• Korean Journal of Construction Engineering and Management
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• v.19 no.3
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• pp.70-78
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• 2018

Due to the increasing concern about climate change, efforts to reduce environmental load are continuously being made in construction industry, and life cycle assessment (LCA) is being presented as an effective method to assess environmental load. Since LCA requires information on construction quantity used for environmental load estimation, however, it is not being utilized in the environmental review at the initial design stage where it is difficult to obtain such information. In this study, a construction quantity computation system based on the standard section was developed for the drainage facilities of the road and utilized in the model to calculate the environmental load. This model can estimate the environmental load by calculating the amount of resources required for LCA using only the information available at the initial design stage. To verify the validity of the model, five validation cases were applied and compared with the unit estimation model and the multiple regression analysis model. As a result, it is confirmed that the mean absolute error rate is 9.94%, which is relatively accurate and effective model in the initial design stage.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.74-84
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• 2017

This paper presents the development of the underwater cleaning robot platform for a higher efficiency in manufacturing industry. Human operators directly go into the cistern and clean sludge after drainage of the water so far. It is sometimes dangerous because of the harmful chemical materials from the product making process. In addition, it takes long time for water drainage and supplying it back. However, the robot cleaning operation does not need to drain water so that it could be applied to the sludge cleaning work at any time without the plant pause. Moreover, it can prevent the safety accidents because human operators are not necessary to enter directly the sludge cisterns. This paper shows the performance of cleaning work that can be applied in the industrial field through the design and development of underwater cleaning robot platform. And these results demonstrate that the developed underwater cleaning robot has great possibilities to clean other industrial water cisterns.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.669-683
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• 2017

The objective of this study is to propose a modification of the previously proposed drainage system for catching the partial leakage of underground concrete structures. Two techniques were proposed for applying the drainage system only to the leaking parts. One was for conveying leaking groundwater to the collection point in the drainage system and the other was for conveying the collected groundwater to the primary drainage system of the underground concrete structure. Four waterproofing materials for conveying leaking groundwater to the catchment point of the drainage system, Durkflex made of porous rubber material, KE-45 silicone adhesive with super strong adhesion, Hotty-gel made of polymeric materials and general silicone adhesive were evaluated for waterproofing performance. Hotty-gel only showed perfect waterproof performance and the other three waterproof materials leaked. The modified drainage system with Hotty-gel and drainage pipe with fixed saddle to convey the leaking groundwater from the catchment point to the primary drainage system were tested on the concrete retaining wall. The waterproof performance and the drainage performance were evaluated by injecting 1,000 ml of water in the back of the modified drainage system at the 7-day, 14-day, 21-day, 28-day, 2-month and 3-month. There was no problem in waterproof performance and drainage performance of the modified drainage system during 3 months. In order to evaluate the construction period and construction cost of the modified drainage system, it was compared with the existing leaching repair method in surface cleaning stage, leakage treatment stage, and protective barrier stage. Total construction period and construction cost were compared in considering the contents of work, repair material, construction equipment, working time, and total number of workers. As a result of comparing and analyzing in each construction stage, it was concluded that the modified drainage system could save construction period and construction cost compared to the existing leaching repair method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.215-218
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• 2012

We have carried out the experiment to investigate optimal drainage time of barley seeding synchronized with rice harvesting in paddy field. Number of emerged barley seedling on moist paddy field was less than that of common paddy field. It is very hard to plow using combine owing to long time to work on wet condition compared to drying condition of paddy field. According to the drainage time, growth and yield of barley were not significantly different. However, late drainage time decreased the spikes per $m^2$. Rice yield and 1,000 husked rice grain weight were not significant depending on drainage times at 15 days, 20 days and 25 days before barley seeding. The range of 1,000 husked rice grain weight was 21.7~22.2 g on different drainage conditions. In results, on considering of soil hardness and time of labor, the optimal contents of soil moisture was about 33%. This study reveals that drainage time at 20 days before barley seeding is proper to increase seedlings and yield.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1222-1229
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• 2011

Railway bridges are divided into ballastless and ballast track bridges. The ballast abrasion occurs on the ballast track upon bridges more than soil roadbed because the track vibration occurs a lot in the ballast track upon bridges due to girder vibration when a train's weight is loaded onto track even though the identical ballast is used. The phenomena of mud pumping especially, which occurs when drainage is not properly secured for heavy rain, leads to the increase of maintenance work load and the decline of ride comfort. There are countermeasures such as ballast change, installation of cross-drainage for poor drainage, gutter establishment, ballast lifting methods, ballast mats and resilient sleepers laying for the mud pumping. The ballast thickness range in domestic railroad construction rule is uniformly set up according to the design speed of railroad and passing tonnage of train without considering field conditions which is considered in foreign railroad companies. The purpose of this study is to verify the effect of vibration decrease by measuring the acceleration, displacement and ride comfort of ballast track with the change of ballast thickness on the ballast track bridges and to suggest the optimal height of ballast on the Yocheon Bridge built for the test in Honam Line.

• Geomechanics and Engineering
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• v.17 no.2
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• pp.181-194
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• 2019

Due to the seepage of groundwater, the resisting force of slopes decreases and the sliding force increases, resulting in significantly reduced slope stability. The instability of most natural slopes is closely related to the influence of groundwater. Therefore, it is important to study slope stability under groundwater seepage conditions. Thus, using a simplified seepage model of groundwater combined with the analysis of stresses on the slip surface, the limit equilibrium (LE) analytical solutions for two- and three-dimensional slope stability under groundwater seepage are deduced in this work. Meanwhile, the general nonlinear Mohr-Coulomb (M-C) strength criterion is adopted to describe the shear failure of a slope. By comparing the results with the traditional LE methods on slope examples, the feasibility of the proposed method is verified. In contrast to traditional LE methods, the proposed method is more suitable for analyzing slope stability under complex conditions. In addition, to facilitate the optimization of drainage design in the slope, stability charts are drawn for slopes with different groundwater tables. Furthermore, the study concluded that: (1) when the hydraulic gradient of groundwater is small, the effect on slope stability is also small for a change in the groundwater table; and (2) compared with a slope without a groundwater table, a slope with a groundwater table has a larger failure range under groundwater seepage.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.727-742
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• 2020

Point cloud-based 3D maps can obtain many kinds of information for maintenance work on forest road networks. This study was conducted to compare the importance of each factor to select the factors required for the mapping of 3D forest road maps. This can be used as basic data for attribute information required to maintain forest road networks. The results of this study found that out of a total of 30 indexes extracted for mapping 3D forest roads, a total of 21 indexes related to stakeholder groups were significantly different. The importance of the index required by the civil service group was significantly higher than that of the other groups overall. In the case of the academic group, the index importance for cut slope, fill slope, and drainage facility was significantly higher. On the other hand, the index importance for the forestry cooperative and forest professional engineer group was mostly distributed between the civil servants' group and the academic group. In particular, the type of drainage system showed the highest value among the detailed indexes. Overall, drainage related factors in this survey had high coefficient values. The impact of water on forest roads was the most important part in road maintenance. In addition, the soil texture had a high value in relation to slope stability. This is thought to be because the texture of the soil affects the stability of the slope.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.1
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• pp.23-30
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• 1999

The effects of polyelectrolytes and enzyme, alone and in combination, were investigated in OCC recycling system. Four types of the polyelectrolytes based on acrylamide, cationic and anionic monomers were applied to the enzyme-treated KOCC stock to improve the strength and drainage properties of testliner. The polyelectrolytes used in this work were designed in terms of molecular weight and charge density. The water conditions used for recycling were also varied. The results showed that the hydrolytic action of enzyme gave reduced surface area and amorphous region of fiber, and as a result, the cationic polymer was lost apparently its flocculating power due to the reduced bonding site of fiber surface. When the hardness and conductivity of water had been controlled to the conditins of OCC paper mill, the application of amphoteric polyelectrolyte to the enzyme-treated recycled stock was the most effective with respect to the strength and drainage properties of testliner.

• Journal of the Society of Disaster Information
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• v.2 no.1
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• pp.53-64
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• 2006

This study presents the laboratory properties on the frost heave under various moisture contents and compaction efforts in pavement subgrade soil. Many researches were conducted on the frost heave. However, the researches with the domestic soils have not been so active until now. In particular, the evaluation of the frost heave in pavement subgrade soils was not established by many researchers. The problems relating with the frost heave have been serious causes in the distresses of pavements. The study was performed using an appropriate field simulation. The research results revealed that the drainage conditions in earth work should be treated cautiously.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.260-269
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• 2020

The Steam Assisted Gravity Drainage (SAGD) process is an enhanced method to extract oil from bitumen which involves surface and central process facilities. This paper describes the Central Process Facilities (CPF) of SAGD and proposes several retrofit plans to the Heat Exchanger Network (HEN). In this approach, the process integration scheme is applied to estimate the energy saving in HENs, and various cases are modeled in favor of a commercial simulator. Throughout this work, a minimum approach temperature of 10℃ is assumed. The results reveal that, due to the HEN optimization using process integration, the heating and cooling duties can be reduced to 29.68MW and 1.886MW, respectively. Compared with the Husky case, all cases considered in this study indicate a potential reduction of at least 6% in total cost, including investment and operation costs.