Determination of the Oldman River Dam foundation shear strength

1991 ◽  
Vol 28 (5) ◽  
pp. 698-707 ◽  
Author(s):  
M. M. Davachi ◽  
B. J. Sinclair ◽  
H. H. Hartmaier ◽  
B. L. Baggott ◽  
J. E. Peters
Keyword(s):  
Shear Strength ◽  
Large Diameter ◽  
Site Investigation ◽  
Bedding Plane ◽  
Plane Shear ◽  
Dam Foundation ◽  
Shearing Resistance ◽  
Oldman River

The paper describes the results of site investigation and laboratory testing and the analysis performed for the determination of foundation shear strength at the Oldman River Dam site in southwestern Alberta, Canada. Horizontally bedded claystones, siltstones, and sandstones at the site contain relatively weak bedding-plane shears that adversely affect foundation stability. Data on the bedding-plane shear characteristics were collected by mapping, borehole coring, shaft exploration, and large-diameter sampling. Shear planes of structure-wide continuity were identified. Numerous laboratory direct shear tests were done to measure in situ and residual shear strengths. The design angle of shearing resistance of selected continuous bedding-plane shears was evaluated by summing the representative residual angle of shearing resistance and components of the angle of shearing resistance due to in situ state, roughness, and thickness of the bedding-plane shears. Relatively flat dam slopes were found to be required for stability. The methods used at the Oldman River Dam should be applicable at other sites located in flat-lying mudrock sequences. Key words: Oldman River Dam, foundation shear strength, sedimentary rocks, bedding-plane shear, residual angle of shearing resistance, in situ state, roughness, thickness.

Controlled displacement-rate in situ shear tests with pore pressure measurements

1985 ◽  
Vol 22 (1) ◽  
pp. 136-142 ◽  
Author(s):  
F. S. Shuri ◽  
D. D. Driscoll ◽  
S. J. Garner
Keyword(s):  
Shear Strength ◽  
Pore Pressure ◽  
Shear Zone ◽  
Large Scale ◽  
Bedding Plane ◽  
Western Canada ◽  
Shear Tests ◽  
Plane Shear ◽  
Clay Seam

Two large-scale in situ shear tests were conducted at a damsite in western Canada. The rock at the site is a Cretaceous shale containing a thin clay seam tentatively identified as a bedding-plane shear zone. The material in this seam is significantly weaker than the intact rock and influences the design of certain features of the dam and structures. In order to provide shear strength data for design, two large blocks of shale were sheared along the clay seam. These tests differed from conventional in situ shear tests in two significant ways: the rate of shear displacement was strictly controlled, and pore pressures (both positive and negative) in the shear zone were carefully monitored throughout the test. This note presents the material properties of the shear zone, describes the test equipment and techniques, and discusses the results obtained. Key words: shear strength, in situ testing, pore pressure, shale.

Determination of In-plane Shear Strength of Unidirectional Composite Materials Using the Off-axis Three-point Flexure and Off-axis Tensile Tests

2010 ◽  
Vol 44 (21) ◽  
pp. 2487-2507 ◽  
Author(s):  
G. Vargas ◽  
F. Mujika
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Tensile Tests ◽  
Unidirectional Composite ◽  
Point Of View ◽  
Experimental Point ◽  
Plane Shear ◽  
Lift Off ◽  
Flexure Test

The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports have been taken into account. Some considerations regarding stress and displacement fields are presented. The in-plane shear characterization has been performed on a carbon fiber reinforced unidirectional laminate with several fiber orientation angles: 10°, 20°, 30°, and 45°. Test conditions for both off-axis experimental methods, in order to ensure their applicability, are presented. Off-axis flexure test is considered more suitable than off-axis tensile test for the determination of in-plane shear strength.

scholarly journals CPT-Based Probabilistic Characterization of Undrained Shear Strength of Clay

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mi Tian ◽  
Xiaotao Sheng
Keyword(s):  
Shear Strength ◽  
Correlation Function ◽  
Random Field ◽  
Site Investigation ◽  
Undrained Shear Strength ◽  
Bayesian Approaches ◽  
Probabilistic Characterization ◽  
Undrained Shear

Applying random field theory involves two important issues: the statistical homogeneity (or stationarity) and determination of random field parameters and correlation function. However, the profiles of soil properties are typically assumed to be statistically homogeneous or stationary without rigorous statistical verification. It is also a challenging task to simultaneously determine random field parameters and the correlation function due to a limited amount of direct test data and various uncertainties (e.g., transformation uncertainties) arising during site investigation. This paper presents Bayesian approaches for probabilistic characterization of undrained shear strength using cone penetration test (CPT) data and prior information. Homogeneous soil units are first identified using CPT data and subsequently assessed for weak stationarity by the modified Bartlett test to reject the null hypothesis of stationarity. Then, Bayesian approaches are developed to determine the random field parameters and simultaneously select the most probable correlation function among a pool of candidate correlation functions within the identified statistically homogeneous layers. The proposed approaches are illustrated using CPT data at a clay site in Shanghai, China. It is shown that Bayesian approaches provide a rational tool for proper determination of random field model for probabilistic characterization of undrained shear strength with consideration of transformation uncertainty.

In situ shear tests of soil blocks with roots

1998 ◽  
Vol 35 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Tien H Wu ◽  
Alex Watson
Keyword(s):  
Shear Strength ◽  
Root System ◽  
Tensile Force ◽  
Failure Surface ◽  
Soil Reinforcement ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Shearing Resistance ◽  
Simplified Procedures

In situ shear tests were performed on soil blocks that contained roots to study the contribution of roots to the shear strength in a case where the shear deformation is not constrained to a thin zone. The shearing resistance of the soil-root system, the tensile force in selected roots, and the deformation of the soil block were measured. The roots were exposed after the test and their positions were determined and used to estimate the initial positions. The root force and the shearing resistance of the soil-root system were estimated with known solutions and compared with measured root force and shearing resistance. None of the roots that passed through the shear zone failed in tension at the maximum displacement. As a consequence, the root resistance is much less than that found in a case where the failure surface is restricted to the boundary between a weak soil and a firm base and where roots are anchored in the firm base and fail in tension. Simplified procedures for estimating root forces are suggested for the case of a thick shear zone.Key words: in situ test, roots, shear strength, slope stability, soil reinforcement, soil–root interaction.

In-Plane Shear Strength Determination of Composite Materials in Laminated and Sandwich Panels

1997 ◽  
Vol 50 (11S) ◽  
pp. S237-S240 ◽  
Author(s):  
J. R. Vinson
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Laminated Composite ◽  
Adhesive Bond ◽  
Shear Stresses ◽  
Plane Shear ◽  
Laminated Composite Materials

A simple test procedure is available to determine the in-plane shear strength of laminated composite materials, as well as other orthotropic and isotropic advanced material systems. The test apparatus is simple, inexpensive, and the flat rectangular plate test specimen is not restricted in size or aspect ratio. In addition to its use for laminated composite materials, the test can also be used for foam core sandwich panels. In sandwich panels, the tests can be used to determine the in-plane shear strength of the faces, the core and/or the adhesive bond between face and core. The shear stresses developed vary linearly in the thickness direction and are constant over the entire planform area.

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