Formation of thin shells from Lemaitre - Tolman - Bondi dust

We consider two different ways to receive a thin shell from Lemaitre - Tolman - Bondi solution for a dust cloud. The first method consists in taking a vanishing thickness limit of a thick dust layer. In that case we show a contradiction between matching conditions on thin shell and field equation for the dust. The second way is a formation of the shell due to the intersection of dust layers. For smooth initial conditions we provide the weak solution of Einstein equations with singular terms in stress-energy tensor corresponding to a thin shell. We show that the obtained thin shells have nonzero tangential pressure in spite of the absence of interaction between Lemaitre - Tolman - Bondi dust particles.