The bank slope of hydropower project inevitably encounter unloading effect in operation, and the periodic rise and fall of water level will further degrade the structure of some rock mass on the bank slope, which is easy to breed landslide and seriously threaten people's life and property safety. Therefore, it is necessary to study the unloading mechanical characteristics of jointed sandstone under the water pressure circulation. In this paper, the sandstone of typical bank slope in the Three Gorges Reservoir area is taken as the test object, and the unloading mechanical properties of sandstone with cross joints of different angles are designed and tested under the circulating water pressure. The result shows that the strength of the cross-jointed rock samples is mainly affected by the inclination angle of the main joint α. As α increases from 0° to 90°, the peak strength increases successively. Under the same main joint inclination angle, the peak strength decreases first and then increases when the secondary joint inclination angle β comes from 0° to 90°, and the overall change amplitude is small. The elastic modulus and deformation modulus increase with the increase of α, and decrease first and then increase with the increase of β. The axial and circumferential strain increases with the number of water pressure cycles, and the increasing velocity first increases and then decreases. The increment of axial strain and circumferential strain is maximum at α=60° and minimum at 90°. The deterioration degree of elasticity and deformation modulus of the samples at α=60° is the largest, and the deterioration of the samples at α=60° is the most obvious due to water pressure circulation.
Guo Yongcheng
,
Wang Shunan
,
Li Jianlin
,
Wang Xingxia
,
Zhu Bo
. Unloading Mechanical Characteristics of Jointed Sandstone under Circulating Water Pressure[J]. Chinese Journal of Underground Space and Engineering, 2025
, 21(2)
: 420
-427
.
DOI: 10.20174/j.JUSE.2025.02.07
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