Impacts of Water Content and Temperature on the Unconfined Compressive Strength and Pore Characteristics of Frozen Saline Soils

Abstract

Frozen saline soils have complex components and are sensitive to temperature, water content, salinity, and pressure, resulting in complicated mechanical properties and pore characteristics. In this paper, laboratory investigations were carried out to measure the compressive strength, porosity increment, and failure modes of frozen saline soils under five water contents (10, 15, 20, 24, and 26%) and five freezing temperatures (−5, −10, −15, −20, and −25°C). Results indicated that with the increase of water content and the decrease of freezing temperature, the compressive strength and peak strain of frozen saline soils become larger, and the brittle failure characteristics become more significant. When the temperature is below −15°C, the degree of freezing will dramatically increase as temperatures drop. Besides, the porosity increment of frozen saline soils shows a linear change with the water content and temperature. According to the results, this increment increases by 0.48–0.55% for every 1% increase in initial water content, and by 0.20 – 0.28% for every 1°C decrease in freezing temperature. In addition, the splitting failure caused by tensile stress is the primary failure mode of frozen saline soils. The results are useful in designing, constructing, maintaining, and upgrading the tundra engineering in China.

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