The metropolitan region of Belo Horizonte city is home to several high-risk areas with a significant number of mass movement occurrences. Additionally, there are cases of movements in areas that are not considered high-risk, where constructions exhibit a medium to high construction standard. This emphasizes that, in addition to disordered occupations, the terrains have a natural susceptibility to the process. Intervention in slopes through cuts and fills is an unquestionable necessity in geotechnical projects to reinforce unstable or damaged areas. This article explores the field of soil nailing and presents the necessary design practices for its utilization, including safety checks based on deterministic, probabilistic, and finite element analysis. The case study is based in Belo Horizonte, more specifically in the 'Buritis' neighborhood, Brazil. The reinforced slope has a height of 18.5 meters and covers a total area of 1425 square meters. Based on different methodologies, the solution was validated as the most technically feasible, executable, and financially viable.

Infrastructure projects on slopes that are exposed to changes in water levels face unique challenges. Fluctuations in water levels can significantly impact the stability and integrity of the slope. Stresses affecting soil nails are influenced by various factors, including changes in groundwater levels due to rainfall, temperature variations, or human activities. While studies have addressed the use of soil nails to enhance slope stability, there has been limited attention to the performance and serviceability of soil nails under cyclic changes in the groundwater table. Lateritic slopes are susceptible to instability due to factors such as extensive weathering, inadequate drainage, and steep cuts. Erosion and slope failure are exacerbated by insufficient vegetation cover, climate-induced degradation, and human activities. This highlights the importance of understanding the stress generated and the interaction between the soil and reinforcing material. In this study, centrifuge modelling was employed to simulate cyclic saturation and desaturation of a lateritic slope in response to fluctuations in groundwater levels. Four centrifuge tests were conducted on slopes with a 5V:1H ratio, both unreinforced and reinforced, at two different soil densities. The slopes were subjected to cycles of saturation and desaturation using a seepage simulator located behind them. Both unreinforced and reinforced slopes exhibited stability within a gravitational range from 1 to 40 g, showing no apparent cracks or settlements. Following the initiation of water flow through the slope, a gradual flow slide failure occurred in the unreinforced slope. When exposed to fluctuating water levels, the utilization of soil nails prevented the development of a continuous slip plane in higher-density slopes, while lower-density modelling revealed a failure slump and tensile cracks on the slope surface. Increased excess pore water pressure during ground saturation reduced effective stress on soil nails, reducing their tensile resistance. Conversely, lowering groundwater levels increased effective stress, mobilizing axial forces in the nails. This cyclic variation caused visible changes in settlements, strains, and tensile cracks in the slope following saturation and desaturation cycles.

Bearing plates made from plastic composites can be used as an alternative to their steel counterparts in rock bolt or soil nail applications. To achieve this goal, an existing recycled highdensity polyethylene bearing plate was investigated and later modified to improve its engineering properties. Laboratory studies were conducted to determine the failure load of the existing and modified plates, and a numerical model was developed for complementary analysis. The results of both efforts clearly showed that the existing bearing plate was not adequate in terms of strength and creep properties, as it quickly yielded with large displacements at relatively low loads. In order to enhance the strength of the plate, both geometric and material modifications are made by our research group to obtain a more efficient plate. Numerical models were used to determine the frame layout, and a series of analyses were performed to evaluate the effects of frame thickness, number and arrangement. Once the design was optimized and finalized, a mold was created to match the new geometry for manufacturing new plates through injection molding. A test setup was also established in the laboratory and numerous compression tests were performed on the manufactured new plates. The measured load-displacement behavior of plates made of polyethylene and polyamide with a variety of additives were discussed separately. It was determined that the new plastic plates reinforced with polyamide through various additives have the potential to reach a strength up to 200-240 kN, which is at least two times higher than the existing one, with distinct economic advantages.

Cyclic loading of deep foundations and soil anchorage elements can lead to failure by accumulation of deformations or loss of strength. Snakeskin-inspired surfaces have been shown to mobilize direction-dependent friction angles and volumetric responses due to their asymmetric profile. This paper presents an investigation on the cyclic interface element behavior of sand-structure interfaces with snakeskin-inspired surfaces with the goal of understanding the potential impact of these surfaces on the cyclic behavior of geotechnical elements. Load- and displacement-controlled cyclic interface shear tests were performed with constant stiffness boundary conditions. Four different snakeskin-inspired surfaces and reference rough and smooth surfaces were tested. The results show that under symmetric shear stress cycles, failure always takes place in the caudal direction (i.e. along the scales) due to the smaller interface friction angles. A shear stress bias can produce a change in the failure direction to the cranial one (i.e., against the scales). An equation is introduced to predict the magnitude of shear stress bias that changes the failure direction. This investigation shows that the snakeskin-inspired surfaces can be used to control the direction of failure of soil-structure interface elements which can help in increasing the cyclic stability and reducing the susceptibility of brittle failure.

The interfacial frictional resistance of anchor solids, bolt, and the surrounding soil of soil nails in the flexible support structures of frozen soil slopes is a key parameter for calculating and evaluating its stability. Based on a series of direct shear tests under the condition of a constant normal load boundary, the shear mechanical behavior of the interface between the soil and a cement slurry block under different soil temperatures, water contents, and normal pressures was studied, and the interfacial deformation mechanism was analyzed. The results show that in the thawing state, with the increase of water content, the shear surface moves from the side close to the soil to the side close to the cement slurry block. However, the shear plane is determined in the direct shear test, which makes the effect of the change of the soil's own strength on the interfacial shear strength smaller. In the frozen state, the behavior of the interfacial shear stress-shear displacement behavior at the same water content varies from strain-hardening type to strain-softening type with the temperature decreasing. The normal displacement is affected by temperature, normal pressure, and water content. At the same temperature, the maximum normal displacement gradually decreases with the increase of water content and normal pressure. At the same normal pressure and water content, the maximum normal displacement tends to increase and then decrease as the temperature drops. Still, the maximum normal displacement in the frozen state is more significant than in the thawing state. At the same water content and normal pressure, the interfacial peak shear strength shows a nonlinear increase with the decrease in temperature. At the same normal pressure and temperature, the interfacial peak shear strength delivers a linear increasing law with increasing water content. The peak interfacial cohesion increases with the decreasing temperature and increasing water content, and this phenomenon is more evident at lower temperatures. The interfacial friction angle does not change significantly with the rise in water content at the same temperature, but as temperature decreases, its average value increases significantly. The research results can provide a reference for the design of slope support structures in cold regions.

Coal-bearing soil slopes are associated with a high risk of landslides when subjected to high soil water content. Steel bars have been used as soil nailing for slope stabilization; however, corrosion may occur in an aggressive environment. Glass fiber reinforced polymer (GFRP) and basalt fiber reinforced polymer (BFRP) bars have higher resistance to corrosion and could be alternatives to steel bars, but their elastic modulus and bonding strength with cement concrete are inferior to steel bars, which may result in lower reinforcement effects against landslides and hence require further investigation. In this study, the mechanical properties of different types of bars were investigated using tensile tests. The mineral composition of the soil samples was analyzed. Subsequently, pull-out tests were conducted on three types of bars (steel, GFRP, and BFRP) embedded in grouts in the soil. Up to 38 test scenarios were investigated, and the results were statistically analyzed using an analysis of variance test. The effects of several factors were studied, including the bar type, water content, soil compaction degree, and soil surcharge. The results showed that the bar type had an insignificant effect on the maximum pull-out loads, indicating the feasibility of using GFRP and BFRP bars as alternatives to steel bars for soil nailing in coal-bearing soil slopes. The reinforcement effect can be weakened by rainfall or drought events and enhanced by higher compaction energy and surcharge loads.