  We consider the geodesic deviation equation, describing the relative
accelerations of nearby particles, and the Raychaudhuri equation, giving the
evolution of the kinematical quantities associated with deformations
(expansion, shear and rotation) in the Weyl type $f(Q,T)$ gravity, in which the
nonmetricity $Q$ is represented in the standard Weyl form, fully determined by
the Weyl vector, while $T$ represents the trace of the matter energy-momentum
tensor. The effects of the Weyl geometry and of the extra force induced by the
nonmetricity-matter coupling are explicitly taken into account. The Newtonian
limit of the theory is investigated, and the generalized Poisson equation,
containing correction terms coming from the Weyl geometry, and from the
geometry matter coupling, is derived. As a physical application of the geodesic
deviation equation the modifications of the tidal forces, due to the
nonmetricity-matter coupling, are obtained in the weak field approximation. The
tidal motion of test particles is directly influenced by the gradients of the
extra force, and of the Weyl vector. As a concrete astrophysical example we
obtain the expression of the Roche limit (the orbital distance at which a
satellite begins to be tidally torn apart by the body it orbits) in the Weyl
type $f(Q,T)$ gravity.
