The significance of shear strength increases on the allowable preload rate for compressible, normally consolidated soils subjected to a flexible strip load is examined. On the basis of representative soil parameters and various assumed boundary conditions, a computer analysis has been made to systematically predict the rates and magnitudes of shear strength increase and the associated settlements which occur as primary consolidation progresses, and to evaluate the bearing capacity of the soil in terms of these strength increases. Results show that, when adequate drainage is provided, weak soils may be expected to experience a measurable increase in bearing capacity during the consolidation process; furthermore, these increases occur in a time which is compatible with many construction schedules. On the other hand, when drainage is inadequate, slow rates of consolidation preclude the occurrence of any reasonable bearing capacity increase, except for cases where the ratio of the horizontal to the vertical coefficients of consolidation is large. Since consolidation settlement at any given time is governed by the magnitude and duration of the applied load, which is, in turn, governed by the rate of bearing capacity increase, the resulting consolidation settlements can be accelerated to any worthwhile degree only for cases where reasonable bearing capacity increases are experienced. Finally, the benefits of optimizing the preload rate decrease significantly for cases where the initial soil strength is high.
ASJC Scopus subject areas
- Civil and Structural Engineering
- Geotechnical Engineering and Engineering Geology