Physical Model Experiments on Failure Mechanism on Slopes of Weathered Basalt Soils during Heavy Rainfall Events

Basalt platforms are widely distributed in many areas of China, where landslides occur frequently. It is well recognized that landslide hazards seriously threaten engineering constructions and property safety. It is, therefore, of great significance to understand deformation and failure behaviors and their mechanisms in basalt slopes to reduce the loss caused by landslides. In this work, the Pengshan Landslide in Zhejiang Province is taken as a prototype and slope model tests are carried out. During the tests, real-time monitoring of pore pressure, earth pressure and slope deformation is conducted. Based on the experimental data, the influence of rainfall intensity and the thickness of a weak interlayer on the slope stability are obtained. It is demonstrated that the rainfall and weak interlayer are the most important factors causing the slope instability of a basalt platform. Furthermore, damage from a basalt platform slope usually starts from local failure, and the slope foot is the most likely sliding part. Moreover, when the rainfall intensity is doubled, the initial deformation time of the slope is reduced by about half and the final failure time is advanced by one-third. In addition, when the thickness of the weak interlayer is doubled, the initial deformation time of slope is shortened by about half and the final failure time is advanced by one-quarter.

Automated summary

Basalt platforms are widely distributed in China and frequently experience landslides. Understanding the deformation and failure behaviors of basalt slopes is crucial to mitigate the damage caused by landslides. In this study, slope model tests were conducted on the Pengshan Landslide in Zhejiang Province, with real-time monitoring of pore pressure, earth pressure, and slope deformation. The results reveal that rainfall intensity and the thickness of a weak interlayer significantly affect slope stability. The study also highlights that local failure is the starting point of damage on basalt platform slopes, with the slope foot being the most susceptible to sliding. Additionally, increased rainfall intensity and weak interlayer thickness accelerate slope deformation and failure.