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  • Title/Summary/Keyword: SOIL CHARACTERISTICS

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Estimation of liquid limit of cohesive soil using video-based vibration measurement

  • Matthew Sands;Evan Hayes;Soonkie Nam;Jinki Kim
    • Geomechanics and Engineering
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    • v.33 no.2
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    • pp.175-182
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    • 2023
  • In general, the design of structures and its construction processes are fundamentally dependent on their foundation and supporting ground. Thus, it is imperative to understand the behavior of the soil under certain stress and drainage conditions. As it is well known that certain characteristics and behaviors of soils with fines are highly dependent on water content, it is critical to accurately measure and identify the status of the soils in terms of water contents. Liquid limit is one of the important soil index properties to define such characteristics. However, liquid limit measurement can be affected by the proficiency of the operator. On the other hand, dynamic properties of soils are also necessary in many different applications and current testing methods often require special equipment in the laboratory, which is often expensive and sensitive to test conditions. In order to address these concerns and advance the state of the art, this study explores a novel method to determine the liquid limit of cohesive soil by employing video-based vibration analysis. In this research, the modal characteristics of cohesive soil columns are extracted from videos by utilizing phase-based motion estimation. By utilizing the proposed method that analyzes the optical flow in every pixel of the series of frames that effectively represents the motion of corresponding points of the soil specimen, the vibration characteristics of the entire soil specimen could be assessed in a non-contact and non-destructive manner. The experimental investigation results compared with the liquid limit determined by the standard method verify that the proposed method reliably and straightforwardly identifies the liquid limit of clay. It is envisioned that the proposed approach could be applied to measuring liquid limit of soil in practical field, entertaining its simple implementation that only requires a digital camera or even a smartphone without the need for special equipment that may be subject to the proficiency of the operator.

Evaluation of GIS-based Soil Loss Amount in Considering Basin Characteristics (유역특성을 고려한 GIS 기반 토양침식량 평가)

  • Guak Dong-Wook;Cho Gi-Sung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.1
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    • pp.89-97
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    • 2006
  • Soil erosion has caused serious environmental problems which threaten the foundation of natural resources. In this paper, we chose RUSLE erosion model, which could be connected easily with GSIS and available generally in mid-scale watershed among soil erosion models, and extracted factors entered model by using GSIS spatial analysis method. First, this study used GIS database as soil map, DEM, land cover map and rainfall data of typhoon Memi (2003) to analyze soil loss amount of Dam basin. To analyze the changes of soil loss in considering basin characteristics as up-, mid- and downstream, this study calculated soil erodibility factor (K), topographic factors (LS), and cover management factor (C). As a result of analysis, K and LS factors of upstream showed much higher than those of downstream because of the high ratio of forest. But C factor of downstream showed much higher than that of upstream because of the high ratio of agricultural area. As a result of analysis of soil loss, unit soil loss of upstream is 4.3 times than soil loss of downstream. Therefore, the establishment of countermeasures for upstream is more efficient to reduce soil loss.

Analysis of the Ecological Characteristics of Vegetation in the Area Adjacent to Sasang Industrial Complex in Pusan Metropolitan City (사상공단 주변 식생의 생태적 특성 분석)

  • 박승범;김석규;남정칠;김승환;강영조;이기철
    • Journal of the Korean Institute of Landscape Architecture
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    • v.30 no.1
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    • pp.75-86
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    • 2002
  • This study was conducted to analyze the change of soil characteristics effect on the condition of urban forest in Sasang parti located near Sasang Industrial Complex. The results of this study are as follows; 1. Soil hardness is increasing from the area of forest, to the entrance, to facilities in that order. Soil acidity pH4.19∼4.23 in Sasang park indicated a high acidity condition. High levers of K, Na, Mg, Ca are shown in the areas composed of high soil hardness. 2. Pinus thunbergii in the overstory tree layer, Alnus japonica in the understory tree layer, and Rhus sylvestris in the shurb layer are shown respectively as dominant species based on the ground survey and the compution of important value. Pinus thunbergii is decreasing, while Alnus japonica and increasing. 3. Oplismenus undulatifolius which has a strong tolerance for air pollution, is shown as a dominant species of herbaceous plants in Sasang park. There are 10 species of Harbaceous in Sasang park compared to 20 species in Molundae park. This shows that deversity in herbaceous plants are imported by air pollution. 4. Species diversity indices of Sasang park is 0.8738∼0.9700 compared to 1.0817∼ 1.233 in Molundae park is due to the good condition of soil environment in addition to air pollution effects. 5. The vitality of Pinus thunbergii is 16.41∼20.42ER in Sasang park, and 12.42∼ 16.81ER, in Molundae park. This shows that tree vitality are impacted by soil characteristics. The regression analysis between tree vitality and soil environment shows the effects of is soil hardness, soil moisture, soil acidity, K, Na, Mg, Ca.

A Study on Disturbance Effect of Clay by Block Sampling (대형자연시료 채취를 통한 시료 교란도 분석에 관한 연구)

  • 신윤섭;김연정;김학중;김영웅
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.325-332
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    • 2003
  • In general, soil characteristics are estimated through the sample gathered by field boring without considering sample disturbance. However, soil characteristics must be changed by the degree of sample disturbance. Therefore it be need to estimate the soil characteristic considering sample disturbance which can be occurred by the change of stress condition, sampling technique and handling method. On this study, we analyzed the sample disturbance by using the methods of volume change, residual effective stress, elastic modulus and the curve of consolidation tests. In order to estimate the relationship between sample disturbance and soil characteristics, we used the piston sample and the block sample. As the results, it should be considered in design that the disturbance of the block sample, which affects the strength and compression properties of clay, is smaller than the disturbance of piston sample.

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Efflorescence Characteristics of Alkali-Activated Slag-Red Mud Soil Mixed Pavement of Red Mud Substitution Rate (알칼리활성화 슬래그-레드머드 흙포장재의 레드머드 대체율에 따른 백화 특성)

  • Kang, Hye Ju;Lee, Yeong;Oh, Du Yeon;Lee, Gyu Yeong;Kang, Suk Pyo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.11a
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    • pp.153-154
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    • 2015
  • This study is alkali-activated slag-red mud soil mixed pavement of efflorescence characteristics analysis of mitigation measures is drawn to the red mud substitution rate in accordance with the alkali-activated slag-red mud soil mixed pavement of efflorescence characteristics were exhibited. As a result of alkali-activated slag-red mud soil mixed pavement is more substitution rate increases appeared to efflorescence is increased.

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Strength Characteristics of Cement-Mixed Soil (시멘트 혼합토의 강도 특성)

  • Kim, Sang-Chul;Lee, Sang-Ho
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.3
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    • pp.49-56
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    • 2005
  • This study was conducted by the tests of materials engineering and soil mechanics to see the strength characteristics of the ‘Cement-Mixed Soil'. To sum up my experiments, I would like to present the results which are the theoretical base and fundamental data to establish the standard design including the design of mixing proportions of the soil as a construction material. In conclusion, in this study the optimum cement mixing ratio is 9% and in this ratio the optimum moisture content of compaction work is 19.3% from the analysis of the strength characteristics, as well as in consideration of the economic profits and nature familiar facts.

Analysis of Settlement Characteristics of Shallow Foundation on Sandy Soil Overlained by Rigid Ground (강성지반위 사질토층에 위치한 얕은기초의 침하량특성분석)

  • Hwang, Hui-Seok;Kim, Dong-Geon;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.34
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    • pp.45-52
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    • 2014
  • In this paper the settlement characteristic of shallow foundation on sandy soil overlained by rigid ground was investigated by analyzing results of model tests. For model experiments, model tests were performed with sandy soils sampled from the field, changing the relative density of sandy soil and the ratio of thickness of sandy layer(H) to the width of model strip footing(B). As result of tests, settlement of sandy soils increases as the value of H/B increases, whereas it increases with relative density of soil. Bearing capacity decreases as the thickness of the sand layer relative to the footing width increases. In order to analyze the settlement characteristics of sandy ground, the results of model tests were compared with the predicted values using the empirical formulas proposed by Terzaghi, De Beer and Schmertmann. The method by De Beer was found to be in good agreements with test results.

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Analysis of soil discharge characteristics in sand with water content (수분 함유량에 따른 모래의 지중방전 특성 분석)

  • Lee, Bok-Hee;kim, Hoe-Gu;Park, Geon-Hun;Lee, Kyu-Sun;Ahn, Chang-Hwan
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.05a
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    • pp.436-439
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    • 2008
  • It has been known that the value of soil resistance drops when a high impulse curennt is injected into a grounding electrode. In this paper, impulse generator is used to investigate the dry soil and wet soil characteristics in cylinderical test cell. The impulse resistances and breakdown characteristics were discussed based on its voltage and current traces. As a result, sand resistances are decreased with increasing the applied currents. It was thought that a decrease in resistance of dry sand with increasing current is due to both thermal and ionization processes. On the other hand, in case there is no water presence in the soil, the reduction in resistance as the currents are of dry sand increased is mainly due to the ionization process.

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Characteristics on Land-Surface and Soil Models Coupled in Mesoscale Meteorological Models (중규모 기상모델에 결합된 육지표면 및 토양 과정 모델들의 특성)

  • Park, Seon K.;Lee, Eunhee
    • Atmosphere
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    • v.15 no.1
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    • pp.1-16
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    • 2005
  • Land-surface and soil processes significantly affect mesoscale local weather systems as well as global/regional climate. In this study, characteristics of land-surface models (LSMs) and soil models (SMs) that are frequently coupled into mesoscale meteorological models are investigated. In addition, detailed analyses on three LSMs, employed by the PSU/NCAR MM5, are provided. Some impacts of LSMs on heavy rainfall prediction are also discussed.

CHARACTERISTICS OF SOME WET CLAY SOILS AFTER REMOULDING TREATMENTS

  • Ou, Yinggang;Chen, Liancheng
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.1036-1042
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    • 1993
  • In order to derive homogeneous remould soil sample, which is very important for obtaining reliable experimental results in terra-mechanics research, the characteristics of two clay soils at high moisture contents after remoulding treatment were investigated . It was found that with the remoulding process employed the coefficients of variation was less than 1.2% for the soil density and the soil could be treated as fully saturated soil. Therefore, the remoulded and will restore after a period of time. Some suggestiions were given follow the results of the drop cone test.

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