Deformation Characteristics of Surrounding Rock and Support Structure in Diversion Tunnel

LING Fei

doi:10.3969/j.issn.1004-7328.2026.07.018

Abstract：To study the effects of surrounding rock and support structure of diversion tunnels on time-dependent deformation of the cavern,numerical calculations were conducted using finite element analysis software to analyze the time-dependent laws of stress and deformation of surrounding rock under different anchor bolt lengths and moisture content conditions.The results show that surrounding rock displacement increases with time,and long anchor bolts can effectively restrict surrounding rock deformation;the longer the anchor bolt,the smaller the surrounding rock displacement.After 80 d of tunnel support,the surrounding rock displacement under the 5.0 m anchor bolt condition decreased by 36.55%and 64.02%compared to the 3.0 m and 2.0 m anchor bolts,respectively.The normal stress of the surrounding rock gradually increases with time,with faster stress increase in the early stage and slower growth in the later stage.Under the 2.0 m anchor bolt condition,the normal stress at 80 d increased by 63.46%compared to that at 40 d,and increased by 1.40%at 360 d compared to that at 320 d.The normal stress of the surrounding rock decreases with increasing moisture content;at 100 d with a moisture content of 20%,the normal stress decreased by 10.74%and 21.74%compared to moisture contents of 14%and 8%,respectively.