Abstract The test pieces of interbedded surrounding rock tunnel with different flatness ratios were prefabricated, to study the deformation and failure characteristics around the interbedded surrounding rock tunnel through tests, and numerical simulation was used to analyze and compare the distribution of stress and strain around the interbedded surrounding rock tunnel. Three different flatness ratios of 0.45 (test specimen S), 0.55 (test specimen M) and 0.65(test specimen L) were used respectively. The study shows that the overall failure mode of test specimen S is compression failure mode (TC mode), obvious compression and shear failure easily occurs at the arch waist, and a tension-shear composite crack is formed near the arch shoulder. Test specimen M was subjected to mixed failure (TX mode), in which obvious tensile failure at the arch crown easily occurred, and obvious compression-shear composite crack was formed at the arch shoulder. Test specimen L was subject to the hole failure (TH mode), in which obvious tensile failure easily occurred at the arch crown, and tension-shear composite crack was formed at the arch foot.Moreover, the distribution of stress and strain around the tunnel is significantly related to the compression failure characteristics of tunnels with different flatness ratios, and the difference of stress levels at the same location of the tunnel is the main reason for the different failure modes of the tunnels with three different flatness ratios.
Abstract：
The test pieces of interbedded surrounding rock tunnel with different flatness ratios were prefabricated, to study the deformation and failure characteristics around the interbedded surrounding rock tunnel through tests, and numerical simulation was used to analyze and compare the distribution of stress and strain around the interbedded surrounding rock tunnel. Three different flatness ratios of 0.45 (test specimen S), 0.55 (test specimen M) and 0.65(test specimen L) were used respectively. The study shows that the overall failure mode of test specimen S is compression failure mode (TC mode), obvious compression and shear failure easily occurs at the arch waist, and a tension-shear composite crack is formed near the arch shoulder. Test specimen M was subjected to mixed failure (TX mode), in which obvious tensile failure at the arch crown easily occurred, and obvious compression-shear composite crack was formed at the arch shoulder. Test specimen L was subject to the hole failure (TH mode), in which obvious tensile failure easily occurred at the arch crown, and tension-shear composite crack was formed at the arch foot.Moreover, the distribution of stress and strain around the tunnel is significantly related to the compression failure characteristics of tunnels with different flatness ratios, and the difference of stress levels at the same location of the tunnel is the main reason for the different failure modes of the tunnels with three different flatness ratios.
HONG Ming FAN Xiang YANG Xiaohua REN Xianda
.Deformation Failure Process and Characteristics of Tunnels with Different Flatness Ratios under Horizontal Interbedding Conditions[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(1): 107-118
2023, Vol. 60 