Development law and growth model of dynamic pore water pressure of tailings under different consolidation conditions

• Published in: PloS one 2022-10, Vol.17 (10), p.e0276887-e0276887
• Main Authors: Du, Changbo, Jiang, Xinqi, Wang, Laigui, Yi, Fu, Niu, Ben
• Format: Article
• Language: English
• Subjects: Anisotropy; Confining; Consolidation; Dam design; Dam engineering; Dams; Design; Dry density; Earthquakes; Engineering and Technology; Equilibrium; Evolution; Friction; Growth models; Internal friction; Liquefaction; Live loads; Load; Mine tailings; Particle size; Pavements; Physical Sciences; Pore pressure; Pore water; Pore water pressure; Pressure ratio; Properties; Ratios; Research and Analysis Methods; Sand; Seismic activity; Seismic design; Seismic response; Silt; Soils; Tailings; Triaxial tests; Vibration analysis; Water pressure
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0276887

Tailings dams are in danger of liquefaction during earthquakes. The liquefaction process can be indirectly reflected by the evolution rule of the dynamic pore water pressure. To study the development law of dynamic pore water pressure of tailing sand under different consolidation conditions, the evolution equation of critical dynamic pore water pressure of tailings under isotropic and anisotropic consolidation conditions was derived based on the limit equilibrium theory. Moreover, the development law of dynamic pore water pressure was expounded theoretically. The dynamic triaxial tests of tailing silty sand and tailing silt under different dry densities, consolidation ratios, and confining pressures were performed. The dynamic pore water pressure ratio and vibration ratio curves of tailings under isotropic and anisotropic consolidation were analyzed, and a dynamic pore water pressure growth index model suitable for both isotropic and anisotropic consolidation was derived. The results showed that the critical dynamic pore water pressure was positively correlated with the confining pressure and average particle size of tailings under isotropic consolidation conditions. The tailings have a limit dynamic effective internal friction angle [phi]dc under the anisotropic consolidation condition. The evolution law of critical dynamic pore water pressure can be judged according to the dynamic effective internal friction angle of tailing sand [phi].sub.d and [phi]dc values. The consolidation ratio significantly affects the dynamic pore pressure growth curve while confining pressure and dry density do not. For different tailing materials, the dynamic pore water pressure ratio is positively correlated with tailing particles. The dynamic pore water pressure growth process of tailing silty sand and tailing silt can be divided into two stages: rapid and stable growths. The development law of two types of tailings can be described by the dynamic pore water pressure growth index model. The research results can provide a theoretical basis for the seismic design of tailings dams in practical engineering.