Aeolian sand along the Hojiakueri Railway in the Taklimakan Desert exhibits poor mechanical properties for direct use as a filler for railway subgrades. Although cemented soil reinforced with single fibers can improve mechanical properties, its limited effectiveness and high cement usage pose significant economic and environmental concerns. This study investigated the improvement of splitting tensile strength (STS) in cemented aeolian sand through hybrid fiber reinforcement. An orthogonal test was designed to evaluate four factors-fiber types (pairwise combinations of basalt, polypropylene, and glass fibers), fiber lengths (3, 6, and 9 mm), hybridization ratios (1:1, 1:3, and 3:1), and fiber contents (4 %o, 8 %o, and 12 %o) - along with their interactions. The performance of cemented aeolian sand reinforced with hybrid fiber (CASRHF) was evaluated through STS tests and scanning electron microscopy (SEM). The results identified the optimal combination as a 1:1 mix of 6 mm basalt and polypropylene fibers with a fiber content of 12 %o. The interaction between hybrid fiber type and fiber length was the most critical factor influencing STS, followed by hybrid fiber type, fiber length, and fiber content. SEM analysis further revealed a linear negative correlation between STS and porosity, providing new insights into the microscopic mechanisms. The findings underscore the importance of optimizing hybrid fiber combinations to meet the performance requirements of railway subgrade beds in aeolian sand regions.

The application of alkali-activated slag (AAS) cementing material to the curing of soft soil foundations has a good engineering application prospect and is economical and environmentally friendly. In this study, three different activators (Na2OnSiO(2), NaOH, Ca(OH)(2)) were used to alkali-activate slag powder to solidify and improve soft soil in inland port areas. In order to explore the mechanical properties and strength formation mechanism of AAS-solidified soil under different activators, mechanical properties, and microscopic tests were carried out. Firstly, with unconfined compressive strength as the evaluation index, an orthogonal test of three factors, such as the type of activator, the amount of activator, and the amount of slag powder, was designed. Then, the unconfined compressive strength, resilience modulus, shear strength, and compression modulus of AAS-solidified soil were tested with the three activators under optimal dosage. Finally, phase composition, SEM-EDS, TG-DTG, and FT-IR analyses were carried out with the three AAS-solidified soils. The results show the following: (1) The factors affecting the unconfined compressive strength of AAS-solidified soil are ordered as follows: the type of activator > the amount of activator > the amount of slag powder. In addition, the optimal factors were as follows: activator type: Na2OnSiO(2); amount of activator: 3%; and amount of slag powder: 20%. (2) In considering the macroscopic mechanical properties, the effect of the activator is Na2OnSiO(2) > NaOH > Ca(OH)(2), and the Na2OnSiO(2) AAS-solidified soil has good early strength. (3) The hydration products of AAS are mainly C-A-S-H gel, N-A-S-H gel, and C-S-H gel, which increase the strength and cohesion of solidified soil. The results show that AAS-solidified soil with 0.7-modulus Na2OnSiO(2) as the activator has good engineering characteristics and can be used for curing soft soil foundations.

This study investigates the collision model of cassava seed stems in precision planters. Utilizing a physical property analyzer and a custom test platform based on collision dynamics principles, we measured and analyzed the forces and recovery coefficients of seed stem collisions. Mixed orthogonal and one-way tests were conducted to identify the main factors affecting the collision recovery coefficient of seed stems, including collision contact material, drop height, seed stem mass, moisture content, drop direction, and seed stem variety. The results from the orthogonal tests indicated that the factors influencing the collision recovery coefficient were ranked as follows: collision contact material > drop height > seed stem mass > moisture content > drop direction > seed stem variety. Notably, the effects of impact contact material, drop height, stem mass, and moisture content were significant, while the effects of drop direction and seed stem variety were relatively insignificant. The one-way test results revealed that the collision recovery coefficients for cassava seed stems with structural steel Q235, rubber sheet, seed stems, and sandy loam soil decreased progressively, with values for SC205 being 0.8172, 0.6975, 0.6649, and 0.6341, respectively, and values for GR4 being 0.7796, 0.7132, 0.6913, and 0.6134, respectively. Furthermore, as drop height increased, the collision recovery coefficient of cassava seed stems decreased; similarly, higher stem mass and moisture content correlated with lower coefficients. To minimize impact during critical stages of cassava planting, transportation, and processing, materials with lower recovery coefficients should be prioritized in equipment design. Incorporating rubber coatings can effectively mitigate collision effects in components such as seed supply and planting mechanisms. These findings provide valuable insights for designing and enhancing key mechanical features in machinery used for planting, transporting, and processing cassava.

This study aimed to address the challenges of solid waste utilization, cost reduction, and carbon reduction in the treatment of deep-dredged soil at Xuwei Port in Lianyungang city of China. Past research in this area was limited. Therefore, a curing agent made from powdered shells was used to solidify the dredged soil in situ. We employed laboratory orthogonal tests to investigate the physical and mechanical properties of the powdered shell-based curing agent. Data was collected by conducting experiments to assess the role of powdered shells in the curing process and to determine the optimal ratios of powdered shells to solidified soil for different purposes. The development of strength in solidified soil was studied in both seawater and pure water conditions. The study revealed that the strength of the solidified soil was influenced by the substitution rate of powdered shells and their interaction with cement. Higher cement content had a positive effect on strength. For high-strength solidified soil, the recommended ratio of wet soil: cement: lime: powdered shells were 100:16:4:4, while for low-strength solidified soil, the recommended ratio was 100:5.4:2.4:0.6. Seawater, under appropriate conditions, improved short-term strength by promoting the formation of expansive ettringite minerals that contributed to cementation and precipitation. These findings suggest that the combination of cement and powdered shells is synergistic, positively affecting the strength of solidified soil. The recommended ratios provide practical guidance for achieving desired strength levels while considering factors such as cost and carbon emissions. The role of seawater in enhancing short-term strength through crystal formation is noteworthy and can be advantageous for certain applications. In conclusion, this research demonstrates the potential of using a powdered shell-based curing agent for solidifying dredged soil in an environmentally friendly and cost-effective manner. The recommended ratios for different strength requirements offer valuable insights for practical applications in the field of soil treatment, contributing to sustainable and efficient solutions for soil management.

Cassava is one of the world's top three tuber crops, and its harvesting mechanization level is low. Digging- pulling cassava harvester is the main research direction of cassava harvesters. However, the soil-loosening components of the existing digging-pulling harvesters have poor loosening effect, high tuber damage rate, and large pulling force of cassava tubers after loosening. The two-sided loosening shovel that digs and loosens the soil on both sides of the tubers has low working resistance and is not easy to damage the tubers, but there are few reports on the impact of its operating performance. Therefore, this study focuses on three common types of two-sided soil-loosening shovels: the offset-wing shovel (OWS), L shovel (LS), and double-wing shovel (DWS). A two-factor, three-level orthogonal experiment is conducted, taking tillage depth (h) and shovel distance (b) as variables, then range analysis and factor impact analysis are carried out. Finally, through comprehensive comparison and optimization, a shovel type with best operational effects and its optimal working conditions are identified. The results show the LS demonstrated optimal performance when the breakage rate and pulling force were minimized. At the optimal combination of h of 0.25 m and b of 0.6 m, the LS has a breakage rate of 7.576% and a pulling force of 291.608 N. This study can provide basis for optimizing the design of loosening parts of digging-pulling cassava harvester.

Currently, studies on Xinjiang desert water conveyance channels primarily focus on the selection of construction technologies, with the effects of bank slope reinforcement and the impact of internal and external factors on slope stability remaining unclear. This study utilizes finite element method to analyze the safety coefficient, overall displacement, and equivalent plastic zone of aeolian soil bank slopes before and after reinforcement during three distinct phases: the completion phase, the water transfer phase, and the water level plunge phase. Orthogonal tests were used to assess the trend and weighting of the influence of factors on bank slopes inside and outside the channel using the introduction of corrected range and Spearman correlation analysis. The findings indicate that the safety coefficient for the bank slopes of the desert channel both before and after reinforcement exceeds 1.30 during all phases. Post-reinforcement, the overall displacement and equivalent plastic zone are controlled compared to the pre-reinforced state. Both sensitivity analyses yielded that the factors affecting the weighting of bank slopes were, in descending order, aeolian soil cohesion > slope angle > angle of internal friction > slope height > unit-weight > thickness of concrete lining > height of the water level in the channel > rate of water level plunge; where aeolian soil cohesion, slope angle, angle of internal friction and thickness of concrete lining favoured the stability of the bank slopes, while others were unfavourable to the stability of the bank slopes. This study aims to provide a reference for the construction of desert water supply projects.

In modern agriculture, with the development and widespread use of agricultural mechanization, mechanical compaction of soils has become a growing problem, resulting in soil degradation in the field. Based on the Boussinesq solution, the soil stress formula for the circular load area is derived, and MATLAB is used to simulate the stress-strain relationship of the soil at different depths. The results show that under the same load conditions, as the soil depth increases, the soil stress gradually decreases, with the most significant stress change occurring at 0.2 m depth. Soil compression experiments conducted using a consolidation instrument revealed that the soil void ratio dropped rapidly under loading of 50-200 kPa, and the decline slowed after 400 kPa. When the soil void ratio decreases to 0.2-0.4, the soil stress changes tend to stabilize. Comparison between the theoretical formula and the compression experimental data indicates that the soil stress gradually decreases as the thickness of the soil layer increases and the pressure load increases, verifying the linear relationship predicted by the theoretical formula.

To investigate the effects of compaction (K), rock content (RC), and wet-dry cycle (WD) on the road performance of carbonaceous mudstone soil-rock mixtures (CMSRM), orthogonal tests were designed to measure the unconfined compressive strength (UCS) and California bearing ratio (CBR). The correlation degree of K, RC, and WD with the UCS and CBR of CMSRM was investigated using orthogonal theory and grey correlation theory. Based on multivariate nonlinear regression analysis, mathematical models of the road performance of CMSRM were built. The results show that the UCS and CBR of CMSRM were positively correlated with K and negatively correlated with the WD. With increasing RC, UCS increased at first and then decreased, while CBR increased continuously. The failure modes of CMSRM change from tensile failure to shear failure as the K increases under uniaxial compression. The RC and WD affect the structural integrity of the failed samples. Combining the results of range analysis, variance analysis, and grey relational analysis, the most significant influence on the UCS is K, and the most significant influence on the CBR is RC. It is recommended to select 94%-96% for K and 40%-60% for RC in engineering.