Theoretical analysis of a new segmented anchoring style in weakly cemented soft surrounding rock |
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| Affiliation: | 1. Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation, Shandong University of Science & Technology, Qingdao 266590, China;2. State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science & Technology, Qingdao 266590, China;3. College of Mining and Safety Engineering, Shandong University of Science & Technology, Qingdao 266590, China;4. College of Civil Engineering and Architecture, Shandong University of Science & Technology, Qingdao 266590, China;1. State Key laboratory of Deep Geomechanics and Underground Engineering, China University of Mining & Technology, Xuzhou 221008, China;2. School of Resource and Earth Science, China University of Mining & Technology, Xuzhou 221008, China;1. State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Xuzhou 221116, China;2. School of Mechanics & Civil Engineering, China University of Mining & Technology, Xuzhou 221116, China;1. School of Mines, China University of Mining & Technology, Xuzhou 221116, China;2. State Key Laboratory Geomechanics & Deep Underground Engineering, China University of Mining & Technology, Xuzhou 221116, China;3. Xin’an Coal Co., Ltd., Zaozhuang Mining Group, Zaozhuang 277000, China;1. Division of Pediatric Gastroenterology, Hepatology and Nutrition, Columbia University Irving Medical Center;2. NewYork-Presbyterian Morgan Stanley Children’s Hospital, New York;3. Department of Pediatrics, St. Barnabas Hospital, Bronx, New York;4. Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Boston Children’s Hospital and Harvard Medical School, Boston, Massachusetts |
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| Abstract: | According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter β. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When β increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ. |
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| Keywords: | Weakly cemented soft rock Segmented anchorage Strain softening Analytical model |
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