###### Abstract  
Construction operations in cold regions may encounter frozen geomaterials. In construction, it is important to understand the processes by which geomaterials fail under common loading conditions to avoid accidents and work efficiently. In this work, an artificial frozen soil-rock mixture was used for uniaxial compression and indirect tension loading analysis to investigate macroscopic failure patterns and soil-rock interface crack evolution mechanisms. To further understand and compare the meso-mechanical failure mechanisms of the soil-rock interface, we used two types of rock block particles with different surface roughness for fabricating frozen artificial soil-rock mixtures. Acoustic emission (AE), ultrasonic plus velocity (UPV), and digital microscopy were utilized here to obtain the sample deformation response and analyze the morphology of the soil-rock interface. The results were as follows. From the perspective of macroscopic observation, bulging deformations and short tension cracks represent the main failure pattern under compression, and a tortuous tension crack in the center of the disk is the main failure pattern under indirect tension. From the perspective of microscopic observation, the soil-rock interface will evolve into a soil-rock contact band for the sample containing a rough rock block. The strength of the soil-rock contact band is obviously larger than that of the soil-rock interface. Three main failure patterns of the soil-rock interface were observed: a crack path through the accurate soil-rock interface, a crack path through the envelope of the rough rock block, and a crack path passing through the rough rock block. The experimental results could provide a reference for foundation engineering, especially in pile foundation engineering in cold regions. frozen soil-rock mixture; failure pattern; soil-rock interface; soil-rock contact band; crack propagation Article  
Feng [PERSON], [PERSON], Li, [PERSON], Tian, Y., [PERSON], [PERSON] Failure Patterns and Morphological Soil-Rock Interface Characteristics of Frozen Soil-Rock Mixtures under Compression and Tension  
soil-rock mixtures (FSRMs), and glacier debris are widespread [1; 2; 3; 4; 5; 6]. The mechanical properties of FSRMs have attracted significant interest during the last 10 years due to their roles in engineering, and FSRMs are more complicated than general SRMs. Prior studies have largely focused on internal components in SRMs such as the rock block proportion, rock size, and rock block shape in terms of macroscopic strength response [7; 8; 9; 10; 11; 12; 13; 14]. In recent decades, many studies have shown that the soil-rock interface is the weak area inside SRMs at normal temperature and that cracks are typically initiated here. The soil-rock interface is generally considered to be the most sensitive part of a SRM to an external load. The mechanical properties of SRMs are strongly affected by the soil-rock interface. To study the failure pattern and the evolution of cracks and rock blocks for SRMs, many scholars have carried out various studies. For example, [PERSON] and [PERSON] [15; 16] investigated crack propagation under uniaxial compressive testing, finding the distributions of cracks were strongly affected by the rock block position, where most of the cracks were located around the rock blocks. [PERSON] et al. [17] studied the mesomechanical characteristics of SRMs, highlighting the stress concentration at the soil-rock interface region and that the failure of the SRM firstly occurred here. Considering only the soil-rock interface region, according to previous studies, the soil particle size, cementation, and the mechanical contrast between blocks and matrices play important roles in the mechanical properties of the soil-rock interface, as well as the crack propagation mode [11; 18; 19; 20].