Abstract To explore the shear resistance effect and failure mechanism of distributed mortise-and-tenon in the pro? cess of dislocation of large-diameter shield tunnel segments, a numerical model was established based on the Jihualu tunnel in Foshan. The laws of shear force-dislocation of circumferential joints under radial and tangential dislocation conditions were revealed. Furthermore, the mechanical characteristics, failure modes and shear bearing capacity of mortise-and-tenon with different sizes in different shear directions were analyzed. And a mechanical model calculating the radial shear bearing capacity of tenon was established. The distributed mortise-and-tenons can restrict lining dislocation, improve the shear resistance of circumferential joints, and inhibit further yielding of oblique bolt and further damage to the concrete. Compression damage of the root of the tenon is severe under radial dislocation condition, which causes the reduction of the shear bearing capacity. And the tenon tends to be sheared off when the height-thickness ratio k is less than 6. While tenon is damaged by local compression due to stress concentration under tangential condition. The calculation results of the mechanical model are consistent with the numerical simulation results, which can provide a reference for the design of the size of the distributed mortise-and-tenon.
Abstract：
To explore the shear resistance effect and failure mechanism of distributed mortise-and-tenon in the pro? cess of dislocation of large-diameter shield tunnel segments, a numerical model was established based on the Jihualu tunnel in Foshan. The laws of shear force-dislocation of circumferential joints under radial and tangential dislocation conditions were revealed. Furthermore, the mechanical characteristics, failure modes and shear bearing capacity of mortise-and-tenon with different sizes in different shear directions were analyzed. And a mechanical model calculating the radial shear bearing capacity of tenon was established. The distributed mortise-and-tenons can restrict lining dislocation, improve the shear resistance of circumferential joints, and inhibit further yielding of oblique bolt and further damage to the concrete. Compression damage of the root of the tenon is severe under radial dislocation condition, which causes the reduction of the shear bearing capacity. And the tenon tends to be sheared off when the height-thickness ratio k is less than 6. While tenon is damaged by local compression due to stress concentration under tangential condition. The calculation results of the mechanical model are consistent with the numerical simulation results, which can provide a reference for the design of the size of the distributed mortise-and-tenon.
2022, Vol. 59 