scholarly journals An Automated Triaxial Testing System Using a Simple Triaxial Cell for Soils

1989 ◽  
Vol 29 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Tej B.S. Pradhan ◽  
Fumio Tatsuoka ◽  
Yoshiyuki Mohri ◽  
Yasuhiko Sato
Keyword(s):  
Triaxial Testing ◽  
Testing System ◽  
Triaxial Cell

Photogrammetry-Based Method to Determine the Absolute Volume of Soil Specimen during Triaxial Testing

2020 ◽  
Vol 2674 (8) ◽  
pp. 206-218
Author(s):  
Sara Fayek ◽  
Xiaolong Xia ◽  
Lin Li ◽  
Xiong Zhang
Keyword(s):  
Unsaturated Soils ◽  
Optimization Techniques ◽  
Triaxial Tests ◽  
Triaxial Testing ◽  
Soil Specimen ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Absolute Volume ◽  
Triaxial Cell ◽  
The Absolute

Triaxial tests are used extensively to evaluate stress-strain behavior for both saturated and unsaturated soils. A literature review indicates that all conventional triaxial test methods measure the relative volume of soil; however, between the initial measurements and the start of the triaxial tests, there are unavoidably disturbances during installation that cause deviation of soil volume from that at the initial condition. Recently image-based methods have been developed to measure the absolute volume of soil specimens. However, these methods still have a major limitation in their inability to determine top and bottom boundaries between the soil specimen, and the top and bottom caps. This paper proposes a photogrammetry-based method to overcome this limitation by developing a mathematically rigorous technique to determine the upper and lower boundaries of soil specimens during triaxial testing. The photogrammetry technique was used to determine the orientations of the camera, and the shape and location of the acrylic cell. Multiple ray-tracings and least-square optimization techniques were also applied to obtain the coordinates of any point inside the triaxial cell, and thus back-calculate the upper and lower boundaries. With these boundaries and the side surface, a triangular surface mesh was constructed and the specimen volume was then calculated in both unconfined compression tests and triaxial tests. The calculation procedures are presented in detail with validation tests performed on a cylindrical specimen to evaluate the accuracy of the method. Results indicate that the accuracy of the proposed method is up to 0.023% in unconfined compression tests and 0.061% in triaxial tests.

Triaxial Testing System for Seismic Frequencies Measurements with Laser Displacement Sensors

2019 ◽  
Author(s):  
Chuan Lu ◽  
Jakob Brandl ◽  
Nathan Deisman ◽  
Richard Chalaturnyk
Keyword(s):  
Triaxial Testing ◽  
Testing System ◽  
Displacement Sensors ◽  
Seismic Frequencies

True Triaxial Testing System for Clay with Proportional-Integral-Differential (PID) Control

2004 ◽  
Vol 27 (2) ◽  
pp. 11756 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
D Mandeville ◽  
D Penumadu
Keyword(s):  
Pid Control ◽  
Triaxial Testing ◽  
Testing System ◽  
True Triaxial ◽  
Proportional Integral

Development and Application of a New Triaxial Testing System for Subzero Rocks

2020 ◽  
Vol 44 (5) ◽  
pp. 20200054
Author(s):  
Yao Bai ◽  
Ren-Liang Shan ◽  
Yong-Xin Wu ◽  
Peng-Fei Sun
Keyword(s):  
Triaxial Testing ◽  
Testing System

Development of an Improved Test Setup for Measuring the Resilient Modulus of Stabilized Pavement Materials

2019 ◽  
Vol 2673 (2) ◽  
pp. 304-313 ◽  
Author(s):  
Stefan Louw ◽  
Rongzong Wu ◽  
Joseph Hammack ◽  
David Jones
Keyword(s):  
Strain Distribution ◽  
Resilient Modulus ◽  
Cyclic Stress ◽  
Triaxial Testing ◽  
Linear Strain ◽  
Test Setup ◽  
Full Depth Reclamation ◽  
State Highway ◽  
Triaxial Cell ◽  
Non Linear

In a recent study to develop mechanistic empirical relationships for full depth reclamation (FDR) in California, it was determined that the commonly used triaxial testing setup detailed in American Association of State Highway and Transportation Officials (AASHTO) T 307 was not suitable for testing stabilized materials. This paper investigates different testing setups, based on a comprehensive literature review, to determine an appropriate approach for measuring strains on both laboratory-compacted and field-cored specimens. Five different test setups were evaluated, ranging from measurements on the top cap of the triaxial cell, to third-point measurements on the specimen. This study also investigated methods of mounting transducer gauge points on the specimen in a repeatable and accurate manner, and for preparing the specimen ends to mitigate point loads. Two field cores, one sampled from an FDR project with cement stabilization (FDR-PC) and the other from an FDR project with foamed asphalt stabilization (FDR-FA), were subjected to unconfined, low stress cyclic triaxial testing using different deviatoric and seating stresses using each of the five test setups. The effects of non-linear strain distribution on the cyclic stress strain curves were compared. Based on these results, the recommended test setup for determining the resilient modulus of the stabilized material is the third point on-specimen setup for measuring strain. This approach was minimally influenced by the non-linear strain distribution, and provided resilient moduli that closely correlated with stiffnesses back calculated from the falling weight deflectometer deflections measured close to the core locations.

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