Pressurized Fluid-Submerged, Internal, Close-Range Photogrammetry System For Laboratory Testing

Description:

Technology # 16-08

 

A Technology for 3-D Measurements of Triaxial Soil Samples

 

The triaxial test, a standard test for measuring soil shear strength, is critical to the design of foundations for all structures founded on soil, such as bridges or buildings. Currently, the cross-sectional area of a triaxial soil sample is assumed during testing, which may lead to strength measurement errors of up to 30%. The device overcomes this error by accurately determining the failure plane of the sample. Furthermore, the internal camera system allows for three-dimensional tracking of hundreds of individual targets on the surface of a sample. Targets are located to within 0.01-mm of their actual location in x-y-z coordinates, allowing for accurate characterization of local deformations on the sample surface. Targets are used to reconstruct three-dimensional models of samples, thereby allowing for measurement of total volumetric changes to within +-0.3% of the actual volume of a sample.

 

Application(s):

 

1) unobstructed, non-contacting, and non-destructive monitoring of a soil sample within the triaxial testing apparatus during all stages of testing

 

2) capture of digital images and video of a soil sample during all stages of testing, and

 

3) three-dimensional modeling of a soil sample at any given stage of testing by using the principles of photogrammetry. 

 

The new system has been shown to provide accurate measurements of soil specimen dimensions, cross-sectional area, level of strain, volume, and failure plane angle as a function of time. The internal system reduces the overall computational effort required for the development of three-dimensional models of soil samples by eliminating many of the required corrections. Currently, there is no reliable alternative for monitoring soil samples during testing.

 

Advantage(s):

 

* Unobstructed observation of soil specimen,

* Elimination of refraction effects through multiple media and curvature of cell wall (simplifies computational efforts).

* Fully functional when submerged in pressurized süicon oil (tested up to a pressure of 150 pounds per square inch or equivalent depth of 350 feet of water).

 

Technology:

A pressurized fluid-submerged, internal, close-range photogrammetry system for laboratory testing improves current triaxial testing methodology. The system allows for 1) unobstructed, remote monitoring of a soil specimen within the apparatus during all stages of testing, 2) capture of digital images and videos of soil specimen during ail stages of testing, and 3) three-dimensional modeling of soil specimen at any given stage of testing using the principles of photogrammetry. The system has been shown to provide accurate measurements of soil specimen dimensions, cross-sectional area, level of strain, volume, and failure plane angle, as a function of time. These parameters are critical to the constitutive modeling of soil behavior. Furthermore, accurate measurement

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The invention is available for licensing. 

For interested parties seeking further information, feel free to contact:

 

Mark Allen Lanoue

Technology Manager / Tech Ventures

University of Arkansas

(479) 575-7243

malanoue@uark.edu

 

Patent Information:
App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Provisional United States 62/259,397 11/24/2015    
Non-Provisional United States 15/360,820 10,542,195 11/23/2016 1/21/2020  
For Information, Contact:
Mark Lanoue
Technology Manager
University of Arkansas
479-575-7243
malanoue@uark.edu
Inventors:
Richard Coffman
Sean Salazar
Keywords:
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