Research Interests

I have broad research interests, both experimental and numerical, in geotecnical engineering. They can be categorized into: 1. Constitutive Modeling and Computation Mechanics; 2. Innovative Geotechnical Testing; and 3. Nano-geomechanics, Bio-geomechanics and Geo-Environmental Sustainability.

Research Highlights

Large-scale railroad ballast triaxial testing
	A custom-made triaxial testing apparatus was designed for testing prototype railroad ballast containing particle size up to 63.5 mm. Unique to this testing apparatus is the use of vacuum as confinement to allow an unobstructed digital image measurement of specimen volume change during testing. Both monotonic and repeated loading triaxial tests were performed to evaluate the validity of the parallel gradation technique. Fatigue behavior including shakedown was also investigated.
Reference Sevi, A.F., Ge, L., and Take, A. (2009). A large-scale triaxial apparatus for prototype railroad ballast testing, Geotechnical Testing Journal, 32(4), 297-304.

Transparent soil and particle image velocimetry (PIV)
	The mixture of silica gel and pore fluid of matched refractive index has been used as transparent media to mimic behavior of sands. Previous study has shown the use of transparent soil and PIV to examine the soil deformation beneath a square footing under vertical static loading in a small scale model test. My research group advanced the use of transparent soil and PIV in 1) examined the dynamic properties including shear modulus and damping ratio; 2) identified low viscosity pore fluid; 3) developed a neural network based digital camera calibration procedure for PIV.
Reference Zhao, H., and Ge, L. (2008). Camera calibration using neural network for image-based deformation measurement systems, Geotechnical Testing Journal, 31(2), 192-197. Zhao, H., Ge, L., and Luna, R., Low viscosity pore fluid to manufacture transparent soil, Geotechnical Testing Journal. (accepted)

Nondestructive testing on compacted soil
	We developed a laboratory procedure for the Briaud Compaction Device to evaluate compacted silt. The modulus determined by the BCD was compared to the dynamic elastic moduli (Young’s and Shear moduli) determined from ultrasonic pulse velocity testing on the same compacted silt samples. We also used the thermal conductivity measurement to correlate to the bulk density and water content. It was further correlated to Young’s modulus, and Shear modulus of the compacted silt, which were determined through ultrasonic pulse velocity measurements.
Reference Weidinger, D.M., and Ge, L. (2009). Laboratory evaluation of the Briaud Compaction Device, Journal of Geotechnical and Geoenvironmental Engineering, 135(10), 1543-1546. Hotz, R.D., and Ge, L. (2010). Investigation of the thermal conductivity of compacted silts and its correlation to the elastic modulus, Journal of Materials in Civil Engineering, 22(4). (in press)