• 제목/요약/키워드: S-Stability

검색결과 8,318건 처리시간 0.035초

Evaluation of unsaturated soil slope stability by incorporating soil-water characteristic curve

  • Zhai, Qian;Tian, Gang;Ye, Weimin;Rahardjo, Harianto;Dai, Guoliang;Wang, Shijun
    • Geomechanics and Engineering
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    • 제28권6호
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    • pp.637-644
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    • 2022
  • Loess soils are unsaturated and widely distributed in the northwest zone in China. Many steep slope of unsaturated are observed are observed to be naturally stable. However, a low factor of safety (FoS) for these slopes would be computed from the slope stability analysis following local code practices. It seems that the analyzed results following the local code practices do not agree with the real condition as observed in the field. It is commonly known that soil suction plays an important role in slope stability due to a higher shear strength of the unsaturated soil as compared with that of the saturated soil. In this paper, it is observed that the computed FoS can also be affected by unsaturated unit weight of the soil. However, the effect of unsaturated unit weight of the soil on the slope stability is commonly ignored in engineering practice. Therefore, both the effects of shear strength and unit weight of the unsaturated soil on the computed FoS of unsaturated soil slope are investigated in this study. It is observed that the unsaturated unit weight of soil on the computed FoS increases with increase in slope angle. It is also observed that the effects of the unsaturated shear strength and unsaturated unit weight on the computed FoS are more significant than the effect of 3D analyses compared to the 2D analyses on the FoS.

CONTROL PHILOSOPHY AND ROBUSTNESS OF ELECTRONIC STABILITY PROGRAM FOR THE ENHANCEMENT OF VEHICLE STABILITY

  • Kim, D.S.;Hwang, I.Y.
    • International Journal of Automotive Technology
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    • 제7권2호
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    • pp.201-208
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    • 2006
  • This paper describes the control philosophy of ESP(Electronic Stability Program) which consists of the stability control the fault diagnosis and the fault tolerant control. Besides the functional performance of the stability control, robustness of control and fault diagnosis is focused to avoid the unnecessary activation of the controller. The look-up tables are mentioned to have the accurate target yaw rate of the vehicle and obtained from vehicle tests for the whole operation range of the steering wheel angle and the vehicle speed. The wheel slip control with a design goal of wheel slip invariance is implemented for the yaw compensation and the target wheel slip is determined by difference between the target yaw rate and actual yaw rate. Since the ESP has a high severity level and the robust control is required, the robustness margin for the stability control is determined according to several uncertainties and the robust fault diagnosis is performed. Both computer simulation and test results are shown in this paper.

소형 어선 및 화물선의 복원성기준 연구 (Study on the Stability Criteria for Small Fishing Vessels and Cargo Ships)

  • 권수연;이희준
    • 선박안전
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    • 통권22호
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    • pp.19-33
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    • 2007
  • According to amendments of ship safety act which comes into force from 4 Nov. 2007, the amended stability criteria should be applied to the small vessels of 12m or more in length. In this paper, the dimensions of domestic small vessels and the casualty reports of capsizing accidents are analyzed. And 58 ships are sampled, modeled for the investigation of the stability performance. Based on the regression analysis of the model ship's allowable metacentric-heights under several stability requirements, stability criteria for small fishing vessels and cargo ships are proposed.

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임상가를 위한 특집 2 - Early loading의 난제 stability dip, 어떻게 극복할 것인가? (Stability dip, the obstacle of early loading protocol, how can it be figured out?)

  • 박창주
    • 대한치과의사협회지
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    • 제51권4호
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    • pp.198-203
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    • 2013
  • Nowadays, it seems like that the concept of the early loading protocol has been intruded between the concept of the immediate loading supported by advanced clinicians and the concept of the conventional loading supported by the prudent clinicians. In particular, the stability dip, which is found to occur usually at 4~6 weeks after dental implant placement because the decrease of the primary mechanical stability is not compensated by the increase of the secondary biologic stability, is frequently pointed out as one of the major causes of early loading failure. In this article, based on our recent clinical investigation about the crestal bone preservation effect of the early loaded NanoTite$^{TM}$ Tapered Certain Prevail$^{(R)}$ (Biomet 3i, USA), the concept of the early loading is revisited. In addition, various methods to overcome the stability dip are reviewed as the oral and maxillofacial surgeon's view point.

에너지안정성 레벨을 이용한 필드로봇의 안정성에 관한 연구 (A Study of Stability for Field Robot using Energy Stability Level Method)

  • 웬치탄;레광환;정영만;양순용
    • 드라이브 ㆍ 컨트롤
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    • 제11권3호
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    • pp.22-30
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    • 2014
  • In this research, the energy stability level method is used for examining the stable state of Field Robot under effects of swing motion, at particular postures of manipulator, and terrain conditions. The energy stability level is calculated by using the dynamic models of Field Robot, subjected to the concept of equilibrium plane and support boundary. The results, simulated by using computing program for estimating the potential overturning of Field Robot, supply useful predictions of stability analysis for designers and operators.

CONTINUOUS SHADOWING AND STABILITY FOR GROUP ACTIONS

  • Kim, Sang Jin
    • 대한수학회지
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    • 제56권1호
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    • pp.53-65
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    • 2019
  • Recently, Chung and Lee [2] introduced the notion of topological stability for a finitely generated group action, and proved a group action version of the Walters's stability theorem. In this paper, we introduce the concepts of continuous shadowing and continuous inverse shadowing of a finitely generated group action on a compact metric space X with respect to various classes of admissible pseudo orbits and study the relationships between topological stability and continuous shadowing and continuous inverse shadowing property of group actions. Moreover, we introduce the notion of structural stability for a finitely generated group action, and we prove that an expansive action on a compact manifold is structurally stable if and only if it is continuous inverse shadowing.