Assessment of Rockfall Hazards of Moziyan in Hechuan District, Chongqing, China
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ORIGINAL PAPER
Assessment of Rockfall Hazards of Moziyan in Hechuan District, Chongqing, China Yuntao Zhou . Shengwei Shi . Hongmei Tang . Linfeng Wang
Received: 23 April 2019 / Accepted: 27 May 2020 Ó Springer Nature Switzerland AG 2020
Abstract Moziyan is an area containing unstable rock masses located in Hechuan District, Chongqing, China and has constantly seen group-occurring rockfalls since 1964. The present study aims to investigate the damage of Moziyan rock mass and protect the mining areas and residential areas from rockfall phenomenon. Mohr–Coulomb model in FLAC–3D Program was built to find out the rockfall initiation position. RocFall program has been used to calculate the distribution curves of stopping positions, bounce height, total kinetic energy, and translational velocity of the falling blocks varying with horizontal distance. According to the simulation results, the stability of Moziyan rock mass is controlled by the unloading cracks behind the slope, and the falling blocks have a maximum bounce height and maximum total kinetic energy of 0 m and 2720.9 kJ respectively at the horizontal position of 461.6 m, where proper protection measures should be adopted to minimize the risk of the damage of the Moziyan rock mass.
Y. Zhou (&) S. Shi Institute of Exploration Technology, Chinese Academy of Geological Sciences, Chengdu 611734, Sichuan, China e-mail: [email protected] H. Tang L. Wang Key Laboratory of Geological Hazards Mitigation for Mountainous Highway and Waterway, Chongqing Municipal Education Commission, Chongqing Jiaotong University, Chongqing 400074, China
Conclusively, the results of simulation indicate that a barrier of 3 m height and 3000 kJ absorption capacity is enough to resist the falling stones with a maximum speed of 13.2 m/s at the horizontal position of 461.6 m. Keywords Rockfall Assessment FLAC–3D RocFall Rock masses in moziyan
1 Introduction Rockfalls are geological hazards in which rock masses detach from the parent rock along discontinuity surfaces such as lithoclase, joints, and bedrock surface and rapidly descend along the slope surface in forms of free-falling, sliding, leaping, bounding, and rolling (Varnes 1978; Whittow 1984). They are widely distributed in mountainous areas where cliffs are developed and impose adverse effects on infrastructures and safety of people. They especially represent a major threat to settlements, mining areas, and pedestrians in towns close to the bottom of cliffs. Therefore, it is vital to take an assessment as the foundation of prevention and control engineering of rockfall hazards. The assessment process of rockfall hazards can be divided into four parts: the analysis of geomechanical and kinematic characteristics of rock masses, the determination of boulder release positions (rockfall
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Geotech Geol Eng
initiation areas) of potentially unstable rock masses, the analysis of trajectories of falling blocks, and recommendations for prevention and control of the hazards (Kol
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