## 7 Conclusions  
In this study, centrifugal model tests were performed to simulate the toppling deformation process of an anti-dip slope with different slope angles, and the following conclusions were obtained.  
The evolution process of toppling deformation of the anti-dip layered rock slope could be divided into four stages: (a) the rock strata topples, and the trailing edge of the slope settles; (b) the rock strata at the slope foot topple and rupture, and the slope rock strata generates \"toppling-bending\" deformation; (c) the toppling-bending zone extends from the foot of the slope to the top, and tension deformation is generated at the crest of the slope; (d) the toppling-bending zone extends until it penetrates the slope and the rock strata generate \"toppling-breaking\" failure.  
When toppling deformation occurs in the anti-dip layered rock slope, a toppling-bending zone is generated from the slope foot and extends to the top of the slope in the form of a ladder until it penetrates the slope. A new secondary toppling-bending zone is generated at the steep slope inside the toppled rock mass caused by the previous first toppling-bending zone and extends upward in a similar way. The larger the slope angle is, the more favourable the development of the anti-dip slope toppling deformation.  
The development depth of the toppling deformation is sensitive to the slope angle. With the other conditions remaining unchanged, the larger the slope angle is, the deeper the development depth of the toppling-bending zone, and the larger the deformation range. That is, the development depth of the toppling-bending zone is positively related to the slope angle.  
The angle between the base plane of the toppling-breaking and the normal i of the rock strata is \(\theta\), and this test indicates that the angle is between 12 and 16. Provided that the dip angle of the rock strata of the anti-dip slope is \(\beta\), when the slope angle \(\alpha\) is less than the angle \(\delta\) between the base plane and the horizontal plane e (\(\delta=\theta+90^{\circ}-\beta\)), then toppling deformation occurs with difficulty in the slope.  
Under identical conditions for the parameters such as the slope height, the dip angle of the rock stratum and the thickness of the rock stratum, the lower the slope angle is, the more likely it is that the toppling deformation will develop into overall slide instability; the steeper the slope angle is, the more likely it is that the toppled rock mass will evolve into a collapse.  
Conceptualization, D.Z. and H.Z. ([PERSON]); methodology, D.Z.; software, H.Z. ([PERSON]); validation, D.Z., H.Z. ([PERSON]) and Z.W.; formal analysis, F.L.; investigation, Q.C.; resources, D.Z.; data curation, H.Z. ([PERSON]); writing--original draft preparation, H.Z. ([PERSON]); writing--review and editing, D.Z.; visualization, D.Z.; supervision, D.Z.; project administration, D.Z.; funding acquisition, D.Z. All authors have read and agreed to the published version of the manuscript.  
The study is financially supported by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project (Chengdu University of Technology) (SKLGP2020Z008), the National Key Research and Development Program of China (2018 YFC1504905), and Department of Natural Resources of Tibet Autonomous Region (Tibetan Finance 2020 0890-1).  
Not applicable.  
The authors thank all funding agencies.  
All authors declare no conflict of interest.