This study aimed to assess the potential of banana-plantain stalk fibers (BPSF) as a raw material for ropes and fabrics used in composites and geotextiles. Fibers were obtained by Biological retting and ropes used for geotextile weaving were obtained by three-strand twisting in order to optimize the mechanical properties of geostalk. The thermal, physical, chemical and mechanical characteristics of the fibers were studied in order to assess the impact of the extraction process on fiber performance. In addition, the microstructure of fibers and ropes was analyzed using Scanning Electron Microscopy (SEM) and the results highlighted the presence of cellulose microfibrils parallel to fiber axis and hemicellulose linked by lignin matrix. These constituents are organized in three concentric layers around the lumen. Elementary chemical analyses using X-ray energy dispersion (EDS), Fourier Transform Infrared (FTIR) and chemical deconstruction using Jayme-Wise protocol were carried out to determine the chemical composition of BPSF, which consists of 51.5 % Carbon, 47.07 % Oxygen and mineral salts that can be highly contribute to soil fertilization after degradation. These chemical constituents represent 40 % cellulose, 21.5 % hemicellulose, 24 % lignin, 0.34 % pectin, 7.2 % lip soluble extractable and 7.36 % water-soluble sugars present in BPSF. Thermal properties of BPSF have been investigated showing the initial degradation around 200 °C. Physical analysis and uniaxial tensile testing were performed to determine the multi-scale physical and mechanical properties of geostalk. Statistical evaluation using Weibull distribution established an increasing rate of physical and mechanical properties from the finest scale to the macroscopic scale. Thus, from the BPSF to the ropes, titer increases from 42.5 ± 4.5 g/km to 7983.4 ± 132 g/km and elongation at break increases from 0.75 ± 0.29 mm for the fibers to 52.42 ± 18.91 mm for geostalk. With mass per unit area of 1869 g/m2, the tensile stress of 1281.05 ± 273 MPa and maximum strength of 15.4 ± 1.74 kN/m, geostalk is a sustainable woven fabric alternative to geosynthetics for soil reinforcement as other limited lifespan geotextiles (geojute, geocoir and geosisal). In addition, the thermal stability and high mechanical properties of fibers and ropes suggest their potential application as reinforced phases in composite materials.

Natural sand has a loose and porous structure with low strength, and is prone to many geoengineering problems that cause huge losses. In this study, an organic polymer-polymer-fiber blend was used to improve the strength of sand. Using a series of laboratory and numerical simulation tests, researchers have investigated the microdamage behavior of an organic polymer and fiber-treated sand in various types of mechanical tests and explored the improvement mechanism. The results showed that the polymer- and fiber-treated sand enhanced the integrity and exhibited differential damage responses under different test conditions. The increase in polymer content induced uniform force transfer, leading to a wider range of particle motion and crack initiation, whereas the fibers adhered and confined the surrounding particles, inducing an arching force chain and dispersive/buckling cracking. Polymer- and fiber-treated sands increased their energy-carrying capacity and improved their energy release, which affected the damage characteristics. Organic polymers, fibers, and sand particles were wrapped around each other to form an effective interlocking structure, which enhances the integrity and mechanical properties of sand. This study provides novel ideas and methods in the polymer-fiber composite treatment of sand in the microscopic field.

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.

This article is dedicated to investigating the properties of soil after its reinforcement with fiberglass elements through large-scale laboratory plate-load tests of various samples that varied in the numbers and lengths of the reinforcing elements. The investigation of the vertical elements considered the diameter increase at the bottom toe by using widening washers. The results were compared relative to each other and to the theoretical calculation results. The theoretical calculations for the settlements were undertaken based on the authors\' proposed method. The method considers the number, shape, area and material of the strengthening elements using a pre-proposed reinforcement area factor µ. This pre-established factor was calculated with reference to the elements\' geometry-the diameter of the vertical elements and the bottom\'s washer diameter-which determined the reinforcement area. A comparison between the reinforced and reference soft sandy soil samples indicated a 25% increase in the deformation modulus after the reinforcement process at a pressure of 25 kPa. Samples with µ ranging from 1.20 to 1.43 were 55-65% stiffer than samples with µ equal to 0.69 at a pressure of 100 kPa. The comparative analysis of the calculated results and the actual laboratory PLT test results was adequate for use for further development.

Research on the mechanism of plant root-soil consolidation is a current focus in research into the ecological restoration of banks. The stability of ecological banks is central to this research, and bank stability is closely related to plant combinations and spacing. Recent research on reinforced anchorage of plant roots has mainly focused on root length and angle, and on other parts of the root system, and only a few studies have examined the combination of different types of roots. In this study, a coupled slope stability assessment system is created, composed of root morphological parameters and involving calculations using the finite element model ABACUS. This paper selects the two banks of the lower reaches of the Tiantang River in the flood zone of Yongding River as the research area, and examines slope surface plants. And then the reinforcement effect of different shrub roots combinations and plant spacing are evaluated for determining the optimal shrub layout, with the aim of solving the instability problem of collapsible silty clay bank slopes and associated risks. The results indicated that when the shrub plant spacing is 0.65 m, the optimal shrub combination is Tamarix chinensis + Philadelphus incanus, and when the shrub plant spacing is 0.75 m, the optimal shrub combination is Tamarix chinensis + Euonymus alatus. The study found that the root system morphology and the fibrous roots amount at the foot of the slope can have different degrees of influence on the shallow soil stability of the silty clay slope under different shrubs plant spacing conditions.

This article is dedicated to developing a ground improvement technique using vertically oriented reinforcement elements prefabricated utilizing fiberglass pultruded pipe and helical shape wideners at the bottom toe. Structures of the prefabricated helical micropiles varied by the length and cross-section area introduced into the soil massive as reinforcing bearing elements. The effect of the reinforcements geometry variation was investigated through a reinforcement factor (µ), based on which a calculation method for measuring settlement of reinforced soil has been previously developed Full-scale field plate load tests were performed before and after reinforcing the soil to investigate the changes in the soil stiffness after the reinforcement process. Comparative analysis between the reinforced and reference soft sandy soil indicates an average increase in the deformation properties of the fiber reinforced soils by 8%, 30%, 63% at the applied pressures of 100, 300, and 550 kPa, respectively. The influence of the fiber reinforced polymers (FRP) geometrical properties on the final composite settlement was determined. A comparative analysis of the calculated and the actual plate load tests results reveals that the previously proposed settlement calculation method is adequate for further development.

Stabilized soils are commonly used as part of pavement construction in highway engineering. The everyday use of this material makes it necessary to classify it. One of the basic methods of determining the mechanical properties of a material is the unconfined compressive strength (UCS) test, from which the material elasticity can be determined. The scope of the research included the design and making of soil mixtures stabilized with polypropylene fibers modified cement. This paper presents the effect of the amount of dispersed reinforcement on the maximum compressive strength, the secant modulus at half the ultimate stress (E50), the secant modulus at the ultimate stress (Es), and the tangent modulus (Et). The materials chapter characterizes the soil, cement, and dispersed reinforcement used. The test methods section describes the tests performed and the procedure for interpreting the results. The results section describes the relationship between elastic modulus and compressive strength. The discussion section compares the obtained results with the works of other authors. The work is concluded with a summary containing the most important conclusions resulting from the work.

The naturally occurring biomineralization or microbially induced calcium carbonate (MICP) precipitation is gaining huge attention due to its widespread application in various fields of engineering. Microbial denitrification is one of the feasible metabolic pathways, in which the denitrifying microbes lead to precipitation of carbonate biomineral by their basic enzymatic and metabolic activities. This review article explains all the metabolic pathways and their mechanism involved in the MICP process in detail along with the benefits of using denitrification over other pathways during MICP implementation. The potential application of denitrification in building materials pertaining to soil reinforcement, bioconcrete, restoration of heritage structures and mitigating the soil pollution has been reviewed by addressing the finding and limitation of MICP treatment. This manuscript further sheds light on the challenges faced during upscaling, real field implementation and the need for future research in this path. The review concludes that although MICP via denitrification is an promising technique to employ it in building materials, a vast interdisciplinary research is still needed for the successful commercialization of this technique.

Roots can effectively consolidate and support the soil and are affected by external forces. To identify the survival strategies and soil reinforcement capability of roots against damaging forces, we investigated Hippophae rhamnoides taproots with a diameter of 1-4 mm in a coal mining subsidence area. To simulate root damage from erosion, an HG100 digital push&pull tester and self-developed experimental installation were used in situ. Relative growth rate, activity, tensile force, and strength of taproots were inhibited by damage. Significant differences occurred in these indicators depending on drawing damage type and level. Inhibition effects from persistent drawing damage on growth and tensile properties were markedly greater than those from instantaneous drawing. Inhibition effects of severe damage were markedly greater than those of mild damage. The number of living roots declined more after persistent drawing or severe injury than after instantaneous or mild damage. The taproots showed self-healing ability, and the inhibitory effect of drawing damage gradually weakened with the time of self-repair, ensuring H. rhamnoides taproots could continue to play a role in soil reinforcement. The self-healing ability of roots should be considered in vegetation restoration of erosion-prone areas to ensure that the roots\' ability to resist erosion is accurately estimated. Novelty statementResearch on the soil reinforcement ability of damaged plant roots is very limited at present. This study provides a new perspective for soil reinforcement: roots can be destroyed by erosional forces while providing support for soil, the self-healing ability of plants determines whether they can provide effective support for soil in the erosive environment.

Micropiles can act as structural support for a new foundation and sustainable solution for existing foundations with advantages such as high load-carrying capacity and use in in situ conditions. Installing micropiles around the footing at some distance from the footing edge could turn out to be extremely helpful for existing distressed foundations where improvement is needed. An experimental investigation is carried out on a laboratory model square footing in the ongoing study, placed on sand, with micropiles driven around the footing. A parametric study focusing on the effect of the slenderness ratio of the micropiles, the state of sand beds, the micropile spacing ratio (S/b), and the micropile edge distance ratio (ED/d) are analyzed. The results demonstrate that the micropiles can appreciably improve the footing\'s settlement characteristics and load-bearing capacity when placed around it. The load-carrying capacity shows some appreciable increase by increasing the slenderness ratio of micropiles, but increasing the slenderness ratio beyond 20 is insignificant. For unreinforced footing, a denser form of sand was found more advantageous in terms of bearing capacity, while as for reinforced footing, micropiles provided maximum improvement for medium-density sand. The improvement in bearing capacity is approximately 22.2% when the spacing ratio is reduced from 0.5 to 0.3. Also, for an edge distance ratio of 3, the improvement in the bearing capacity ratio is 76% higher than that of unreinforced footing. Multivariate linear regression showed a strong correlation between the experimental and predicted bearing capacity ratio.