An Improved Calculation Method for the Factor of Safety and Its Application to the Stability Analysis of Deep Foundation Pits in Red Clay

2014 ◽  
Vol 11 (12) ◽  
pp. 4319-4328
Author(s):  
Yuanzhong Zhou
2013 ◽  
Vol 790 ◽  
pp. 299-305
Author(s):  
Xiao Song Tang ◽  
Yong Fu Wang ◽  
Ying Ren Zheng

The paper adopts the interface element to simulate the joints so as to systematically and quantitatively study the deformation around tunnel, the mechanic state of lining and the stability under different inclining angles of joints. The result shows that the deformation around tunnel deteriorates mainly along the joint during the inner convergence effects of surrounding rock. When the inclining angle α=45°, the deformation around the tunnel is most serious, followed by that when α=90°, α=60°, α=30° and α=0°. At the same time, the influence of inclining angle on the distribution of the axial force of lining is comparatively small. But the distribution of bending moment and shear change obviously where the joints penetrate the tunnel. The tunnel stability of surrounding rock is the poorest when α=90° and the tunnel is most stable when α=0°. The stability of surrounding rock changes little when α is between 30° and 60°. The research result provides an effective calculation method for the forecast of deformation, the design of structure and the stability analysis of jointed tunnel. It is also helpful for the monitoring of construction and calculation of jointed tunnel in the future.


2011 ◽  
Vol 90-93 ◽  
pp. 676-679 ◽  
Author(s):  
Ting Kai Nian ◽  
Ke Li Zhang ◽  
Run Qiu Huang ◽  
Guang Qi Chen

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.


2019 ◽  
Vol 12 (6) ◽  
pp. 163-169
Author(s):  
C. Rajakumar ◽  
P. Kodanda Rama Rao

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.


Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 861
Author(s):  
Radoslav Majdan ◽  
Rudolf Abrahám ◽  
Katarína Kollárová ◽  
Zdenko Tkáč ◽  
Eva Matejková ◽  
...  

Vehicle lateral stability is evaluated using the static overturning angle. The correct value of this parameter depends on the calculation method. The aim of this study was to compare the latest standard with previously published methodology, to propose two alternative methodologies (Models 1 and 2) and to analyze the influence of various levels of rear wheel ballast weights and overall tire widths on the stability of universal and subcompact tractors. The results showed a significant regression effect of the rear wheel ballast weight on static overturning angle. The influence of the rear wheel ballast weight was higher in the subcompact tractor than in the universal tractor due to a larger distance between the height of the center of gravity and the center of the rear axle. Comparing the latest standard with the previously published methodology, the highest difference values were 13.82% and 7.30%. Both models are based on the previously published methodology and differ from each other in rolling and slope lines. The methodology proposed in Model 2 differed from the standard similarly to the previously published methodology; therefore, it is irrelevant. Model 1 reached differences of only −1.81% and −1.63%, representing a minimal difference from the standard.


1977 ◽  
Vol 14 (2) ◽  
pp. 258-262 ◽  
Author(s):  
E. C. Kalkani

The stability of a rock wedge resting on two intersecting discontinuities is examined under excavation unloading forces. The variation of the factor of safety as well as the external force required to restore a certain factor of safety is examined for a range of values of ambient stress coefficient and for a variation in the distance of a crack from the cut face of the wedge.


1999 ◽  
Vol 36 (6) ◽  
pp. 1151-1171 ◽  
Author(s):  
G J Pauls ◽  
E Karl Sauer ◽  
E A Christiansen ◽  
R A Widger

The stability of slopes at bridge abutments across the Carrot River in east-central Saskatchewan was not influenced significantly by drawdown after flooding in the spring of 1995. Traditional methods of analysis for rapid drawdown predicted the factor of safety of slopes on highly plastic clays of proglacial Lake Agassiz would drop to 0.65 from an initial value of 1.0. Deformation along a well-defined slip plane has persisted at a more or less constant, slow rate since the bridge was constructed in 1975. The river rose approximately 10 m during a flood in the spring of 1995, yet there was only minimal response in piezometers and no measurable increase in the rate of deformation recorded by inclinometers. Pore-water pressures from a steady state seepage model, which was calibrated from piezometer measurements, were integrated into a stability analysis. Changes in pore-water pressures caused by flooding and subsequent drawdown were characterized from a transient seepage model using the flood hydrograph as a flux boundary. The stability analysis integrated with the transient seepage model estimated the factor of safety would drop from 1.0 to 0.91 after drawdown. Field measurements indicated the reduction in factor of safety was even less.


Due to increasing in the population and vehicular volume the existing roads are becoming inadequate. To overcome this problem, widening of existing roads or embankments are obtained, which required a huge amount of soils of suitable properties but due to industrialization and urbanization the availability of good soils are getting reduced because of which the construction should be carried out with unsuitable or weaker soils of inadequate properties and also the widening process involves accumulation of large land area which results in uneconomic of project. In this study three different soils are considered to analyze the influence of weaker soils on embankment widening which involves the stability analysis and reinforcement contribution analysis. Also study involves optimization of embankment widening using Different embankment sections with different slope angles ( via 1V:1H, 2V:1.5H, 2V:1H and 2.5V:1H ) and geo-synthetic reinforcement, which results in reductions of additional land required and backfill material but ensuring minimum factor of safety of 1.5. The analysis performed based on Limit equilibrium methods using SLOPE/W software. The results shows that the reinforcement mobilizes the stabilizing force in embankment which increases the stability and corresponding factor of safety of embankment and for the reinforced section the factor of safety value is a contribution of both reinforcement and shifted critical slip circle and percentage of contribution depends upon slope angle, soil properties & reinforcement. The cost analysis of embankment widening with different soils and different slope angles shows that steep section is the most economical section in all the cases


Author(s):  
Jian-Min Zhang ◽  
Jianhong Zhang ◽  
Gang Wang ◽  
Yang Chen

This paper presents a study of stability of a trial quay wall of large diameter cylinders at the Yangshan Port, China. Stability analysis of the quay wall during construction is carried out using finite element method. The results of the analysis indicate that a turnover failure is potential for the single cylinder subjected to a five year design wave action. The case when the cylinder is empty is the critical situation during construction. Filling the cylinder right after the installation is an effective way to increase the stability. After the quay wall has been formed by joining the single cylinders, the safety against overturning is reevaluated. The factor of safety of the quay wall is assessed to be 1.5 under a fifty year design wave action.


1978 ◽  
Vol 15 (2) ◽  
pp. 283-305 ◽  
Author(s):  
F. Tavenas ◽  
R. Blanchet ◽  
R. Garneau ◽  
S. Leroueil

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.


2020 ◽  
Vol 14 ◽  
Author(s):  
Xuansheng Cheng ◽  
Junliang Hong ◽  
Qingchun Xia ◽  
Haibo Liu ◽  
Fei Gao ◽  
...  

Background: At present, there is few researches on the stability of the supporting structure of bored piles with steel supports for deep foundation pits, and it is even less common to use this support method for deep foundation pits in sandy pebble stratum. This paper studied the stability of the deep foundation pit support of the Southwest Jiaotong University Station in Chengdu, China, using the stability analysis theory of bored piles with steel supports for deep foundation pits Objective: The study aims to show the stability of steel supports for deep foundation pits Methods: The overall stability, anti-overturning stability and uplift stability of the foundation pit are important components of the stability analysis of bored piles with steel supports for deep foundation pits. Aiming at the designed method and parameters of the bored piles with steel support for the deep foundation pit, an in-depth theoretical analysis and calculation of the overall stability, anti-overturning stability and uplift stability of the deep foundation pit is conducted respectively Results: The results show that the stability of the deep foundation pit using bored piles with steel support meets the requirements, meaning the design of this support form is safe and reasonable, thus ensuring the smooth progress of the project. Conclusion: The stability analysis of deep foundation pits in sandy pebble stratum provides ideas for the optimization of deep foundation pits and a reference for the stability analysis of deep foundation pits in sandy pebble stratum and other types of stratum.


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