Effect of Vertical Flow on Consolidation Degree of Foundation with Vertical Drains in Large-Strain Consolidation Theory

摘要

Vertical flow has an important effect on consolidation rate of ultra-soft soil, but the influence law and influence level on the degree of large-strain consolidation have not been quantitatively evaluated. Based on the negative axisymmetric large strain consolidation (NALSC) model, the variation laws of calculation error of consolidation degree ignoring vertical flow with consolidation time and strain are studied under different values of H/r(e) (ratio of soil thickness to influence radius), w(0)/w(L) (ratio of initial water content to liquid limit) and k(h)/k(v) (ratio of horizontal permeability coefficient to vertical permeability coefficient). Taking 10% as the error threshold, the H/r(e) values ignoring vertical flow are given, and the difference between them in the theories of large-strain and small-strain is discussed. The results show that the effect of vertical flow on degree of stress consolidation (U-p) is greater than degree of strain consolidation (U-s). The H/r(e) values neglecting the effect of vertical flow on the degree of consolidation in large-strain theory are less than those in small-strain theory. The calculation errors affected by vertical flow decrease with the increase of H/r(e) and k(h)/k(v). Error of U-s affected by vertical flow decreases, whereas error of U-p increases with the increase of w(0)/w(L). The effect of vertical flow on the degree of consolidation is greater when well resistance is considered.