Sensitivity analysis of short piles embedded in homogeneous soil. Part I (theoretical formulation)

Optimum Design of Pile Foundation by Automatic Grouping Genetic Algorithms

“…The above equation is different from the equivalent pier method [7], where the pile group is replaced by a pier containing the piles and soil between them. Instead of treating the pile group as a deep foundation to compute the settlement, (10) evaluates the settlement on the basis of the Mindlin equation [20] and uses an equivalent settlement coefficient ϕ e , which represents the ratio of the pile group's settlement based on Mindlin equation [20] to that based on equivalent pier method. ϕ e considers the effect of pile-soilraft interaction on the settlement of pile foundation.…”

“…Its value depends on the number of piles, the ratio of pile diameter to pile spacing, pile diameter to pile length, and raft length to raft width, and can be directly obtained by JGJ 94-2008 for easy use. To reduce the error between practical settlement and computed one based on elasticity theory, an experience coefficient ϕ is used in (10), which describes the ratio of the measured settlement to computed settlement with respect to various soils. Furthermore, p 0 is the average value of additional pressure of the raft with a quasi-permanent load combination.…”

“…In addition, Δz i is the thickness of the ith soil layer. ϕ, n s , and E si have the same meanings as (10):…”

“…Some researches [10][11][12][13][14][15] introduced the concept and theory of structural optimization into the pile design process, and employed the gradient-based methods with prerequisite 2 ISRN Civil Engineering for differentiability and continuity of constraints/objective to solve the optimization problem. In addition, other efforts [8,16] have been done based on genetic algorithms (GAs) which have no prerequisite for differentiability and continuity.…”