• Title/Summary/Keyword: stability analysis Stability chart

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Proposal of a Mechanically Rigorous Slope Stability Chart (역학적으로 엄밀한 사면안정도표의 제안)

  • 김종민
    • Journal of the Korean Geotechnical Society
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    • v.20 no.1
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    • pp.121-129
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    • 2004
  • In this study, a slope stability chart for assessing stability of homogeneous simple soil slopes is proposed. Most existing slope stability charts are based on limit equilibrium method, which is not rigorous in mechanical standpoint. Meanwhile, limit analysis based on the principle of virtual work and the bound theorems of plasticity is suitable for evaluating the stability of geotechnical structures such as slope due to its simplicity in computation and mechanical rigor. Numerical limit analysis taking advantage of finite elements and linear programming can consider various slope conditions and, in addition, find the optimum stability solution with effeciency. In this study, a numerical limit analysis program in terms of effective stress is developed and a mechanically rigorous slope stability chart is proposed by performing stability analyses for various slope conditions. Pore pressure ratio, commonly used in stability charts, is applied to consider the effects of pore pressure for effective stress analysis. As a result of comparison between proposed stability chart and Spencer's stability chart, it was found that Spencer's chart solutions are biased to lower bound which means conservative in design.

A Study on the Chatter Analysis & Dynamic Stability of Drilling Mchine (드릴링 M/C의 Chatter 해석과 동적안정성에 관한 연구)

  • Park, Jong-Kweon;Lee, Hu-Sang
    • Journal of the Korean Society for Precision Engineering
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    • v.6 no.2
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    • pp.77-87
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    • 1989
  • This study is carried out to estimate the influence of cutting speed on the dynamic stability of a drilling machine. The theoretical stabilityu chart is constructed by using the measurd dynamic characteristics of the drilling machine. The critical cutting width and speed predicted from the stability chart show excellent agreements with those measured. Therefore it is confirmed that the analysis technique used in this study is useful for the prediction of the dynamic instability and improvement of the dynamic characteristics of drilling machines.

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A comparative study on slope stability by program and stability cahrt (프로그램과 도표에 의한 사면안정해석의 비교연구)

  • Ju, Gyeong-Hun;Kim, Ju-Cheol;Lee, Jong-Gyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 1994.09a
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    • pp.253-258
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    • 1994
  • Recently, computer technique for the analysis of slope stability enable to reduce a considerable time and efforts. And also, stability problems can be approached by using stablility chart which was basically developed to handle the problems under simple conditions only. Most of the conventional slope stability computer programs and stability chart are still based on the general limit equilibrium method. 16 types of sample slopes and 2 types of failure slope were compared and analysed by stability charts and programs. This research work intend to apply 4 types of conventional computer programs based on the same theoretical backgroung and 7 types of stability charts for solving the same stability problems and the results and compared and analysed in order to justify their reliability.

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Strain Analysis of Crust at the Stabilization Stage Using and Applied Statistical Analysis

  • Kim, Hyeong-Sin;Yun, Hyun-Seok;Chae, Byung-Gon;Choi, Jung-Hae;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.25 no.1
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    • pp.9-20
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    • 2015
  • A strainmeter goes through a period of instability immediately after installation. To determine the stability of strainmeters installed around the Andong fault zone, South Korea, an x-MR control chart analysis and a T2 control chart analysis were conducted. The x-MR control chart analysis used an empirically determined 3σ control limit line to identify abnormal data in recently installed strain gauges. In the T2 control chart analysis, the control limit line was set at a confidence of 95%. A comparison of the early stage of measurement with the terminal stage of measurement for three months after installation indicates that stabilization depends on the location and direction of each strain gauge in x-MR control chart analysis. In the T2 control chart analysis, the number of values exceeding the control limit line decreased as the terminal stage was approached. Based on these results, it is suggested that the 3σ control limit line of an x-MR control chart can be used as a standard for single gauge stability, and that the 95% confidence limit of a T2 control chart analysis could be used as the standard for the stability of multi-gauge strainmeters.

A Study of Reinforced Design Chart for Soil Nailing Slopes (Soil Nailing 공법을 적용하기 위한 사면보강 설계도표에 관한 연구)

  • Seo, Jin-Won;Kim, Hak-Moon;Jang, Kyung-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.1009-1019
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    • 2009
  • Soil nailing method is widely used in reinforcing slopes and excavating earth. The analysis of nail-reinforced slopes, in order to determine the economical length ratio and nail angle, complicated analytical need to be applied by means of computer programs. Therefor this suggested Soil stability Chart for nailed slopes which may be very useful for pre-design, rapidly design, and final check. Three slope types, three nail length and three nail angles are selected for the stability analysis by using limit equilibrium method of Bishop and French Method. From the above results, this study propose the slope reinforced design charts for dry season and rainy season. This proposed reinforced design charts can check dry season as well as rainy season, also these charts can provide reinforcing requirement, soil nail's economical length ratio and nail angle as well.

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A Study on the Development of a Stability Chart for Yield Seismic Coefficient of Soil Slope Using Limit Analysis (한계해석을 이용한 토사면의 항복지진계수 산정도표 제안 연구)

  • Choi, Sang-Ho;Kim, Jong-Min
    • Journal of the Korean Geotechnical Society
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    • v.26 no.3
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    • pp.47-57
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    • 2010
  • Yield seismic coefficient plays an important role in the estimation of permanent displacement of a soil slope subjected to earthquake using Newmark's sliding block theory. However, yield seismic coefficients currently used in practices are not mechanically rigorous since most of them are estimated using limit equilibrium methods considering equilibrium condition only. Therefore, estimation of permanent displacement of a soil slope based on existing yield seismic coefficient may cause problems. Limit analysis estimating the range of mechanically rigorous solution is thought to be effective in evaluating the validity of existing yield seismic coefficient. In this study, a simple stability chart for yield seismic coefficient useful in practices is proposed by considering various slope conditions including stability number, slope inclination, strength parameters, etc.

The Design Charts for Soil Nailing Slopes Through Limit Equilibrium Method (한계평형해석을 사용한 Soil Nailing보강사면의 설계도표의 제안)

  • Kim, Hak-Moon;Jang, Kyung-Jun;Seo, Jin-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.10
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    • pp.2794-2802
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    • 2009
  • Soil nailing method is widely used in reinforcing slopes and excavating earth. The analysis of nail-reinforced slopes, generally require complicated computer programs. The purpose of this paper is suggest, Soil stability Chart for nailed slopes which are very useful for pre-design, rapidly design, and final check. Three slope types, three nail lengths and three nail angles are selected for the stability analysis by using limit equilibrium method form Bishop and French. From the above results, this study propose the reinforced design charts for examine the necessity of reinforcement can be examined. The suggested stability chart and Taylor's Slope Stability Chart, showed similar safety factors. This Soil Nailing design charts can provide the solutions for necessity of reinforcement, economical of nail's length ratio and installation angle as well.

Thresholds of Rainfall Duration and Intensity for Predicting Abrupt Landslide Occurrence (돌발 산사태 예·경보를 위한 강우기준 설정 연구)

  • Kim, Seong-Pil;Park, Jae-Sung;Bae, Seung-Jong;Heo, Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.4
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    • pp.53-58
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    • 2014
  • The objective of this study is to suggest rainfall threshold for landslide forecasting and warning. For this study, we chose the research area where landslide have occurred. And we performed infiltration-stability analysis with rainfall intensity-duration. As the results of this study, slope stability variation chart with rainfall intensity-duration are established. This kind of chart is believed to be able to be used for forecasting and warning the landslide caused by rainfall.

Stability Analysis of Toppling Failure in Rock Slopes (암반사면의 전도파괴에 대한 안정해석)

  • 이명재;이인모
    • Geotechnical Engineering
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    • v.14 no.2
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    • pp.55-66
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    • 1998
  • The purpose of this paper is to formulate and apply the stability analysis of toppling failure by considering the variation of discontinuity characteristics, slope geometry, and loading conditions. The stability condition on toppling failure of rock slope is mainly iuluenced by the dip angle $\alpha_B$ and H/t ratio. In order to check toppling failures in design, the stability charts composed of dip angle $\alpha_B$ versus H/t ratio have been constructed in the paper. In general, smaller dip angle $\alpha_B$ and smaller dip angle $\alpha_B$ and smaller H/T ratio give safer condition. The suggested curves change rapidly at the chitical point around the sone, H/t=4~6. The stable zone in stability charles becomes smaller due to step angle $\data$.

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