Characterization of expansive soils for the foundation of an irrigation canal in the Peruvian Andes, Cabana-Mañazo case

Alterations in water content in swelling soils cause volume variation, which implies constructive, socioeconomic and environmental damage. This paper characterizes the swelling soil located in an irrigation canal of the Peruvian Altiplano and its behavior of the properties by addition of lime in 5, 10, 15 and 20% of the total weight. Finding that the sample of the station 6+575 has combined presence of montmorillonite clays in a percentage of 13.52% together with the group of kaolinites in a percentage of 1.31%, consequently, it makes expandable clay of high plasticity. The soils of the station 6+250 have the characteristics of kaolinite clay, which distinguishes it as having low plasticity. In the swelling tests the high expansiveness was found, in the station 6+575, which has decreased with the addition of lime. Considering that concrete canals are generally of small thickness it would be important to consider the slightly dangerous effects on irrigation infrastructure.

EFFECT OF WASTE GLASS POWDER ON THE SWELLING AND STRENGTH CHARACTERISTIC OF DISTRICT KARAK EXPANSIVE CLAY

Expansive soils are generally considered problematic due to undesirable geotechnical characteristics like expansion, shrinking, settlement, and heaving. Such soils have low shear strength which decreases after wetting or other physical aggravations. Subsequently, such soils need proper improvement before constructing a structure on them. Different industrial wastes have been used for the stabilization of weak soil in the past. In the current investigation, the impact of waste glass powder (WGP) on the strength and swelling characteristic of swelling soils have been assessed. The primary target of this examination was to research the utilization of waste glass powder in geotechnical applications for controlling the settlement and expanding qualities. For this reason, the local expansive soil of district Karak, Pakistan was selected and their engineering properties were assessed. The experimental work consists of conducting the consistency limits, California bearing ratio (CBR), specific gravity standard Procter tests. The mentioned tests were carried out on both natural as well as modified specimens. For modification purposes, waste glass powder (WGP) was added in different proportions with the incremental rate of 4%, for instant 0%, 4%, 8%, 12%, 16%, and 20%. The addition of waste glass powder greatly reduced the swelling properties of the tested soil and also improved the engineering characteristics. A maximum reduction in swelling was observed at 20% addition of waste glass powder. Similarly, the liquid limid also reduced, and the specific gravity and maximum dry density increased at optimum glass powder content.

Enhancing Engineering Properties of Expansive Soil Using Marble Waste Powder

Owing to its propensity to swell when in contact with water, expansive soil causes severe structural problems and shrinks when they dry out. Soil stabilization is a well-known method used to enhance the soil's physical and engineering properties and is commonly adopted for improving soil structures. The mechanical stabilization of different soils is evaluated by adding varying proportions of marble dust (10, 20, 30 percent) of Penjwen, Said Sadiq and Pirmam marble waste powder) to expansive soil. Shear strength and consolidation parameters, such as void ratio, compression index, and sample swelling index, were determined as basic properties. The marble dust is obtained from the cutting and grinding of real marble from the Erbil marble factory in the experimental program. The addition of marble dust decreases the swelling percentage, with an increase in the percentage of marble powder in swelling soils. It is concluded that the swelling in Bastora soil is more than that of Erbil Airport soil, based on the swelling index studies.

Structural Performance of Shear Loaded Precast EPS-Foam Concrete Half-Shaped Slabs

Precast concrete elements provide a feasible way to expedite on-site construction; however, typical precast components are massive, making their use particularly undesirable at construction sites that suffer from low load-bearing capacity or have swelling soils. This research aims to develop an optimal lightweight expanded polystyrene foam concrete (EPS-foam concrete) slab through a consideration of various parameters. The precast EPS-foam concrete half-shaped slabs were prepared with a density and compressive strength of 1980 kg/m3 and 35 MPa, respectively. Quarry dust (QD) and EPS beads were utilized as substitutions for fine and coarse aggregates with replacement-levels that varied from 5% to 22.5% and 15% to 30%, respectively. The use of EPS beads revealed sufficient early age strength; at the same time, the utilization of quarry dust in EPS-foam concrete led to a more than 30% increase in compressive strength compared to the EPS-based mixtures. Two hundred and fifty-six trial mixes were produced to examine the physical and mechanical characteristics of EPS-foam concrete. Three batches of a total of four EPS-foam concrete half-shaped slabs with spans of 3.5 and 4.5 m and thicknesses of 200 and 250 mm were prepared. Findings showed that the ultimate shear forces for the full-scale EPS-foam concrete half-shaped slabs were approximately 6–12% lower than those of the identical concrete samples with a 2410 kg/m3 average density, and 26–32% higher than the theoretical predictions. Also, it was observed that the self-weight of EPS-foam concrete was reduced by up to 20% compared to the control mixtures. Findings revealed that the prepared precast EPS-foam concrete half-shaped slabs could possibly be applied as flooring elements in today’s modern infrastructure.

PREDICTION OF THE BREAKING STRESS OF CLAYEY SOILS FROM TCHI DEPRESSION TO BENIN.

The phenomena of shrinkage and swelling of clay soils depending on the water content are manifested by disorders affecting mainly individual houses, often not very rigid and superficially founded. The superficial foundations of infrastructures built on swelling soils are subjected to several stresses due to shrinkage and swelling phenomena. These stresses are the cause of damage to the frames in the form of cracks, or even lead to the partial or total breakage of the structure when it is built without special precautions. In order to control these induced stresses and to safeguard these infrastructures, it is necessary to control the breaking stress so that the dimensioned foundations do not cause the structure to break. The objective of this study is to develop a model to estimate the breaking stress thanks to the physical parameters of these soils. To achieve this, we performed several physical and mechanical tests on swelling soil samples taken from the study area, the results of which we used to use the established non-linear least squares method of swelling pressure prediction models. The models were based on test results from 24 soil samples. The tests were carried out in accordance with the French NF standards. This study has shown that the shear strength of a soil is a function of several physical parameters, mainly: pre-consolidation stress and plasticity index. We obtained the model qu=(2.9-1.181.IP). σ'p allowing us to predict the shear strength for the study area. This model is obtained with a regression coefficient precision r2 = 98.50%.