Thermal influences of stabilization on warm and ice-rich permafrost with cement: Field observation and numerical simulation

Highlights: • In-situ test and heat transfer model were conducted to analyze thermal effects. • Equivalent age can precisely reflect heat release process of cemented frozen soil. • Thermal radius of dry mixing pile is 0.6m in permafrost layer with 15% cement. • Thermal radius increased exponentially with decrease of ground temperature. -- Abstract: In this paper, the dry cement was mixed with warm and ice-rich permafrost to improve its mechanical and physical properties. The changes of temperature of improved soil with different cement dosage were measured by in-situ test. Then, the temperature field of the improved soil in-situ test was calculated by mathematical model of heat conduction and hydration equation with consideration of temperature effect. Based on the built calculation model, we have simulated the radius of thermal disturbance and refreezing time in the process of improvement on warm and ice-rich permafrost with deep mixing method. It can be concluded from the results that, (1) heat transfer model with temperature effect can precisely calculate the changes of temperature field during the curing of cemented frozen soil; (2) in the field test, when the cement dosage is less than 15% by weight of frozen soil, the increase of temperature in cemented soil is not obvious, the peak of temperature increase appears only when the dosage is more than 20%; (3) when the dry deep mixing method with is adopted to improve the warm and ice-rich permafrost, the maximum radius of thermal disturbance increases exponentially with the decrease of mean annual ground temperature, the refreezing time decreases hyperbolically with the decrease of mean annual ground temperature.