Damage features and dynamic formation mechanism of the Tangjiashan landslide triggered by the Wenchuan earthquake with a composite hypocenter

Abstract

The Wenchuan earthquake triggered many landslides, which caused many casualties and led to considerable property losses. Due to the compositionality of the hypocenter mechanism of the Wenchuan earthquake, research on the effects of a composite hypocenter on the dynamic responses of landslides is urgently necessary. Using geological field investigations, a block discrete element method simulation, and related theoretical analysis, the dynamic formation mechanism and main controlling mechanical factors of the Tangjiashan landslide were revealed. The results demonstrated the following. Firstly, the dynamic responses of the slope involved progressive deformation, critical failure, disintegration, fragmentation, collision, climb, return, and accumulation. Secondly, when the earthquake lasted for approximately 23 s, the critical failure occurred, and the sliding mass near the shoulder reached a vertical acceleration of approximately 2.8 g at this time. Thirdly, the second and third subhypocenters contributed to the progressive deformation and critical failure, and vertical seismic forces were dominant contributions to these responses. Fourthly, the disintegration, fragmentation, collision, climb, return, and accumulation were mainly controlled by the self-gravity and local topography and were slightly influenced by subhypocenters. Based on these conclusions, the study of the dynamic formation mechanism of this type of landslide has increased the level of understanding.

Keywords:

• Composite hypocenter
• hypocenter mechanism
• Tangjiashan landslide
• dynamic response mechanism
• block discrete element method simulation

Data availability statement

The raw point data in Figure 5 were derived from the China Earthquake Networks Center at https://www.cenc.ac.cn/. The data (including the code used for DEM simulation) that support the findings of this study are available from the corresponding authors upon reasonable request.

Author contributions

C.X., Y.Y., F.C., W.L. and H.L. performed the investigation; C.X. performed the simulation; C.X. and F.C. wrote the manuscript. All authors reviewed and edited the manuscript. Y.Y. supervised the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are grateful to all the reviewers for their great comments. We gratefully acknowledge the financial support from the National Key Research and Development Program of China (grant no. 2018YFC1504802) and Supported by the Fundamental Research Funds for the Central Universities of China (grant no. 2022YJSDC24).