Aspects of the behaviour of compacted clayey soils on drying and wetting paths

Abstract

A relatively large number of drying and wetting tests have been performed on clayey soils compacted at the standard or modified Proctor optimum water content and maximum density and compared with tests on normally consolidated or overconsolidated soils. The results show that drying and wetting paths on compacted soils are fairly linear and reversible in the void ratio or water content versus negative pore-water pressure planes. On the wet side of the optimum, the wetting paths are independent of the compaction water content and can be approached by compaction tests with measurement of the negative pore-water pressure. Correlations have been established between the liquid limit of the soils and such properties as the optimum water content and negative pore-water pressure, the maximum dry density, and the swelling or drying index. Although based on a limited number of tests, these correlations provide a fairly good basis to model the drying–wetting paths when all the necessary data are not available.Key words: compaction, unsaturated soils, clays, drying, wetting, Proctor conditions.

Hydromechanical behavior of a quasi-saturated compacted soils on drying-wetting paths-experimental and numerical approaches

“…The standard Proctor optimum, water content and maximum density are consistent with the values given by the correlations of [5] (Fleureau et al 2002), and [8] (Biarez and Favre 1975), based on the liquid limit of the material, as shown in Table 1. According to the USCS classification [9], the marl is a highly plastic clay (CH) with a percentage of CaCO 3 ranging from 30 to 40%.…”

“…Several methods were used to control suction in the samples [5]. For suction lower than 20 kPa, the samples were placed on tensiometric plates, and a negative pressure was applied to water, the air pressure being atmospheric.…”

“…In the laboratory, the characterization of compacted soil is generally carried out by standardized Proctor tests [1,2,3]. In the literature, many studies are devoted to the behavior of compacted soils on drying wetting paths [4,5] and the induced cracking desiccation [6,7]. This paper presents an experimental and numerical investigation carried out on a compacted marl on dryingwetting paths.…”

From saturated to unsaturated conditions and vice versa

“…However, this will not always be the case, and for drying tests on samples that are normally consolidated or lightly overconsolidated at the start of drying, the DR and M yield surfaces will be reached in a different sequence. Examples of such drying tests on normally consolidated or lightly overconsolidated reconstituted soil samples include those reported by Vicol [75], Fleureau et al [21] and Cunningham [17]. Figures 13 and 14 show GCM simulations of drying tests performed on a normally consolidated sample (Fig.…”

“…[18,21,57,69,75]). To include, in such experimental investigations, the influence that dry density (or plastic volumetric strain) has on the airentry point, it is useful to conduct the same type of airdrying paths on several samples that have been previously pre-consolidated to different values of stress.…”