• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.1
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• pp.1561-1579
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• 1969

In Korea, the duty of water in paddy fields was measured at the Agricultural Experimental Station in Suwon about 60 years ago. After that time some testing has been made in several places, but the key points in its experiment were the water depth of evapo-transpiration. Improved breeds, progress in cultivation and management techniques as well as development of measuring apparatus in recent years have necessitated the review of the duty of water in paddy fields. The necessity of reviewing the conventional methods has become even more important, as no source of information has been made available through survey of water utilization on a soil use basis which requires data on peculiar features of the water depth of evapo-transpiration. For example, the duty of water in paddy field is largely affected by the water depth of evapo-transpiration in connection with the wetted paddy field, whereas in connection with the normal paddy fields without this characteristic the vertical percolation become the predominant factor in measuring the decreasing depth of water. Therefore, it becomes important. that not only the water depth of evapotranspiration but also the vertical percolation process should also be observed in order to arrive at a realistic conclusion. As the vertical percolation has aclose relationship to the height of the underground water, the change of the latter can be measured. As the conclusion of this experiment, the following subjects are indicated. 1. In order to determine the economic duty of water in paddy fields on a basis of varying soil features, the varying soil features in the benifited area should be investigated thoroughly. The water depths of evapo-transpiration(ET) ratio to evaporation in the evaporator(V) on a basis of the varying soil features are as follows: clay loam ET/V = 1.11, loam ET/V = 1.64, sandy loam ET.V = 1.63 2. The decreasing depth of water consists of the water depth of evapotranspiration, the vertical per colation and the percolation of foot path. Among these three, the percolation of foot path can be utilized again. 3. As the result of this experiment, it shows the decreasing depth of water as follows. clay loam 9.3 mm/day, loam 13.5mm/daty, sandy loam 15.3mm/day 4. On a basis of the varying soil features and the height of the underground water, the vertical percolation varies. 5. The change of the vertical percolation on a basis of the varying soil features shows as follows: clay loam $1{\sim}2$ mm/day, loam $2{\sim}3$mm/day, sandy loam $3{\sim}4$mm/day 6. The level of the underground water changes sensibly by priority of clay loam, loam, sandy loam. When it rains, the level of the underground water rises fast and falls down slowly. 7. The level of the underground water changes within the scope of 25cm 8. The transpiration ratio is given in table 8 and their value are as follows: clay loam 168.8, loam 255.6, sandy loam 272.5

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.175-181
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• 2004

This study is about a section where underground water level occurs at the underground 5m depth by the excavation of the ground, as a stream is adjacent to a excavation section of High Speed Railway ${\bigcirc}{\bigcirc}$ Station construction sections and a reservoir being always full of water is located at the left side of the construction section. Therefore this test is executed for the design and construction of buoyance anchors able to permanently prevent buoyance by the underground water level at working and for the stable construction and permanent smooth maintenance of structures. In this test, bar type anchors are divided according to their length and standard to execute test-anchor test, and In spot test, 9 test-anchors test, proof test to construction process, suitability test and acceptance test are executed 4 times to 9 test-anchors by dividing anchors according to the length of permanent anchor, the outer diameter of bar and boring diameter. Standard motion characteristic centering on load transmission and break mechanism of bar-type anchors for the prevention of buoyance will be showed in the thesis.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.631-641
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• 2014

Characteristics of water-level changes in the Temporary Gulpocheon Discharge Channel were identified by observing and analyzing changes in the subterranean water level induced by hydrological stresses the underground aquifer. The subterranean water level refers to the level at which the pressure of subterranean water passing through the corresponding position has an equipotential value that is in equilibrium with the atmospheric pressure at that location. This water level is not fixed but changes in response to hydrological stress. It can be identified by repeatedly measuring the distance from the observation point to the surface of the subterranean water. The subterranean water-level change equation and the variance range of the hydrological curve of subterranean water over 24 hours at the Gimpo-Gimpo National Groundwater Monitoring Network (NGMN) were used as assessment factors. The variance characteristics of the subterranean water at the 18 monitoring system locations were classified into three impact, observational wish, and non-impact. The impact type accounted for 50% of the subterranean water of and accurately reflected the water-level changes due to hydrological stress, showing that distance is the major controlling factor. The observational wish type accounted for 27.8% of the subterranean water, and one of the two assessment factors did not meet the assessment factors. The nonimpact type accounted for 22.2% of the subterranean water. This type satisfied the two assessment factors and represents subterranean water-level changes response to precipitation.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.183-192
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• 2012

Although underground water resource has relatively less pollution rate compared with surface water, its recovery faces many difficulties due to poor management. Our country monitors underground water to manage it effectively through auxiliary observation network for underground water. In this paper, we suggest water-well auto measure system based on Geosensor for business efficiency increase of water-well management and realtime monitering. In this system is consist of user GUI(Graphic User Interface) composed with water-well information and movement sub-observation network prototype system composed with GPS(Global Positioning System) and wireless sensor node such as water temperature, water level, electrical conductivity. In this system is using the light of the sun for self-power, variety water-well information collected wireless sensor node was a wireless transmitting/receiving a using CDMA(Code Division Multiple Access) module. Also, for promote with user ease, user GUI express that water-well collected in GIS(Geographic Information System) map. For performance evaluation of the proposed system, we perform experiment using sensing information through designed sub-observation network. And we was proved superiority of the proposed system through qualitative evaluation with other paper.

• Korean Journal of Organic Agriculture
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• v.19 no.1
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• pp.121-134
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• 2011

For this study, Smilex powder, a pesticide, was sprayed on the Altari radish, and then underground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1000) were evenly sprayed on the Altari radish respectively. Samples of Altari radishs for residual pesticide analysis were taken two hours, 1 day, 7 days, and 15 days after treatments, and the detectable concentration and degradability of procymidone, the pesticide residue, were measured. The results obtained are as follows: 1. When detectable concentration of procymidone within the altari radish was measured, treatment plots sprayed with underground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1000) were found to show lower detectable concentration than the non-treatment plot which was sprayed with pesticide only. Especially, the treatment plots sprayed with Chitosan solution (${\times}$500), and with wood vinegar solution (${\times}$1,000) showed lower values than the average. 2. When the degradability of procymidone within the Altari radish was measured, the plot treated with Chitosan solution (${\times}$500) and the plot treated with wood vinegar solution (${\times}$1,000) were found to have relatively higher degradability of procymidone. There were not much differences among testing materials in the degradability of residual pesticides. However, the plot treated with Chitosan solution (${\times}$500) showed higher degradability. In terms of average degradability with time, degradability increased sharply 7 days after the foliar application of testing materials. 3. When the daily far-sighted view survey was conducted in order to find out growth disorder and damage on the Altari radish plants by the treatment of un-derground water, Chitosan solution (${\times}$500), and wood vinegar solution (${\times}$1,000), no symptomatic physiological disorders was observed on all the plants tested during the whole growing season at the tested concentration level.

• Journal of Industrial Technology
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• v.5
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• pp.81-89
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• 1985

A Mise-$\grave{a}$-la-masse method is to use a subsurface conductive mass itself as one current electrode of a pair by connecting it directly to one pole of a voltage source, the second current electrode being placed on the ground surface at a great distance and connected to the other pole. This paper is to study the modified Mise-$\grave{a}$-la-masse method using a water tank, that is, the second current electrode is placed on the underground level instead of being placed at a great distance, to find the geometry and the continuity of ore bodies.

• Journal of the Korean Geotechnical Society
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• v.31 no.6
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• pp.71-82
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• 2015

Recently, due to the expansion of urban infrastructure for the citizen convenience, the shield tunnel construction has increased considering the civil complaints minimization and construction stability. Most shield tunnels are designed based on the assumption of the undrained condition that underground water does not inflow, but they are operated in the field as drained tunnels with drainage facility to drain underground water. Therefore, the drained condition needs to be considered in the shield tunnel design. It is also necessary to consider the weathered granite soil that is widely distributed throughout the country and consequently is encountered in most of construction sites. In this paper, the model test which can control total stress and pore water pressure and simulate the underground tunnel located in the weathered granite soil below ground water level is conducted. Total stress, pore water pressure and an inflow water into an inner pipe were measured using the testing device. Test results showed that the total stress in a drained condition was lower than in an undrained condition because pore water pressure decreased in a drained condition and an inflow water into an inner pipe was proportional to the loading stress in a drained condition. As a result, if a drained condition is considered in the shield tunnel design, the more economical design can be expected because of the stress reduction of the lining.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.87-92
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• 2015

Cultivation on reclaimed tidal land is often difficult in the problem such as high salinity of soil, bad drainage because of high level of groundwater. Many researches have been made efforts to solve these problems, but effect of improvement is low and practicality is insufficient. In this study, through numerical analysis of the transport properties of salt and water, we suggested underground drainage of the reclaimed land and the desalination promotion methods in the soil. The results of characteristic of desalination and seepage analysis of underdrain show that underdrain is able to increase twice of the underground seepage amount when installing perforated pipe with horizontal filter (width 50cm) more than installing only the perforated pipe. For soil which coefficient of permeability is below $1{\times}10^{-4}cm/s$ that desalination with pond water is not possible, a method to increase the permeability of the soil is necessary. Therefore, it was concluded that application of underdrain using perforated pipe with horizontal filter would be low-cost and practical.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.421-435
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• 2012

Rock excavation (removal) tests are performed with effective parameters using an abrasive waterjet. For verification of the field rock excavation capabilities, the removal performance and level of efficiency are analyzed for hard granite rock in terms of the water pressure, exposure time of the jet, and the standoff distance. In particular, experimental tests are performed with a long standoff distance required condition in the real excavation field. The rock removal performance level changes according to the rock properties. In this study, various rock specimens are used and P-wave velocities are measured in order to determine the correlation between the removal performance and the P-wave velocity. As a result of the experimental study, the effect of waterjet parameters on rock removal is analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.118-125
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• 2016

This paper proposes the appropriate waterproofing methods for underground structures after applying different types of waterproofing materials on the concrete test specimens and selecting the best results out of humidity testing in winter conditions. Results of the testing showed that the underground structures absolutely require relevant waterproofing application based on the environmental conditions; when applied with interior waterproofing, the results showed that the concrete maintained high level of humidity and reinforcing steel within the concrete layer corroded. However, when applied with exterior waterproofing, it was shown that the waterproofing layer prevent direct contact with water and concrete, thereby protecting the concrete structure and improving overall durability. It follows that during underground structure construction, exterior waterproofing methods are have shown by an effective method for improving the durability as well as providing a comfortable interior environment for users.