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      Assessment of the Excavation Damaged Zones in the Surrounding Rock of an Underground Powerhouse under High In Situ Stress Using an Acoustic Velocity Detecting Method

      1 , 2 , 1 , 3
      Advances in Civil Engineering
      Hindawi Limited

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          Abstract

          Excavation damaged zones (EDZs) in deeply buried underground powerhouse have become major obstacles to design and support, which potentially threaten safety and stability and increase construction and support costs. In this study, investigations of the EDZs were performed by applying an acoustic velocity detecting method in Houziyan hydropower project, southwest of China. A total of 38 testing boreholes distributed in high sidewalls of the main powerhouse were carried out, and corresponding 153 curves were obtained and analyzed. Then, EDZs were divided into highly damaged zone (HDZ), slightly damaged zone (SDZ), and excavation influence zone (EIZ), respectively. Furthermore, we classified the wave velocity curves into four categories: type I, type II, type III, and type IV. EDZs were qualitatively assessed based on the curve categories; in addition, we used a qualitative assessment method, which mainly involved an index of damage degree named D. The assessment results show that HDZ, but not SDZ, was significantly asymmetrically distributed in the upstream (average depth of 4.1 m) and downstream (average depth of 7.5 m) high sidewalls; in partial areas, depth of HDZ exceeded the length of designed rock bolts, which indicates that rock bolts cannot restrain crack development and EDZs evolution. Generally, EDZs distribution was consistent with deformation and failure phenomena distribution; compared to the field failure phenomena, the assessment results were reliable and reasonable. Finally, EDZs formation mechanism was discussed, and it can be concluded that the relatively large intermediate principal stresses σ 2 were a critical driving factor of the EDZs evolution.

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          Rationality evaluation of production deployment of outburst-prone coal mines: A case study of nantong coal mine in Chongqing, China

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            Continuum analysis of the structurally controlled displacements for large-scale underground caverns in bedded rock masses

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              Excavation Optimization and Stability Analysis for Large Underground Caverns Under High Geostress: A Case Study of the Chinese Laxiwa Project

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                Author and article information

                Journal
                Advances in Civil Engineering
                Advances in Civil Engineering
                Hindawi Limited
                1687-8086
                1687-8094
                July 04 2020
                July 04 2020
                : 2020
                : 1-13
                Affiliations
                [1 ]College of Mining, Liaoning Technical University, Fuxin, Liaoning 125105, China
                [2 ]Yunnan Minbao-Kungong Blasting Engineering Co., Ltd., Kunming, Yunnan 650093, China
                [3 ]Faculty of Electric Power Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
                Article
                10.1155/2020/7297260
                4846e304-334e-437d-b5e0-ac9f8fc2cda7
                © 2020

                http://creativecommons.org/licenses/by/4.0/

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