Shear Strength Performance of Electrokinetic Geosynthetics Treated Soft Clay after Water Immersion

Abstract

The strength aspect of clay soil is a critical concern in practical engineering design. Electroosmosis (EO) has been adopted as a foundation treatment technology in some projects to increase the strength of soft clay. In order to widen the understanding on shear strength performance of EO-treated soil, the behavior of EO-treated soft clay using electrokinetic geosynthetics (EKG) as electrodes under the effect of water immersion was evaluated and compared with that of vacuum preloading (VP) treated soft clay under similar conditions. The main finding was that the EO-treated soil when immersed in water offered more resistance to the change in average water content than VP-treated soil. The average shear strength of EO-treated soil fell by 36.6% during 4 extra days of immersion. When the immersion time was extended to 10 days, the average shear strength fell by 65.4%. In contrast, the immersion time had little influence on the shear strength of VP-treated soil. Hence, if EO-treated soft clays are to be subjected to short-term water immersion, the shear strength of the treated foundations should be reappraised to ensure the safety of the engineering projects.

Engineering application of vacuum preloading combined with electroosmosis technique in excavation of soft soil on complex terrain

“…Although the mean values of the soil index parameters after VPE treatment improved slightly, their COV significantly increased, which was attributed to the inhomogeneity strengthening effect of VPE for different dewatering amounts of electroosmosis flow between the anodes and the cathodes in the horizontal direction and the decay of vacuum pressure and voltage potential in the vertical direction [ 26 ]. The COV of soil parameters after VPE treatment all increased compared to that before treatment.…”

“…Plate-shaped plastic vertical drains (PVDs) and electric vertical drains (EVDs) were vertically inserted into the excavation depth of the soil with a spacing of 0.7 m in a square layout, as shown in Fig 2A and 2B . Detailed information for EVDs has been introduced by Sun et al [ 26 ]. Above the soil surface 1 m of PVDs and EVDs were reserved and wound around the horizontal corrugated filter tube (40 mm in diameter) with a spacing of 1.4 m, as shown in Fig 2C .…”

Shear Strength and Durability of Expansive Soil Treated with Recycled Gypsum and Rice Husk Ash

“…Regardless of curing days, the unconfined compressive strength of the samples was reduced to around 20 to 30 kPa. Sun et al [64] noted a reduction in undrained shear strength of soft clay treated with electrokinetic geosynthetics when moisture content increased in the specimens. This inverse relationship is caused by decreased cohesive forces that bind soil particles [65].…”

“…The stress-strain behavior of expansive soils is dependent on the moisture content. Soils on the dry side of the optimum value display brittle behavior, while soils on the wet side display ductile behavior [64]. Samples that did not undergo durability testing incurred brittle failure, as shown in Figure 8a, since test specimens were prepared with moisture that was less than the optimum values.…”