MIAB^{©}

ISSN 0236-1493

Mining informational and analytical bulletin

(scientific and technical journal)

The data on stress state of two-way tunnel lining at different stages of soil mass defrostation are presented in terms of a section in a two-way running tunnel. The research activities included determination of frozen soil characteristics, selection of soil mass model, construction of calculation model, calculations and finding of major variation patterns in the stress state of tunnel lining. It is found that after lining construction, injection of mortar in the gap behind the lining and development of strength, the lining takes over loads of rock pressure and hydrostatic pressure transferred from external boundaries of frozen soil. During defrosting, after partial thawing of soil, extra compression of the lining takes place with the simultaneous degradation of the lining–soil cohesion. This results in the increase in the stresses on the inner layer of the lining, on the one hand, and in the decrease in the stresses on the outer layer of the lining, on the other hand. After complete thawing of soil mass, the lining takes over total hydrostatic pressure. At the same time, the ascending force of groundwater manifests itself, which reduces the load due to rock pressure. As a consequence, the maximum stresses at the lining outback reduce slightly. On the whole, no hazardous stresses arose in the lining at any stage of defrostation. The worst estimated scenario is interaction of the lining with nonuniformly thawed soil. In this case, the lining experiences asymmetry of stresses and shift of peak compressive and tensile stresses off the central axes of the tunnel.

** For citation: **Pleshko M. S., Pleshko M. V., Voynov I. V., Kostyukhov A. V. Stress state analysis of twoway tunnel lining at different stages of soil defrostation.

**Keywords**

Tunnel, lining, mathematical model, artificial freezing, stresses.

**Issue number**: 10 **Year**: 2019 **ISBN**: 0236-1493 **UDK**: 624.195 **DOI**: 10.25018/0236-1493-2019-10-0-160-171 **Authors**: Pleshko M. S., Pleshko M. V., Voynov I. V., Kostyukhov A. V.

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