Engineering Properties Of Soil Research Articles

Consolidation behaviour of palm-oil-fuel-ash-based geopolymer treated soil

In recent times, geopolymers have gained attention as a soil stabilisation binder due to their ability to improve the engineering properties of soil while remaining eco-friendly. This study seeks to investigate the stabilisation of soft soil using palm-oil-fuel-ash (POFA)-based geopolymers. A geopolymer was created by combining POFA with an alkaline activator solution composed of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The mechanical and microstructural behaviours of two clayey soil types (samples S1 and S2) stabilised with four doses of the POFA-based geopolymer (G10PA, G20PA, G30PA and G40PA) were studied by conducting one-dimensional consolidation, California bearing ratio (CBR) tests, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The optimum dosage found was G40PA for both soil samples. The CBR value of S1-G40PA was 1.7 times that of S1, while that of S2-G40PA was nearly 1.5 times that of S2. The void ratio of S1 was significantly reduced from 0.70 (untreated sample) to 0.56 (S2-G40PA), whereas for S2, it was decreased from 1.43 (untreated sample) to 0.43 (S2-G40PA). The microstructural analysis (FESEM) revealed that changes in material composition correlate with the consolidation behaviour, with the geopolymer gel-binding effect enhancing the mechanical properties of stabilised soils.

An Examination of the Effect of Chemically Induced Damage on the Monotonic and Cyclic Shearing Behavior of Biocemented Sands

Abstract Microbially induced calcite precipitation is a biomediated soil improvement method that can improve the engineering properties of granular soils. Although improvements in soil engineering behaviors afforded by biocementation have been extensively characterized, there remains limited understanding of the anticipated long-term engineering behavior of biocemented soils following progressive chemical damage that may be experienced following initial applications. In this study, 10 direct simple shear tests were performed to investigate the effect of chemically induced damage on the drained monotonic and undrained cyclic shearing behaviors of biocemented loose Ottawa F-65 sand. All specimens were either uncemented, biocemented to different cementation levels corresponding to shear wave velocity increases (ΔVs) between 150 and 500 m/s, or biocemented to a ΔVs near 250 or 500 m/s and then subjected to degradation injections, which induced chemical damage and achieved ΔVs reductions of either 100 or 200 m/s. For all specimens, Vs and soil calcium carbonate content measurements were performed to assess improvement magnitudes, cementation uniformity, and evaluate magnitudes of chemically induced damage. As expected, increases in biocementation levels as captured by Vs increases were shown to progressively improve drained monotonic and undrained cyclic shearing behaviors. Following chemically induced damage, however, behavioral improvements were largely retained and were found to be consistent with the nondegraded biocemented specimens on the basis of similar Vs values. The performed tests provide the first examination of the expected long-term engineering behaviors of biocemented sands and yield new understandings regarding the anticipated impacts of chemical damage on behaviors relevant to subsurface liquefaction mitigation applications and other geotechnical use cases.

Experimental analysis of bearing capacity of soil with the addition of processed E-waste

Soil is the base material for any construction, for the stability of a structure, it is compulsory that the soil used should certainly meet engineering requirements. If not satisfied soil is neglected or certain additives are mixed to enhance the engineering properties of soil. Those additives are known as stabilizers. They are added to natural soil to make it more stable. In recent years utilization of waste in soil has gained attention. In the present experimental study, Soil samples were prepared from the soil near a lake in Lambhua from the region Sultanpur, Uttar Pradesh. This paper shows the outcome of the experimental program done to determine the effect of different dosages of processed E-waste mainly PCB (Printed Circuit Board) in clayey soil (CH). Random hand mixing added different proportions of E-Waste (2%, 5%, 8%, and 10%) to the natural soil. The performance of E-waste with soil was determined with the help of these tests; Atterberg’s limit, Specific Gravity, and California Bearing Ratio (CBR). These experiments were done to identify the amount of enhancement in the strength properties of the soil with respect to the parent soil. From the results, it was found that the bearing capacity of the soil enhances with the addition of processed E-waste.

A numerical model of water evaporation from cracked soil

Cracking is a common phenomenon in clayey soils under soil-atmosphere interaction. It strongly promotes water evaporation and further affects thermo-hydro-mechanical behavior and engineering properties of soils. In this study, a new numerical approach is proposed to simulate water evaporation in cracked soils. The new approach divides the cracked soil into two domains: the soil domain follows a coupled hydro-thermal approach and the air domain follows Fick’s law. The boundary conditions of the two domains are identified by the vapor flux with a suction-related evaporation model. Two sets of numerical tests are performed to examine the effects of air humidity and segmentation method on soil evaporation rate and volumetric water content profile versus time. Results reveal that soil water content near soil surface and soil crack surface decreases more rapidly. The more segments of crack surface are conducted, the more realistically it can reflect the variation of crack surface evaporation in depth, but it will increase the computational burden. Air humidity does affect the rate of evaporation and the larger the relative humidity, the lower evaporation rate. Furthermore, the presented numerical approach provides a benchmark for a satisfactory description of water evaporation from a clayey soil with cracks.

Use of Sawdust Fibers for Soil Reinforcement: A Review

A frequent problem in geotechnics is soils with inadequate physical–mechanical properties to withstand construction work, incurring cost overruns caused by their engineering improvement. The need to improve the engineering properties of soils is not recent. The most common current alternatives are binders such as cement and lime. The climate change observed in recent decades and the uncontrolled emission of greenhouse gases have motivated geotechnical and geoenvironmental researchers to seek mechanisms for soil reinforcement from a more sustainable and environmentally friendly approach by proposing the use of recycled and waste materials. An alternative is natural fibers, which can be obtained as waste from many agro-industrial processes, due to their high availability and low cost. Sawdust, as a by-product of wood processing, has a rough texture that can generate high friction between the fiber and the matrix of the soils, leading to a significant increase in its shearing strength and bearing capacity. This concept of improving the properties of soils using natural fibers distributed randomly is inspired by the natural phenomenon of grass and/or plants that, when growing on a slope, can effectively stabilize the said slope.

Influences of Paraffin-Based Phase Change Material on Soil Engineering Properties

Paraffin-based phase change materials (PPCMs) have been recognized as a potential tool to regulate soil temperature and reduce the freeze–thaw impact on soil. However, as a new filling material for geotechnical structures, such as dam core walls, the engineering applicability of PPCM-mixed soil (PS) needs to be further studied. In this paper, the influences of PPCM on the soil engineering properties (i.e., compaction characteristics, consolidation properties, mechanical behaviors, and permeability) and the PPCM leakage behavior were studied through a series of laboratory experiments. The results showed that the addition of PPCM results in an obvious decrease in the maximum dry density and optimum water content, a slight change in the compression coefficient, a significant reduction of the plasticity and cohesion, and an enhancement of the friction angle and impermeability. In addition, the PPCM in PS specimens will leak under the constant hydraulic gradient or vacuum saturation, and the leaked mass is positively related to the initial PPCM content. The PS specimens after 64-day seepage will still have a good impermeability. This paper is an important prerequisite for the practical applications of PS and provides a basis for its performance improvement.

Stabilization of Soil Using Concrete Slush Waste and Polyester Fibres

Abstract: Soil stabilization is a technique used in civil engineering to enhance the engineering properties of soil so that it can withstand large loads without shear failure. Many chemicals, by products and waste materials can be utilized for stabilization. In the present work, the behavior of soil after addition of the Concrete Slush Waste (varying proportion 4%, 8% and 12%) and Polyester Fibre (varying proportion 0.5%, 0.75%, and 1.0%; length 40 mm) was studied at different proportion and then various soil properties like Optimum Moisture Content, Maximum Dry Density, California Bearing Ratio, and Unconfined Compressive Strength values were determined. To conclude the current experimental research, it was ascertained that a combination of Concrete Slush Waste and Polyester Fibre can be used to improve the various engineering properties of soil.

Soil Stabilization by Using Lime and Fly Ash at Ahirwadi

Abstract: Soil stabilization is a crucial aspect of civil engineering, particularly in the construction of infrastructure projects. This study investigates the effectiveness of lime and fly ash as soil stabilizers and their combined application for enhancing soil properties. The objective of this research is to evaluate the changes in the geotechnical properties of soil treated with lime and fly ash, including compressive strength, shear strength, and durability. In this experimental study, different proportions of lime and fly ash were mixed with the soil samples to determine the optimal combination that yields the highest improvement in soil characteristics. The laboratory tests conducted on the stabilized soil samples included compaction tests and unconfined compressive strength tests. The samples were cured for different periods to assess the long-term performance and durability of the stabilization technique. The results indicate that the addition of lime and fly ash significantly improves the soil's engineering properties. The lime effectively increases the soil's pH, reducing plasticity and improving workability. The fly ash, on the other hand, enhances the pozzolanic reactivity and improves the soil's strength and durability. The combination of lime and fly ash demonstrates synergistic effects, leading to further improvements in the stabilized soil's properties.

Application of an Artificial Neural Network Model Based on Mineral Composition to the Prediction of Physical and Mechanical Properties

The physical and mechanical properties of soil are crucial in engineering construction, but conducting extensive experimental tests can be time-consuming, laborious, and subject to uncertainties due to the heterogeneity of the soil and variations in experimental conditions. Soil is composed of various minerals, and the mineral composition is the fundamental determinant of various physical and mechanical properties of the soil. The purpose of this study is to establish a convenient and reliable soil property prediction model based on mineral composition. To achieve this end, a dataset comprising the percentage content of different minerals in the soil, as well as the soil’s mechanical and physical properties, was collected. Using artificial neural network methods, prediction models for liquid limit, plastic limit, internal friction angle, and cohesion of the soil were developed based on mineral composition. Each model’s performance was evaluated through deviation analysis, and models with poor prediction accuracy were optimized using a genetic algorithm. The results demonstrate that the neural network model based on mineral composition can accurately predict soil properties with high applicability. This research provides a method for accurately predicting the majority of engineering properties of soil using experimental data on mineral composition, which is significant for cost savings and improving work efficiency in engineering projects.

Effect of biocementation on the engineering properties of sand soils under different flow rates and treatment durations

Effect of biocementation on the engineering properties of sand soils under different flow rates and treatment durations

Recycling and conservation of calcium carbide slag in dispersive soil modification: An evaluation of early age performance

The disposal of calcium carbide slag (CCS) is still a serious problem for areas that rely on the polyvinyl chloride industry, especially in the northern part of China. To assess the early effectiveness of CCS in treating dispersive soil, mechanical, chemical, and microscopic tests were conducted. The pH and conductivity EC were also measured to evaluate the effect of active ions. Validation test was also conducted on a natural dispersive soil from northern Shaanxi to prove the improving effectiveness of CCS on the dispersivity of soil. Results showed that adding 2% CCS significantly limits the dispersivity of the soil and improves its resistance to water erosion and mechanical properties. Increases of 11 times and 4.8 times were observed when CCS content increased from 0% to 5% and curing time increased from 0 to 28 days for compressive and tensile strength, respectively. The correlation between dispersivity and mechanical properties with pH and EC during curing was found to be significant. This relationship is closely linked to the dissolution and consumption behavior of the active ions that are abundant and contributed by the functional oxides in the CCS. Microscopic tests indicated that the porous particle structure of CCS improves the mechanical properties and limits the dispersivity of soil, due to physical strengthening and carbonization reaction in the early stage of CCS application. The subsequent release of Ca2+ and the formation of C-S-H/C-A-H cementitious hydrates played a vital role in controlling chemical dispersivity and further improving the mechanical properties of the dispersive soil. This was accomplished through ion replacement and pozzolanic reactions that were supported by the abundant active ions. Validation test show that CCS could efficiently improve the engineering properties of dispersive soil and the recommended mixture ratio is 2–5%.

Effect of Engineering Properties of Soft Clay Soil Stabilized with Limestone, Eggshells Powder and Eggshells Ash

Effect of Engineering Properties of Soft Clay Soil Stabilized with Limestone, Eggshells Powder and Eggshells Ash

Soil stabilisation for laying road foundations: Way forward with organic soil treatment

In Malaysia, the remediation of soils polluted by organic compounds is a challenging issue in environmental engineering. Improper treatment and conventional remove-and-replace approaches have low performance in terms of cost and sustainability. Hence, chemical stabilisation has been utilised worldwide to enhance the engineering properties of organic soils. This study focused on stabilising organic soil using cementitious-based chemicals blended with netted-polymeric fibre to improve its strength. This paper reviews the relevant past work as a basis for work in the pipeline. The study aims to determine the effectiveness of netted-polymeric fibre reinforcement on the shear strength characteristics of the stabilised organic sand. The fibre has tensile resistance that can be mobilised by normal pressures acting on fibre reinforcement soil. The best mixture of sand, clay, organic content and stabiliser for organic soil treatment will be identified as the way forward. The shear strength characteristics of the stabilised organic soil samples would then be evaluated parametrically using field application considerations.

Impact of microplastic pollution in terrestrial ecosystem on index and engineering properties of sandy soil: An experimental investigation

Sandy soils cover a major portion of various natural and managed ecosystems. Soil health plays a key role in achieving sustainable development goals 2, 3,11, 12, 13 and 15. The engineering properties of soil are crucial in determining the stability and safety of structures. The increasing microplastic contamination in the soil ecosystem creates a need to study the effect of terrestrial microplastic contamination on the strength and stability of soil and therefore on the index properties and engineering properties of the soil. The present paper investigates, the effects of varying concentrations (2 %,4 %,6 % (w/w)) of Low-density polyethylene (LDPE), Polyvinyl chloride (PVC), and High-density polyethylene (HDPE) microplastics on the index properties and engineering properties of sandy soil for varying observation days. The moisture content, specific gravity, shear strength, compaction characteristics and permeability are found to be significantly altered by changing the concentrations of microplastics but, insignificant changes are observed with respect to observation days. The shear strength value of non-contaminated sandy soil is 1.74 kg/cm2 which reduces after 5th observation days as 0.85 kg/cm2, 0.90 kg/cm2, and 0.91 kg/cm2 for 2 %, 4 %, and 6 % LDPE microplastic contamination respectively. Similar trends are observed for PVC and HDPE microplastic contamination. It is also observed that although the shear strength value decreases, the cohesion value increases for the microplastics-contaminated sandy soil. The coefficient of permeability for non-contaminated sample is 0.0004 m/s which reduces for 2 % LDPE microplastic contamination to 0.000319 m/s, for 4 % to 0.000217 m/s, and 6 % to 0.000208 m/s respectively. Similar trends of are observed for the PVC and HDPE microplastic contamination. The soil strength and structural stability are affected due to alterations in soil index and engineering properties. The paper provides detailed experimental evidence of the impact of microplastic pollution on index properties and engineering properties of sandy soil.

Investigation on mechanical properties of biomimetic mineralized mortar incorporated with boric acid modifier

Microbially induced carbonate precipitation (MICP) has been intensively studied as a potential method to improve engineering properties of soil. However, MICP has limitations due to the introduction of microorganisms and the difficulty of controlling the calcium carbonate crystal precipitation model. This study proposed biomimetic mineralized mortar based on the biomimetic-chemically induced carbonate precipitation (BCICP) method with boric acid as a crystal modifier. Similar to the bacteria in MICP, boric acid can promote the nucleation of calcium carbonate and the adsorption of calcium carbonate on the surface of sand particles. Besides, the boric acid concentration can effectively change the precipitation mode of calcium carbonate. Unconfined compression strength (UCS) test and microscopic characterization were conducted to investigate the mechanism of boric acid modifying calcium carbonate crystal growth and precipitation morphology. The results show that with the increase of boric acid concentration, the reinforcement efficiency of calcium carbonate increased. With the increase of boric acid concentration, the crystalline calcium carbonate changed from a cube-shaped calcite with a smooth surface to a spherical calcite with a rough surface and the coating pattern of calcium carbonate distribution on the surface of sand particles was weakened, while the bonding-filling pattern was enhanced. Besides, the cementing fluid concentration can also affect the reinforcement efficiency of calcium carbonate and with the participation of boric acid, biomimetic mineralized mortar can use the high concentration cementing fluid to achieve effective strength enhancement. This study confirms that boric acid could effectively modify the form and distribution of calcium carbonate between sand particles, and enhance the cementation between calcium carbonate and sand particles.

Characterization of engineering properties of deep-water soils in the South China Sea

The characterization of the geological and geotechnical properties of marine sediments is crucial for the exploration of subsea oil and gas resources. In this study, the engineering properties of deep-water soils recovered from the South China Sea (SCS) were in detail characterized via a series of laboratory tests to explore their physical, mechanical, mineralogical and microstructural behaviors. The results show that the index properties of deep-water soils are characterized by high natural water content, high void ratio, high Atterberg limits, but low density. The sensitivity of these soils is higher than 10, indicating their strong natural structure, which significantly controls the shear behavior and failure model. The intact samples show strain-softening to strain-hardening behavior with an increase in the confining pressure, while reconsolidated samples consistently show strain-hardening phenomenon under any level of confining pressure. The cyclic T-bar penetration tests show a dramatic strength degradation behavior of the intact samples. The compression curves of the intact samples always lie above the remoulded ones, and there is an obvious yielding phenomenon for the intact samples. The deep-water soils exhibit high thixotropy, as proposed by a criterion to evaluate the thixotropic capacity of soils. The mineralogy and microstructure analysis indicate that biogenic silica and an open flocculated structure might be the underlying reasons for the unique physical and mechanical properties of deep-water soils. The findings through this study provide essential parameters for related engineering applications and a deeper insight into understanding the unique properties of deep-water soils.

Investigation of shear strength of sand–bentonite mixtures with boron additives at high temperature for energy geo-structures

The soils surrounding energy geo-structures are exposed to high temperatures and temperature cycles. Changes in the engineering properties of soils should be investigated under thermal effects and soils that are highly durable against temperature changes are needed for thermo-active geo-structures. Generally, bentonite or sand–bentonite mixtures (SBMs) are preferred as natural barrier soil materials. Hence, the engineering properties of these natural soil materials against high temperatures should be improved. Boron, which has high thermal resistivity, reduces the heat expansion of materials, when added to soils may increase the durability of buffer materials at high temperatures. In the present study, the effects of tincal and ulexite additives were observed on the shear strength behavior of SBMs at 80 °C and room temperature. The general results showed that with the contribution of boron, the shear strength of the SBMs increased with increasing temperature. The effect was more pronounced for 20% SBMs at high temperature. Tincal and ulexite can be used to increase the shear strength of SBMs at high temperatures.

A REVIEW ON SOIL CONTAMINATION SOURCES: IMPACT ON ENGINEERING PROPERTIES AND REMEDIATION TECHNIQUES

Soil contamination produced by improper management of various petroleum and industrial products causes potential risks to the environment and soil engineering properties. Such contamination causes environmental deterioration and adversely affects soil engineering performance, altering almost all geotechnical properties. Several remediation techniques have been proposed to decontaminate the polluted soils. Choosing the best technique depends on both the energy consumption during operation and the treatment efficiency. The lack of a universally appropriate treatment method and the unavoidable expansion of contaminated land have justified the sake of reviewing the behavior of contaminated soils to develop both environmentally and geotechnically suitable soils for construction projects. The present paper reviewed some soil contamination sources’ backgrounds, effects, and remediation methods. Soils influenced by petroleum hydrocarbons and industrial effluents were evaluated. According to the reviewed studies, contaminants are evidenced to have a negative impact on soils' geotechnical characteristics by increasing settlement and swelling, reducing shear strength, and decreasing permeability. The need to restore the engineering characteristics of soils suggest the necessity to use remediation or stabilization technique. The electrochemical method, bioremediation, and stabilizing by additives are revealed to be efficient in improving the engineering properties and performance of contaminated soils.

Clayshale stabilization using active natural lime to increase the shear strength of soil

Clayshale not used in construction because it is easily weathered when exposed to air and water to reduce the soil shear strength. As a result, this decline can cause geotechnical engineering problems, and clayshale needs stabilization. This study aims to determine the shear strength of clayshale by adding variations of 5%, 8%, and 11% lime. Tests carried out to obtain soil parameters include soil index and engineering properties. Based on laboratory tests, the original clayshale soil has a 33.2% liquid limit, a 6,1% plasticity limit, and a 27,1% plasticity index. Hence, clayshale soils belong to the CL(clay-low plasticity) category based on the USCS. Adding lime variations can increase the specific gravity and the optimum moisture content of the clayshale soils. Still, it can reduce the dry unit weight and the plasticity index value on clayshale soils. The triaxial test on the original clayshale soil sample obtained a cohesion(c) value of 0.20kg/cm2 and friction angle(f) of 6.38°. In contrast, the values of c and f occurred the highest increase from the original clayshale soil with the addition of 8% lime, so lime can be used as an alternative in soil stabilization because it can increase the shear strength of the soil.

Van Gölü Havzası ve Civarının Depremselliğine Genel Bir Bakış

Bu çalışma kapsamında, Van Gölü Havzası ve civarı için özellikle aletsel dönemde meydana gelmiş depremler ve bunların artçı şok verileri kullanılarak yapılan çalışmalardan elde edilen sonuçlar değerlendirilmiştir. Farklı sismolojik parametrelerin kullanıldığı bu çalışmaların bulguları derlenerek, bölgenin gelecekteki deprem riski/tehlikesi karşısındaki durumu ortaya koyulmaya çalışılmıştır. Aletsel ve tarihsel dönemde büyüklüğü 5.0 ve üzerinde olan birçok depremin meydana geldiği bölgede, son olarak 23 Ekim 2011 (Mw=7.1) ve 09 Kasım 2011 (Mw=5.8) tarihlerinde Van şehir merkezi civarında meydana gelen yıkıcı/hasar verici iki deprem bölgenin farklı özelliklerdeki aktif fay mekanizmalarına sahip olduğunu göstermiştir. Sonuç olarak, özellikle Van Gölü’nün hemen doğusu ile Çaldıran, Muradiye, Özalp, Saray ve Erciş civarında yakın gelecekte deprem tehlikesi diğer bölgelere göre büyük olarak ifade edilebilir. Ayrıca, Van Gölü Havzası ve civarının gerek jeofizik yöntemlere gerekse yapısal incelemelere dayalı farklı parametreler (zemin büyütmesi ve sismik hasar indisi gibi) kullanılarak zemin mühendislik özellikleri ve yapı-zemin etkileşimi açısından değerlendirmesi de bu çalışmada incelenmiştir.