The stability of stage-constructed embankments on soft clays

1978 ◽  
Vol 15 (2) ◽  
pp. 283-305 ◽  
Author(s):  
F. Tavenas ◽  
R. Blanchet ◽  
R. Garneau ◽  
S. Leroueil
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Text Analysis ◽  
Factor Of Safety ◽  
Initial Period ◽  
Stability Conditions ◽  
Soft Clays ◽  
North Shore ◽  
The North ◽  
The Stability

The stage construction of seven high embankments on soft clays on the north shore of the St. Lawrence Valley has provided an excellent opportunity to check the applicability of the concepts of limit and critical states to the analysis of the behaviour of clay foundations.The construction pore pressures have confirmed the development of a significant consolidation in the initial period of construction.The consequences of this consolidation on the behaviour of the clay, in particular in terms of available strength, and on the method of stability analysis have been found entirely consistent with the general model proposed by Leroueil, Tavenas, Mieussens and Peignaud.It is suggested that the so-called [Formula: see text] analysis based on the vane shear strength corrected according to Bjerrum gives the minimum factor of safety and may be too conservative during stage construction. Effective stress analyses are shown to be more representative of the true stability conditions, and they have been successfully used to accelerate the construction of the embankments.

scholarly journals Slope Stability Analysis of Kattery Watershed in Nilgiris District

2019 ◽  
Vol 12 (6) ◽  
pp. 163-169
Author(s):  
C. Rajakumar ◽  
P. Kodanda Rama Rao
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Internal Friction ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Slope Stability Analysis ◽  
Strength Parameter ◽  
Angle Of Internal Friction ◽  
Shear Strength Parameter ◽  
The Stability

The slope stability analysis is always under severe threats in many parts of nilgiris district, causing disruption, loss of human life and economy. The stability of slopes depends on the soil shear strength parameters such as Cohesion, Angle of internal friction, Unit weight of soil and Slope geometry. The stability of a slope is measured by its factor of safety using geometric and shear strength parameter based on infinite slopes. In this research, investigation was carried out at 5 locations in Kattery watershed in nilgiris district. The factor of safety of the slope determined by Mohr Coulomb theory based on shear strength parameter calculated from direct shear test which is a conventional procedure for this study. Artificial. Neural Network (ANN) Model is used to predict the factor of safety. The input parameters for the (ANN) are chosen as Cohesion, Angle of internal friction, Density and Slope angle and the factor of safety as output. The results obtained in ANN method were compared with that of conventional method and observed a good agreement between these two methods.

scholarly journals Iterative stability analysis for general polynomial control systems

2021 ◽  
Author(s):  
Bo Xiao ◽  
Hak-Keung Lam ◽  
Zhixiong Zhong
Keyword(s):  
Stability Analysis ◽  
Lyapunov Function ◽  
Control Systems ◽  
Polynomial System ◽  
Stability Conditions ◽  
General Polynomial ◽  
Main Challenge ◽  
Detailed Simulation ◽  
Feasible Solutions ◽  
The Stability

AbstractThe main challenge of the stability analysis for general polynomial control systems is that non-convex terms exist in the stability conditions, which hinders solving the stability conditions numerically. Most approaches in the literature impose constraints on the Lyapunov function candidates or the non-convex related terms to circumvent this problem. Motivated by this difficulty, in this paper, we confront the non-convex problem directly and present an iterative stability analysis to address the long-standing problem in general polynomial control systems. Different from the existing methods, no constraints are imposed on the polynomial Lyapunov function candidates. Therefore, the limitations on the Lyapunov function candidate and non-convex terms are eliminated from the proposed analysis, which makes the proposed method more general than the state-of-the-art. In the proposed approach, the stability for the general polynomial model is analyzed and the original non-convex stability conditions are developed. To solve the non-convex stability conditions through the sum-of-squares programming, the iterative stability analysis is presented. The feasible solutions are verified by the original non-convex stability conditions to guarantee the asymptotic stability of the general polynomial system. The detailed simulation example is provided to verify the effectiveness of the proposed approach. The simulation results show that the proposed approach is more capable to find feasible solutions for the general polynomial control systems when compared with the existing ones.

An analysis of the stability of thawing slopes, Ellesmere Island, Nunavut, Canada

2000 ◽  
Vol 37 (2) ◽  
pp. 449-462 ◽  
Author(s):  
Charles Harris ◽  
Antoni G Lewkowicz
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Active Layer ◽  
Factor Of Safety ◽  
High Arctic ◽  
Ellesmere Island ◽  
Sensitivity Analyses ◽  
Pore Water Pressures ◽  
Hot Weather ◽  
The Stability

Active-layer detachment slides are locally common on Fosheim Peninsula, Ellesmere Island, where permafrost is continuous, the active layer is 0.5-0.75 m thick, and summer temperatures are unusually high in comparison with much of the Canadian High Arctic. In this paper we report pore-water pressures at the base of the active layer, recorded in situ on two slopes in late July and early August 1995. These data form the basis for slope stability analyses based on effective stress conditions. During fieldwork, the factor of safety within an old detachment slide on a slope at Hot Weather Creek was slightly greater than unity. At "Big Slide Creek," on a slope showing no evidence of earlier detachment failures, the factor of safety was less than unity on a steep basal slope section but greater than unity elsewhere. In the upper slope, pore-water pressures were only just subcritical. Sensitivity analyses demonstrate that the stability of the shallow active layer is strongly influenced by changes in soil shear strength. Possible mechanisms for reduction in shear strength through time include weathering of soils and gradual increases in basal active layer ice content. However, we suggest here that soil shearing during annual gelifluction movements is most likely to progressively reduce shear strengths at the base of the active layer from peak values to close to residual, facilitating the triggering of active-layer detachment failures.Key words: detachment slides, Ellesmere Island, pore-water pressures, gelifluction.

Stability of Road Embankments in Soft Clay

1974 ◽  
Vol 11 (1) ◽  
pp. 72-88 ◽  
Author(s):  
Kaare Flaate ◽  
Terje Preber
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Factor Of Safety ◽  
Soft Clay ◽  
Total Stress ◽  
Routine Procedure ◽  
The One ◽  
Marine Clays

Slides in soft marine clays frequently occur during construction of road embankments in Norway. This paper outlines the routine procedure used for a stability analysis of such embankments, based on a total stress concept. Using these procedures, eight slides were investigated, and it was found that the minimum factor of safety obtained could give a too conservative picture of the actual conditions. The minimum factor of safety, which is the one normally used, varied between 0.73 and 1.10. Taking all uncertainties into consideration, an analysis based on a total stress concept as outlined herein must be considered acceptable. The study gives no basis for evaluating the accuracy of the measured shear strength values.

Coning motion stability of spinning missiles with strapdown seekers

2016 ◽  
Vol 120 (1232) ◽  
pp. 1566-1577 ◽  
Author(s):  
S. He ◽  
D. Lin ◽  
J. Wang
Keyword(s):  
Stability Analysis ◽  
Scaling Factor ◽  
Guidance System ◽  
Necessary Condition ◽  
Stability Conditions ◽  
Motion Stability ◽  
Model Derivation ◽  
The Stability ◽  
Stability Issues ◽  
Sufficient And Necessary Condition

ABSTRACTThis paper investigates the problem of coning motion stability of spinning missiles equipped with strapdown seekers. During model derivation, it is found that the scaling factor error between the strapdown seeker and the onboard gyro introduces an undesired parasitic loop in the guidance system and, therefore, results in stability issues. Through stability analysis, a sufficient and necessary condition for the stability of spinning missiles with strapdown seekers is proposed analytically. Theoretical and numerical results reveal that the scaling factor error, spinning rate and navigation ratio play important roles in stable regions of the guidance system. Consequently, autopilot gains must be checked carefully to satisfy the stability conditions.

Stability Analysis of a 3D Vertical Slope with Transverse Earthquake Load and Surcharge

2011 ◽  
Vol 90-93 ◽  
pp. 676-679 ◽  
Author(s):  
Ting Kai Nian ◽  
Ke Li Zhang ◽  
Run Qiu Huang ◽  
Guang Qi Chen
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Failure Mode ◽  
Factor Of Safety ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Reduction Procedure ◽  
Interesting Issue ◽  
Earthquake Load ◽  
The Stability

The stability and failure mode for a 3D vertical slope with transverse earthquake load and surcharge have been an interesting issue, especially in building excavation and wharf engineering. In order to further reveal the seismic and surcharge effect, a three-dimensional elasto-plastic finite element(FE) code combined with a strength reduction procedure is used to yield a factor of safety and failure mode for a vertical slopes under two horizontal direction pseudo-static(PS) coefficient and surcharge on the slope top, respectively. Comparative studies are carried out to investigate the effect of seismic coefficient, surcharge intensity and location on the stability and the failure mechanism for a 3D vertical slope including an inclined weak layer. Several important findings are also achieved.

On Stability Analysis of Switched Linear Time-Delay Systems under Arbitrary Switching

2015 ◽  
pp. 480-515 ◽  
Author(s):  
Marwen Kermani ◽  
Anis Sakly
Keyword(s):  
Stability Analysis ◽  
Time Delay ◽  
Lyapunov Function ◽  
Continuous Time ◽  
Delay System ◽  
Delay Systems ◽  
Stability Conditions ◽  
Time Delay Systems ◽  
Arbitrary Switching ◽  
The Stability

This chapter focuses on the stability analysis problem for a class of continuous-time switched time-delay systems modelled by delay differential equations under arbitrary switching. Then, a transformation under the arrow form is employed. Indeed, by using a constructed Lyapunov function, the aggregation techniques, the Kotelyanski lemma associated with the M-matrix properties, new delay-dependent sufficient stability conditions are derived. The obtained results provide a solution to one of the basic problems in continuous-time switched time-delay systems. This problem ensures asymptotic stability of the switched time-delay system under arbitrary switching signals. In addition, these stability conditions are extended to be generalized for switched systems with multiple delays. Noted that, these obtained results are explicit, simple to use, and allow us to avoid the problem of searching a common Lyapunov function. Finally, two examples are provided, with numerical simulations, to demonstrate the effectiveness of the proposed method.

Development of Fuzzy Controllers with Dynamics Regarding Stability Conditions and Sensitivity Analysis

2004 ◽  
Vol 8 (5) ◽  
pp. 499-506 ◽  
Author(s):  
Radu-Emil Precup ◽  
◽  
Stefan Preitl ◽  
Péter Korondi ◽  
Keyword(s):  
Sensitivity Analysis ◽  
Control System ◽  
Stability Analysis ◽  
Stability Conditions ◽  
Fuzzy Controllers ◽  
Electrical Drives ◽  
Points Of View ◽  
The Stability ◽  
Predictive Effect

The paper presents development techniques for fuzzy controllers with dynamics and with predictive effect dedicated to some electrical drives with variable inertia. The development techniques are presented regarding the stability analysis based on programs developed in Matlab & Simulink. In addition, it presents points of view regarding the sensitivity analysis on the basis of some sensitivity models associated to the control system.

Stability of Internal Modes in Circularly Cylindrical MDH Equilibria

1980 ◽  
Vol 35 (1) ◽  
pp. 75-79
Author(s):  
D. Lortz ◽  
J. Nührenberg
Keyword(s):  
Stability Analysis ◽  
Pressure Gradient ◽  
Plasma Boundary ◽  
Cylindrical Symmetry ◽  
Magnetic Axis ◽  
Marginal Stability ◽  
Stability Conditions ◽  
The Stability

Abstract The stability of internal modes, i.e. modes which leave the plasma boundary unperturbed, is discussed for magnetohydrostatic equilibria in circularly cylindrical symmetry. Stability analysis can be performed analytically by expansion near the magnetic axis. Marginal stability conditions relating the pressure gradient and the shear are determined.

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