Rock and Soil Mechanics ›› 2021, Vol. 42 ›› Issue (4): 976-990.doi: 10.16285/j.rsm.2020.5384

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Physical model experiment on failure mechanism and NPR anchor cable control effect of layered counter-tilted slope

TAO Zhi-gang1, 2, REN Shu-lin1, 2, HAO Yu3, LI Qiang3, FU Qiang4, HE Man-chao1, 2   

  1. 1. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology Beijing, Beijing 100083, China 2. School of Mechanics and Civil Engineering, China University of Mining and Technology Beijing, Beijing 100083, China 3. Production Technology Department of Inner Mongolia Taiping Mining Co., Ltd., Bayan Nur, Inner Mongdia 015300, China 4. China National Gold Group Hong Kong Co., Ltd., Beijing 100011, China
  • Online:2021-04-12 Published:2021-08-25
  • About author:TAO Zhi-gang, male, born in 1981, PhD, Associate Professor, Doctoral supervisor, mainly engaged in of teaching and research rock mechanics and engineering disaster control.
  • Supported by:
    the National Natural Science Foundation of China (NSFC) (41941018) and the Fundamental Research Funds for the Central Universities (2015QB02).

Abstract: Taking the large-scale toppling failure counter-tilted slope in Changshanhao open-pit mine in Inner Mongolia as engineering background, a layered counter-tilted slope geological generalized physical model was constructed based on similar theory. Physical model tests were performed under three different conditions: unreinforced, ordinary Possion’s Ratio(PR) anchor cable reinforcement, and constant resistance and large deformation Negative Possion’s Ratio (NPR) anchor cable reinforcement. Then infrared thermal imaging system, strain monitoring system and digital speckle displacement measurement system were used comprehensively to monitor the temperature field, strain field and displacement field respectively during the entire counter-tilted slope excavation test. Finally the deformation characteristics and instability mechanism of layered counter-tilted slope were investigated, and the reinforcement effects under different reinforcement measures were compared and analyzed. The research results show that the deformation process of counter-tilted slope has obvious deformation characteristics of "superimposed cantilever beam". Its toppling mechanism is mainly manifested in three stages: initial crack formation, crack development, and sliding surface penetrating and slope instability. The PR anchor cable failed during the excavation and could not resist the large deformation of the slope. In contrast, the NPR anchor cable has the characteristics of high constant resistance, large deformation and energy absorption, which can effectively prevent the occurrence of counter-tilted slope instability and provide a new way for slope engineering reinforcement.

Key words: counter-tilted slope, model experiment, reinforcement measures, NPR anchor cable, toppling failure