Shuiwen dizhi gongcheng dizhi (Nov 2022)
An analysis of non-penetration cracks in anti-dip rock slope based on centrifugal test
Abstract
The fracture extension of rock bridges between structural surfaces in different parts of the slope leads to the damage of the anti-dipping laminated rock slope. In order to study the controlling effect of fracture extension of non-penetrating fractures in the slope on the evolution of the slope, the centrifugal model test of the anti-dipping laminated rock slope containing multiple groups of non-penetrating fractures is carried out with the right shoulder of the Miaowei Hydropower Station as the geological prototype to analyze the deformation characteristics of non-penetrating fractures in the anti-dipping laminated rock slope. The results show that the fractures of rock formations containing non-penetrating fractures within the slope finally show five types of fracture patterns, including inter-fracture bridge penetration, penetration between gently dipping fractures and the upper rock layer, penetration between steeply dipping fractures and the lower rock layer, penetration between steeply dipping fractures and the port of gently dipping fractures, and fracture of rock layers at non-fractures, with inter-fracture bridge penetration as the main fracture pattern. Based on fracture mechanics and combined with the principle of fracture superposition, it is found that the instability factor of the rock layer at the main fracture section is the smallest at 1/3 of the slope height and gradually becomes larger towards the foot and both sides of the slope top, while the stress intensity factor gradually decreases from 1/3 of the slope height to the foot and the top of the slope. The fracture extension of cracks controls the slope evolution and is greatly influenced by the crack rate and the tip stress field around the cracks. At the early stage of slope evolution, the compression and settlement of the back edge of the slope and the compression and shear damage of the local rock cracks are the main features, and the dip angle of the rock layers changes greatly, showing a trend of becoming larger from the upper part of the slope to the lower part of the slope. At the middle of the evolution, the fracture extension of the back edge of the slope forms the main fracture surface, and the angle of the rock layers in the middle and upper part of the slope changes greatly. At the end of the evolution, the number of fractures remains stable, and the main deformation feature is characterized by the redistribution of the location of fractured rock layers, the formation of secondary fracture surfaces, further compression between broken rock layers, and further destabilization of the slope body.
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