Problem $3\mathrm{.}2$: Analyze the stability of the concrete gravity dam shown in Figure $3\mathrm{.}54$ for the usual and unusual loading combinations. The following data will be taken in the solution. $f=0\mathrm{.}85,=0\mathrm{.}60,{}_s=6$MPa,${}_c=30$MPa,${}_f=100$MPa, ${}_{\text{c}\text{o}\text{n}}=24k\frac{N}{m^3},=10k\frac{N}{m^3},$ normal operating level is $+75m,$ ice load is $60k\frac{N}{m},h_s=5m,{}_s=11k\frac{N}{m^3},=32.$ In the solution, determine $H^{**}$ and $t_c$ values from Equations $(3\mathrm{.}25)$ and $(3\mathrm{.}26),$ respectively.