Study on the Deflection Pattern of Principal Strain Axis during Progressive Failure of Tunnel-type Anchorage in Soft Rock
(1.College of River and Ocean Engineering, Chongqing Jiongtong University, Chongqing 400074; 2.School of Civil Engineering, Chongqing University, Chongqing 400045; 3.Chongqing Rock Foundation Research Center, Yangtze River Scientific Research Institute,Chongqing 400014)
Abstract：
To reveal the progressive failure evolution mechanism of tunnel-type anchorage in soft rock during loading, this study focuses on the problem of strain localization during progressive failure of tunnel-type anchorage. A combined approach of similarity model testing and digital image correlation (DIC) technology was used to systematically investigate the development and evolution of the maximum principal strain around the main cracks in the surrounding rock during load bearing of tunnel-type anchorage. Special attention was given to the rotation characteristics of the maximum principal strain axis within the concentrated strain zone throughout the loading process. The results show that: (1) the principal strain axes near the strain concentration zone exhibit clockwise rotation near the crack tip and counterclockwise rotation within the zone; (2) as the load increases, the rotation angle of the principal strain axis at most points within the zone tends to stabilize or slightly decrease; (3) a decrease in the roughness of the anchor-rock interface reduces the displacement in the tensile direction of the anchor plug during the middle and late stages of failure; (4) when new concentrated strain zones develop on both sides of the original principal axis, the rotation of principal axis outside the zone no longer tends to stabilize after change.
LIU Jie LIU Xinrong2 HAN Yafeng1,
2 LIANG Ninghui
.Study on the Deflection Pattern of Principal Strain Axis during Progressive Failure of Tunnel-type Anchorage in Soft Rock[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(3): 190-200
2025, Vol. 62 