Cohen-Macaulay-ness in codimension for simplicial complexes and expansion functor

‎In this paper we show that expansion of a Buchsbaum simplicial‎ ‎complex is $\CM_t$‎, ‎for an optimal integer $t\geq 1$‎. ‎Also‎, ‎by‎ ‎imposing extra assumptions on a $\CM_t$ simplicial complex‎, ‎we prove‎ ‎that it can be obtained from a Buchsbaum complex‎.‎