Rainfall-induced landslides are a significant hazard in areas covered by granite residual soil in northern Guangdong Province. To study the response of granite residual soil landslides to rainfall, the most severely affected area during the floods in June 2022 and April 2024 was chosen as the study area. Geological investigations and field artificial rainfall tests were conducted to explore the deformation evolution characteristics of granite residual soil slopes under continuous heavy rainfall and to reveal the failure mechanism of rainfall-induced landsliding events. The results indicate that the granite residual soil can be divided into two layers, and the slope structure can be subdivided into three models from the geological point of view. Given that the deformation and failure characteristics of the surficial landslides are highly similar across the three models, the three models can be consolidated into a single model composed of granite residual soil and weathered granite. The intensity and persistence of rainfall are the main triggering factors of landslides in this area. The landslides are primarily characterized by surficial sliding with a traction sliding failure mode, mainly involving a granite residual soil layer thickness of about 1-3 m. The increased rate of water content and the range of pore water pressure can be used as primary indicators for slope deformation and failure. Additionally, shear dilatancy deformation during slope movement effectively mitigates deformation rates. Furthermore, debris flow is identified as a secondary disaster resulting from landslides, with landslide deposits serving as potential sources for debris flow.

This paper presents a case study of the clogging of a slurry-shield tunnel-boring machine (TBM) experienced during tunnel operations in clay-rich argillaceous siltstones under the Ganjiang River, China. The clogging experienced during tunneling was due to special geological conditions, which had a considerably negative impact on the slurry-shield TBM tunneling performance. In this case study, the effect of clogging on the slurry-shield TBM tunneling performance (e.g., advance speed, thrust, torque, and penetration per revolution) was fully investigated. The potential for clogging during tunnel operations in argillaceous siltstone was estimated using an existing empirical classification chart. Many improvement measures have been proposed to mitigate the clogging potential of two slurry-shield TBMs during tunneling, such as the use of an optimum cutting wheel, a replacement cutting tool, improvements to the circulation flushing system and slurry properties, mixed support integrating slurry, and compressed air to support the excavation face. The mechanisms and potential causes of clogging are explained in detail, and the contributions of these mitigation measures to tunneling performance are discussed. By investigating the actual operational parameters of the slurry-shield TBMs, these mitigation measures were proven to be effective in mitigating the clogging potential of slurry-shield TBMs. This case study provides valuable information for slurry-shield TBMs involving tunneling in clay-rich sedimentary rocks.