To study the influence factors of sub peak adfreezing strength at the interface between frozen soil and structure

the typical fine sand located in the Hexi area of Nanjing subway construction site was selected as test sample. The large-scale multi-functional frozen soil-structure interface shearing instrument was optimized and improved to conduct direct shear tests of adfreezing strength considering multi-influencing factors. Based on the specific definition and the agreement of quantitative criteria for sub peak adfreezing strength

it was found that the shear stress was typical of steepness after the limit peak

and the peak post shear stress changed periodically . The relationships among sub peak adfreezing strength

interface temperature

roughness and normal stress were fitted and found to be inverse proportional linearity

quadratic polynomial

proportional linear relationship respectively. Through the database management software

it was found that the normal stress and roughness were the key influencing factors

but the interface temperature was non-critical influencing factors. The three-element sub peak adfreezing strength prediction model coupled with interface temperature

normal stress and roughness was constructed by multivariate nonlinear regression. It can provide important adfreezing strength parameters for artificial freezing reinforcement design

shield construction and underground structure design in artificial freezing reinforcement area or permafrost area.