Soil Reinforcement Material Research Articles

Triaxial drained behaviour of disposable face mask fibre reinforced sand

ABSTRACT The widespread usage of disposable face masks (DFM) during the COVID-19 pandemic has exacerbated waste management challenges, prompting an investigation into their potential reuse as a soil reinforcement material. Previous researchers have investigated the effect of mask fibres on pavement subbases and the environmental problems caused by these fibres. This study examines the mechanical properties of sandy soil enhanced with shredded and layered DFM under triaxial testing conditions, focusing on key parameters like shear resistance, elastic modulus, stress-strain characteristics, axial resistance, failure envelope, and brittleness index. Results show that adding DFM significantly improves soil cohesion, friction angle, shear strength, and peak deviatoric stress, especially at higher fibre contents and relative densities. However, increased DFM fibre content was associated with reduced elastic modulus, which stabilised in specimens with layered DFM, suggesting complex interactions between DFM content and soil mechanics. Concerns include potential void formation leading to asymmetric settlement and environmental issues on non-biodegradable fibre integration in soil. These findings highlight the need for meticulous mixture preparation, large-scale studies, and environmental assessments to evaluate the impact of using DFM in soil reinforcement, particularly for road construction and slope stabilisation. This research provides crucial insights into the potential of DFM for soil reinforcement.

Static and seismic stability investigation of a bamboo grid reinforced slope with different stepped reinforcing arrangements

Bamboo is primarily used as a soil reinforcement material to build roadways and stabilize slopes and river banks. The current study aims to examine how bamboo grid reinforcing slopes behave in the form of various stepped reinforcing arrangements. The static and seismic characteristics of a slope reinforced with a bamboo grid were examined through 3D numerical analyses employing the finite element program MIDAS GTS NX (340) 2023 v1.1. In this study, the Strength Reduction Method (SRM), a crucial technique in finite element analysis, is utilized to compute the factor of safety and displacement in static stability analysis. Seismic stability analysis is conducted using non-linear time history analysis, examining the changes in critical slope parameters in response to seismic excitation. Three distinct arrangements of bamboo grids were employed to enhance slope stability. Static stability analysis, considering the factor of safety and deformation, was conducted for various bamboo grid-reinforced slope arrangements. Additionally, a comprehensive seismic analysis was performed specifically for the type 2 bamboo grid reinforcement arrangement, using the seismic record from the 1971 San Fernando Down earthquake. The safety factor increases by 52.10%, 68.67%, and 62.65% for type 1, 2, and 3 arrangements, respectively, compared to the unreinforced slope. Consequently, the type 2 bamboo grid-reinforced slope arrangement exhibits superior stability in terms of the safety factor. The lateral displacement of the type 2 arrangement is minimal compared to other types. Furthermore, a bamboo grid-reinforced slope with a vertical spacing of 1.5 m demonstrates less deformation than slopes with different vertical spacings. The seismic stability of the slope body surpasses other sections of the bamboo grid-reinforced slope.

Settlement Performance of Bamboo Dendrocalamus Asper for Improving Peat Soil Reinforcement Stability

Soil reinforcement is the geotechnical application for the soil mass reinforcement elements to increase the shear characteristics of the soil grid. Bamboo is a sustainable source for the wood industry that has been applied in construction soil foundations as a soil reinforcement material. The use of bamboo types Dendrocalamus asper for soft soil reinforcement stability is important and commonly used. Peat, as a very soft soil, is known as problematic soil, and organic soil has poor shear strength and high compressibility. In construction especially for peat soil foundation or subgrade, it has settlement and deformation because of loss of strength. The peat soil from Kampung Puteri Menangis, Benut Pontian Johor has been used in the experimental work to determine the displacement of the settlement performance characteristics without and with the laminated beams of bamboo Dendracalamus asper. Without bamboo, the displacement of the settlement reduces from 22.4% to 6.8% within 1 hour. The use of 1 layer of laminated bamboo reinforcement on the foundation base reduced the displacement of the settlement from 27.2% to 8.9%. The displacement continuesto decrease from 19.3% to 5.8% fortwo layers of laminated bamboo reinforcement, and 18.9% to 5.9% for 3 layers of laminated bamboo reinforcement. At each stage and duration, the peat shows displacement in compression, and the settlement of the reinforcement stability is smaller than in the other stage.

An Estimation Model of the Ultimate Shear Strength of Root-Permeated Soil, Fully Considering Interface Bonding

Roots can be seen as natural soil reinforcement material. The prediction and quantitative evaluation of the shear strength of root-permeated soil is the focus of vegetation slope protection, in which the bonding effect of the root–soil interface is the key factor. Taking the roots of Chinese fir trees as an example, the shear resistance test of root–soil interface bonding strength and the direct shear test of root-permeated soil with different root area ratios and inclination angles were carried out. The results indicated that the bonding strength of the root–soil interface could be quantified by interfacial cohesion and friction angle. The shear strength of root-permeated soil increased with the root area ratio, and its relationship with the inclination angle of root relative shear direction was: 45° > 90°. In addition, an estimation model of the ultimate shear strength of root-permeated soil was developed, in which the bonding effect of the root–soil interface was quantified by the interface bonding strength parameters. The soil stress, root diameter, root length, and the initial angle between the root and shear direction can be considered in the estimation model. The rationality and accuracy of the estimated model were verified through the comparison of experimental results and Wu’s model. The proposed model can be used to calculate the stability of the biotechnical reinforcement landslides and evaluate the shear strength of the root-permeated soil.

Effect of fiber length on the consolidation parameters of coir fiber-reinforced soft clay

Coir fibers are natural fibers with high tensile strength and pressure resistance, making them an alternative soil reinforcement material. However, the effect of fiber length on improving soil consolidation properties has yet to be largely explored. Therefore, this study investigated the effect of the length and content of coir fibers on soft soil mechanical behavior through a series of one-dimensional consolidation tests. Fibers of >10 mm to 30 mm and >30 mm to 50 mm lengths were mixed randomly into the soil with varying content, ranging from 0.00% to 1.25% of the total weight of the mixture. The relationship between the effective stress and the void ratio was explored, unveiling that the void ratio of soil specimens reinforced with coir fibers decreased more gradually than those unreinforced. An increase in the fiber content reduced the compression index (Cc) value and enhanced the coefficient of consolidation (Cv) value, with longer fibers producing more significant values due to more excellent interactions between fibers. Fibers of >30 mm-50 mm yielded optimum Cc and Cv values at the fiber contents of 0.50% to 0.75%.

Evaluating the Effect of Nano-SiO2 on Different Types of Soils: A Multi-Scale Study

A rapid growth in the population leads to a large increase in engineering construction. This means there is an inevitability in regard to building on problematic soils. Soil reinforcement becomes an important subject due to the fact that it is a concern for engineers and scientists. With the development of nanotechnology, more and more nanomaterials are being introduced within the practice of soil reinforcement engineering. In this study, the reinforcing effect of novel nanomaterial nano-silica (SiO2) applied to different kinds of soils was systematically studied. The nano-SiO2-reinforced soil possessed lower final water evaporation loss, and evaporation rates. The nano-SiO2 increased the shear strength of clayey soil and sandy soil under both cured and uncured conditions, but the reinforcing effect on clayey soil was more obvious. The addition of nano-SiO2 promotes the friction angle and cohesion of clayey soil; further, it also increases the cohesion of sandy soil. The unconfined compressive strength of clayey soil was enhanced by nano-SiO2, meanwhile, the nano-SiO2-reinforced soil possessed greater brittleness. The microstructure of nano-SiO2-reinforced soil is shown via SEM analysis, and the results of X-ray diffraction (XRD) tests show that there are no new mineral components generated during the reinforcing process. It was also found that nano-SiO2 possessed little influence on the soil pH value. Adding nano-SiO2 will not damage the original chemical environment of the soil. The microstructure of nano-SiO2-reinforced soil was observed to prove the results above. In general, nano-SiO2 is an excellent soil additive that can improve the mechanical properties of both clayey soil and sandy soil effectively. This research provides more ideas and directions for the purposes of selecting soil reinforcement materials.

Komparativna analiza učinkovitosti otpada od orezivanja palmi i geotekstila na stabilizaciju posteljice

This paper proposes a novel and environmentally friendly solution for subgrade stabilization that not only contributes towards waste material recycling but also enhances the bearing capacity of subgrade soil. Laboratory plate load tests were conducted under static loads to evaluate the potential use of palm tree pruning waste (PTPW) as a soil reinforcement material instead of commercially manufactured geotextiles, as well as to analyse the impact of the reinforcement depth, number of reinforcement layers, and the relative density of the subgrade material. The results revealed that as the number of reinforcements increased, the load-bearing pressure behaviour of the reinforced subgrades improved. Furthermore, when the reinforcement depth decreased, the load-bearing pressure behaviour improved significantly. All PTPW-reinforced subgrades performed better than geotextile-reinforced subgrades under the same conditions. Additionally, the bearing capacity improvement in the reinforced subgrades was evaluated based on the bearing capacity improvement factor (BCIF). The highest BCIF was obtained when the PTPW was used as a reinforcement with two layers at a sand subgrade relative density of 80 %.

Stablization of Clayey Soil Via Lime and Plastic Fibre for Advanced Foundation Proposition.

Abstract: Soil is the most widely used and basic material for civil engineering. The soil is used for houses, walls, bridges and roads. The Earth provides various types of soil and varies in its properties, scale, composition and textures. The earth's soil is a natural fine grain rock that contains one or more minerals from Earth, which have metal oxides and traces of organic matter. Based on the structure, the clay has quite a range of characteristics. It's slow, and difficult to accelerate, and used for something small. This study is aimed at achieving soil engineering properties for subgrade. In the subgrade construction, waste plastic bottles are used from waste disposal and the application of raw waste soil reinforcement materials and tried to stabilize the clay soil in different strong lime percentages (2 percent, 4 percent, 6 percent, 8 percent, 10 percent, and 12 percent). Testing of the strength of the clay earth, like Maximum Dry Density (MDD) and California Bearing (CBR) was done at different plastic strip percentages. In order to measure improvements in technologies, the clay floor swelling index and the microscopic examination also are performed. Keywords: Clay soil, Lime, Plastic, fiber material.

USING WASTEPAPER SLUDGE ASH (WSA) AS A MATERIAL FOR SOIL STRENGTHENING FOR THE CONSTRUCTION OF LAYERS OF PAVEMENT

The article considers the possibility of using wastepaper sludge ash (WSA) as a soil reinforcement material for the construction of layers of road wear. Loamy sand, sandy loam, silty clay loam, silty clay were chosen as soils for strengthening. The maximum density of the soil skeleton at optimum humidity was established by the method of Proctor. Wastepaper sludge ash and Portland cement grade 400 were used separately for soil strengthening. Six compositions of strengthened soil for each type of soil were investigated according to the strength criterion of water-saturated samples at the age of seven, fourteen and twenty-eight days. The research results indicate that wastepaper sludge ash can be used to strengthen different types of soils with the achievement of following grades of stabilized soil: M10, M20, M40.

Influence of vetiver root on strength of expansive soil-experimental study.

Grassroots have received more attention than the traditional method as soil reinforcement materials, especially the use of vetiver and other vegetation protection methods to treat expansive soil slope, have been tried and applied. To study the influence of grassroots on the strength properties of expansive soil, the laws of vetiver root growth over time and its vertical distribution of root content(δ) were firstly investigated by the experiment of planting vetiver. Then different δ and depth of planted soil were obtained. Simultaneously different δ and water content(ω) of grafted soil were made. With the direct shear test, the shear strength parameters of root-soil with different δ were analyzed. The shear test on root-soil composites with different δ was carried out to compare the strength characteristics of planted and grafted soil. The results showed that the δ of vetiver decreased with the increase of depth, and the δ of each layer increased with the growth period. The δ of 180d was 70.5% higher than that of 90d. The cohesion(c) of root-soil can be increased by more than 97%, and internal friction angle(φ) can be increased by more than 15.4% after 180 days. The c of 90 d vetiver root system can be increased by more than 18%, and the φ can be increased by more than 1.5%. At each depth, the c and φ of composite soil increases with the increase of δ, and the increment of cohesion (Δc) and the increment of internal friction angle (Δφ) increase with the increment of δ. But the increase in the ω will weaken the shear strength parameters of root-soil. Under the condition of the planted root system and grafted root system, the influence degree of δ on strength parameter of root-soil is different, and the law of strength parameters versus δ of grafted soil of 365d is similar to that of planted soil of 90d. And the root reinforcement of grafted soil is weaker than planted soil. Hence the grafted soil can´t accurately reflect the root-soil interaction of the existing root system.

Laterite Soil Behavior - Geotextile (Study of Laterite Soil, Tanah Laut District)

Land has different specifications and characters from each type. The land has the main function is as a support of a building construction be it buildings, roads, etc. Seeing from the function is inseparable from the mechanical properties of the soil such as cohesion (c) and soil shear angle (¢) where the higher the carrying capacity of the soil the better. The contact force (interface) between the soil surface and the surface of the soil reinforcement material is very dependent on the type of soil. Soil-geotextile contact will influence the carrying capacity of the soil, especially shear strength and soil cohesion. At present research on contact style interface (5) of laterite-geotextile soil. The method used in this research is to use laboratory-scale experimental methods. This research was conducted with the condition of the soil sample not submerged in water (unsaturated). The test results may be known laterite in Tanah Laut has value ratio 5/|) of 0.89 for the type of woven geotextile (HRX250), while the value of the ratio 5/(|) of 0.86 for the type of nonwoven geotextile (TS600).

Use of bamboo mat as a potential soil reinforcement material – An experimental study

This paper discusses the results of laboratory model tests on cohesionless soils reinforced with different weaving patterns of bamboo mat. Bamboo mat with diagonal weaving and rectangular weaving patterns was used for the present study. The optimum placement depth and with of reinforcement layer were fixed based on the previous studies carried in the bamboo mat reinforced soil. The amount of material used for the production of two different types of mat kept almost equal and compared their performance as a soil reinforcement material. An improvement factor of 2.47 was obtained for the diagonal pattern for a settlement ratio of 30% whereas, in the rectangular pattern, it was 2.17. The test results indicate that the inclusion of the bamboo mat improves the bearing capacity of soil and the weaving patterns have some influence on the performance of reinforced soil bed. The heave formations on the soil bed during the test for both unreinforced and reinforced conditions were also reported here.

Stability Analysis of Soil Embankment Slope Reinforced with Polypropylene Fiber under Freeze-Thaw Cycles

Polypropylene fiber is a common soil reinforcement material which is used to reinforce a common clay in northeast China. Numerical analysis method was performed to investigate the effect of polypropylene fibers on stability of embankment slope subjected to freeze-thaw cycles. The orthogonal experiments of three factors (freeze-thaw cycle, fiber content, and fiber length) and three levels were carried out, and the corresponding nine groups of specimens were made, whose shear strength parameters (internal friction angle and bond force) were measured by direct shear test. Then, the experimental results were analyzed by analysis of variance and range analysis so that the optimum fiber content and fiber length can be determined. The finite element model of typical high-fill soil slope of freeway in northeast China was established whose basic material parameters were taken as the parameters of shear strength of different freeze-thaw cycles under the optimum fiber content and fiber length. The concept of shear strength reduction was introduced into the finite element model, and the convergence of the finite element model was taken as the judging criterion of slope stability. Thus, stability analysis of soil embankment slope reinforced with polypropylene fiber under freeze-thaw cycles was realized. The results show that the addition of fibers improves the cohesion under the action of freeze-thaw cycles, and the internal friction angle is improved in the case of freezing and thawing. This phenomenon leads to the improvement of the stability of the embankment slope in a freeze-thaw cycle. The improvement is particularly noticeable in the case, and this improvement effect decreases as the number of freeze-thaw cycles increases.

COMPARISON OF THE BEHAVIOR OF FIBER AND MESH REINFORCED SOILS

Soft soil does not have good soil properties and is not suitable for constructing pavement structures as shear strength is required to resist the shear stress developed by traffic loading. To increase shear strength in this study, lime is used as the soil stabilizing agent and fiber and mesh are used as the soil reinforcement materials. The proper amount of lime added to soil will increase the shear strength as the lime-treated soil will decrease moisture susceptibility and migration. Shear strength of the lime-treated soil can be further improved by adding reinforcement materials such as fiber and mesh. The reinforcement materials will interlock with groups of particles and provide tensile strength to the soil matrix. The type of soil used in this study is high plasticity elastic silt with sand which is classified using the Unified Soil Classification System (USCS). Quicklime (calcium oxide) is used in this study at the minimum amount required for stabilizing the soil, which is 9%. The amount of fiber and mesh added to the soil sample is 0.5% of the dry weight of the soil used. Cylindrical samples were prepared with a moisture content of 22% (OMC) for untreated soil and 21% (OMC) for lime-treated soil samples. The lime-treated soil samples were cured for 7, 14, 28, 56, 90 and 120 days. Unconfined compression tests were conducted to determine unconfined compressive strength (UCS) and stress-strain characteristics. The unconfined compressive strength of the lime-treated samples increased as curing period increased but the failure strain decreased. The UCS and failure strain for reinforced lime-treated soil samples are higher than the unreinforced lime-treated soil samples.

Effects of the loading rate and cyclic loading on the strength and deformation properties of a geosynthetic

The paper describes monotonic and cyclic load-extension tensile tests performed on a geocomposite used as soil reinforcement material. The effects of the loading rate and cyclic loading on the geocomposite behaviour are important to improve numerical codes. This study showed that the damping ratio tends to decrease, while the stiffness tends to increase, with the loading cycles. The unload and reload stiffness are not very sensitive to the loading frequency, for the range of values analysed. The damping ratio tends to decrease with frequency of loading. Previous cyclic loading did not induce significant reduction of the geosynthetic tensile strength.

Strength of soil reinforced with fiber materials (Papyrus)

Construction of building and other civil engineering structures on weak or soft soil is highly risky because such soil is susceptible to differential settlements, poor shear strength, and high compressibility. Various soil improvement techniques have been used to enhance the engineering properties of soil. Soil reinforcement by fiber material is considered an effective ground improvement method because of its cost effectiveness, easy adaptability, and reproducibility. Hence, in the present investigation, papyrus fiber has been chosen as the reinforcement material, and it was randomly included into the soil at four different percentages of fiber content, i.e., 5, 10, 15, 25% by volume of raw soil. The main objective of this research is to focus on the strength behavior of soil reinforced with randomly included papyrus fiber. Direct shear, consolidation, and displacement tests were performed on papyrusreinforced specimens with various fiber contents. The results of these tests have clearly shown a significant improvement in the failure deviator stress and shear strength parameters (c and φ) of the studied soil with a percent addition of 10% (the preferred percent). Moreover, this addition ratio reduced the displacement of the soil under loading. It can be concluded that papyrus fiber can be considered an appropriate soil reinforcement material.