Mechanical Behavior of Clean Sand at Low Confining Pressure: Verification with Element and Model Tests

Abstract

Confining pressure significantly influences the mechanical behavior of soil. Understanding geotechnical problems related to low confining pressures requires precise modeling of soil behavior at low confining stress. Yet laboratory tests, including element tests under low confining pressure, are so far quite limited. In this note, a series of element tests under low confining pressure (5–20 kPa) were carried out to investigate the effect of low confining pressure on the mechanical behavior of loose and medium dense Toyoura sand. Element tests include undrained cyclic loading tests, as well as drained and undrained strain-controlled monotonic loading tests. The results show that loose sand under low confining pressure behaves much like dense sand under higher pressure. Model tests of slope failure flow under microgravity, carried out to supplement the element test results, also confirmed the previously mentioned mechanical behavior. The results obtained in this paper provide a more fundamental understanding of geotechnical problems related to low confining stress.