Soil Swelling Research Articles

Strength Mechanism of a Swelling Soil Improved with Jute Fibers: A Laboratory Treatment

Strength Mechanism of a Swelling Soil Improved with Jute Fibers: A Laboratory Treatment

Theoretical Decay Results of a Swelling Soils System with Frictional Damping Versus Viscoelastic Damping

Theoretical Decay Results of a Swelling Soils System with Frictional Damping Versus Viscoelastic Damping

AI-Based Estimation of Swelling Stress for Soils in South Africa

Soil swelling is one of the major causes of structural failure, due to excessive moisture saturation and desaturation moisture. In situ measurement of swelling stress is somewhat impossible and requires tedious routine site observation. The use of artificial intelligence to predict the swelling stress of in situ soil is highly recommended, because of the complex behavior of soil upon moisture absorption. Because of this challenge, this study is channeled towards the prediction of swelling stress using basic geotechnical properties to save the challenges of repeating geotechnical experimental tests. In this study, the swelling stress of soils collected from 15 locations in 5 sites across South Africa has been predicted by using the artificial neural network (ANN), genetic programming (GP), and evolutionary polynomial regression (EPR)-based intelligent techniques. Multiple data were collected through laboratory experiments on the predictors: gravimetric moisture content (GMC), plasticity index (Ip), dry density (γd), free swell index (FSI), degree of saturation (S), matric suction (Ψm) and the target, and swelling stress (Psm). This predictive model was aimed at proposing models, which will help earthwork designers and constructors in South Africa overcome the rampant visit to the laboratory in search of soil data needed for geotechnical engineering designs. The soils showed their potential for swelling, which was eventually confirmed by the sensitivity analysis of the intelligent models. The performance indices of the models showed that ANN outclassed the other techniques with a performance accuracy of 93.6% at an error of 1.9%. Also, the sensitivity analysis showed that the plasticity index and matric suction were the most influential to the models. With the predicted models, future earthworks in South Africa can quickly forecast swelling stress prior to designs and construction more so in hydraulically bound environments.

Stabilization of expansive soils using nontraditional chemical additives

The aim of this study is to analyze the stabilization effects of an expansive soil using three different nontraditional chemical additives, in this case: white cement and nano-silica as admixture, waste granite dust, and a new liquid polymer soil stabilizer (i.e. liquid granite). The engineering properties such as soil consistency, linear shrinkage and soil swelling behaviour of a bentonite treated with these stabilizing agents were investigated. Furthermore, the bearing capacity of the stabilized bentonite was analyzed through the California Bearing Ratio test (BCR) and a laboratory foundation model. The experimental program consisted of three series of tests. In the first series, the tests were performed on an expansive soil reinforced with 2%, 4%, 8%, and 10% of white cement combined with 2% of nano-silica. Another series of tests consisted of samples mixed with different percentages of granite powder (5%, 10%, 15%, and 20%). In the third series, liquid granite as a soil stabilizer was blended with soil specimens at various concentrations (1%, 2%, 3%, and 4%). For all admixtures, the results showed a marked improvement in soil consistency, an important decrease in linear shrinkage, a considerable reduction on the expansion index, and a significant improvement of CBR and soil bearing capacity. Moreover, two empirical correlations were proposed between the bearing capacity parameters (i.e. CBR and Improvement factor) and the expansion index.

Swelling and collapse behavior of unsaturated expansive subgrades stabilized with recycled glass

The swelling and collapse behaviors of expansive soils cause significant damage to light infrastructures such as pavements. This study investigates the swell-collapse behavior of expansive clay subgrade improved using recycled glass (RG) under unsaturated conditions. First, the optimum recycled glass content (ORGC) was determined based on the reduction in swelling potential. Next, static compaction tests were carried out on clay specimens stabilized at ORGC to establish a constitutive surface, namely virgin compaction surface (VCS) that exhibited the relationship between the moisture, stress and deformation states. The capability of the VCS in interpreting the swell-collapse responses was evaluated by applying various state paths. One-dimensional compression tests were conducted on specimens to investigate the mechanisms of swelling and collapse under a range of moisture contents and stress levels. Findings showed that the specimens’ behavior at ORGC = 25 % followed the developed VCS during loading, unloading and wetting paths, except those prepared at low moisture contents and wetted under low stresses. Utilizing the volume change data, a prediction model was developed and validated to estimate the swelling and collapse potential at ORGC. The proposed model provides a practical methodology to predict the volume change response of mixtures of fine and granular pavement materials through unsaturated soil theory.

Geotechnical properties of cohesive soils used in the construction of subgrade for the development of the railways in the Azov-Black Sea region

This work is devoted to the determination and systematization of the properties of clay soils used in the construction of new railway tracks in order to develop the railway network in the Azov-Black Sea region of Russia. To this end, classification characteristics are determined by traditional laboratory methods, and the possibility of soil swelling under excessive moisture is estimated. In addition, the compressibility of soils is studied as the main factor ensuring the trouble-free operation of the subgrade of railways during their long-term operation. Soil samples for measurements were taken from open pits located near construction sites at an extended length of construction of 530 km. The new regression relations proposed in the work provide in some cases the accuracy of determining the soil characteristics close to the accuracy of laboratory tests. They may be in demand when monitoring the accuracy of laboratory tests of soil properties of other open pits and increasing the speed of pre-design surveys during further development of the railroad network in this region.

The influence of dangerous geological and technogenic processes during engineering and geological research and environmental safety for construction in the modern period

Problems Statement and Purpose. Reliability of construction, protection of the territory from dangerous geological and technogenic processes, assessment of impact of construction and reconstruction objects on the environmental safety of the territory should be based on high-quality materials of engineering investigations. Today in Ukraine, the conditions of construction and reconstruction have significantly increased the requirements for the quality and composition of engineering research. At the same time, there are a number of natural and social factors that increase the degree of geotechnical and environmental risks during construction, there is no system that ensures the mandatory implementation of state regulations, which has an extremely negative effect on the quality of research materials. These questions are of particular importance given the volume of work that awaits us in the reconstruction of our country. The purpose of article is to once again draw attention to the problems in the field of engineering and geological investigations for construction, which largely depend on the safety and comfort of our living, to formulate proposals for improving the state of affairs in anticipation of the large-scale recovery of our country and the possibility of entering the regulatory field of the EU. Data & Methods. The legislative framework of Ukraine in the field of engineering and geological investigations for construction has been analyzed. Results. The article provides an analysis of the state with the legislative base in Ukraine regarding engineering surveys, the system that ensures mandatory compliance with the requirements of regulatory documents, factors that increase man-made and environmental risks in construction, proposed measures aimed at improving the quality of survey materials. 4 factors have been established that systematically affect the quality of engineering and geological investigations and the safety of construction: 1) most accidents and deformations of buildings and structures are associated with processes in the "base - foundation" system; 2) about 80% of the territory of Ukraine is characterized by complex engineering and geological conditions, with manifestations of almost all dangerous geological processes: seismicity, karst, landslides, reworking of banks, subsidence, soil swelling, etc.; 3) a significant increase in the specific weight of construction in conditions of dense urban construction and reconstruction of existing buildings in the total volume of construction; 4) social and economic conditions. An example of a change in the qualitative characteristics of underground hydrosphere (chemical composition and increase in the aggressiveness of groundwater), which had an impact on the reliability of construction and the ecological component at the studied area, has been considered.

Soil Swell Accommodation by Compressible Inclusions

This manuscript documents an exploratory study aimed towards the development of a mix-less technique to reduce heave caused by soil swell. The technique involves the placement of compressible inclusions in the soil mass, such that the swell deformation that would otherwise displace or distort a proximate structure is accommodated by the inclusions (i.e., is consumed in compressing them). Experimental results have confirmed that the swell-induced displacements of a free boundary in the vicinity of an inclusion are reduced in proportion to the extent to which the soil compresses the inclusion and in proportion to the inclusion’s compressibility. Simulation results have indicated that swell accommodation can produce stress reductions on fixed boundaries and reductions in the heave experienced by a slab resting on an expansive soil layer that houses compressible inclusions. Stress arching around inclusions emerges as a potential contributor to the minimization of settlements incurred by susceptible structures upon the retrofitting of their foundation soils with inclusions horizontally trenched at depth.

Expansive Soil Stabilization Using Alkali-Activated Fly Ash

Expansive soil swells with water and shrinks with water loss, causing serious safety problems for construction projects. This study emphasizes alkali-activated binder (NaOH excited fly ash) stabilized expansive soil. We found that swelling decreased with an increase in the amount of NaOH in alkali-activated binder. It was found that the alkali-activated binder stabilized expansive soils (AABS) had higher shear strength than untreated expansive soils (US), manifested by increased cohesion and friction angle. In AABS, the highest cohesion and the highest shear strength were found when the NaOH mass was 6% of the fly ash mass. The strength of AABS was similar to that of US without curing. AABS had higher strength than US after 7 and 14 days of curing. The unconfined compressive strength increased with extension of curing time. Combined with XRD and SEM analysis, it was shown that the mechanism of AABS was the formation of C–S–H and (C,N)–A–S–H and the change in the internal structure of expansive soil. This investigation can solve both the expansive soil problem and provide new concepts for green development.

Conceptual Model of Expansive Rock or Soil Swelling

The paper presents a simple yet efficient way to track the void ratio, the water content, and the degree of saturation of a swelling material during saturation. The research aimed to quantitatively describe the drying and wetting processes of the swelling material, which should enable their better understanding and easier modelling. Two identical tall samples, named “twins”, were formed by consolidating the paste prepared from the swelling material in which montmorillonite is the dominant mineral. The twins were together exposed to one-dimensional drying. After drying, lasting for 40 days, one twin was dissected to determine its water content profile. The other twin was subjected to 1D wetting (ponded infiltration experiment) with a constant water column for a period of 21 days and then dissected to determine the moisture profile. The sample preparation reduces uncertainties about the initial state. The results show that during wetting, the material follows a path in the e-w plot which is parallel to the full saturation curve. After reaching some degree of saturation, the path becomes parallel to the residual (shrinking) line. The proposed model predicts the primary and secondary phases of swelling, and under appropriate conditions, it assumes the tertiary phase.

Flexible Pavement Resiliency and Mitigation Strategies Following Adverse Environmental Events

Water accelerates flexible pavement damage in various ways, including subgrade and granular pavement materials strength reduction, frost heave, swelling of expansive subgrade soils, and asphalt binder stripping of aggregate in asphalt concrete (AC) mixes. This paper presents case studies of AC pavement sections in the U.S. that withstood high moisture events with limited effect on pavement performance and no immediate need for major maintenance or rehabilitation actions. The case studies comprise pavement sections in Florida and Louisiana that were subjected to catastrophic flooding events, a pavement section in Delaware that is constantly exposed to tidal water level variations, and pavement sections in Montana and Minnesota that experience seasonal freeze-thaw. These cases illustrated that flexible pavements could withstand climatic changes when appropriately designed and constructed. Mechanically or chemically stabilized subgrade, proper drainage, and/or minimizing plastic fines in unbound layers are all techniques that could effectively control moisture damage.

Swelling of sulfate-bearing soil: A case study of A1 highway pavement failure

Lime stabilization is one of the most commonly used methods for improving weak road subgrades, but it becomes very problematic in sulfate-bearing soils. This article presents results of a case study in which the sulfate attack was the most probable reason for a significant deformation of a highway pavement founded on lime-stabilized Doggerian clay. Macroscopic analysis revealed partial degradation of the concrete structure, a larger extent of stabilization than designed, and large gypsum crystals in the native soil. Chemical tests indicated a very high content of sulfates in the soil (> 10,000 mg/kg of SO4) and in the groundwater (> 3,000 mg/l of SO42-). The maximum free swelling strain (εvolmax = 3–6%) and the swelling pressure (pcmax = 56 kPa) of the clay, determined in the Wasiliew apparatus and the oedometer tests, were not large enough to be considered as the only cause of the pavement damage. Sand-cement and clay-lime mixtures, which simulated stabilized soil layers in the road profile, were observed for several months in oedometric tests, under various loading conditions. The swelling of Sa-Cem was negligible, but the Cl-Lim mixtures turned out to be much more expansive than the natural soil (εvolmax up to 21%, pcmax = 230 kPa) with a much longer duration of volume increase. The samples were flooded with distilled water or hard groundwater to clarify whether the constant access of the material to sulfates is important in the swelling process, but the results were unequivocal. X-ray diffraction revealed that the addition of lime resulted in the formation of secondary minerals: butlerite, portlandite, and ettringite. The presence and swelling of ettringite in the stabilized sub-base soil layers was eventually agreed to be the most probable reason for the pavement deformation. These results indicate the need to introduce an obligatory investigation of the level of sulfates in clayey subbase soils subject to lime stabilization.

The Effectiveness of Residual Soil, Orashi River Sand, and Sombrero River Sand as Stabilizing Agents for Subgrade Soil of Highway Pavement

The study investigated the effect of different stabilization materials, including residual soil and river sands, on the properties of subgrade soil for road and pavement structures. The results showed that the chemical composition of the subgrade soil was dominated by calcium, aluminum, and silicon, indicating a mineral clay soil. The use of stabilization materials led to a decrease in fines content and an increase in maximum dry density. The behavior of optimum moisture content was non-linear, and the liquid limit of the stabilized subgrade soil decreased significantly for all three materials, indicating a decrease in soil swelling ability. The study also revealed that the use of composite materials of cement and residual soil or river sand can improve the properties of subgrade soil and lead to an increase in unconfined compressive strength. The findings of this study can aid in the selection of appropriate stabilization materials and methods, and in the optimization of the use of these materials in road construction for improved strength and durability. Further research is needed to fully understand the characteristics of subgrade soil and determine the most effective methods for its stabilization and management. This study investigates the effects of residual soil and river sands on the mechanical properties of subgrade soil, with a focus on liquid limit, plastic limit, plasticity index, and unconfined compressive strength. The results suggest that residual soil, Orashi River sand, and Sombrero River sand are effective stabilizing agents for subgrade soil, with an increase in strength observed with increasing percentages of stabilizing material. However, there is an optimum content of stabilization material required to achieve maximum strength values, beyond which the strength decreases. The study also highlights the importance of considering the effect of soaking on the strength of subgrade soil and demonstrates the effectiveness of using composite .........

Influence of Salt Permeants on The Swelling and Strength Behavior of Fibre Treated Black Cotton Soil

Due to the limited availability of the bentonite in India, this investigation was initiated to check the suitability of using black cotton (BC) soil for liner application. Since, the waste tires, which are a major environmental concern, is mixed with the balck cotton soil as reinforcement material to reduce the desiccation cracks caused by shrinkage of the soil. As the salts present in leachate alter the liner material's geotechnical properties, the tire fibre mixed black cotton soil were tested for swelling and strength in the presence of various concentration of NaCl and CaCl2 salts. For this investigation, three different percentages of tire fibres (5, 10, and 15%) and two concentrations of salt permeants (i.e., 0.1 and 1N) were selected. The result indicated a reduction in the swelling and strength of BC soil with the addition of tire fibres. This reduction becomes pronounced with the higher concentration of various permeant salts. The swelling time of fibre-treated soils is reduced with the rise in concentrations from the time-swell relationship. According to unconfined compressive strength (UCS) test data, the ductile behaviour of soil sample increased with addition of fibre content. Finally, results suggested that the acceptance of tire fibre content for liner application is up to 10%, including different salt effects.

An Experimental Investigation on Shear Strength Behaviour of Unsaturated Clays on Effect of Spent Bleaching Earth and Misspend Cement

Abstract: In any kind of structure, expansive clay is a major cause of undulations. Numerous structures suffer damage and serious problems as a result of expansive soil swelling. The viability and environmental suitability of waste materials are the subject of extensive research by numerous research organizations. Waste products from the cement warehouse and oil industry include wasted bleaching earth and misspend cement. It is the best method to use in expansive soils to avoid issues with dumping and storage. Unconfined compressive strength and tri-axial compressive strength were used to identify a stabilization process. Any structure's stability depends on the strength of the underground soil on which it is built. All of a structure's loads are basically transferred to the ground directly. There are a variety of failures that can occur if the underlying soil is not stable enough to support transferred loads, including structure settlement, cracks, and so on. Soil improvement is necessary to solve this problem because it reduces the risk of structural damage in the future and reduces construction costs. To make ordinary soil stable enough to support the structural loads, a variety of improvements can be made. In this study, both regular and stabilized soil can be used in a number of tests. This paper explains the strength behavior of SBE treated black cotton soil reinforced with MC. The various percentage of SBE as 5%, 10%, 15%, 20% and 25% was used to find out the optimum value of RBI Grade. MC has been randomly included into the SBE treated soil at four different percentages of MC content, i.e. 2%, 4%, 6%, 8% and 10%.

Critical stress evaluation of rigid pavement due to the presence of water in expansive soil subgrade

The use of various types of rigid pavement is widespread because of its superiority in resisting heavy load vehicles. However, traffic loading complexity and subgrade response cause uncertainty during the design process. The presence of water in expansive soil issue swelling affected the flexural behavior of a rigid pavement slab. Rigid pavement relies heavily on the support and stability of the subgrade. Plain concrete is very weak in resisting tensile stresses so that the failure of rigid pavement slab structures often occurs in the expansive subgrade zone. Therefore, this study aims to numerically analyze the relationship between variations in the thickness of rigid pavement slabs on the flexural behavior parameters, such as critical and tensile stresses that affected water in expansive soil. The concrete’s performance limit was determined, using its material’s constitutive equation curve, and the data were analyzed using the finite element method. The results showed that the presence of water in expansive soil caused a change in soil volume (swelling), a reduction in soil bearing capacity (shrinking), and consequently, a rigid pavement cracked due to water variations in the subgrade. Generally, increasing the thickness of rigid pavement is a common method for mitigating the detrimental effects of expansive soil swelling. It is possible to provide reinforcement in other forms, which provide an opportunity to improve the performance of the concrete slab as a rigid pavement. For example, stabilization of expansive soil with materials capable of reducing its expansive power can be done but it requires large resources to realize it. Another method is to provide reinforcement to the rigid pavement slab structure, so that the rigid pavement slab is able to withstand traffic loads and also the expansion and shrinkage behavior of the expansive soil

Expansive Soil Swelling Test of Small Scale Laboratory Model on Sambungmacan Soil, Central Jawa

Soil is one of the most important elements in any civil engineering work, almost all construction activities are related to soil. One of the most common soil problems is expansive soil. This type of soil has a high potential to expand when compared to other types of soil. This research aims to find out how expansive the tested soil is and how it reacts when wetting. The test in this research is experimental, where the expansive soil test is modeled in a rectangular test box with a soil volume of 0.08 m3. The swelling and expansion pressures were measured using proving rings and dials, each totaling five units. The expansive soil used came from Sambungmacan Subdistrict, Sragen Regency, Central Java. The results of the property index test of Sambungmacan soil have a plasticity index percent value of 49.33% and a liquid limit (LL) of 90.16%. The test results showed that the maximum swelling reached 28.3% of the initial soil height of 200 mm and the maximum soil swelling pressure reached 103.23 kPa with a moisture content of 22.62%. The maximum pressure that occurs in each proving ring is at an average moisture content of 31.81%. The results of this study also show the effect of every 1% moisture content will produce a percent soil swelling of 0.40% to 1.08% and the average percentage of swelling pressure that occurs is in the range of 4.65 kPa to 10.26 kPa at every 1% swelling.

Comparison of Costus dewevrei De Wild. and T. Durand Admixture with Lime and Cement in Soil Stabilization

The study investigated the use of cement and lime as composite mixture with Costus dewevrei De Wild. & T. Durand as for soil stabilization aimed at improving the properties of expansive soils used for road pavement. The maximum dry density (MDD), optimum moisture content (OMC), consistency limits, California bearing ratio (CBR) and unconfined compressive strength (UCS) of the soil were subjected test to ascertain the performances of the cement and lime with bagasse composite. The results showed that the composite materials improved the soil properties, but the maximum dry density (MDD), optimum moisture content (OMC), liquid limit (LL), plasticity index (PI), California bearing ratio (CBR) and unconfined compressive strength (UCS) of the expansive soil stabilized with cement and bagasse ash composite were greater than the soil samples stabilized with lime and bagasse ash composite. Meanwhile, the value of plastic limit (PL) obtained from the soil sample stabilized with lime and bagasse ash was higher than the value recorded in the soil sample stabilized with cement and bagasse ash. The optimum values UCS and CBR were recorded at 8% combined proportion of bagasse ash with cement and lime. Therefore, the improvement recorded in the soil properties proved that the combined effect of bagasse ash obtained from Costus dewevrei De Wild. & T. Durand and cement or lime, is effective and can be applied as stabilization material to reduce shrinkage and swelling of expansive soil that often lead to road pavement failure.

Foundation for waterlogged bases with conical void design

The article presents hollow foundations that play a multifunctional role: drainage to accelerate the process of consolidation of weak water-saturated cohesive foundation soils, drainage in case of obvious underflooding, anti-barrage in case of latent underflooding, as well as compensating for possible swelling or frost heaving of the clay soils. The adopted design solution makes it possible to transfer the load from the foundation to the soil foundation that includes loose cavity filling material through a more developed support area than a foundation with a flat footing. Unlike the solid foundation, the hollow foundation has a higher bearing capacity by 120 N more, and in the intervals of high loads (> 400 N) the settlement of the hollow foundation develops with an occasional lag from the settlement of the solid foundation. The use of hollow concrete foundations makes it possible to expand the area of application of prefabricated foundations, simplify their manufacture, increase their bearing capacity and ensure their strength and durability, while reducing the material intensity and cost of construction.

A State-of-the-Art Review and Numerical Study of Reinforced Expansive Soil with Granular Anchor Piles and Helical Piles

Expansive soils exist in many countries worldwide, and their characteristics make them exceedingly difficult to engineer. Due to its significant swelling and shrinkage characteristics, expansive soil defies many of the stabilization solutions available to engineers. Differential heave or settlement occurs when expansive soil swells or shrinks, causing severe damage to foundations, buildings, roadways, and retaining structures. In such soils, it is necessary to construct a foundation that avoids the adverse effects of settlement. As a result, building the structure’s foundations on expansive soil necessitates special consideration. Helical piles provide resistance to uplift in light structures. However, they may not fully stabilize foundations in expansive soils. A granular anchor pile is another anchor technique that may provide the necessary resistance to uplift in expansive soils using simpler methods. This review and numerical study investigate the fundamental foundation treatments for expansive soils and the behavior of granular anchors and helical piles. Results indicate that granular anchor piles performed better than helical piles for uplift and settlement performance. For heave performance, the granular anchor and helical piles perform nearly identically. Both achieve heave reductions greater than 90% when L/H > 1.5 and D = 0.6 m.