Model tests on uplift behaviors of belled pier foundation in coarse-grained salty soils

Based on the uplift model tests, the uplift working behaviors of belled pier foundation with different thicknesses and crystalline and dissolved states of coarse-grained salty soils are obtained. The results show that the uplift loads lead to obvious ground heave surrounding the belled pier foundation, which induces circumferential and radial cracks in the soils around the foundation. Moreover, the ground heave extent is approximately circular as the uplift loads increase. The uplift displacement decreases with the growing distance from the center of foundation, and the uplift displacement gradient increases with the increasing uplift loads. The load-displacement curves exhibit a typical softening tendency. The uplift bearing capacity of salty soils in the crystalline state increases at larger thickness of coarse-grained salty soils, and is also higher for the salty soils in crystalline state than that for the salty soils in dissolved state. The geometric shape of failure surface can be described by a straight line equation with slope in the underlying coarse-grained soils different from that in the surface salty soils. The uplift angles of the surface salty soils in crystalline and dissolved states are approximately 34°and 18°, respectively, while 32°for the underlying soils without salt.