Taking the granite specimen with multiple fissures as the main research object, the mechanical response and failure mechanism of the granite specimen under uniaxial compression tests were analyzed by constructing a numerical analysis model based on cohesive element and Voronoi polygons techniques. Furthermore, the effects of geometric characteristics (spacing, length, width) on the peak mechanical response, damage energy, number and proportion of micro-cracks, failure mode and so on are further studied. The results show that the numerical analysis model can accurately reproduce the complex intergranular occlusion and multi fissures network structure of granite specimens, and reveal the dominant role of fissure angle on the failure mode, and the significant influence of fissure geometric characteristics on the number and proportion of micro-cracks, peak mechanical response and damage energy. The crack path and failure mode are significantly affected by the change of fissure angle and spacing, while the increase of fissure length and width leads to more rapid failure and lower peak mechanical response. The damage energy increases gradually with the increase of fissure spacing, but decreases with the increase of fissure length and width. This study not only deepens the understanding of the mechanical behavior of granite samples under complex geological environments, but also provides theoretical support for accurate assessment and effective reinforcement of rock mass stability in engineering practice.

The monopile foundation is a popular foundation type for offshore wind turbines; due to the harsh marine environment, there are lateral loads applied on the monopile foundation from winds and currents, and scouring also often occurs around the pile, reducing the bearing capacity and impacting the normal operation of offshore wind turbines. A series of 1 g model tests is conducted to investigate the lateral load response and scouring response of the monopile in sand. Based on the experimental results, the characteristics of the pile’s load-displacement curves, bending moments, and p-y curves under the effects of scour were analyzed. Particle Image Velocimetry technology was adopted to analyze the deformation development rules of soil particles around the pile. It is found that under the same lateral load, the maximum bending moment of the pile increases and the bearing capacity is reduced as the scour depth increases, the scour width increases, or the scour slope decreases. The effects of scour depth, slope, and width on pile bearing stability decrease successively. Soil displacements and strains in the passive zone in front of the pile develop gradually in both radial and vertical directions.