  We present a systematic study on the strange and multi-strange particles
production in Pb+Pb collisions at $\sqrt{S_{NN}} = 2.76$ TeV based on the
PACIAE model simulations. Two different mechanisms, namely the single string
structure variations and multiple string interactions, are implemented in the
simulations. These modifications give rise to an enhancement of the string
tension value involved in the Lund string fragmentation framework and generate
more strange particles in the hadronic final state. By comparing the simulation
results with the ALICE experimental data, it turns out that the inclusion of
the variable effective string tension in the PACIAE model is capable to reach
an improved agreement between theory and experiment on the strangeness
production in Pb+Pb collisions.
