Two high-salinity soils with different types of salts were tested to assess the effects of freeze-thaw (F-T) cycles on their volumetric and low-temperature shear behavior. The testing program, including freeze-thaw cycling and triaxial testing, is described in detail. Experimental results, including volumetric change and low-temperature stress-strain behavior and shear strength parameters are presented, and the causes of changes in shear strength parameters are analyzed. The research results show that soils with a high chloride salt content ($\ge 15\%$ ) and a low sulfate salt content ($\le 0.5\%$ ) exhibited very small volumetric contractions, whereas soils with a low chloride-salt content ($\le 5\%$ ) and a high sulfate-salt content ($\ge 1.5\%$ ) demonstrated very large volumetric expansion after freeze-thaw cycling. There appears to be a residual state for saline soils, at which the void ratio and the stress-strain behavior remains unchanged with an increasing number of F-T cycles. The residual void ratio and the stress-strain behavior at the residual state are much different from those at the initial state for soils with low chloride-salt content and high sulfate-salt content. The large salt expansion and the drop in the apparent cohesion of the soil with a low chloride-salt content and a high sulfate-salt content after F-T cycling is of concern for engineering purposes. These volumetric change and shear strength parameters have a direct or indirect impact on geotechnical analyses, such as assessments of slope stability and bearing capacity and/or load capacity of shallow and deep foundations in similar saline soils.

Frozen soils, including both those seasonally frozen and perennially frozen, exists extensively in Alaska and other cold regions. During past earthquakes, widespread damage was observed in deep foundations in the ground, and frozen ground appears to be the direct cause of at least some of that damage. The aim of this paper is to investigate the effects of seasonally frozen soil on deep foundations during lateral loads induced by earthquakes, ice, wind, vehicular impacting, and other loads with a short duration, and to recommend simplified tools for design practices. Two identical reinforced concrete-filled steel pipe piles were tested to large deformations at unfrozen and frozen soil conditions to demonstrate the effects of seasonally frozen soil on the lateral behavior of steel pipe piles. The pile tested at unfrozen condition behaved as a rigid pile, and the other at deep seasonally frozen condition formed a very shallow plastic hinge. Pile performance data in deep seasonally frozen silts were u...

One of the most important lessons learned from Alaska’s major earthquakes is that lateral spread of frozen ground crust overlying liquefiable soils induced extensive bridge foundation damage. A shake table experiment was performed to study the interaction mechanisms of frozen soil-pile foundation in this scenario. Data collected from the shake table experiment were presented and analyzed. Three plastic hinges formed on the model pile: one at the ground crust surface, one at the ground crust-loose sand interface induced by strong confinement of the stiff ground crust, and one within the partially liquefied medium dense sand layer induced by laterally spreading ground crust. The failure mechanisms of single piles revealed in this experiment corresponded well with pile-pile cap connection failures observed in previous earthquakes and the frozen ground crust can be thought of as acting like a natural pile cap that restricts the rotation of the single pile head. This study provided data for computer model calibration and helped gain insight into the frozen ground crust impact on the seismic performance of piles under lateral spread induced by liquefaction.

A simplified nonlinear method was proposed to evaluate lateral behavior of a pile located in or nearby a slope, based on the traditional p‐y method. This method was validated with field test results of a steel pipe pile in clay and model tests of piles in sand slopes. The comparison indicated that the calculated horizontal displacement and bending moment of piles agree well with experimental results. Then, parametric studies were performed, and it shows that horizontal displacement, rotation, bending moment, and shear force increase along with increasing slope angles; the depth of maximum moment locates at about 1.6 D below ground surface for horizontal ground, while this value turns to be about 3.6 D and 5.6 D for sloping ground of 30° and 60°, respectively. The study clearly shows that slope angle has a significant effect on the deflection and lateral capacity of piles.