Accelerated Consolidation
In the case of vertical drains, the value of the resulting degree of consolidation is increased by the effect of the radial degree of consolidation Ur. The resulting value of the deformation in the consolidated layer in the construction stage is then multiplied by the degree of consolidation Uav,r (or Uav,r,red if the drains do not pass through the entire consolidation layer).
where: | Uav,r | - | resulting degree of consolidation (with the effect of drains) |
Uav | - | ||
Ur | - | radial degree of consolidation |
Radial degree of consolidation is calculated as follows:
where: | ch | - | horizontal consolidation coefficient [m2/day] |
t | - | time [days] | |
de | - | affected area around the drain |
For triangular layout:
For square layout:
where: | b | - | spacing between drains |
where: | dw | - | diameter of the sand drain |
If plastic strips are used, the equivalent diameter dp is considered instead of dw:
where: | bp | - | width of plastic strip |
t | - | thickness of plastic strip |
Literature:
Principles and Practices of Ground Improvement, Jie Han, 2015.
Simplified Method for Consolidation Rate of Stone Column Reinforced Foundations, Jie Han and Shu-Lin Ye, Journal of geotechnical and geoenvironmental engineering, 2001.
A Theoretical Solution for Consolidation Rates of Stone Column-Reinforced Foundations Accounting for Smear and Well Resistance Effects, J.Han and S.L.Ye, 2002.