• Journal of Biosystems Engineering
• /
• v.42 no.4
• /
• pp.265-275
• /
• 2017

Purpose: This study aims to identify the most stable boring shape among the circle, square, and inverted-triangle types in order to be applied to the development of a tractor-pulled underdrain boring device. Methods: The underdrain boring devices designed with the circle, inverted triangle, and square types were analyzed by numerical analysis, and they were evaluated by soil moisture and underground water level in the test field. Results: The results of the numerical analysis indicated that the increases in displacement, and strain when a uniform load is placed on the surface soil with soil weight were in the order of the inverted-triangle type, square type, and circle type. The soil moisture content and the underground water level after rainfall showed the largest difference in the order of the circle type, square type, and inverted-triangle type, indicating that the circle type had the largest drainage effects after rainfall. Conclusions: The overall findings of this study show that the circle type is the most stable among the circle, square, and inverted-triangle types.

• Advances in environmental research
• /
• v.3 no.4
• /
• pp.321-335
• /
• 2014

Eight trace metals, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn, were measured in the urban soil of Guwahati City, Assam, India from 31 sites representing five different types of land use, residential, commercial, industrial, public utilities, and roadside. Cd and Co occurred in very low concentrations (Cd << Co) in all types of land use without any significant variation from one type of land use to another. Ni concentrations were more than those of Co, and the concentrations depended on land use pattern. Average Cr and Cu concentrations were ${\geq}100mg/kg$, but Cr had a significantly higher presence in industrial land use. Pb concentrations showed similar trends. The two metals, Mn and Zn, were present in much larger amounts compared to the others with values ${\geq}300mg/kg$. Industrial and roadside soil contained much more Mn while commercial soil was enriched with Zn. Toxicity Characteristic Leaching Procedure (TCLP) was used for elucidating the mobility characteristics of the eight heavy metals. Mn suffered the highest leaching from commercial land (9.9 mg/kg on average) and also from other types of land. Co, Cu and Pb showed higher leachability from commercial soils but the leached concentrations were less than those of Mn. The two metals, Zn and Ni, were leached from residential land in considerable amounts. The TCLP showed Mn to be the most leachable metal and Cr the least.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.13 no.5
• /
• pp.180-188
• /
• 2010

This study was carried out to evaluate the analysis of environmental change (forest resources and soil water conservation by land types) after planting for prevention of between 2003 and 2006 from the stone hazarding areas in Guizhou province, China. Mean diameter growth of the trees was highest for Melia azedarach, followed by Robinia pseudoacacia, Lonicera fulvotomentosa, Choerospondias axillaris, Cupressus duclouxiana, and Eucommia uimoides Oliv. Mean height growth of the trees was greatest for R. pseudoacacia, followed by Ilex kudincha, M. azedarach, C. duclouxiana, C. axillaris, E. uimoides Oliv, Zanthoxylum bungeanum, and L. fulvotomentosa. Tree biomass was greater at the afforestation sites by 1.22-1.71 ton/ha compared to that of severely eroded mountain areas. The capacities of soil water conservation by land types were 2,790 ton/ha at latent rock desertification farmland, 2,655 ton/ha at rock desertification farmland, 1,680 ton/ha at dolomite sandstone hilly country, 1,650 ton/ha at halfstony hilly country, and 1,590 ton/ha at karst physiognomy site. Soil erosion was estimated to be 1,285 ton/$km^2$ which had been 2,178 ton/$km^2$ before afforestation. Also, we should be continuative manage after planting for prevention of the stone hazarding areas in Guizhou province, China.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.78-83
• /
• 2000

Over twenty thousand types of bryohytes are existed in the world. Bryophytes are generally considered to be primitive plants and seriously neglected by even in botany area. Bryophytes includes mosses, liverworts, and hornworts. They thrive in humid environments and require water to survive. Some types, however, can recover after serious dehydration, even after years of complete dehydration. They generally absorb water and nutrients not from roots which is called rhizoid, but through entire body. The rhizoids are nonchlorophyllose fillamentous branches and attach the body to substratum such as soil and rocks. The attachment of mosses in soil surface provides a good protection from soil erosion by runoff water. In this presentation, reviewed and discussed are ecological characteristics and engineering perspectives of mosses, particularly with respect to soil and water conservation.

• Structural Engineering and Mechanics
• /
• v.35 no.3
• /
• pp.301-314
• /
• 2010

The paper presents the results and conclusions of dynamic load tests that were conducted on a road bridge over the Mokrzyca river in Wroclaw (Poland) made of galvanized corrugated steel plates (CSP). The critical speed magnitudes, velocity vibration, vibration frequency were determined in the paper. The dynamic analysis is extremely important, because such studies of soil-steel bridges in the range of dynamic loads are relatively seldom conducted. Conclusions drawn from the tests can be most helpful in the assessment of behaviour of this type of corrugated plate bridge with soil. In consideration of application of this type of structure in the case of small-to-medium span bridges, the conclusions from the research will not be yet generalized to all types of such solutions. The detailed reference to all type of such bridge structures would be requiring additional analysis (field tests and calculations) on the other types of soil-steel bridges.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.1466-1483
• /
• 2008

This paper discusses the development of an up-to-date computerized CPT (Cone Penetration Test) based soil engineering classification system to provide geotechnical engineers with a handy tool for their daily design activities. Five CPT soil engineering classification systems are incorporated in this effort. They include the probabilistic region estimation and fuzzy classification methods, both developed by Zhang and Tumay, the Schmertmann, the Douglas and Olsen, and the Robertson et al. methods. In the probabilistic region estimation method, a conformal transformation is used to determine the soil classification index, U, from CPT cone tip resistance and friction ratio. A statistical correlation is established between U and the compositional soil type given by the Unified Soil Classification System (USCS). The soil classification index, U, provides a soil profile over depth with the probability of belonging to different soil types, which more realistically and continuously reflects the in-situ soil characterization, which includes the spatial variation of soil types. The CPT fuzzy classification on the other hand emphasizes the certainty of soil behavior. The advantage of combining these two classification methods is realized through implementing them into visual basic software with three other CPT soil classification methods for friendly use by geotechnical engineers. Three sites in Louisiana were selected for this study. For each site, CPT tests and the corresponding soil boring results were correlated. The soil classification results obtained using the probabilistic region estimation and fuzzy classification methods are cross-correlated with conventional soil classification from borings logs and three other established CPT soil classification methods.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1998.04a
• /
• pp.89-97
• /
• 1998

This study is intended to investigate the seismic responses of bridge structures considering site effects. The site effects in the seismic analysis of bridge structures were classified into two parts. At first, the seismic responses of the structures on each "soil profile types" of the code were evaluated in accordance with code-specified method and compared with results of time-history analysis method. And next, as a second stage of the study, the responses of the two different soil with considerably different soil properties, even though they are classified to the same "soil profile types" of the code, were evaluated and compared each other. The first part of study is purposed to evaluate the applicability of code-specified method, while the other part is purposed to find the variance of the seismic responses from the different soil sites in the same soil profile types of the code. For the analysis, two major methods of the code, single-mode spectral anaysis and multi-mode spectral analysis, were used and the time-history analysis method which is expected to give more accurate responses was also used for the comparison purposes. For the time-history analysis, time-domain analysis technique of the lumped-mass model with frequency-independent soil springs and dampers was adopted and artificially generated spectra of the code was used as input motion. As the results of the study, the code specified methods for the seismic responses considering the site effects were verified to give the results in conservative side for the most of the cases. However, for the structures on the site with considerable flexibility, the responses of the bridge girders or deckplates by the code methods both in section forces and horizontal movement responses, may have much smaller values than the actual responses. Therefore, more detailed analysis considering the flexibility of the base soil may be required to have more reasonable results in girder responses.in girder responses.

• Journal of agriculture & life science
• /
• v.44 no.6
• /
• pp.45-50
• /
• 2010

Soil characteristics by site types (slope, topography and stand) were analyzed to provide the basic information for sustainable management of Nari basin in Ulleung Island. The content of total N of Nari basin was lowest at the north slope, this site had also significantly low soil pH and content of available P. The result of soil pH and content of total N analysis by topography, ranged from 5.13 of summit to 5.59 of plain and from 0.63% of plain to 0.87% of hill, respectively. Soil pH, content of total N and available P by stand were significantly different, which showed that stand types are more significant in explaining the soil properties. Available P content by slope, topography and stand ranged from 2.79 to 8.46 ppm, 3.99 to 8.46 ppm and 5.03 to 11.59 ppm, respectively. It was concluded that forest soil around Nari basin has relatively low available P content compared to other forest soil.

• Korean Journal of Agricultural Science
• /
• v.45 no.2
• /
• pp.143-153
• /
• 2018

Soil characteristics along with various container lengths have an important role in the early survival rate and growth of seedlings by influencing the seedling quality. This experiment was conducted to investigate the effect of container length and different soil mixtures on the growth of poplar in a greenhouse. Two types of soil, homogeneous vs. heterogeneous, were used along with two container lengths (30 vs. 60 cm). The heterogeneous soil was made by dividing 50% vermiculite from a mixture of 25% vermicompost and 25% nursery soil in volume. For the homogeneous soil, the above three soil types were mixed together. Populus euramericana clone cuttings were planted in late April, and then, the growth height, root collar diameter (RCD) and biomass were measured in August. The height of the poplar was not significantly affected by container length and soil type, but the RCD was significantly affected by soil type. Leaf and root biomass was higher at the long container than at the short container for both soil treatments, but stem biomass was lower at the heterogeneous soil than at the homogeneous soil treatment. Root to shoot biomass ratio was higher at the heterogeneous soil treatment than at the homogeneous soil treatment by 12%. In conclusion, heterogeneous soil along with a long container is suitable to increase the carbon allocation into the root.

• Journal of Biosystems Engineering
• /
• v.22 no.2
• /
• pp.117-126
• /
• 1997

A series of soil bin experiment was carried out on sandy loam to investigate if it is possible to predict implement draft by some analog tool. Chisel configuration resembling a cone penetrometer section was used as an analog tool. The angle of cone was 30 degree. Three types of tillage implement, or oriental janggi, moldboard plow and chisel plow were chosen for this study. Experimental tillage speed was 0.22, 0.33, 0.49 m/s ad tillage depth was 8, 12, 16cm. For the experimental tillage speed range, the increase of tillage speed did not affect the tillage draft for the three types of implement and analog tool, but as the tillage depth increased, tillage draft of the three types of implement and analog tool increased linearly. The linear relationship was found between the tillage draft of analog tool and that of three types of tillage implement for the experimental tillage depth and speed range with high value of $R^2$ Thus it was concluded from the above results that an analog tool can be used to predict the tillage draft of oriental janggi, moldboard plow and chisel plow. But more experiment for various soil types and theoretical verification are needed for more generallization.