caa a22 4500 463163680 CHVBK 20180406164755.0 cr unu---uuuuu 170326e20070501xx s 000 0 eng 10.1007/s11242-006-9059-2 doi (NATIONALLICENCE)springer-10.1007/s11242-006-9059-2 Low-frequency dilatational wave propagation through unsaturated porous media containing two immiscible fluids [Elektronische Daten] [Wei-Cheng Lo, Garrison Sposito, Ernest Majer] An analytical theory is presented for the low-frequency behavior of dilatational waves propagating through a homogeneous elastic porous medium containing two immiscible fluids. The theory is based on the Berryman-Thigpen-Chin (BTC) model, in which capillary pressure effects are neglected. We show that the BTC model equations in the frequency domain can be transformed, at sufficiently low frequencies, into a dissipative wave equation (telegraph equation) and a propagating wave equation in the time domain. These partial differential equations describe two independent modes of dilatational wave motion that are analogous to the Biot fast and slow compressional waves in a single-fluid system. The equations can be solved analytically under a variety of initial and boundary conditions. The stipulation of "low frequency” underlying the derivation of our equations in the time domain is shown to require that the excitation frequency of wave motions be much smaller than a critical frequency. This frequency is shown to be the inverse of an intrinsic time scale that depends on an effective kinematic shear viscosity of the interstitial fluids and the intrinsic permeability of the porous medium. Numerical calculations indicate that the critical frequency in both unconsolidated and consolidated materials containing water and a nonaqueous phase liquid ranges typically from kHz to MHz. Thus engineering problems involving the dynamic response of an unsaturated porous medium to low excitation frequencies (e.g., seismic wave stimulation) should be accurately modeled by our equations after suitable initial and boundary conditions are imposed. Springer Science+Business Media, Inc., 2006 Dilatational waves nationallicence Immiscible fluid flow nationallicence Poroelastic behavior nationallicence Lo Wei-Cheng Department of Hydraulic and Ocean Engineering, National Cheng Kung University, 701, Tainan, Taiwan aut Sposito Garrison Department of Geophysics, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA aut Majer Ernest Department of Geophysics, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA aut Transport in Porous Media Kluwer Academic Publishers 68/1(2007-05-01), 91-105 0169-3913 68:1<91 2007 68 11242 https://doi.org/10.1007/s11242-006-9059-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11242-006-9059-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lo Wei-Cheng Department of Hydraulic and Ocean Engineering, National Cheng Kung University, 701, Tainan, Taiwan aut NATIONALLICENCE 700 1- Sposito Garrison Department of Geophysics, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA aut NATIONALLICENCE 700 1- Majer Ernest Department of Geophysics, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA aut NATIONALLICENCE 773 0- Transport in Porous Media Kluwer Academic Publishers 68/1(2007-05-01), 91-105 0169-3913 68:1<91 2007 68 11242 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer