Deformation Law and Settlement Mechanism of Silt Caused by Cyclic Risefall of Water Table

Abstract:

As a common phenomenon of groundwater in shallow soil layers, the cyclic risefall of water table usually causes the change of soil structure and properties, having impacts on the deformation and subsidence of foundations. In order to solve the above problems, this paper takes the silt in Luoyang area as the research object for the model test, and studies the periodic variation law of pore water pressure and earth pressure in different layers of silt at different stages under the action of cyclic risefall of water table. Based on the above exploration, the arising settlement deformation can be studied. The results show that the periodic change of pore pressure is the main reason of the periodic deformation of silt, and the variation laws have the similarity. The pore water pressure responses instantaneously with the cyclic risefall of water table while the variation of deformation shows the hysteresis. The oscillating pore water pressure is the primary cause of the saturationunsaturated state transition in the silt and the dissipation of the residual pore water pressure is the driving force of the settlement deformation.

Key words:cyclic rise fall of water table; settlement; pore water pressure; earth pressure