scholarly journals Local Stability of Trench for Diaphragm Walls Passing through Deep Weak Interlayer

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Chen-Liang An ◽  
Wei-Xing Feng ◽  
Qiang-Hu Zhao ◽  
Luo-Luo Ji ◽  
De-liang He ◽  
...  
Keyword(s):  
Internal Friction ◽  
Local Stability ◽  
Limit Equilibrium ◽  
Great Influence ◽  
Equilibrium Analysis ◽  
Diaphragm Wall ◽  
Local Instability ◽  
Angle Of Internal Friction ◽  
Weak Interlayer ◽  
The Stability

When trench construction of the diaphragm wall passes through an ultradeep and weak interlayer, local instability of the trench wall occurs easily. To study the mechanism of the local instability in the trench and by considering the effect of soil arching based on the length of the trench and the angle of internal friction in the weak interlayer, the disturbed area of the trench is defined to be a semiellipse and the local failure stability model of the semiellipse is established. The local stability safety factor of the trench wall is obtained by the limit equilibrium analysis of the model. By conducting parameter sensitivity studies, the results show that the thickness of the overlying strata, the unit weight of the slurry, the angle of internal friction, and the cohesion of the weak interlayer have a great influence on the stability of the trench wall. The semiellipsoid model is used to analyze the stability of the trench wall of the diaphragm wall of a subway station. The calculated results are basically consistent with the field monitoring results. All the work of the paper shows that the model is practical to some extent.

scholarly journals Slope Stability Analysis of Highway Embankment with Different Height and Slope by Varying the Properties of Soil

2021 ◽  
Vol 9 (VII) ◽  
pp. 3066-3072
Author(s):  
Prof. R. Y. Kale
Keyword(s):  
Internal Friction ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Practical Importance ◽  
Equilibrium Analysis ◽  
Unit Weight ◽  
Cross Sectional ◽  
Angle Of Internal Friction ◽  
Side Slope

The analysis of slope stability has received wide attention nowdays because of its practical importance. To provide steepest slopes which are stable and safe, various investigation are ongoing. The main objective of the project is to analyze slope of embankment by calculating factor of safety. So that an appropriate side slope can be chosen and use for the construction of highway. For this, limit equilibrium analysis has been done using GEO5 software. Swedish circle method (Graphically) has been used to performed manually analysis. In the present study, data collected from the site which is located near Shivni Village, Ner-Yavatmal road. “The construction of Samruddhi Mahamarg” is being constructed at that site. It is having high embankment heights upto 9meter. The values of unit weight of soil(γ), angle of internal friction(ϕ), cross sectional details of embankment and side slope of embankment were taken from that site. In this study, embankment of different heights (3 to 9m) under different 8 slopes (i.e. 1:2, 1:1.75, 1:1.5, 1:1.25, 1:1, 1:0.83, 1:0.7, 1:0.58), different values of cohesion and friction angle were considered. The analysis has been performed on two different cases: Case I stands for single layer of soil and Case II stands for double layer of soil by varying the value of cohesion and angle of internal friction the changes occur in the value of factor of safety were checked by comparing both results obtained by manual method and by GEO5 software. From this investigation it is found that increasing the value of cohesion and angle of internal friction, the factor of safety against slope stability increases. And for a particular height of embankment factor of safety increases with increase in the flatness of slope. From these results, it is better to use C-ϕ soil rather than ϕ soil as it gives maximum FOS as compared to sandy soil. From the analysis of doubled layered soil, it has been concluded that condition 2(with both soil cohesive) found satisfactory better with respect to condition 1(when one soil cohesive and one soil sandy). By considering condition 2 (both soil cohesive), it has been found that the increment of 25 to 30% in the FOS of condition 1 takes place.

scholarly journals Research Progress on Stability of Slurry Wall Trench of Underground Diaphragm Wall and Design Method of Slurry Unit Weight

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
Chenghua Shi ◽  
Weichao Yang ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Design Method ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Diaphragm Wall ◽  
Research Progress ◽  
Unit Weight ◽  
Extensive Literature ◽  
Slurry Wall ◽  
The Stability

This paper performs an extensive literature survey and example investigation on the stabilisation of slurry wall trenches during the construction of diaphragm wall panel trenches, and the failure modes of slurry wall trench instability, the stability theoretical analysis models and methods, the slurry formation and its protection mechanism, the influence of related factors on slurry wall trench stabilisation, and other related problems are summarized and analyzed emphatically. And then, based on the limit equilibrium analysis method, the mechanical models of the overall stability and local stability of the trench wall are established, respectively, and the design method of slurry unit weight is derived to ensure the stability of the trench wall. Furthermore, an example application shows that the established slurry unit weight design method is reliable. At last, this paper also proposes the focus and direction for follow-up work, that is, to construct an accurate and effective theoretical analysis model of slurry wall trench instability considering the influence of multiple factors and the calculation method of the slurry cake and its mechanical or mathematical relationship with slurry quality.

Influence of C and Φ Values on Slope Supporting by Soil Nailing Wall in Thick Miscellaneous Fill Site

2013 ◽  
Vol 706-708 ◽  
pp. 504-507 ◽  
Author(s):  
Di Wu ◽  
Peng Wang ◽  
Guo Qiang Liu
Keyword(s):  
Internal Friction ◽  
Great Influence ◽  
Friction Angle ◽  
Soil Nailing ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Angle Of Internal Friction ◽  
The Stability ◽  
Slice Method

In recent years, soil nailing wall supporting technology is widely applied in the design of pit supporting. However, in the design of deep foundation pit supporting in miscellaneous fill site, the values of cohesion and angle of internal friction, that is c and φ, are too conservative to be chosen, so the security and economy cannot be obtained together. To study the influence of c and φ values on deep foundation pit supporting design in miscellaneous fill site, Lizheng-FSPw60 was the analysis software, and the circular sliding simple slice method was the theory. It is concluded that cohesion and internal friction angle of the soil have great influence on the stability of the soil nailing wall. Analysis and practice show that if c and φ values are reasonably chosen, the slope supported by soil nailing wall in thick miscellaneous fill site will be much safer, and the project will be less wasteful.

scholarly journals Stability Control of Narmab Dam and Sensitivity Analysis of Reliability Coefficients

2018 ◽  
Vol 4 (9) ◽  
pp. 2197 ◽  
Author(s):  
Atanaz Bahrami Balfeh Teimouri ◽  
Ahad Bagherzadeh Khalkhali
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Internal Friction ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Stability Control ◽  
The Body ◽  
Angle Of Internal Friction ◽  
The Stability ◽  
Static Conditions

Static and quasi-static stability analysis of embankment dams is of vital importance in different stages of dam’s design, construction and operation. The stability can be studied using different techniques which are generally analyzed through Limit Equilibrium Method. Base on this main method, the critical slip surface is selected and the shear strength required to counter the slip at the selected surface is obtained and compared with shear strength of the soil at that surface in order to obtain confidence coefficient. In the present research, the Geo-studio Slope/w software that is a geotechnical software based on finite element method and is widely used in geotechnical field, is employed in order to analyze the stability of the body and foundation of Narmab dam in Golestan province. Narmab dam is a homogeneous embankment dam with a height of 60 m, crest length of 807 m and reservoir volume of 115 million cubic meters. The confidence coefficients provided by the software are compared to the permissible confidence coefficients. Moreover, the sensitivity of the confidence coefficients values to the changes in the effective factors, adhesion and internal friction coefficient, is analyzed. The analyses were performed on 8 values (±5, ±10, ±15, ±20) of c and φ and the obtained values of confidence coefficients were compared. In addition, a comparison was made between different methods of stability analysis. According to the static and quasi-static conditions, Narmab dam is stable in all loading stages (End of Construction, First Impounding and Steady State Seepage and In general, only for the static conditions of the end of construction stage, the sensitivity of adhesion is greater than the angle of internal friction, but, in other conditions and stages, the sensitivity of friction angle has more effects.

Analyses for the stability of potash tailings piles

1993 ◽  
Vol 30 (3) ◽  
pp. 491-505 ◽  
Author(s):  
Delwyn G. Fredlund ◽  
Zai Ming Zhang ◽  
Karen Macdonald
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Field Studies ◽  
Equilibrium Analysis ◽  
Limit Equilibrium Analysis ◽  
Dissipation Model ◽  
The Stability

The stability of potash tailings piles is investigated using a pore-water pressure generation and dissipation model together with a limit equilibrium analysis. It is found that a shallow toe failure mode is generally the most applicable and that the stability may be influenced by pore-water pressure migration below the pile. It is suggested that field studies would be useful in evaluating stability in the toe region of the pile. Key words : potash tailings, slope stability, pore pressure dissipation, solutioning.

scholarly journals Brasília municipal solid waste landfill: a case study on flow and slope stability

2021 ◽  
Vol 44 (3) ◽  
pp. 1-13
Author(s):  
José Fernando Jucá ◽  
Alison Norberto ◽  
José Ivan Santos Júnior ◽  
Fernando Marinho
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Limit Equilibrium ◽  
Drainage System ◽  
Equilibrium Analysis ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Cause Of Failure ◽  
Leachate Level ◽  
The Stability

For geotechnical and environmental reasons, landfills are positioned above the regional water table and thus are formed in unsaturated conditions. This condition can be different if the drainage system and the rain regime of the site are such that they create a level of internal liquid in the landfill. During January and February 2019, excessive movements occurred in the slopes of the Brasília sanitary landfill. A geotechnical investigation indicated that the raised leachate level caused by the clogging of the drainage system contributed to the landfilled waste movements. The limit equilibrium analysis was used to predict the relationship between leachate level and slope stability. In order to understand the process that led to the rupture, flow and stability analysis by limit equilibrium were performed. The parameters associated with flow, water retention capacity, and shear strength were obtained based on literature evaluations. In addition, data from tests were used, which allowed to define more accurately the distribution of pore pressures of liquid that led to the failure. This study allowed to define the cause of failure and also to establish the role of the drainage system in maintaining the stability of the landfill. The studies indicated that although the gain of shear strength of landfill due to the unsaturated condition is negligible, the process of flow in unsaturated medium, associated with climatic aspects, are fundamental for a medium- and long-term analysis.

Formation and Stablity of the Sky Pond Landslide Dam, China

2011 ◽  
Vol 243-249 ◽  
pp. 3189-3200 ◽  
Author(s):  
Yan Hui Song
Keyword(s):  
Yellow River ◽  
Limit Equilibrium ◽  
Landslide Dam ◽  
Equilibrium Analysis ◽  
Qualitative Assessment ◽  
Hydropower Station ◽  
The Yellow River ◽  
Geological Conditions ◽  
Dammed Lake ◽  
The Stability

The Sky Pond landslide dam is located in Muchang valley, a branch of the Yellow River branches. From this point it is about 6Km to the mouth of the valley from where the Yellow River flows 0.8Km downwards to the planned Jishi gorge hydropower station. The Sky Pond landslide dam is actually formed by two landslides from both the left and right bank slopes and completely blocks the seasonal river channel. The volume of the landslide dam is about 14 millions m3 with 2.37 millions m3 water stored in the dammed lake under the condition of perennial mean water level. Because (1) the dam body is large in width and thickness; (2) the dammed lake water is small both in volume and weight compared to the landslide dam; (3) recharge to the dammed lake is basically the same as the discharge every year; and (4) there is a natural spillway in the dam body, the landslide dam is present at least 750 years after its formation. Although landslide dams which have existed for several hundreds to thousands of years are generally considered as stable, there are remains which may fail catastrophically. In order to analyze the stability of the Sky Pond landslide dam and provide justification for the future engineering decisions, this paper describes the engineering geological conditions near the landslide dam and the characteristics of the dam body, and a detailed discussion of the formation mechanism of the landslide. Based on engineering geology investigation, a qualitative assessment of the stability of the dam and an analysis of the probability of dam overtopping and piping is carried out. Limit equilibrium analysis has been used to calculate the stability of the dam slope under various operational conditions. Results of the stability analyses indicate that the Sky Pond landslide dam should remain stable and does not present a potential theat to the planned hydropower station.

scholarly journals Research on the Influence of Weak Interlayer in Open-Pit Slope on Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhong Shuheng ◽  
Miao Yinjun
Keyword(s):  
Sliding Mode ◽  
Limit Equilibrium ◽  
Open Pit ◽  
Weak Layer ◽  
Overall Stability ◽  
Weak Interlayer ◽  
Different Depths ◽  
Dip Angle ◽  
The Stability ◽  
Theoretical Results

The weak interlayer in the slope meets with water threatening the overall stability of the slope. Sequestration location of the weak layer has an impact on the stability of the slope. Based on this, taking the south-side slope of Fushun West Open-Pit Mine as the background, the limit equilibrium method was used to study the influence of different depths and dip angles of weak interlayers on the factor-of-safety and sliding mode of the slope. After analyzing the effect, a bottom friction experiment was conducted to verify the theoretical results. The research results show that, as the buried depth of the weak layer becomes larger and the dip angle becomes smaller, the safety factor of the slope increases. Dip angle and depth both affect the sliding mode of the slope. This can provide a reference for study of the influence mechanism of weak interlayer on slope stability in multi-weak-layer slopes.

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