  A family of conforming mixed finite elements with mass lumping on triangular
grids are presented for linear elasticity. The stress field is approximated by
symmetric $H({\rm div})-P_k (k\geq 3)$ polynomial tensors enriched with higher
order bubbles so as to allow mass lumping, which can be viewed as the Hu-Zhang
elements enriched with higher order interior bubble functions. The displacement
field is approximated by $C^{-1}-P_{k-1}$ polynomial vectors enriched with
higher order terms to ensure the stability condition. For both the proposed
mixed elements and their mass lumping schemes, optimal error estimates are
derived for the stress with $H(\rm div)$ norm and the displacement with $L^2$
norm. Numerical results confirm the theoretical analysis.
