Stabilization of Weak Clay with Strong Sand and Geogrid at Sand-Clay Interface

Abstract

The load-bearing capacity of a weak clay subgrade can be increased by placing a strong granular base course of limited thickness on top of the clay layer. The load-bearing capacity can be increased further, or the thickness of the granular base course can be reduced, by separating both layers by a geogrid. Laboratory model test results for the ultimate bearing capacity of a rigid strip loading on the surface of a granular soil underlain by a soft clay with a layer of geogrid at the interface of the two soils are presented. The optimum thickness of the granular soil layer and the critical width of the geogrid layer required to derive the maximum benefit from the reinforcement were determined. Model test results on the permanent settlement of the rigid strip load caused by cyclic loading of low frequency are presented.

Influence of geosynthetic reinforcement on the load-settlement characteristics of two-layer subgrade

“…A little is known about the deformation of two-layer reinforced soil systems under repeated loading (Das et al, 1998). The most common design approach to this problem is based on the empirical formulae.…”

Improvement of Bearing Capacity of Shallow Foundation on Geogrid Reinforced Silty Clay and Sand

“…The first systematic study to improve the bearing capacity of strip footing by using metallic strip was by Binquet and Lee [1,2]. After Binquet and Lee's work, several studies have been conducted on the improvement of load bearing capacity of shallow foundations supported by sand reinforced with various reinforcing materials such as geogrids [3][4][5][6][7][8][9], geotextile [10][11][12], fibers [13,14], metal strips [15,16], and geocell [17,18].…”

“…The ratio of improvement in the bearing capacity can be expressed in a nondimensional form as bearing capacity ratio (BCR) which is the ratio of bearing capacity of reinforced soil to bearing capacity of unreinforced soil. Several studies [5,6,26] show the effect of various parameters (e.g., / , ℎ/ , / , and / ), types of geosynthetic materials (e.g., geogrid, geotextiles, and geocell), effects of footing width ( ), types of soils, layer of soils, and so forth. But no studies are available on silty clay soil of Carbondale, Illinois, related to the improvement in bearing capacity of rectangular footing by placing sand layer on top of silty clay soil (i.e., two-layered soil) and geogrid system.…”

Performance of Sand-Treated Clay Subgrade Supporting a Low-Volume Flexible Pavement

“…Experimental results indicated that 20% sand with clay admixture adequately improved the properties of existing active clay for construction of highway embankments. In a similar study by Braja et al, the load-bearing capacity of a weak clay subgrade was increased by a strong granular base course on top of the weak clay layer (15). The optimal thickness of the granular soil layer with varying cyclic loading of low frequency and permanent settlement was studied.…”

“…Mechanical stabilization of soft soils with sand has been adopted by many researchers (14,15). Sand, which is widely available, can be easily transported to the construction site and mixed with base materials according to specifications.…”