevation Model) with road networks was suggested and the proper spatial resolution of DEM was identified finer than 15 m. To test the model applicability, 32 points on the road networks were selected and the hydrographs of each point were generated. The test showed reasonable results that increase the road runoff from the high elevation roads to the low elevation roads and the road runoff considering rainwater drainage from the road also showed reasonable results.

• International Journal of Highway Engineering
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• v.20 no.3
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• pp.47-57
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• 2018

PURPOSES : The permeable pavement type has been rapidly developed for solving problems regarding traffic noise in the area of housing complex and heavy rainwater drainage in order to account for the climate change. In this regards, the objective of this study is to figure out the characteristics of pavement types. METHODS : The laboratory test for deriving optimum asphalt content (OAC) was conducted using the mixtures of the permeable asphalt surface for the pavement surface from Marshall compaction method. Based on its results, the pavement construction at the test field was conducted. After that, the site performance tests for measuring the traffic noise, strength and permeability were carried out for the relative evaluation in 2 months after the traffic opening. The specific site tests are noble close proximity method (NCPX), Light falling deflectometer test (LFWD) and the compact permeability test. RESULTS : The ordered highest values of the traffic noise level can be found such as normal dense graded asphalt, drainage and porous structure types. In the results from LFWD, the strength values of the porous and drainage asphalt types had been lower, but the strength of normal asphalt structure had relatively stayed high. CONCLUSIONS :The porous structure has been shown to perform significantly better in permeability and noise reduction than others. In addition to this study, the evaluation of the properties and the determination of the optimum thickness for the subgrade course under the porous pavement will be conducted using ground investigation technique in the further research.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.491-498
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur minerals pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this study the generation characteristics and the prediction of ARD of various road cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Sixteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.38-45
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• 2023

In this study, the removal efficiency of road sweeping and sand filter facility for removing total suspended solid (TSS) as nonpoint source pollution from expressway was evaluated for the last 10 years (2012~2021) using ROADMOD. ROADMOD is a screening level model and was calibrated for runoff rate and TSS loading both at the inlet, which is the loading from the drainage area, and the outlet, from the sand filter facility. The drainage area is 715 m² and the dimensions of sand filter facility are 1.5 m (wide) × 3.8 m (length) × 1.5 m (depth). The monitoring period for model calibration was the rainfall event during Aug. 31~Sep. 1, 2021 and the amount of rainfall was 74.5 mm. As a result of calibration, the determination coefficients (R²) of the flow rate were 0.66 and 0.86, for the inlet and outlet, respectively, and those of TSS loading were 0.50 and 0.84, for the inlet and outlet, respectively. Considering that ROADMOD is a screening level model, the calibration results were reasonable to evaluate the best management practices (BMPs) on the expressway. Using ROADMOD simulation results for 2012~2021, the average yearly runoff rate from the expressway was 82% and removal efficiency was 9% for road sweeping, 35% for sand filter facility, and 39% for both road sweeping and sand filter facility.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.107-117
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• 2006

Recently, there has been a remarkable trend of using aggregates at sizes smaller than 13 mm for drainage asphalt pavement (DAP) in order to reduce the noise generated between vehicle tires and road surface. These DAPs have their performance and durability seriously worsen after several years in-service due to the clogging of void space and the abrasion. This paper proposes the use of large size aggregates in porous asphalt mixtures to overcome these defects. Results of laboratory and field experiments on asphalt mixtures with several aggregate gradations are investigated and compared. The study focuses on advantages of DAP using large size aggregate and on particle size combinations containing no fine aggregates of size 2.36 mm or less, which have not been considered in current engineering practice.