Performance-dependent Humidity State Division of Subgrade in Seasonal Frozen Region

摘要

Short-term surge in the spring thaw of liquid water is one of the root causes of structural performance of subgrade weakening seasonal frozen region. Ice and water phase transition changed the strength and deformation of subgrade. Especially in wet soil near the freezing line is serious; excessive moisture caused the subgrade structural stability and resistance to deformation is significantly reduced. This article beyonds the conventional definition of seasonal frozen soil area subgrade state. Division method is proposed for the performance of seasonal frozen soil area subgrade humidity conditions. Introduction of the "weak subgrade layer" concept to characterize thawing ice mixed state under the most unfavorable state of subgrade. To study the source of subgrade humidity and its main influencing factors in seasonal frozen region. To grasp time and space distribution characteristics of seasonal frozen subgrade humidity. To build classification method of subgrade modulus and deformation decay. To divided subgrade humidity state into the normal balance, the completely frozen and the ice-water mixed base on the correlation between structure performance and seasonal fluctuations of subgrade humidity. To determine the harmful period comprehensively for subgrade structure performance combination with freezing front and subgrade work area in seasonal frozen region. Emphatically analysis on the evolution law of subgrade performance at thawing ice-water mixed period.