Relationship Between Temperature and Earth Pressure for a Rigidly Framed Earth Retaining Structure

Abstract

The relationship between temperature and earth pressure acting on a rigidly framed earth-retaining structure (RFERS) subject to wide temperature variation was explored. A distressed RFERS open concrete garage that retains 11 m (36 ft) of soil was instrumented. After some repairs, movement of the building was monitored and recorded hourly for a period of four and a half years. The monitoring revealed complex temperature-dependent soil–structure interactions. The measured displacements were used to calculate the earth pressure coefficient using closed form equations that were developed by treating the structure as an equivalent cantilever beam, and calibrating the expression using a total of 42,000 FEM models. The data indicated that the coefficient of earth pressure behind the monitored RFERS had a strong linear correlation with temperature. During the cold season the building contracted, and the retained soil followed. During the hot season, the building was unable to overcome the earth pressure, thus it expanded away from the soil, resulting in a cumulative annual displacement. The coefficient of lateral earth pressure changed by approximately 0.005/°C, varying in the range of 1.25–1.5, depending on the season. The study also reveals that thermal cycles, rather than lateral earth pressure, caused some of the structural elements to fail.