Hadronic interaction features using multiple muon events deep underground

The MACRO underground experiment performed a systematic experimental study of muon bundle structure. The aim is to gain a better understanding of the features of high energy cosmic ray interactions. The reliability of the hadronic interaction model in reproducing the shower development features at the highest energy can be studied selecting high multiplicity muon bundles. We present here the analisys of the muon lateral distribution (decoherence function) based on two different method( detector dependent and detector independent method), the decoherence function in a high multiplicity event subsample and the search for muon clusters