This paper presents a laboratory study of the effect of naturals (hemp fibers) and synthetics fibers (glass fibers) on the mechanical behavior of sandy soil (natural Chlef sand). A series of shear direct tests were carried out on medium dense (RD= 50%) and dense (RD= 80%) Chlef samples sand with different naturals and synthetics content fibers ranging from 0, 0.25, 0.5, 0.75 and 1% and under three normal stress of 50, 100 and 200 kPa. The test results show that the addition of fibers has a significant effect on the shear strength of the sand-fiber mixture, however, this shear strength increases with the increase of the fibers content, the normal stress applied and the relative density until up an optimal fibers content of 0.5% for the glass fibers and 0.75% for the hemp fibres. Beyond these optimal fibres content, the shear strength decreases. The internal friction angle and the cohesion are significantly influenced by the fibres content.

This study presents an integrated approach that combines laboratory testing, numerical modeling, and artificial intelligence to enhance the assessment of soil behavior and slope stability. Direct shear tests were conducted on soils stabilized with varying proportions of lime and pozzolana under normal stresses of 50, 100, 200, and 300 kPa, with curing periods of 7 and 28 days. The results demonstrate a significant increase in shear strength, cohesion, and the internal friction angle with increasing stabilizer content and curing time, highlighting the synergistic effect of the lime–pozzolana mixture. The improved geotechnical parameters were subsequently incorporated into PLAXIS 2D simulations to evaluate the stability of an earthen dam using the c–φ reduction method within the framework of the Mohr–Coulomb model, resulting in a substantial improvement in the factor of safety. To mitigate the high computational cost associated with repeated finite element simulations, a Physics-Informed Neural Network (PINN) was developed as a surrogate model. The PINN accurately predicted displacement and stress fields while incorporating the governing elastostatic equations, achieving errors below 3

Soil reinforcement remains a vital task of a geotechnical engineer. There are a few support strategies for counting sands considered in this field that are strengthened by combined hydraulic binder (such as cement) and/or fibres. The behaviour of such mixtures (sand–cement and sand–cement–fibre mixtures) in terms of direct shear response has been subject to a lot of controversy in the literature. The base material used in the framework of this study is Chlef sand (taken from Chlef Valley, Algeria), mixed with cement and reinforced with synthetic fibres and considering the use of a direct shear device. , mixed with cement and reinforced with synthetic fibres. The types of fibres in terms of the materials used in the manufacture as well as their length and physical characteristics can improve the stress/strain response of sands. Laboratory results show that the shear strength response of sand–cement mixture increases the shear strength of this last and that it was observed with the addition of cement to the sand. The tests done on the mixtures of sand and cement and on fibre-reinforced mixtures showed better strength compared with just sand or cemented sand alone. Adding fibre to the mixture improved the soil’s ability to withstand shear forces. As the threshold value, the fibre content should be at least 0.15% in order to make a noticeable improvement in the mechanical properties. This increase in shear strength is noticed accompanied by a limitation in the samples’ contractiveness.

Introduction. This paper presents a laboratory study investigating the mechanical behavior of silty soil reinforced with hydraulic binders (cement and lime) using a direct shear apparatus. A series of direct shear tests was performed on silty soils treated with hydraulic binders. Methods. The tests were conducted at a relative density of 50 %, under three normal stresses, with cement and lime contents of 0, 1, 3, 5, and 7 %, and a water content of 10 %. Results. The shear strength of cement-treated silt increases with cement content up to 6 % and then stabilizes. For lime-treated silt, the shear strength decreases at a lime content of 1 % and then stabilizes; thus, the contractive behavior increases with higher lime content. The internal friction angle increases with cement content and then stabilizes, with a slight decrease observed at a cement content of 7 %. Cohesion increases linearly with cement content. Lime addition enhances soil contractiveness; cohesion increases slightly up to a lime content of 3 % and then decreases. For the silt treated with the cement–lime mixture, the test results show that shear strength increases with normal stress compared to the untreated soil.

This experimental study is to find a solution to reduce the amount of waste and at the same time improve the geotechnical properties of fine soils. Compaction, odometer, direct shear tests, and unconfined compression tests were carried out on a clay with a very high degree of plasticity mixed with 0

Sand mixed with fines content is always found in the soils projects and represent a discussion subject in many research items in the literature. This article aims to study the behaviour of soils representing by two different sands containing plastic fines content, emphasizing the variation of important parameters in soils behaviour in terms of stress/strain variation, compressibility and consolidation. Bentonite was used in particular to introduce the sands (Chlef sand and standard sand). A series of oedometric and a rectilinear box shear tests carried out to study how sand and bentonite mixtures behave together. To achieve this objective, fines content of 10, 20 and 30

The aim of this article is to investigate how varying the content of plastic and non-plastic fines influences soil behavior. Initial relative density is particularly highlighted in the experiments. Test findings indicated that the fine content plays a significant role in reducing the dilatant character of the soil for sand-silt samples. The quantity of fine particles present in the mixture affects the soil’s ability to liquefy, but only up to a certain fine content of 40

"Investigating the behavior of silty soils reinforced with geotextile layers in terms of shear strength and deformation in a laboratory setting is the study's objective described in this paper. This work includes an experimental study based on a series of undrained monotonic triaxial tests, which were carried out on clean sand from Chlef, medium dense (Dr = 50%), mixed with silt content fluctuating between 0 and 30%. The mechanical behavior was examined and discussed in this paper by varying the number of geotextile layers (Ng = 1, 2, 3) and the fines content where the samples were consolidated under 100 kPa confining pressure. Experimental results on unreinforced and reinforced silt/sand soils by geotextile layers show that the quantity of geotextile layers is growing in the studied samples improves the shear strength characteristics of the soil, nevertheless, lessen the radial deformations cause the pore water pressure to rise instead. However, the pore water pressure increases while the deviatoric stress decreases as the percentage of fines increases."

This paper presents a laboratory study on the monotonic behaviour of saturated chlef sand (Algeria). Through its history, many different phenomena have been observed in this soil (Chlef sand, Al-Asnam earthquake 10 October). For this laboratory study, a series of tests were performed on sand samples from Chlef to see how the initial relative density and lateral pressure (confining) affected how the sand behaved. The tests results indicated that the increase in the relative density and the confining stress significantly affects the undrained monotonic behaviourof the sand under study resulting in an amplification of the dilatant character with the increase in the relative density, on the other hand a decrease in the dilatant character with the increase in the initial confinement pressure. The results also indicate a strong correlation between the shear strength measured by the stress deviator and the effective mean pressure P'.

This study explores the impact of non-plastic fines content, initial confining pressure, and grading characteristics on the undrained shear strength and excess pore pressure of sand-silt mixtures; a series of undrained compression triaxial tests were carried out on reconstituted Chlef sand (Algeria) samples with different percentages of silt content (Fc = 0, 5, 10, 15, and 20

The identification of static liquefaction susceptibility is crucial for ensuring the safety and cost-effectiveness of structures. However, traditional estimation methods are often inefficient, time-consuming, and costly. In this study, a new alternative model was developed using ten advanced machine-learning methods, such as Deep Neural Network (DNN), Extreme Learning Machine (ELM), Support Vector Regression (SVR), LASSO regression (LASSO), Random Forest (RF), Ridge Regression (Ridge), Partial Least Square Regression (PLSR), Stepwise Regression (Stepwise), Kernel Ridge (KRidge), and Least Square Regression (LSR), to predict static liquefaction susceptibility in sands containing plastic fines. The model was trained on a dataset of 114 unconsolidated undrained triaxial shear tests implemented on saturated sand, and collected from the literature. Eight relevant factors were chosen based on literature recommendations as input parameters. The machine-learning methods were evaluated using six performance measures and K-fold cross-validation approach. The study found that the Deep Neural Network (DNN) model outperformed others, providing more accurate predictions and the closest to the experimental values. Finally, a reliable and easy-to-use graphical interface named "StaLique2024" was developed based on the DNN model. This latter will greatly offer a reliable and user-friendly graphical interface, facilitating efficient estimation of static liquefaction for researchers and civil engineers while saving time and money.

This study was carried out to describe the mechanical behavior of different materials in terms of shear strength, cohesion and friction. For this purpose, an experimental shear tests were carried out. The soils used for the preparation of the samples were the Chlef sand, Chlef silt and M’zilla clay and a mixture composed of 50% of silt and 50% of clay. The soils were prepared by mixing Chlef sand with fines content of silt, clay or clay silt ranging from 0, 10, 20, 30 and 40%. The tests were conducted on sand samples prepared at a relative density of 20% representing a loose state and subjected to three normal stresses of 100, 200 and 400 kPa. All the tests were conducted at constant displacement rate of 1.00 mm/min. From the obtained results, it can be seen that the clean sand showed the highest shear strength at a small strains. At large strains, sands with 30% clay rather than 30% clay silt showed the highest shear strengths respectively. More contracted sands have the greatest increased maximum shear strengths. The sand with clayey silt, at a fine content of 20%, develops the most increased cohesion, among the other silty-clayey sands, together with the most reduced shear strength in elastic behavior. The sand with 40% of silt content develops a greater internal friction angle, however, the other silty sands, showed reduced shear strength, at the same behavior. To validate these findings, numerical simulations were performed on sand-silt mixtures using the hypoplastic model. The results indicated that the hypoplastic model accurately predicts the shear behavior of sand-silt mixtures in direct shear test, providing realistic insights into the effects of fines on the mechanical properties of the soil. Keywords: Sand, Silt, Clay, Fines Content, Shear Strength, Friction, Cohesion.

The present article seeks to examine and discuss the experimental results that were obtained from a series of straight box shear tests. For this, different soils were prepared with clean sand, which was brought from the Wilaya (Province) of Chlef that is located in northern Algeria, mixed with silt from the same site, clay from the town of M'zilla or clayey loam that is composed half of this same clay and half of silt. The percentages of sand replacement by the selected additions were 0, 10, 20, 30, and 40% in mass ratio. The samples thus prepared were then tested with respect to dry shear, under the normal stresses equal to 100, 200, and 400 kPa. The results obtained showed that the shear strength of the sand from Chlef decreases when the silt content increases from 0 to 40%. With regard to the sand-clay and sand-silt-clay mixtures, it was found that the shear strength decreases until reaching a threshold value that coincides with the addition content of 20%. Then, beyond that value, it begins to increase as the addition fraction increases. Likewise, it turned out that cohesion increases with increasing silt content, while for sand-clay and sand-silt-clay mixtures, this cohesion increases until reaching a maximum value which coincides with the addition of 20% silt content. The same trend was observed for the variation of the direct shear strength, while the friction angle exhibited an inverse behavior.

This paper presents a detailed study on improving slope stability through soil reinforcement using cement under both static and dynamic conditions. Experimental shear tests were conducted on clay samples taken from an unstable slope section, with varying cement contents (5

This paper reports the results of a series of drained and undrained triaxial tests on Chlef soil reinforced with stone columns surrounded by geotextiles. The tests are carried out on reconstituted samples having an initial density index Id =0.50 and which are subjected to an initial confining pressure of 100 kPa. In order to create stone columns that can be realized in situ, sand grains with an average diameter of 2 mm are used to manufacture the tested specimens. In addition, we used 70 and 10 mm for the length and diameter of the stone column, respectively. The test results show that, in one hand the stone columns’ presence affects significantly the soil shear strength, that increases according to the stone columns number and reduces the soil contractiveness (vertical strain), and in the other hand, it decreases the interstitial pressure. Encasement improves the effectiveness of the stone column and raises the rigidity of the reinforced soil by reinforcing the stone column with geotextiles. Furthermore, the secant modulus increases versus of the stone columns number, which is due to the inverse proportionality of this modulus to the axial strains. In addition, the internal frictions increase following a linear evolution law with the increase in the number of inclusions of reinforcements stone columns.

This article presents the effect of silt proportion on the hypoplastic parameters (exponent n, granular hardness hs, exponent α, and exponent β) used for numerical simulation, calculation of emax, and transitional fines content (Fct). Fifteen oedometer tests were carried out at various relative densities (RD = 30, 65, and 80 FC_t FC_t depends on the stress level and maximum void ratio, which are calculated from the parameters of the hypoplastic model (eio, hs, ps, n).

This paper presents an experimental thorough study on geocell reinforced loose sand (Dr = 25%), focusing on the improvement of the shear strength in undrained conditions. The experimental program includes a series of undrained compressive tests (CU) performed on loose sand samples with and without reinforcement. The experimental tests are performed for various geocell height (Hg = 15, 25 and 35 mm) and at different level of effective confining pressure (sigma'(c) = 50, 100 and 200 kPa). The obtained results show a significant effect of geocells height and initial confining pressure on the shear strength of the reinforced sand. The apparent cohesion of the reinforced soil increases linearly with the axial strain while the friction angle is rather constant and slightly dependent on the sample deformation.

This paper examines the effect of fiber content and relative density (RD) on the hydro-mechanical behavior of Chlef sand. The hydro-mechanical behavior of the sand-fiber mixture was evaluated by 45 permeability tests and 30 direct shear tests in the laboratory. Tests were performed on reconstituted specimens at different relative densities (RD = 15, 50 and 70

The cracks caused by desiccation induce rapid failures as rapid shallow landslides in stiff and fragile clayey soils. Several environmental structures such as landfill liners and road embankments are often constructed by compaction of a series of soil layers. These works suffered in many cases of disorders due to desiccation. One of the potential valuable techniques to reduce these disorders is the short fibers reinforcement. Fibers reduce the cracks propagation and the geometric cracks characteristics such as the length, depth and opening. The paper presents an experimental characterization of the crack pattern observed in compacted samples at optimum water content (OMC) with and without fibers reinforcement. 2D Image Analysis has been used to investigate the characteristics of the geometric cracks. Alfa natural short fibers used to assure the reinforcement, reduced the carks' propagation by stopping the propagation and reducing their 3D opening (surface opening and depth growth). The role of fibers to improve the tensile strength and reduce the growth of the crack has been well-highlighted. At this stage, a simple model was calibrated to predict the tensile strength for reinforced soil specimens with short fibers considering various fibers contents and fiber's geometrical characteristics.