Analysis on deformation and load action features of large-deformation bias highway tunnel in soft rock

作者：Lai Hongpeng^*; Yang Wanjing; Xie Yongli

来源：Journal of Central South University(Science and Technology), 2014, 45(6): 1924-1931.

• Bias
• Compressive and tensile stress
• Large-deformation
• Primary support
• Soft rocks
• Step excavation
• Surrounding rock
• Tunnel engineering

In order to find out the distortion and load features of bias highway bedded with soft-rock and severe distortion, citing the project of Yi-Ba Highway Lying Buddha Tunnel in the study, field tests on two typical cross sections were carried out and the features of load and of supports distortion at early phase were analyzed. The results show that the surrounding rock of bias highway tunnel is at high speed of deformation during prior-period, which has stability of long duration and large value of horizontal convergence. The stress of surrounding rock at early stage adds at high speed, and also with changes of long duration. Heavy pressure lies in horizontal surrounding rock and the maximum value lies in the spandrel of comparative bad-condition side of surrounding rock. The concentrated comparative stress lies in the steel arch of good-condition side and concentrated compressive and tensile stress in the other side. The steel arch is severely distorted. Comparatively heavier tensile stress of shotcrete lies in the bad-condition side with serious cracks and large areas of spalling occurred, while the other side carries comparatively heavier compressive stress without meeting the compressive strength of C20 shotcrete. Ahead-of-supporting strength in bad-condition side should be increased, deformation allowances should be increased, primary supports should be increased, and three step excavation method and reserving core soil should be adopted.

• 出版日期2014