Earth Pressure Distribution for Deep Excavations in Gravel Formations

There are no available guidelines for lateral earth pressure envelope in gravel formations, especially for high gravel content ranging from 70% to 86%. Design of retaining structures and anchors in gravel is typically based on empirical experience and that was often too conservative. Therefore, this research collects 25 deep excavation cases in gravel deposits in Taichung areas. The value of apparent earth pressure had the tendency to increase as the depth of excavation increased. Comparison was made with the apparent earth pressure envelopes. The acquired shape of the envelope was trapezoid. However, the value of the coefficient of apparent earth pressure was less than half of the values suggested by various researchers. The distributions of apparent earth pressure at different excavation depths, 15, 20, and 27 m, could be obtained and normalized based on this study. The shape of the envelopes is similar to the one suggested by researchers, but the apparent earth pressure is much less.