  We simulate the measurement of the triscalar Higgs coupling at LHC(8,14) via
pair production of h(125 GeV). We find that the most promising hh final state
is bb gamma gamma. We account for deviations of the triscalar coupling from its
SM value and study the effects of this coupling on the hh cross-section and
distributions with cut-based and multivariate methods. Our fit to the hh
production matrix element at LHC(14) with 3 ab^-1 yields a 40% uncertainty on
this coupling in the SM and a range of 25-80% uncertainties for non-SM values.
