• Title/Summary/Keyword: slope efficiency

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Study on the Travel and Tractive Characteristics of the Two-Wheel Tractor on the General Slope Land(III)-Tractive Performance of Power Tiller- (동력경운기의 경사지견인 및 주행특성에 관한 연구 (III)-동력경운의 경사지 견인성능-)

  • 송현갑;정창주
    • Journal of Biosystems Engineering
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    • v.3 no.2
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    • pp.35-61
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    • 1978
  • To find out the power tiller's travel and tractive characteristics on the general slope land, the tractive p:nver transmitting system was divided into the internal an,~ external power transmission systems. The performance of power tiller's engine which is the initial unit of internal transmission system was tested. In addition, the mathematical model for the tractive force of driving wheel which is the initial unit of external transmission system, was derived by energy and force balance. An analytical solution of performed for tractive forces was determined by use of the model through the digital computer programme. To justify the reliability of the theoretical value, the draft force was measured by the strain gauge system on the general slope land and compared with theoretical values. The results of the analytical and experimental performance of power tiller on the field may be summarized as follows; (1) The mathematical equation of rolIing resistance was derived as $$Rh=\frac {W_z-AC \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\] sin\theta_1}} {tan\phi \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]+\frac{tan\theta_1}{1}$$ and angle of rolling resistance as $$\theta _1 - tan^1\[ \frac {2T(AcrS_0 - T)+\sqrt (T-AcrS_0)^2(2T)^2-4(T^2-W_2^2r^2)\times (T-AcrS_0)^2 W_z^2r^2S_0^2tan^2\phi} {2(T^2-W_z^2r^2)S_0tan\phi}\] $$and the equation of frft force was derived as$$P=(AC+Rtan\phi)\[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]cos\phi_1 \ulcorner \frac {W_z \ulcorner{AC\[ [1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]sin\phi_1 {tan\phi[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\]+ \frac {tan\phi_1} { 1} \ulcorner W_1sin\alpha $$The slip coefficient K in these equations was fitted to approximately 1. 5 on the level lands and 2 on the slope land. (2) The coefficient of rolling resistance Rn was increased with increasing slip percent 5 and did not influenced by the angle of slope land. The angle of rolling resistance Ol was increasing sinkage Z of driving wheel. The value of Ol was found to be within the limits of Ol =2\ulcorner "'16\ulcorner. (3) The vertical weight transfered to power tiller on general slope land can be estim ated by use of th~ derived equation: $$R_pz= \frac {\sum_{i=1}^{4}{W_i}} {l_T} { (l_T-l) cos\alpha cos\beta \ulcorner \bar(h) sin \alpha - W_1 cos\alpha cos\beta$$The vertical transfer weight $R_pz$ was decreased with increasing the angle of slope land. The ratio of weight difference of right and left driving wheel on slop eland,$\lambda= \frac { {W_L_Z} - {W_R_Z}} {W_Z} $, was increased from ,$\lambda$=0 to$\lambda$=0.4 with increasing the angle of side slope land ($\beta = 0^\circ~20^\circ) (4) In case of no draft resistance, the difference between the travelling velocities on the level and the slope land was very small to give 0.5m/sec, in which the travelling velocity on the general slope land was decreased in curvilinear trend as the draft load increased. The decreasing rate of travelling velocity by the increase of side slope angle was less than that by the increase of hill slope angle a, (5) Rate of side slip by the side slope angle was defined as $ S_r=\frac {S_s}{l_s} \times$ 100( %), and the rate of side slip of the low travelling velocity was larger than that of the high travelling velocity. (6) Draft forces of power tiller did not affect by the angular velocity of driving wheel, and maximum draft coefficient occurred at slip percent of S=60% and the maximum draft power efficiency occurred at slip percent of S=30%. The maximum draft coefficient occurred at slip percent of S=60% on the side slope land, and the draft coefficent was nearly constant regardless of the side slope angle on the hill slope land. The maximum draft coefficient occurred at slip perecent of S=65% and it was decreased with increasing hill slope angle $\alpha$. The maximum draft power efficiency occurred at S=30 % on the general slope land. Therefore, it would be reasonable to have the draft operation at slip percent of S=30% on the general slope land. (7) The portions of the power supplied by the engine of the power tiller which were used as the source of draft power were 46.7% on the concrete road, 26.7% on the level land, and 13~20%; on the general slope land ($\alpha = O~ 15^\circ ,\beta = 0 ~ 10^\circ$) , respectively. Therefore, it may be desirable to develope the new mechanism of the external pO'wer transmitting system for the general slope land to improved its performance.l slope land to improved its performance.

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Study on the Travel and Tractive Characteristics of the Two-Wheel Tractor on the General Slope Land(Ⅲ)-Tractive Performance of Power Tiller- (동력경운기의 경사지견인 및 주행특성에 관한 연구 (Ⅲ)-동력경운의 경사지 견인성능-)

  • Song, Hyun Kap;Chung, Chang Joo
    • Journal of Biosystems Engineering
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    • v.3 no.2
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    • pp.34-34
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    • 1978
  • To find out the power tiller's travel and tractive characteristics on the general slope land, the tractive p:nver transmitting system was divided into the internal an,~ external power transmission systems. The performance of power tiller's engine which is the initial unit of internal transmission system was tested. In addition, the mathematical model for the tractive force of driving wheel which is the initial unit of external transmission system, was derived by energy and force balance. An analytical solution of performed for tractive forces was determined by use of the model through the digital computer programme. To justify the reliability of the theoretical value, the draft force was measured by the strain gauge system on the general slope land and compared with theoretical values. The results of the analytical and experimental performance of power tiller on the field may be summarized as follows; (1) The mathematical equation of rolIing resistance was derived as $$Rh=\frac {W_z-AC \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\] sin\theta_1}} {tan\phi \[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]+\frac{tan\theta_1}{1}$$ and angle of rolling resistance as $$\theta _1 - tan^1\[ \frac {2T(AcrS_0 - T)+\sqrt (T-AcrS_0)^2(2T)^2-4(T^2-W_2^2r^2)\times (T-AcrS_0)^2 W_z^2r^2S_0^2tan^2\phi} {2(T^2-W_z^2r^2)S_0tan\phi}\] $$and the equation of frft force was derived as$$P=(AC+Rtan\phi)\[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]cos\phi_1 ? \frac {W_z ?{AC\[ [1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\)\]sin\phi_1 {tan\phi[1+ \frac{sl}{K} \(\varrho ^{-\frac{sl}{K}-1\]+ \frac {tan\phi_1} { 1} ? W_1sin\alpha $$The slip coefficient K in these equations was fitted to approximately 1. 5 on the level lands and 2 on the slope land. (2) The coefficient of rolling resistance Rn was increased with increasing slip percent 5 and did not influenced by the angle of slope land. The angle of rolling resistance Ol was increasing sinkage Z of driving wheel. The value of Ol was found to be within the limits of Ol =2? "'16?. (3) The vertical weight transfered to power tiller on general slope land can be estim ated by use of th~ derived equation: $$R_pz= \frac {\sum_{i=1}^{4}{W_i}} {l_T} { (l_T-l) cos\alpha cos\beta ? \bar(h) sin \alpha - W_1 cos\alpha cos\beta$$The vertical transfer weight $R_pz$ was decreased with increasing the angle of slope land. The ratio of weight difference of right and left driving wheel on slop eland,$\lambda= \frac { {W_L_Z} - {W_R_Z}} {W_Z} $, was increased from ,$\lambda$=0 to$\lambda$=0.4 with increasing the angle of side slope land ($\beta = 0^\circ~20^\circ) (4) In case of no draft resistance, the difference between the travelling velocities on the level and the slope land was very small to give 0.5m/sec, in which the travelling velocity on the general slope land was decreased in curvilinear trend as the draft load increased. The decreasing rate of travelling velocity by the increase of side slope angle was less than that by the increase of hill slope angle a, (5) Rate of side slip by the side slope angle was defined as $ S_r=\frac {S_s}{l_s} \times$ 100( %), and the rate of side slip of the low travelling velocity was larger than that of the high travelling velocity. (6) Draft forces of power tiller did not affect by the angular velocity of driving wheel, and maximum draft coefficient occurred at slip percent of S=60% and the maximum draft power efficiency occurred at slip percent of S=30%. The maximum draft coefficient occurred at slip percent of S=60% on the side slope land, and the draft coefficent was nearly constant regardless of the side slope angle on the hill slope land. The maximum draft coefficient occurred at slip perecent of S=65% and it was decreased with increasing hill slope angle $\alpha$. The maximum draft power efficiency occurred at S=30 % on the general slope land. Therefore, it would be reasonable to have the draft operation at slip percent of S=30% on the general slope land. (7) The portions of the power supplied by the engine of the power tiller which were used as the source of draft power were 46.7% on the concrete road, 26.7% on the level land, and 13~20%; on the general slope land ($\alpha = O~ 15^\circ ,\beta = 0 ~ 10^\circ$) , respectively. Therefore, it may be desirable to develope the new mechanism of the external pO'wer transmitting system for the general slope land to improved its performance.

In-situ monitoring and reliability analysis of an embankment slope with soil variability

  • Bai, Tao;Yang, Han;Chen, Xiaobing;Zhang, Shoucheng;Jin, Yuanshang
    • Geomechanics and Engineering
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    • v.23 no.3
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    • pp.261-273
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    • 2020
  • This paper presents an efficient method utilizing user-defined computer functional codes to determine the reliability of an embankment slope with spatially varying soil properties in real time. The soils' mechanical properties varied with the soil layers that had different degrees of compaction and moisture content levels. The Latin Hypercube Sampling (LHS) for the degree of compaction and Kriging simulation of moisture content variation were adopted and programmed to predict their spatial distributions, respectively, that were subsequently used to characterize the spatial distribution of the soil shear strengths. The shear strength parameters were then integrated into the Geostudio command file to determine the safety factor of the embankment slope. An explicit metamodal for the performance function, using the Kriging method, was established and coded to efficiently compute the failure probability of slope with varying moisture contents. Sensitivity analysis showed that the proposed method significantly reduced the computational time compared to Monte Carlo simulation. About 300 times LHS Geostudio computations were needed to optimize precision and efficiency in determining the failure probability. The results also revealed that an embankment slope is prone to high failure risk if the degree of compaction is low and the moisture content is high.

A Study on Treatment of the Cutting Rock Slopes - A Case study on the sloping work of the Po-Chun C.C Project and the Moon-Hak Sports complex project - (암반(岩盤) 절토비탈면 처리에 관한 사례연구 - 포천 C.C 조성 및 문학운동장 비탈면처리공을 중심(中心)으로 -)

  • Kim, Kil-Dong;Lee, Jae-Keun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.1 no.1
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    • pp.95-101
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    • 1998
  • In order to seek a efficiency of site cooperation and slope stabilization in a rock sloping work, it would rather take into consideration, in its importance, a concurrent performance of civil works and landscaping works than give any part a special priority. It can enable us to achieve an expanded scope of landscaping works and improvement of slope scenery via this sort of cooperation. However, this can not be achieved without assurance on the slope stabilization and scenic view of the project owner, and further via this cooperation, environmentally familiar works can be performed, becoming natural environment and minimizing damages on surrounding scenery and environment. It is foreseeable that improvement of functions of civil equipment, introduction of technology and development of landscaping materials can facilitate an improvement in the betterment of slope scenery. Landscaping related parties need to enhance their understanding of rock sloping and scenic view based on knowledge on the fundermental understanding of slope stabilization and on the base rock characteristics.

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A Study on the Learning Efficiency of Multilayered Neural Networks using Variable Slope (기울기 조정에 의한 다층 신경회로망의 학습효율 개선방법에 대한 연구)

  • 이형일;남재현;지선수
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.20 no.42
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    • pp.161-169
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    • 1997
  • A variety of learning methods are used for neural networks. Among them, the backpropagation algorithm is most widely used in such image processing, speech recognition, and pattern recognition. Despite its popularity for these application, its main problem is associated with the running time, namely, too much time is spent for the learning. This paper suggests a method which maximize the convergence speed of the learning. Such reduction in e learning time of the backpropagation algorithm is possible through an adaptive adjusting of the slope of the activation function depending on total errors, which is named as the variable slope algorithm. Moreover experimental results using this variable slope algorithm is compared against conventional backpropagation algorithm and other variations; which shows an improvement in the performance over pervious algorithms.

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Implementation and Test of Hydraulic Control System for the Tractor Leveling (트랙터의 수평제어를 위한 유압 시스템의 특성 실험)

  • Lee, S. S.;Oh, K. S.;Hwang, H.
    • Journal of Biosystems Engineering
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    • v.24 no.5
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    • pp.383-390
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    • 1999
  • When a tractor travels slope lands, problems of operator safety and the reduction of job efficiency usually occur. Therefore, maintaining the tractor body being horizontal is critical to improve the security of traveling and the job performance. An experiment was made in a soil bin using the experimental model system built and equipped with a leveling control system. Adaptability of the control system was tested and investigated by analyzing system response in time and frequency domains. Control response time of hydraulic cylinder with 10lpm flow rate on a step input of 10$^{\circ}$slope was about 0.42sec. And it showed a linearly increasing trend without any hunching state. A steady state error of 0.6$^{\circ}$occurred but it was negligible. The hydraulic control system showed a little phase differences within the range of 0.4Hz input frequency. The experimental model showed that implementation of the proposed tractor control system to on slope lands tractor was feasible.

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Study on Dangerous Cut-slopes Distribution Using Inventory Data in Chungcheongdo (절토사면 현황자료를 이용한 충청도 관내 위험절토사면 분포 연구)

  • Kim, Jin-Hwan;Koo, Ho-Bon;Rhee, Jong-Hyun;Yun, Chun-Joo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.858-862
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    • 2008
  • KICT has been carrying out inventory research on the cut slopes of national roads. Inventory research results are basic data used in cut slope management system. Inventory data are classified by general status, cut slope characteristics and inspector opinion. Cut slope inventory data are utilized to figure out dangerous slopes and decide survey ranking of detailed safety diagnostication. This paper drew the distribution of dangerous cut slopes using inventory data in Chungcheongdo, then verified an efficiency on distribution of dangerous cut slopes by comparing occurrence frequency of real collapsed cut slopes.

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Numerical investigation of geocell reinforced slopes behavior by considering geocell geometry effect

  • Ardakani, Alireza;Namaei, Ali
    • Geomechanics and Engineering
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    • v.24 no.6
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    • pp.589-597
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    • 2021
  • The present study evaluates geocell reinforced slope behavior. A three dimensional analysis is carried out to simulate soil and geocell elastoplastic behavior using the finite difference software FLAC3D. In order to investigate the geocell reinforcement effect, the geocell aperture size, thickness, geocell placement condition and soil compaction had been considered as variable parameters. Moreover, a comparison is evaluated between geocell reinforcing system and conventional planar reinforcement. The obtained results showed that the pocket size, thickness and soil compaction have considerable influence on the geocell reinforcement slope performance. Moreover, it was found that the critical sliding surface was bounded by the first geocell reinforcement and the slope stability increases, by increasing the vertical space between geocell layers. In addition, the comparison between geocell and geogrid reinforcement indicates the efficiency of using cellular honeycomb geosynthetic reinforcement.

Stability Assessment on the Final Pit Slope in S Limestone Mine (S 석회석광산에서의 최종 잔벽사면의 안정성 평가)

  • Sun, Woo-Choon;Lee, Yun-Su;Kim, Hyun-Woo;Lee, Byung-Joo
    • Tunnel and Underground Space
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    • v.23 no.2
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    • pp.99-109
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    • 2013
  • The slopes of open-pit mine are typically designed without considering the reinforcement and support method due to the economical efficiency. However, the long-term stability of final pit slope is needed in some case, therefore the appropriate measures that can improve the stability are required. In this study, the field survey and laboratory test were carried out in S limestone mine. The stability assessment of final pit slope was performed through the stereographic projection method, SMR, and numerical analysis. And countermeasures for stabilization were proposed. The results of analysis show that full scale of slope failure is not expected but the failures of bench slope scale are likely to occur. In oder to increase the stability of bench slope, we suggested the remedial methods as follows: excavating the final pit slope by pre-splitting blasting, placing the wide berm in the intermediate bench slope and installing the horizontal drainage hole in the place of local ground water runoff.

Pollutant Runoff Reduction Efficiency of Surface Cover, Vegetative Filter Strip and Vegetated Ridge for Korean Upland Fields: A Review

  • Park, Se-In;Park, Hyun-Jin;Yang, Hye In;Kim, Han-Yong;Yoon, Kwang-Sik;Choi, Woo-Jung
    • Korean Journal of Environmental Agriculture
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    • v.37 no.3
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    • pp.151-159
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    • 2018
  • BACKGROUND: In this review paper, the effects of surface cover (SCV), vegetative filter strip (VFS), and vegetated ridge (VRD) on the pollutant runoff from steep-sloping uplands were analyzed to compare the pollutant reduction efficiency in runoff ($PRE_{runoff}$) of the practices and to investigate how slope and rainfall parameters affect the $PRE_{runoff}$. METHODS AND RESULTS: The $PRE_{runoff}$ of SCV, VFS, and VRD for pollutants including suspended solids and biological oxygen demand was compared by analysis of variance. The effect of slope and rainfall parameters on the $PRE_{runoff}$ was explored by either mean comparison or regression analysis. It was found that the $PRE_{runoff}$ differs with the practices due to different pollutant reduction mechanisms of the practices. Though the $PRE_{runoff}$ was likely to be affected by site condition such as slope and rainfall (amount and intensity), more comprehensive understanding was not possible due to the limited data set. CONCLUSION: The $PRE_{runoff}$ of SCV, VFS, and VRD differed due to the distinctive mechanisms of pollutant removal of the practices. It is necessary to accumulate experimental data across a variety of gradient of slope and rainfall for comprehensive understanding of the effects of the practices on pollutant runoff from steep-sloping uplands.