Subgrade deformation forecast of frozen soil based on phase space reconstruction

The rules of permafrost subgrade deformation were analyzed by maximal Lyapunov exponent method, the phase space reconstruction of subgrade deformation was discussed. It is pointed that various delay time and embedment dimension are two important influence factors on the exponent, when delay time equals 1, embedment dimension equals 5, steady maximal Lyapunov exponent is 0.005 28. Using the exponent value, the maximal relative error of deformation forecast value and measure value is 0.749%, the minimal relative error is 0.135%. The results indicate that maximal Lyapunov exponent ideally reflect the chaos characteristic of subgrade deformation, forecasting subgrade deformation by maximal Lyapunov exponent is feasible.