Diagnostic model of crack for tunnel lining based on gray and catastrophe theories
Zhang Su-le · 2015
In order to evaluate the stability of crack for tunnel lining by using finite monitoring data,wavelet transform was applied to analyze the monitoring data of cracks for tunnel lining,the high frequency part caused by environmental change and test error was eliminated,and the low frequency part caused by surrounding rock pressure variation was kept,thus,the timedependent deformation of lining crack was decomposed.The GM(1,1)gray prediction model of time-dependent deformation of lining crack was built based on gray theory to predict the later development of lining crack by using early monitoring data.The stability criterion of lining crack was established based on the equilibrium conditions of cusp catastrophe model.The diagnostic model of lining crack was established based on gray and catastrophe theories,and two typical lining cracks were analyzed based on the model.Analysis result indicates that the stability criterion values of two cracks are larger than 0,so,they do not meet the instability condition.The measuredvariations of crack widths are less than 0.2 mm,the variation rates are less than 0.002 mm·d-1,which shows that two cracks are basically stable.Obviously,this diagnostic model can predict the development tendency of lining cracks correctly.6figs,19 refs.