Abstract：Taking the rock anchor beam on the third floor of the underground main power house on the left bank of Shuangjiangkou hydropower station，the world?s highest dam，as the research object，the rock anchor beam surrounding rock failure is characterized by fan shape，plate crack and uplift deformation to the free face. A typical rock burst failure type of super high stress and brittle granite-“sector plate crack uplift type”concept is proposed. It is found that the number and angle of new cracks increase with the increase of the groove width when the groove depth remains unchanged；When the width of the groove is constant，the number and angle of the new cracks increase with the depth of the groove；When the depth and width of the groove remain unchanged，the overbreak increases the number and angle of the new cracks. The concepts and calculation methods of ultra-high stress，brittle rock fracture angle and maximum rock fracture angle are put forward. By using the concept of maximum fracture angle，the concept design of natural formation of rock anchor beam excavation and the refined excavation method of rock anchor beam can be used for reference to similar underground hydropower plants and Sichuan Tibet railway projects in the future.
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2023, Vol. 42 
