The structural performance of buried drainage pipes is gradually deteriorating under the influence of external loads and chemical and microbial corrosion. It is crucial to reinforce them and improve their bearing capacity for safe use. One of the important technologies used to extend the service life of deteriorated pipes is the use of fiber-reinforced cementitious composites (FRCC) for spray repair. Combined with the current situation of drainage pipes, this article introduces the basic properties of FRCC, briefly describes the requirements for material performance for drainage pipe spraying rehabilitation, reviews the structural bearing capacity of drainage pipes repaired by spraying with FRCC, and discusses the relevant research and engineering applications of the spraying method. Studies show that FRCC has high strength and corrosion resistance, and excellent sprayability. The structural performance of the host pipe is significantly improved after repair, but measures should be taken to enhance the interfacial bonding performance during the repair. In the design of the liner wall thickness, there is no unified calculation theory, and the existing methods have not considered the influence of secondary load on the structure. It is recommended to combine the type of pipe defects and the degree of deterioration in further study.

The creep mechanical behavior of the slip zone soil is distinctive and assumes a vital role in the identification and prediction of landslide evolution, but the rock content and structure dictate its creep properties. This study examines the Outang landslide in the reservoir region of middle Yangtze River, where the slip zone soil shows considerable variability in particle size distribution, with gravel content varying between 35% and 55%. To investigate the creep characteristics of the slip zone soil, large-scale direct shear creep tests were conducted, focusing on the variations in peak strength and long-term strength under different gravel content conditions. PFC^3D numerical simulations were subsequently performed to elucidate the internal mechanisms connecting gravel content, microstructure, and macroscopic mechanical strength. A three-dimensional continuous-discrete coupled model was built to investigate the influence of gravel content on landslide deformation features, accounting for fluctuations in gravel content. The numerical findings indicate that gravel content markedly affects the displacement and deformation characteristics of the landslide. As the gravel concentration rises, landslide displacement progressively diminishes, with elevated gravel content enhancing the structural integrity of the landslide mass. This study underscores gravel content as a pivotal element in landslide deformation and reinforces its significance in assessing landslide stability and forecasting.

Gully bank instability provides critical sediment supplies for debris flow hazards in alpine canyon regions. The physical processes of unconsolidated bank failure driven by coupled rainfall and flood scouring require further experimental characterization. This study performs flume model experiments under two test scenarios, that is, flood loading with and without antecedent rainfall. Macroscopic failure features and subsurface hydrological responses are monitored via a dual perspective visual system and pore‐water pressure sensors. Results indicate that flood‐driven gully bank failure manifests as typical retrogressive landslides caused by cantilever undercutting. External toe erosion destroys basal support and reshapes bank geometry, whereas flood infiltration increases pore water pressure and reduces matric suction to weaken soil shear strength. Although antecedent rainfall may degrade soil mechanical properties by raising moisture content, earlier landslide initiation and larger failure magnitude are observed under the no‐rainfall condition, with the main failure processes completing within 90 s. Rainfall drives fine particles to migrate downward and fill subsurface voids, increasing soil compactness. This improved antierosion capacity partially offsets the moisture‐induced strength loss, resulting in a smaller overall failure volume during the rainfall present test. Derived from simplified laboratory conditions, these findings offer mechanistic insights into rainfall and flood triggered gully bank instability and support hazard related research for alpine debris flow catchments.