Recently, bio-inspired technology utilizing the anisotropy of friction between structure-soil has garnered significant attention. In particular, new pile designs not only enhance shaft friction but also gain prominence by reducing the use of cement, which has traditionally been a key material in ground treatment and improvement. Previous studies have quantitatively verified the increase in interface shear resistance through direct shear tests and cone penetration experiments. However, conventional finite element analysis methods face limitations in analyzing the shaft friction behavior between piles with scale and the surrounding soil. In this study, the Coupled Eulerian-Lagrangian (CEL) technique, a large deformation analysis method built-in ABAQUS, is employed to simulate the penetration of cone with textured shaft. Numerical analyses are conducted to investigate changes in cone penetration resistance according to the geometric characteristics of the surface scale. To minimize numerical errors occurring in the cone and surrounding soil meshes, a three-dimensional generalized mesh is proposed for the cone and its surrounding elements. A total of 13 cases, comprising seven different cone designs and two penetration direction conditions, are analyzed. The results showed that under the same penetration load, penetration depth decreased as the scale height increased, the scale length narrowed, and the scale tapered in height.

Inspired by the anisotropic shear behavior of the snakeskin, an innovative suction caisson with a bio-scale sidewall of the snakeskin is proposed, which is called the scale suction caisson (SSC). Compared with traditional suction caisson (TSC), the interface friction decreases when the SSC penetrates to the seabed, but increases as the SSC is pulled out. Therefore, the SSC has better installation and service performance than the TSC. The model tests are carried out to investigate the penetration behaviors of the SSC. The study shows the penetration resistance depends on the aspect ratio of the bio-scale surface, and the corresponding value increases with increasing the diameter of bio-snakeskin surface D1, but firstly decreases and then increases with increasing the height of bio-scale surface H1. More sand bypasses the end of the sidewall into the SSC and the sand inside the SSC is loosened under the seepage, causing the soil plug inside the caisson. In the half-caisson model tests, the soil heave inside the caisson under the different penetration depths is captured with an HD camera, and the permeability coefficient k can be further calculated. Considering the variation of the permeability coefficient k, a method of calculating the critical suction is provided.

Microbially induced carbonate precipitation (MICP) technology is employed to reinforce the surface soil of a dam, aiming to prevent erosion caused by water flow and damage to the dam slope. The relationship between penetration depth, calcium carbonate content, and bonding depth was investigated at eight measuring points on the sand slope surface of a mold under different reinforcement durations. It was observed that as grouting reinforcement times increased, there was a gradual increase in calcium carbonate content but a rapid rise in penetration resistance. Moreover, the bonding depth of sand on the bio-reinforced sand slope increased with higher levels of calcium carbonate content. Microbial grouting reinforcement enhanced soil particle bonding force, requiring water flow to overcome this force for activation of sand particles. Consequently, microbial grouting reinforcement significantly improved shear strength and critical starting flow velocity on sand slope surfaces. The experimental results demonstrated that after MICP surface treatment through spraying, a dense and water-stable hard shell layer composed of bonded calcium carbonate and soil particles formed continuously on sample surfaces, effectively enhancing the strength and erosion resistance of sandy soils. These findings provide reliable evidence for silt slope reinforcement and dam erosion prevention.

Tailings dust can negatively affect the surrounding environment and communities because the tailings are vulnerable to wind erosion. In this study, the effects of halides (sodium chloride [NaCl], calcium chloride [CaCl2], and magnesium chloride hexahydrate [MgCl26H2O]), and polymer materials (polyacrylamide [PAM], polyvinyl alcohol [PVA], and calcium lignosulfonate [LS]) were investigated for the stabilization of tailings for dust control. Erect milkvetch (Astragalus adsurgens), ryegrass (Lolium perenne L.), and Bermuda grass (Cynodon dactylon) were planted in the tailings and sprayed with chemical dust suppressants. The growth status of the plants and their effects on the mechanical properties of tailings were also studied. The results show that the weight loss of tailings was stabilized by halides and polymers, and decreased with increasing concentration and spraying amount of the solutions. The penetration resistance of tailings stabilized by halides and polymers increased with increasing concentration and spraying amount of the solutions. Among the halides and polymers tested, the use of CaCl2 and PAM resulted in the best control of tailings dust, respectively. CaCl2 solution reduces the adaptability of plants and therefore makes it difficult for grass seeds to germinate normally. PAM solutions are beneficial for the development of herbaceous plants. Among the three herbaceous species, ryegrass exhibited the best degree of development and was more suitable for growth in the tailings. The ryegrass plants planted in the tailings sprayed with PAM grew the best, and the root-soil complex that formed increased the shear strength of the tailings.

Addition of microsilica improves the mechanical properties of mixtures containing Ca(OH)2 due to the chemical reaction between SiO2 in microsilica and Ca(OH)2 in the composition of prepared mixtures. This study aims to compare the efficiency of different microsilica-based mulches in sand stabilization. Several mixtures were prepared through combining microsilica with clay, lime, gypsum, and cement. Data were analyzed as a factorial experiment based on completely randomized design with treatments including: 1) mulch type: microsilica-clay-lime, microsilica-clay, microsilica-cement, microsilica-lime, microsilica-clay-gypsum, and microsilica-gypsum; 2) thickness: one- and two-layers, and 3) time (7 and 60 days) in 3 replications. Penetration resistance (PR), shear strength (SS), threshold friction velocity (V), and soil loss (SL) were measured. Results revealed that microsilica-clay-lime and microsilica-cement showed the highest PR (6.02 kgcm-2), SS (7.08 and 6.71 Ncm-2, respectively), and V (18.25 and 18.11 ms-1, respectively), and the lowest SL which makes them the most suitable mulches for sand stabilization.