Analysis of the effects of sizes

shapes and wetting condition on crushing strength and modes of calcareous sand can be accomplished using a statistical method by subjecting particles with different sizes and shapes to single particle crushing tests through automatically uniaxial loading system and the crushing process

and modes of particles were observed and recorded with the help of microscopic probe. In addition

the micro-uniaxial loading device supported by in-situ X-ray μCT scan was used to scan the crushing process of two calcareous sand particles with high precision

and the effects of internal pore structure were deeply investigated by image processing and analysis technology. The results show that the characteristic strength of calcareous sand particles is decreased with increasing sizes. While for the particles with similar sizes

the characteristic strength of compact particles is the largest

followed by platy particles and bladed particles

and elongated particles are the least. The crushing process of calcareous sand particles can be summarized as three crack forms and three fracture patterns

which are single crack

cross crack

arch crack and patterns I

II

III

respectively. Finally

analysis results of μCT images show that the cracks caused by particle crushing concentrated mainly in the dense internal pores

which indicated that internal pore structure has an important influence on the crushing behavior of calcareous sand particle.