Soil shear strength in static and dynamic conditions
This section is fully dedicated to the study of shear strength determination and to the comparison between different type of testing conditions in static and dynamic applications.
A selection of white papers, presentations and technical articles collected to improve the knowledge on this issue.
Test conditions of each system type are also described in the Wykeham Farrance complete range of Shear machines dedicated area and are summerized in the image here below.
Apart from these systems, shear strength determination can also be evaluated by triaxial testing or quick tests as laboratory shear vane tester.
Triaxial tests will be the subject of future deepening of this section Technology Communication.
Direct shear box and ring shear test comparison: why does internal angle of friction vary?
S.N. Osano - Dept. of Civil engineering, University of Nairobi, Kenya
The direct shear box and the ring shear test as conventionally used for measuring the strength parameters of soils for use in classical stability analysis have the major disadvantage that th estress conditions in th especimen during the test are not known...
Drained residual stength for landslides
Timothy D.Stark, F. ASCE, P.E.and Manzoor Hussain, S.M. ASCE - University of Illinois
Drained residual strength is considered applicable for the analysis of slopes with preexisting shear surface. Torsional ring and direct shear tests were performed to investigate the gain in strength, if any, along preexisting shear surface with time. This study shows that after estabilishing the dained residual strength conditions, a measurable strength greater than the drained residual strength is obtained in both torsional ring and direct shear tests at effective normal stresses of 100 kPa or less. However...
A simple technique for determining the shear stregth of fine grained unsaturated soils using the conventional direct shear apparatus
S.K. Vanapalli - Lakehead University, Thunder Bay, Ontario Canada; J.J. Lane - EBA Engineering Consultants Ltd, Edmonton, Alberta, Canada
In recent years, several investigators have developed semi-empirical procedures for predicting the shear strength of unsaturated soils using computing techniques. The input parameters for predicting the unsaturated shear strength include effective shear strength parameters and the soil-water characteristic curve data. The soil-water characteristic curve data is represented as a mathematical equation in the shear strength function. The prediction procedures developed and proposed in the literature are however based using limited experimental data...
Automatic shear machine: who chose it?
The list of SHEARMATIC - pneumatic automatic shear machine's users worldwide
Automatic shear machine for large particles samples up to 300 x 300 mm
The list of SHEARMATIC 300 - hydraulic automatic large shear machine's users worldwide
Cyclic simple shear test on saturated sands
A.Soriano, H. Patino, J.Gonzalez - Universidad Politécnica de Madrid; M. Valderrama - Ingenierìa del Suelo S.A.
The academic articles here proposed concern some examples of design where the dynamic response of important structures have been analyzed through a campaign of laboratory investigation where a consistent number of cyclic simple shear tests have been carried out.
The CSS test consists in the application of a cyclic shear stress causing the angular distortion of a soil element and the continuous rotation of the principal axes of stresses and strains. This condition of stresses simulates quite correctly the situation that occurs within the underground layers of soils when, for example, a seismic event occurs.
System for the Characterization of Soil Samples through Cyclic and Dynamic Tests
In geotechnical engineering, the triaxial test is the laboratory test most commonly used to determinate the stress-strain relationship of a soil, in order to obtain reliable soil parameter, replicating stress conditions experienced during excavations, constructions or natural events.
Dynamic triaxial system for shear strength- stress evaluation
A presentation dedicated to Dynamc Triaxial test systems.
Dynamic triaxial system: who chose it?
The list of DYNATRIAX - dynamic triaxial testing system's users worldwide
Resonant column. To get the real picture
The experience of the autonomous province of Trento testing laboratory.
"Firstly stress is applied to the sample to reproduce the in-situ conditions. All the characteristics of the sample are monitored (level of consolidation, saturation ecc.) and when the desired values are reached, we determine the dynamic shear modulus by shear waves measurement.
In the Caldès Castle restoration project we succeeded in getting very good quality undisturbed samples..."
Resonant column for the definition of the local sismic hazard
A presentation dedicated to resonant column/torsional shear test system.
Resonant column and torsional shear system: who chose it?
The list of RESONANT COLUMN's users worldwide
Soil testing using a Chirp RC
A. Cavallari, Megaris
The Resonant Column (RC) test is the standard to determine dynamic and static parameter of soils and rocks under different shear strain and confining conditions. The test consists of vibrating a cylindrical specimen in torsion establishing a fundamental mode, measuring the resonant frequency and amplitude of vibration with a frequency search.