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Calculation of Frost Heave Force and Analysis of Frost Heave Mechanism Induced by Water Accumulation in Voids behind Tunnel Lining in Cold-regions
(1. School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan750021；2. School of Civil Engineering，Central South University，Changsha 410075)
Abstract This study investigates the issues of lining cracking and spalling caused by frost heave of accumulated water in voids behind lining in cold-region tunnels. Theoretical research on the calculation of frost heave force of accumulated water in voids behind tunnel lining was conducted. By introducing a frost heave force calculation model that accounts for drainage conditions, the freezing process of accumulated water in circular wedge-shaped voids under temperature fluctuations was analyzed, and the mechanism of frost heave force formation was revealed. The results show that the frost heave force increases with the height of the void but changes insignificantly with the void length. For voids outside the waterproof layer, the drainage coefficient is 0, and no frost heave force is generated during freezing.For voids inside the waterproof layer, when the drainage channel freezes first (drainage coefficient=1), the closer the drainage channel is to the bottom of the void, the larger the drainage coefficient and the bigger the frost heave force in the void. Freezing of water in the void begins at the thinnest edge and progresses toward thicker regions of the void. Under daily cyclic temperature fluctuations, the melting process of ice in the void is homology to the freezing process, that is ,the phenomenon of freezing and thrawing first. Under daily periodic fluctuations, the freeze-thaw and water recharge-freeze processes in voids inside the waterproof layer lead to a gradual increase in frost heave force.
Abstract：
This study investigates the issues of lining cracking and spalling caused by frost heave of accumulated water in voids behind lining in cold-region tunnels. Theoretical research on the calculation of frost heave force of accumulated water in voids behind tunnel lining was conducted. By introducing a frost heave force calculation model that accounts for drainage conditions, the freezing process of accumulated water in circular wedge-shaped voids under temperature fluctuations was analyzed, and the mechanism of frost heave force formation was revealed. The results show that the frost heave force increases with the height of the void but changes insignificantly with the void length. For voids outside the waterproof layer, the drainage coefficient is 0, and no frost heave force is generated during freezing.For voids inside the waterproof layer, when the drainage channel freezes first (drainage coefficient=1), the closer the drainage channel is to the bottom of the void, the larger the drainage coefficient and the bigger the frost heave force in the void. Freezing of water in the void begins at the thinnest edge and progresses toward thicker regions of the void. Under daily cyclic temperature fluctuations, the melting process of ice in the void is homology to the freezing process, that is ,the phenomenon of freezing and thrawing first. Under daily periodic fluctuations, the freeze-thaw and water recharge-freeze processes in voids inside the waterproof layer lead to a gradual increase in frost heave force.
XU Peng1 YANG Ruisong1 WU Yimin2
.Calculation of Frost Heave Force and Analysis of Frost Heave Mechanism Induced by Water Accumulation in Voids behind Tunnel Lining in Cold-regions[J] MODERN TUNNELLING TECHNOLOGY, 2024,V61(6): 55-63
2024, Vol. 61 