The Effect of Cementation on Granular Materials

by
Rajarajan Narayanasamy, MSE

University of Texas at Austin, 2002
Supervisor: Jon E. Olson

The numerical simulation of the physical behavior of uncemented and weakly cemented sands is carried out using modeling software based on the Discrete Element Method (DEM). A procedure is developed for triaxial and wave propagation tests using the numerical model. Simulations were carried out to investigate how deformation is influenced by various material properties, such as density, grain stiffness, cement stiffness and cement strength. The stiffness of the grains and cement control Young's modulus while inter-granular friction and the cement strength affect the strength of the specimen. The amount of cement at contact points and timing of cementation also affect the stress-strain behavior of the specimen. The numerical results compare well with the laboratory experiments. The density, stiffness of the material and cement, and the amount of cement affect compression and shear wave velocities (Vp and Vs). A study on the frequency of a propagating wave suggests that specimens with small values of L/D ratio yield better waveforms and less discrepancy in wave velocities. The effect of stress anisotropy on wave velocities is also analyzed. In general, shear waves polarized parallel to the maximum principle stress show higher velocity, but the presence of a wellbore can alter these results.

Back to theses index