Experimental investigation of the direct shear strength parameters of compacted snow

Abstract

Abstract. Compacted snow is utilized as a building material in various construction and engineering applications across global high-latitude regions. For the safety assessment of snow and ice structures in cold regions, cohesion and internal friction angle are key shear strength parameters for compacted snow. Direct shear tests were carried out on low-density natural snow and high-density artificial snow in a −10 °C cold laboratory. In total, 112 test conditions were designed to quantify the effects of initial density, sintering time and sintering temperature on shear strength parameters at normal stresses below 100 kPa. Results show that under high sintering degree conditions and low normal pressures, the shear stress–displacement curve tends to exhibit strain softening. As initial density increases from 300 to 650 kg m−3, both cohesion and internal friction angle increase linearly. With sintering time increasing from 0 to 60 d, cohesion first rises and then falls, while the internal friction angle steadily decreases. As sintering temperature decreases from −5 to −25 °C, cohesion decreases, whereas the internal friction angle increases slightly. A Genetic Algorithm-Back Propagation (GA-BP) neural network was utilized to construct a shear strength prediction model, taking density, sintering time, sintering temperature, and normal stress as inputs, and offering benchmark values for cohesion and internal friction angle under various conditions. These benchmarks can be adaptively adjusted when additional influencing factors require consideration. This study provides essential strength parameters for the design and construction of compacted snow structures and offers a framework for accounting for the influence of other factors on these parameters.