Shear strength parameters from back-analysis of single slips

Géotechnique ◽  
2001 ◽  
Vol 51 (4) ◽  
pp. 373-374 ◽  
Author(s):  
L. D. Wesley ◽  
V. Leelaratnam
Keyword(s):  
Shear Strength ◽  
Back Analysis ◽  
Shear Strength Parameters ◽  
Strength Parameters

A landslide in till near Warman, Saskatchewan, Canada

1985 ◽  
Vol 22 (2) ◽  
pp. 195-204 ◽  
Author(s):  
E. Karl Sauer ◽  
E. A. Christiansen
Keyword(s):  
Shear Strength ◽  
Water Table ◽  
Back Analysis ◽  
Clay Content ◽  
Aerial Photographs ◽  
Adjacent Area ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Residual Shear Strength ◽  
Insight Into

Little information is available about typical shear strength parameters of tills in southern Saskatchewan even though till is the most common earth material used for construction in this region. The Warman landslide in the South Saskatchewan River Valley provides some insight into the shear strength characteristics of a till, and the results are compared with laboratory tests. The till is from the Upper till of the Sutherland Group, which has a high clay content relative to the underlying and overlying tills. A back analysis of the landslide produced [Formula: see text]′ = 27° assuming c′ = 0. Comparison with laboratory test data and results from a similar landslide near Lebret, Saskatchewan, suggests that [Formula: see text]′ = 22.5° with c′ = 7 kPa may be appropriate "residual" shear strength parameters. A rising water table appears to have been the main contributing factor to instability between 1969 and 1984. There is a possibility, however, that at the 1:50 return interval for flood levels on the river, erosion at the toe of the landslide debris may be a significant factor. Numerous slump scars in the form of small amphitheatres, presently inactive, can be observed in the aerial photographs of the adjacent area. These failures likely occurred intermittently, depending on fluctuating water table and river flood levels. Key words: landslide, till, correlation, stratigraphy, back analysis, shear strength, residual, aerial photographs.

Application of the Complex Variable Differential Method in the Back Analysis of Geotechnical Engineering

2010 ◽  
Vol 168-170 ◽  
pp. 2439-2444
Author(s):  
Ming Wei Liu ◽  
Ying Ren Zheng
Keyword(s):  
Shear Strength ◽  
Complex Variable ◽  
Back Analysis ◽  
Optimization Method ◽  
Differential Method ◽  
Analysis Method ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Measuring Point ◽  
The Stability

On the stability analysis of complex slope, the determination of rock-soil masses shear strength parameters is very important. It’s very necessary to use the back analysis method to verify experiment result of rock-soil masses parameters for the important slope engineering. Because the sensitivity of shear strength parameters to displacement parameters is very poor, so that we couldn’t get the satisfactory shear strength parameters result by traditional back analysis method. Aiming at the problems of traditional back analysis method, this paper puts forward a totally new method of back analysis, which is applicable to the shear strength parameters of rock-soil masses through the integration of complex variable differentiation method, optimization method and elastic-plasticity finite-element method. The method mathematically back calculates shear strength parameters of rock-soil masses on the basis of displacement of measuring point. The sample calculation result indicates that the method possesses high accuracy and searching efficiency, and is a method of back analysis of displacement deserving popularizing.

Stability of swelling clay embankments

1979 ◽  
Vol 16 (1) ◽  
pp. 140-151 ◽  
Author(s):  
R. A. Widger ◽  
D. G. Fredlund
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Back Analysis ◽  
Triaxial Tests ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Total Strength ◽  
Swelling Soils ◽  
Pore Water Pressures ◽  
Matrix Suction

A common occurrence in cuts or fills of swelling soils is their reduction in strength with time. At the time of compaction, the clay generally has a high matrix suction. Correspondingly, it has a high strength and will stand at relatively steep side slopes. With time, the soil generally tends towards saturation and the matrix suction reduces towards zero. There is a reduction in total strength and if the gravitational forces are too large, the slope fails.During the past several years, numerous cut and fill slopes have been observed in the Regina area of Saskatchewan. Many of these slopes have remained stable for 4–6 years and then failed. There has been a 20 year history of observations on the Belle Plaine overpass west of Regina. Field and laboratory investigations have been conducted.With a knowledge of the geometry of the slope and failure plane, the simplified Bishop method of stability analysis was used to perform a 'back-analysis' to assess the shear strength parameters. The shear strength parameters from the laboratory program are compared with those calculated from the stability analyses. The analyses indicate that the peak shear strength parameters from triaxial tests on the softened Regina clay (i.e., c' = 5 kPa and [Formula: see text]), with the appropriate pore water pressures, give a factor of safety of 1 for the failed surface. The effect of spring thawing appears to be to produce the condition of most serious pore water pressures.

scholarly journals Stability analysis of construction and demolition waste (CDW) deposits in theabandoned quarry of Profitis Ilias, Kozani, Greece.

2013 ◽  
Vol 47 (4) ◽  
pp. 1706
Author(s):  
G. Konstantopoulou ◽  
N. Spanou
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Back Analysis ◽  
Field Tests ◽  
Construction And Demolition Waste ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Demolition Waste ◽  
Waste Dumps ◽  
Wide Range

Abandoned quarries become favourable sites for uncontrolled waste dumps, causing major safety hazards because of potential mass movements. An old quarry, near the town of Kozani, is filled with 772.000 m3 Construction and Demolition Wastes (CDW), containing a variety of materials (aggregates, wood, metals, plastics, bricks, soil etc.), in a wide range of fragment sizes, from clay to boulders. The size of particles and voids influence the behaviour of the filled slope, affecting both shear strength and drainage characteristics. Major factors that should be considered in a stability analysis for CDW, include waste material and soil cover composition, overall degree of compaction, moisture contented, permeability, pore pressure and shear strength parameters. Shear strength parameters were chosen by bibliographic references based on specialized field tests of similar materials. The analyzed profiles computed slip zones of low thickness and range. Therefore, successive back analysis was conducted to the sites of mapped cracks, aimed to determinate the mechanical properties of the slope during the failure. Since, friction angle and bulk density were retained for back analysis, the cohesion was examined. Although deposits are composed of loose heterogeneous materials, which have not been condensed, cohesion exists owing to the "interlocking" of the varying particle size of materials.

scholarly journals Determination of Shear Strength Parameters of Rock Mass using Back Analysis Methods and Comparison of Results with Empirical Methods

2017 ◽  
Vol 2 (11) ◽  
pp. 35
Author(s):  
Ehsan Bakhtiyari ◽  
Ali Almasi ◽  
Akbar Cheshomi ◽  
Jafar Hassanpour
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Limit Equilibrium ◽  
Back Analysis ◽  
Empirical Method ◽  
Crushed Rock ◽  
Empirical Methods ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Engineering Parameters

In this study, using the collected data from 4 slope failures in one of the central mines of Iran, the shear strength parameters of jointed and crushed rock masses using back analysis method are calculated and its results are compared with the values obtained from the empirical methods.  In this regard, firstly, the identification of failures is investigated and then geometrical and geological engineering parameters of slopes are collected and recorded by field survey. At this stage, using the Hoek-Brown criterion, shear strength parameters of the rock mass are estimated. Then, using appropriate software for slope stability analysis (limit equilibrium method software: SLIDE and numerical method software: FLAC), and assuming that safety factor is one, the shear strength parameters for sliding surfaces are determined. Finally, the results obtained from this analysis are compared with the results of the empirical methods and then suggestions are made to modify the input data of empirical method

Application of Back Analysis Method in Selecting Shear Strength Parameters for Hutoumao Landslide

2014 ◽  
Vol 1065-1069 ◽  
pp. 11-14
Author(s):  
Yong Jun Li ◽  
Chao Liu ◽  
Li Jun Su
Keyword(s):  
Shear Strength ◽  
Laboratory Experiment ◽  
Back Analysis ◽  
Analysis Method ◽  
Shear Strength Parameters ◽  
Strength Parameters

Laboratory experiment and back analysis are common methods for selecting shear strength parameters. However, every way has its shortcomings. A way combining two methods is used to determine shear strength parameters for Hutoumao landslide. The result can meet the need of project according to comparison experience value.

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