Geomechanics Laboratory


The Geomechanics Laboratory contains tools for 3D visualization, geomechanical computations, analog experiments and geologic mapping.

motor-driven deformation apparatus

Analog Modeling: Our new deformation apparatus is composed of two plates, one movable and the other stationary, that can be simultaneously moved in two orthogonal directions by two computer-controlled step motors. Strain trajectories are defined in advance and imported into the computer in the form of CAD files. The computer distributes motion on the two motors to reproduce the desired trajectory. The apparatus can simulate any kind of geological setting (pure extension, compression and strike-slip, as well as transtension, transpression and inversion).

Analog hardware: 1 3D laser scanner, 1 PC, 1 video camera and full equipment for photo editing. With a maximum resolution of 200 dpi, the 3D scanner can track differences in elevation in the order of 100 Microns. Typical models are a quarter million points, after oversampling and optimization. The custom-built PC with 4Gb of RAM, a 256 Mb Nvidia GeForce 7300GT permits fast data acquisition and 3D image analysis. The computer is also equipped with movie and photo editing software (Adobe Premiere; AutoDesk Cleaner XL 1.5;Adobe Creative Suite). The video camera (Canon Elura) is supplemented by two spotlights and tripods to ensure for homogeneous lighting of the model surface. Wet clay and a power drill for water-clay mixing are also available. Our department machinist,a John Sweeney is designing a motorized, computer-controlled movable arm to closely control the position of the scanner in order to avoid the distortions that may derive from poor overlapping when merging contiguous 3D scans.

laser scanner and PC

measuring in situ rock stiffness with a Schmidt hammer

Mapping: Mapping equipment includes a total station with digital data output, a portable, sub-meter precision receiver for the Global Positioning System (GPS) and other standard surveying and mapping equipment.

Computational resources: Computational hardware includes 2 PCs, 1 SGI server and 7 SGI desktop computers. One custom-built Linux workstation is primarily for creation of 3D fault meshes, and an additional custom-built dual-processor PC with a Nvidia GeForce 6600GT high-end video card for both 3D mesh generation and numerical model computation. The 7 SGI O2 computers in the teaching/research lab are used for model construction and 3D data visualization and one SGI Origin 300 dual-processor server is used for model computation. These computers are outfitted with a suite of software for modeling construction, running and result analysis. 

Geomechanics software: Geomechanics Software includes commercial and academic codes such as ANSYS, POLY3D, and FRIC2D.  These codes offer a wide variety of approaches (2D and 3D, kinematic and mechanical, BEM and FEM) to investigate rock deformation. Additionally, Cooke and students have developed an html-based pre-processor for Poly3D that allows the user to interactively prescribe and visualize the input configuration of the fault system prior to running the models.

3D model of active faults in the Los Angeles basin, CA

 

 Model Development and Data analysis: Data analysis software includes NAG Explorer and Transform for data visualization, Excel, Steoronet, Maple for computations as well as ArcView for Geographical Information Systems (GIS) map analysis. Midland Valley LTD supports the geomechanics research at UMass with mulitple licences for 2DMove and 3DMove structural anlaysis and restoration software. This software is used to develop three-dimensinal fault models and to analyze deformation of folding. Additionally, a host of word and image processing software is used to facilitate desktop publishing along with black and white and color laser printers.

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