Approximate method for determining the influence of water and porosity on the Gruneisen gamma

An expression showing the dependence of the zero pressure Gruneisen gamma (GAMMA0) for solids on the water content (W) and total porosity (phi) of the material under consideration has been developed. It has been assumed in this treatment that the effects of the water can be treated separately from those of the solid material. Then GAMMA0 for the composite material is simply a linear combination of the individual Gruneisen gammas for the water (GAMMA/sub 0W/) and dry, porous material (GAMMA/sub 0S/), with the terms weighted according to the amount of water present, i.e., GAMMA0 = WGAMMA/sub 0W/ + (1 - W)GAMMA/sub 0S/. Values of GAMMA/sub 0S/ are found by using a technique where the Gruneisen gamma for dry, porous material is proportional to (1 - phi)5 times that for solid material. Using the derived expression for GAMMA0 the effects of varying W and phi were studied. For constant W, GAMMA0 decreases with increasing phi. However, for constant phi, the effect of varying W depends upon the value of phi