Development of Pervious Concrete Pile Ground-Improvement Alternative and Behavior under Vertical Loading

Abstract

Permeable granular columns are used to increase the time rate of consolidation, reduce liquefaction potential, improve bearing capacity, and reduce settlement. However, their behavior depends on the confinement provided by surrounding soil, which limits their use in very soft clays and silts, and organic and peat soils. This research effort aims to develop a new ground-improvement method using pervious concrete piles. Pervious concrete piles provide higher stiffness and strength that are independent of surrounding soil confinement while offering permeability comparable to granular columns. This proposed ground-improvement method can improve the performance of different structures supported on poor soils. To achieve the goal of the research project, four vertical load tests were performed on one granular column and three pervious concrete piles. In this paper, the material properties of pervious concrete, the developed installation method, and the vertical load response of pervious concrete and aggregate piles are presented, and the variation of soil stresses and displacement during pile installation are briefly discussed. The experimental test results show that the ultimate load capacity of the pervious concrete pile was 4.4 times greater than that of an identical granular column. In addition, the ultimate load capacity of a pervious concrete pile installed using the developed technique was 2.6 times greater than a precast pervious concrete pile. The used installation method created nonuniform lateral soil displacement and increased vertical and horizontal soil stresses.