Details

Autor(en) / Beteiligte

• Dvorkin, Jack
• Berryman, Jim
• Nur, Amos

Titel

Elastic moduli of cemented sphere packs

Ist Teil von

• Mechanics of materials, 1999-07, Vol.31 (7), p.461-469

Ort / Verlag

Lausanne: Elsevier Ltd

Erscheinungsjahr

1999

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We present a method for estimating the effective elastic moduli of a dense random pack of identical elastic spheres with elastic binder (cement). The cement concentration in the pore space varies from a few percent (where it fills the space at grain contacts) to 100%. To construct the solution we start at a small cement concentration value where the effective moduli of the pack are given by the contact cement theory (CCT). The next, and most important, step is to obtain the (unknown a priori) elastic moduli at 100% cement concentration. To do so, we: (1) treat the starting cemented pack, that is a three-phase system of grains, cement, and voids, as an elastically equivalent two-phase system of voids in a homogeneous matrix; (2) apply an effective medium theory (EMT) to find the elastic moduli of this matrix; and (3) calculate the effective moduli of this matrix with the voids filled with cement. We treat these moduli as the desired moduli of the pack with 100% cement concentration. We interpolate between this point and the initial (small cement concentration) point by using the EMT to populate the no-void elastic body with voids. Using CCT as the initial construction point gives us control over the microstructure of the composite which proves to be crucial in this modeling. The results predict the compressional elastic modulus (that is the product of density and compressional-wave velocity squared) from wave-propagation experiments on epoxy-cemented glass beads, ice-cemented Ottawa sand, and in-situ acoustic data in natural sands cemented by gas hydrate within experimental accuracy.