Study On Consolidation Theory For Vertical Drains With Exponential Flow

In the traditional consolidation theory, the velocity of flow v, is linearly related to the hydraulic gradient, i. While the case is not true with high plastic clay. The pattern that v, is exponentially related to i was proposed by Slepicka(1960), i.e. v=kim. Because of the complexity of exponential flow, little research has been reported on consolidation of vertical drains with exponential flow. On the basis of previous research, analytical studies are made to improve the theory of consolidation by vertical drains with exponential flow. As follows, the main original work and achievements include:(1) The analytical solution for consolidation by vertical drains considering exponential flow and smear effect is deduced and the corresponding solution of excess pore water pressure and radial degree of consolidation is obtained exactly. Then the consolidation behavior is analyzed by parameters study. It shows:in initial stages of consolidation, the increase of m will accelerate the consolidation rate, and will slow down the consolidation rate in the later stage. If m>1, the consolidation rate increases with the larger value of q0, which is opposite if m<1. The increase of s、Kh/Ks and n will slow down the consolidation rate.(2) The analytical solution for consolidation by vertical drains considering exponential flow and smear effect under vacuum preloading is deduced. So is the solution of excess pore water pressure and radial degree of consolidation. Then the research on consolidation behavior by parameters study shows:if m>1, the consolidation rate with k1=k2=0increases much faster than the case that k1=k2=1, which is opposite if m<1.(3) The analytical solution for consolidation by vertical drains considering exponential flow under variation of permeability coefficient in smear zone is derived and the solution of excess pore water pressure and radial degree of consolidation is obtained. Then the influence on the consolidation behavior is investigated. The result shows:the larger average value of permeability coefficient in smear zone, the faster rate of consolidation.