Effect of three-dimensionality and soil creep on the distribution of vertical stressesσ _y above tunnels constructed in the body of a high earth-rock dam

Conclusions

• 1. The effect of three-dimensionality of the site on the distribution of stressesσ _y above the tunnels is considerable; the narrower the site, the greater this effect.

• 2. A deficit of the values ofσ _y relative toγ _sy is noted in all stages of constructing the dam.

• 3. The maximum stressesσ _y above the tunnels are reached in the middle sections of the tunnels and are slightly less thanγ _sy, which can be considered equal to the latter.

• 4. Near the tunnel walls are noted zones having a practically zero value, which is an important factor that must be taken into account when calculating the strength of the tunnels.

• 5. The levels of stressesσ _y near the canyon walls considerably lag behindγ _sy, which applies to all construction stages. On the basis of calculating the SSS of the dam in a three-dimensional rheological formulation, we can propose a stepped scheme of the acting vertical loads, which leads to a saving of tunnel concrete.