Act~ : 'VIechanica 76, 89--104 (1989) 1
CorrectionsUpon close inspection of their paper [1], the authors noticed a number of errors that have to be corrected. First of all, the coefficients ax2 and a2~ in equation (13) are not equal. This poses a problem with the reciprocal relation, because unwanted terms appear in equation (19) involving volume integrals of both solid displacements ~ and relative fluid displacements @~. To avoid this, the problem must be reformulated with the absolute fluid displacements Ui replacing wi. In that ease, equations (1) are replaced by Biot's equations in their original formwhile equations (6) and (8) can be disregarded. Next. it should be noted that aij in (4.1) and (10.1) has to be replaced by zo. These changes affect equations (13)
~,i + Xi = (o~s 2 -bs) ~i + (e~s 2 + bs) U~ --(e,~ + e~) (sh~ + ~i)(13) Now, in order to leave all material from Sections 4, 5, 7 and 8 unaffected by the above changes except for the key substitution of Ui in place of wi, the tractions ii should be replaced by ii* = u Equation (48), however, remains as it is apart from changing Np~j to Ujkj. There are also some typing errors. On the first line following equation (15), the term right-hand side must be replaced by the term left-hand side, while the opposite must happen on the first line following equation (19). Also, on the first integral in equations (16), (18) and (19) the primes must be moved from the stresses vii, * to the strains gii, g. A term was missing from equation (34)