Mechanisms of massive failure for flowthrough rockfill embankments

1995 ◽  
Vol 32 (6) ◽  
pp. 927-938 ◽  
Author(s):  
Vinod K. Garga ◽  
David Hansen ◽  
D. Ronald Townsend
Keyword(s):  
Key Words ◽  
Failure Mechanism ◽  
Slope Failure ◽  
Darcy Flow ◽  
Experimental Measurements ◽  
Embankment Slope ◽  
Rockfill Dam ◽  
Downstream Slope ◽  
The Stability ◽  
Rotational Failure

A modified wedge method for the analysis of the stability of a downstream slope of a flowthrough rockfill dam is presented. The results from this wedge analysis are compared with results from a conventional Bishop method of analysis, and both are compared with experimental measurements of the forces at incipient failure from model tests performed on simple granular embankments in hydraulic flumes. The proposed wedge method, based on a nonrotational failure mechanism, compared more favourably with experimental observations than did the Bishop method of analysis, based on a rotational failure mechanism. It is also concluded that the Bishop method is very conservative for the analysis of such rockfill slopes. Key words : rockfill embankment, slope failure, bursting forces, model slopes, non-Darcy flow.

scholarly journals PERENCANAAN TUBUH BENDUNGANAIR LUAS KABUPATEN KAUR PROVINSI BENGKULU

2019 ◽  
Vol 9 (1) ◽  
pp. 23-37
Author(s):  
Robet Firmansyah ◽  
Besperi Besperi ◽  
Muhammad Fauzi
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
The Body ◽  
Rockfill Dam ◽  
Discharge Plan ◽  
Downstream Slope ◽  
Flow Filtration ◽  
The Stability ◽  
Base Elevation ◽  
Filtration Capacity

The purpose of this study was to plan the dimensions of the dam body that is technically feasible to build, as well as secure the stability. Flood discharge plan used amounted to 1,152 meters cubic/ sec with a return period of 1000 years. Based on the analysis that has been done, get a plan of flood water level is + 303,22 meters, surveillance obtained high of 3,0 meters, the body of the dam crest elevation gained + 306,22 meters high dam that is obtained by subtracting the height elevation of the peak body dam with a base elevation of the dam is 56,16 meters, width of the dam crest beacon of 11.0 meters, rockfill the upstream slope of 1:3 and for rockfill downstream slope is 1: 2,.25. Using the scheme of depression line formation with drainage leg with a graphic way, do not occur out of the body dam seepage and flow filtration capacity value of the calculation, Q = 9,553 x 10-5 meters cubic / sec, smallest than 2% Qinflow mean = 5,785 mmeters cubic / sec, dam secure against flow filtration. The stability of the main dam of landslide with the value of safety factor in a variety of conditions, namely dams both empty and fully charged in a normal state or an earthquake, for rockfill dam by calculating the weight of the dam, sliding moment, pore water pressure and earthquake loads. Using the method of slices Fellenius glide plane, the value obtained above safe rate (1,2), the planneddam safety to landslides

Forensic Analyses and Rehabilitation of a Failed Highway Embankment Slope in Texas

2021 ◽  
pp. 036119812199635
Author(s):  
Burak Boluk ◽  
Anand J. Puppala ◽  
Sayantan Chakraborty ◽  
Puneet Bhaskar
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Engineering Properties ◽  
High Plasticity ◽  
Slope Failures ◽  
Lime Treatment ◽  
Embankment Slope ◽  
The Stability ◽  
Highway Embankment

A comprehensive investigation was designed and conducted to identify the potential causes of failure of a highway embankment slope in Texas and evaluate the effectiveness of lime treatment to rehabilitate the failed slope. Highway slopes built with high plasticity clays often experience shallow slope failures after exposure to repeated wet–dry weathering cycles. Lime stabilization generally reduces the swell–shrink potential, enhances the engineering properties of problematic clayey soils, and can potentially prevent surficial slope failures. However, exposure to wet–dry cycles can negate some of the benefits of lime treatment and therefore a study was conducted to address the use of this lime treatment to stabilize embankment slopes. Extensive laboratory tests were conducted to study the effect of weathering cycles on the degradation of hydro-mechanical properties of untreated and lime-treated soils. Rainfall-induced slope stability analyses were performed to investigate the probable causes of slope failure and evaluate the stability of lime-treated surficial slope. The optimum stabilizer dosage and treated layer thickness required for the slope rehabilitation were determined based on laboratory tests and numerical analysis results. The stability analysis results indicate that the degradation of surficial soil’s hydro-mechanical properties and the development of a perched water table during prolonged rainfall possibly caused the slope failure. The post-treatment increase in shear strength properties, reduction in moisture fluctuations recorded by embedded moisture sensors, and the presence of newly installed underlying drains are expected to prevent recurrence of surficial slope failures. Salient results from this study are covered in this paper.

Investigation of the stability of boundary layers by a finite-difference model of the Navier—Stokes equations

1976 ◽  
Vol 78 (2) ◽  
pp. 355-383 ◽  
Author(s):  
H. Fasel
Keyword(s):  
Finite Difference ◽  
Stability Theory ◽  
Stokes Equations ◽  
Time Dependent ◽  
Linear Stability Theory ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Navier Stokes Equations ◽  
The Stability ◽  
Small Periodic

The stability of incompressible boundary-layer flows on a semi-infinite flat plate and the growth of disturbances in such flows are investigated by numerical integration of the complete Navier–;Stokes equations for laminar two-dimensional flows. Forced time-dependent disturbances are introduced into the flow field and the reaction of the flow to such disturbances is studied by directly solving the Navier–Stokes equations using a finite-difference method. An implicit finitedifference scheme was developed for the calculation of the extremely unsteady flow fields which arose from the forced time-dependent disturbances. The problem of the numerical stability of the method called for special attention in order to avoid possible distortions of the results caused by the interaction of unstable numerical oscillations with physically meaningful perturbations. A demonstration of the suitability of the numerical method for the investigation of stability and the initial growth of disturbances is presented for small periodic perturbations. For this particular case the numerical results can be compared with linear stability theory and experimental measurements. In this paper a number of numerical calculations for small periodic disturbances are discussed in detail. The results are generally in fairly close agreement with linear stability theory or experimental measurements.

scholarly journals Unsteady Gapwise Periodicity of Oscillating Cascaded Airfoils

1982 ◽  
Author(s):  
F. O. Carta
Keyword(s):  
Unsteady Flow ◽  
Fourier Coefficient ◽  
Phase Angle ◽  
Leading Edge ◽  
Experimental Measurements ◽  
Pressure Data ◽  
Linear Cascade ◽  
Aerodynamic Damping ◽  
The Stability ◽  
Interblade Phase Angle

Tests were conducted on a linear cascade of airfoils oscillating in pitch to measure the unsteady pressure response on selected blades along the leading edge plane of the cascade and over the chord of the center blade. The pressure data were reduced to Fourier coefficient form for direct comparison, and were also processed to yield integrated loads and, particularly, the aerodynamic damping coefficient. In addition, results from two unsteady theories for cascaded blades with nonzero thickness and camber were compared with the experimental measurements. The three primary results that emerged from this investigation were: (a) from the leading edge plane blade data, the cascade was judged to be periodic in unsteady flow over the range of parameters tested, (b) as before, the interblade phase angle was found to be the single most important parameter affecting the stability of the oscillating cascade blades, and (c) the real blade theory and the experiment were in excellent agreement for the several cases chosen for comparison.

Numerical analysis of the anti-seepage measures for high earth rockfill dam on deep overburden

2012 ◽  
Vol 170-173 ◽  
pp. 1872-1877 ◽  
Author(s):  
Jun Yan ◽  
Si Hong Liu ◽  
Bin Zhou
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Seepage Field ◽  
Seepage Analysis ◽  
The Real ◽  
Rockfill Dam ◽  
The Stability ◽  
High Rockfill Dam ◽  
At Home

The anti-seepage measures of a high earth rockfill dam built on the foundation with a deep overburden affects the stability and safety of the dam greatly. Nowadays there are few researches on this area both at home and abroad. On the basis of the finite element seepage analysis of the Pubugou high rockfill dam in which core walls and two cut-off walls are designed as the anti-seepage measures, the real seepage behavior of the seepage field is obtained in this paper, as well as the seepage characters of the seepage field under different arrangements of the cut-off walls. The conclusions have a certain referential value for the design of the anti-seepage measures for the similar projects with the foundation of a deep overburden.

scholarly journals Failure Mechanism and Mitigation Measures of the G1002 Electricity Pylon Landslide at the Jinping I Hydropower Station

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Gang Luo ◽  
Yutian Zhong ◽  
Yuanxiang Yang
Keyword(s):  
Failure Mechanism ◽  
Power Transmission ◽  
Heavy Precipitation ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Hydropower Station ◽  
Residual Soil ◽  
Valley Slope ◽  
Jinping I Hydropower Station ◽  
The Stability

On August 29 and 30, 2012, local extreme rainfalls struck the construction area of the Jinping I Hydropower Station, Xichang, China, and triggered many geohazards. The upper region of the left valley slope 200 m downstream of the dam failed and slid, exposing the D-pile of the G1002 electricity pylon and threatening the entire power transmission line. Therefore, guaranteeing the stability of the residual soil masses in the rear area of the main scarp and the safety of the G1002 electricity pylon became a primary emergency task. Geological field surveys, topographical mapping, study of the failure mechanisms, and stability evaluations were carried out from October 12, 2012, to November 7, 2013. It is revealed that the failure mechanism of the G1002 electricity pylon landslide is flood-induced tractive sliding along the interlayer between the colluvium and the bedrock, significantly influenced by heavy precipitation and frequent blasting activities during the dam construction. The residual soil masses around the G1002 electricity pylon foundation are unstable under rainfall conditions. In order to ensure the stability of the residual soil masses and pylon foundation, a mitigation measure of the anchor cables combined with lattice frame beams was proposed and applied in practice. This paper provides insights into the problems associated with the selection of the locations of electricity pylons in ravine regions as well as mitigation strategies for similar landslides.

scholarly journals Comparative study of material point method and upper bound limit analysis in slope stability analysis

2020 ◽  
Vol 2 (1) ◽  
pp. 44-57
Author(s):  
Lianheng Zhao ◽  
Nan Qiao ◽  
Zhigang Zhao ◽  
Shi Zuo ◽  
Xiang Wang
Keyword(s):  
Stability Analysis ◽  
Upper Bound ◽  
Limit Analysis ◽  
Slope Failure ◽  
Slip Surface ◽  
Material Point Method ◽  
Material Point ◽  
Critical Slip Surface ◽  
The Stability ◽  
Upper Bound Limit Analysis

Abstract The upper bound limit analysis (UBLA) is one of the key research directions in geotechnical engineering and is widely used in engineering practice. UBLA assumes that the slip surface with the minimum factor of safety (FSmin) is the critical slip surface, and then applies it to slope stability analysis. However, the hypothesis of UBLA has not been systematically verified, which may be due to the fact that the traditional numerical method is difficult to simulate the large deformation. In this study, in order to systematically verify the assumption of UBLA, material point method (MPM), which is suitable to simulate the large deformation of continuous media, is used to simulate the whole process of the slope failure, including the large-scale transportation and deposition of soil mass after slope failure. And a series of comparative studies are conducted on the stability of cohesive slopes using UBLA and MPM. The proposed study indicated that the slope angle, internal friction angle and cohesion have a remarkable effect on the slip surface of the cohesive slope. Also, for stable slopes, the calculation results of the two are relatively close. However, for unstable slopes, the slider volume determined by the UBLA is much smaller than the slider volume determined by the MPM. In other words, for unstable slopes, the critical slip surface of UBLA is very different from the slip surface when the slope failure occurs, and when the UBLA is applied to the stability analysis of unstable slope, it will lead to extremely unfavorable results.

scholarly journals Comprehensive Method to Test the Stability of High Bedding Rock Slop Subjected to Atomized Rain

2020 ◽  
Vol 10 (5) ◽  
pp. 1577
Author(s):  
Zheng-jun Hou ◽  
Bao-quan Yang ◽  
Lin Zhang ◽  
Yuan Chen ◽  
Geng-xin Yang
Keyword(s):  
Slope Failure ◽  
Rock Slope ◽  
Evaluation Method ◽  
Failure Modes ◽  
Similarity Theory ◽  
Fem Simulation ◽  
Strength Reduction ◽  
Comprehensive Method ◽  
The Stability ◽  
Bedding Rock Slope

In the construction of high dams, many high rock slope failures occur due to flood discharge atomized rain. Based on the steel frame lifting technique and strength reduction materials, a comprehensive method is proposed in this paper to study the stability of high bedding rock slope subjected to atomized rain. The safety factor expression of the comprehensive method and the evaluation method for deformation instability were established according to the similarity theory of geomechanical model, failure criterion, and mutation theory. Strength reduction materials were developed to simulate the strength reduction of structural planes caused by rainfall infiltration. A typical test was carried out on the high bedding rock slope in the Baihetan Hydropower Station. The results showed that the failure modes of the bedding rock slope were of two types: sliding–fracturing and fracturing–sliding. The first slip block at the exposed place of the structural plane was sliding–fracturing. Other succeeding slip blocks were mainly of the fracturing–sliding type due to the blocking effect of the first slip block. The failure sequence of the slip blocks along the structural planes was graded into multiple levels. The slip blocks along the upper structural planes were formed first. Concrete plugs had effective reinforcement to improve the shear resistance of the structural planes and inhibit rock dislocation. Finite element method (FEM) simulation was also performed to simulate the whole process of slope failure. The FEM simulation results agreed well with the test results. This research provides an improved understanding of the physical behavior and the failure modes of high bedding rock slopes subjected to atomized rain.

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