Currently, the primary source of pollution is crude oil production. Crude oil production has dramatic consequences for farmlands, communities, and in terms of the construction materials required for earthworks. The main aims of the present study were to reduce the level of pollution caused by oil production in the Khurmala soil and then reuse it as a construction material. Soil remediation using the solidification/stabilization method was applied in the field using Portland limestone cement (CEM II). The performance of using CEM II in the remediation process was then investigated in the laboratory by taking the natural, contaminated, and treated soils from the Khurmala site. Furthermore, the results of the soils were compared with their corresponding soil samples using ordinary Portland cement (OPC). The comparison was performed by investigating the physical, chemical, and mechanical properties of the soils. The discussion was supported using the scanning electron microscopy (SEM) results. Chemical and SEM results revealed that there were fourfold and tenfold decreases in the percentage of oil and grease using OPC and CEM II, respectively, confirming the higher performance of using CEM II over OPC. The values of the coefficient of permeability, shear strength parameters, and California bearing ratio of the treated soils were significantly improved, compared to those of the contaminated soils.

The present research aims to explore experimentally the performance and modes of failure of the wetting-induced collapse of fully penetrating reinforced and unreinforced models of a short single sand column in a collapsible soil subjected to partial inundation through a series of model tests under high constant total stress of more than 200 kPa. A specific loading frame and a test container were designed to apply vertical pressure and measure vertical movements of the columns . The experimental test results demonstrated that providing only sand columns in collapsing soil have no significant contribution in reducing the large volume change and sudden collapse when wet. In contrast, geosynthetic-encased columns prevented the occurrence of wetting-induced collapse and highly reduced the sudden vertical movements to a gradual process under relatively high applied pressure. Additionally, a slight change in the dry density of the soil had a dramatic influence on the behaviour of the wetting-induced collapse and modes of failure. In this study, the experimental test results and theoretical results from different analytical approaches in the literature have confirmed that it is practically possible to apply high total stress of more than 300 kPa on a single footing on collapsible soils subjected to wetting condition.

This paper investigates the capacity of a single laterally loaded pile in single- and multi-layered sandy soils under dry, unsaturated and saturated conditions for a wide range of void ratios. Two Linear ariable Differential Transformers (LVDT) were employed to measure lateral displacements. For unsaturated tests, on one layer and two layered sandy soils, suction was controlled using the hanging column technique. Two different suction levels were applied to the soils. The results demonstrated that, the capacity of a single laterally loaded pile in single- and multi-layered sandy soils, under unsaturated conditions, were greater than those in dry and saturated conditions for loose, medium and dense states. Comparison between experimental data for unsaturated tests and several proposed mathematical expressions in the literature for calculating the capacity of a single laterally loaded pile in sandy soils showed a significantly good fit between measured and predicted values of the capacity of the piles where Bishop’s stress is used in the expressions instead of effective stress, confirming the importance of inclusion of suction and degree of saturation in mathematical models when unsaturated conditions of soils were investigated.