Buried pipes are subjected to static and dynamic loads depending on their areas of use. To mitigate the risk of damage caused by these effects, various materials and reinforcement methods are utilized. In this study, five buried uPVC pipes designed in accordance with ASTM D2321 standards were reinforced with three different ground improvement materials: Geocell, Geonet, and Geocomposite, and experimentally subjected to dynamic impact loading. Acceleration, velocity, and displacement values were obtained from the experiments. Subsequently, finite element analysis (FEA) was performed using the ABAQUS software to determine stress values and volumetric displacements in the pipes, and the model was validated with a 5-7% error margin. In the final stage of the study, a parametric analysis was conducted by modifying the soil cover height above the pipe and the Geocell thickness in the validated finite element model. The parametric study revealed that the displacement value in the pipe decreased by 78% with an increase in soil cover height, while a 16% reduction was observed with an increase in Geocell thickness. The results demonstrate that the soil improvement techniques examined in this study provide an effective solution for enhancing the impact resistance of buried pipeline systems.

The ability to predict the soil mechanical parameters swiftly is critical for off-road vehicle mobility. This paper introduces a novel interpretation methodology for determining critical soil mechanical parameters by impact penetration tests, enabling rapid and remote assessment of terramechanics properties. Initially, the method employs the Mohr-Coulomb constitutive model and the Coupled Eulerian-Lagrangian (CEL) finite element method to generate a dataset of soil impact penetration resistance and acceleration responses. Subsequently, a Radial Basis Function (RBF) neural network is employed as a surrogate model and integrated with the Nondominated Sorting Genetic Algorithm II (NSGA-II) to accurately interpret parameters such as density, cohesion, internal friction angle, elastic modulus, and Poisson's ratio. Experimental validation using sand and silty clay from Yangbaijing, Tibet, confirmed the accuracy and robustness of the method. The results indicate that the mean absolute percentage error for interpreted values was below 25%, with relative errors for some key parameters even below 10%. Furthermore, each single-condition calculation was completed on a standard computer in less than one minute. Comparative analyses with other algorithms, including MIGA and POS, demonstrated the superior performance of NSGA-II in avoiding local optima. The proposed interpretation framework offers a rapid, reliable, and remote solution for identifying the soil mechanical properties. Its potential applications range from disaster mitigation and emergency response operations to extraterrestrial soil exploration and other scenarios where in-situ investigations are challenging.

Contact Lens (CLs) are often disposed of via toilet or sinks, ending up in the wastewater treatment plants(WWTPs). Millions of CLs enter WWTPs worldwide each year in macro and micro sizes. Despite WWTPs'ability to remove solids, CLs can persist and potentially contaminate watercourses and soils. This study evaluates whether different CLs degrade in WWTP aeration tanks. Six daily CLs (Nelfilcon A,Delefilcon A, Nesofilcon A, Stenfilcon A, Narafilcon A, Somofilcon A) and four monthly CLs (Lotrafilcon B,Comfilcon A, Senofilcon A, and Samfilcon A) were immersed in aeration tanks for twelve weeks. Theirphysical and chemical properties, including water content (WC), refractive index (RI), chemical prop-erties (Fourier Transform Infrared Spectroscopy), and mechanical properties were assessed. Results show that all CLs maintained their physical appearance after 12 weeks. Neither Nelfilcon A norNarafilcon A exhibited significant changes in WC and RI, (p>0.05, Tukey test), while other daily lensesshowed variations in at least one parameter. Among monthly CLs, only Senofilcon A showed significant differences in both WC (p0.05 Tukey test). However, Somofilcon A displayed significant changes in stress at break (p<0.0001,Tukey test), and Elongation at Break (p<0.05, Tukey test). No changes were found in the chemicalstructure of any CLs suggesting that twelve weeks in WWTP aeration tanks is insufficient for CLsdegradation. Thesefindings highlight CLs as a potential emerging pollutant, emphasizing their persis-tence in sludge or migration into watercourses and soils (c) 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. Thisis an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Alkali-activated concrete (AAC) is a focal point in green building material research due to its low carbon footprint and superior performance. This study seeks to enhance the impact resistance of recycled aggregate concrete (RAC) by elucidating the synergistic mechanisms of alkali activation, nano-modification, and fiber reinforcement. To this end, four mix designs, incorporating NaOH and NaOH-Na2SiO3 systems with 2 % nano-SiO2(NS), were developed and assessed through setting time, compressive strength, drop hammer impact tests, and XRD/ SEM analyses. The NaOH-Na2SiO3 system exhibited a 23.5 % increase in compressive strength over NaOH, achieving 28.41 MPa, while NS refined pore structures, elevating strength to 32.2 MPa; XRD/SEM analyses confirmed mechanisms of pore refinement and interfacial enhancement. In the optimized system, the NT12-C5 formulation, incorporating polypropylene fiber (PPF) and recycled carbon fiber (RCF), exhibited superior impact resistance, with NS enhancing interfacial bonding between carbon fiber and the matrix, resulting in a 47.8 % increase in initial crack impact energy. The Weibull model validated the reliability of impact performance. Furthermore, life cycle assessment revealed that Soil Solidification Rock Recycled aggregate concrete (SSRRAC) substantially reduced carbon emissions compared to ordinary Portland cement (OPC), while maintaining competitive economic costs. This study's innovations include: (1) synergistic optimization of low-carbon AAC performance using NaOH-Na2SiO3 and NS; (2) optimized PPF/RCF formulations promoting the reuse of waste carbon fiber; and (3) application of the Weibull model to overcome conventional statistical constraints. Collectively, these findings establish a theoretical and practical foundation for the global development of sustainable building materials.

During the global coronavirus (COVID-19) pandemic, a huge amount of personal precautionary equipment, such as disposable face masks, was used, but further usage of these face mask leads to adverse environmental effects. Here, we evaluated the feasibility of using mask chips to reinforce clayey soil, testing this with static and impact loading, including uniaxial compression, diametral point load, and drop-weight impact loading tests. The concurrent influences of shape, size, and percentage of waste material were considered. Generally, the contribution of shredded face mask (SFM) was majorly attributable to its tensile reinforcement. As a consequence, the strength of the mixture, measured by the static tests, was increased. This property was enhanced by the addition of rectangular mask chips. We determined the optimum percentage of SFM, beyond which the uniaxial compression strength and the point load strength index decreased. An increase in the percentage of SFM in the soil produced a higher damping coefficient and lower stiffness coefficient, causing greater flexibility. This trend increased beyond 1.2% of SFM (by volume of clay soil). Generally, based on our results, 1-1.5% of SFM was the optimum content.

Pipe piles, such as offshore monopiles, may suffer from considerable damage at the pile tip during installation because of contact with an obstacle such as a boulder or a stiff soil layer but also because of amplification of a pre-deformation or pre-dent. This damage is often referred to as pile tip buckling initiation in the former situation and extrusion buckling in the latter. This paper reports on a series of model tests carried out to verify the numerical model and understand pile tip buckling during impact driving in saturated, dense sand. The test program includes three different scenarios: tests with an initial dent at the pile tip, tests with a fixed rigid body and tests with free-moving rigid bodies (boulders) placed at a certain depth in the sand. The results show that the soil stress level strongly influences pile tip buckling. At high soil stress levels, the penetration rate of the pile decreases progressively. Notably, the wall thickness of the pile has a significant effect on the penetration curve in the case of pre-dented piles. The tests with boulders at low soil stress levels show that the buckling behavior is strongly influenced by the shape of the boulder, by the point of initial contact and by the movement of the boulder. Only small deformations can be observed at the pile tip due to the contact with a spherical steel boulder, whereas the test with the imperfectly shaped stone boulder caused considerable damage to the pile under otherwise equal test conditions.

In this study, impact compression tests on low-temperature concrete were conducted using a split Hopkinson pressure bar. The impacts of low temperatures on the strength, fractal, and energy characteristics of concrete were analyzed. The damage evolution mechanism of the microcrack density was discussed based on microscopic damage theory and microscopic tests. The results demonstrated that the impact fractal dimension and energy dissipation density of low-temperature concrete were positively correlated with the strain rate. The strain rate sensitivity of the impact fractal dimension was significantly affected by low temperature at low strain rates; however, low temperature had little effect at high strain rates. The pore water transformed into ice at negative temperatures, the fracture energy of the concrete increased, and the energy dissipation density increased. More than 50 % of the capillary and free water inside the concrete was frozen at -10 degrees C; approximately 30 % of the capillary and free water and 65 % of bound water did not freeze when the temperature was -30 degrees C. The macropores did not collapse under the action of ice filling at high strain rates; however, microcracks were generated around them. With a decreasing temperature, the threshold stress for microcrack propagation increased, crack propagation required more energy, and the microcrack density decreased.

Photovoltaic panels (PVPs) in grasslands are arranged in such a way that they capture rainfall, which subsequently drips from the edges and causes splash erosion in the grassland, ultimately destroying the natural ecological environment. As such, PVPs can adversely affect fragile saline-alkali habitats, but the precise ecological impact of PVP-caused rainfall splash erosion on saline-alkali grassland has yet to be quantified. To explore the impact of splash erosion on the saline-alkali grassland under PVPs, an investigation was performed here on various surfaces commonly underneath PVPs. These surfaces were typical bare saline-alkali surface (B), Suaeda glauca surface (S) and Leymus chinensis surface (L), and all were positioned under PVPs in the Songnen Plain saline-alkali grassland. The soil splash erosion ditch morphology, the plant community status, and the field-measured soil properties of the three underlying surfaces were all analyzed as part of this investigation in accordance with the observed impact of splash erosion on the three underlying surface ecosystems. Ultimately, the splash erosion generated four ditches in the underlying surfaces, with the degree of soil loss ranked from greatest to smallest as B > S > L. According to the RDA results, vegetation coverage was the main factor affecting splash ditch morphology. The vegetation of the S. glauca surface was fragmented following splash erosion. Much of the S. glauca in the splash erosion ditch died, resulting in a 33.47 %-64.66 % reduction in coverage. In contrast, L. chinensis maintained a higher coverage, which means that it inhibited splash erosion more effectively. For the bare surface, the rainfall splash reduced pH and Ec, and S. glauca began to grow along the edge of the ditch. Collectively, our study quantified the impact of rain splash erosion under PVPs in a saline-alkali grassland ecosystem, comparing the difference in the degree of splash erosion among three different underlying surfaces.

Effective erosion mitigation in the Pisha sandstone region is crucial for soil and water conservation in the Yellow River Basin, yet existing vegetation measures are inadequate in water-limited environments. This study examines the application of drought-tolerant biological soil crusts (biocrusts) for erosion control on sandstone slopes and evaluates their erosion-reducing effects under varying coverage and slope conditions through controlled artificial rainfall experiments. Key findings include: (1) biocrusts coverage demonstrated a linear relationship with initial runoff generation time and an exponential relationship with stable runoff generation time. On average, biocrusts delayed initial runoff generation by 396.32 % and extended stable runoff generation time by 153.93 %, thereby increasing the threshold for both initial and stable runoff generation on Pisha-sandstone surfaces. (2) biocrusts reduced runoff volume by an average of 23.89 %, enhanced infiltration volume by 69.19 %, decreased sediment yield by 64.24 %, and lowered the soil erosion modulus by 68.98 %. These results indicated significant promotion of water infiltration and reduction of water erosion. Both effects were positively influenced by coverage and negatively impacted by slope gradient. A critical slope angle of 15 degrees and a critical coverage of 60 % were identified. When the slope was gentle (S 15 degrees), the negative impact of slope predominated, diminishing the positive effect of biocrusts. Additionally, when coverage reached or exceeded 60 %, further increaseing in coverage accelerated the enhancement of infiltration and erosion reduction. Below this threshold, the rate of improvement gradually diminished with increasing coverage. (3) The structural equation model further elucidated that biocrusts mitigate erosion by enhancing the coverage, thereby reducing runoff velocity and modifying the runoff regime. This mechanism effectively dissipates runoff energy, leading to a decreased soil detachment rate and alleviation of soil erosion. Additionally, the relationship between runoff energy and soil detachment rate follows a power function curve, providing an effective method for predicting erosion in Pisha sandstone area. Consequently, biological soil crust technology shows considerable potential for preventing water erosion damage on Pisha sandstone slopes across various gradients.

Frozen-soils with different moisture contents (MCs) often experience freeze-thaw cycles (FTCs) owing to fluctuations in seasonal or day-night temperature. The influence of FTC on the impact dynamic mechanical properties of frozen-soils with different MCs was investigated in this study. The impact dynamic compression tests on frozen-soils with different MCs (20%, 25%, and 30%) following varying numbers of FTC (0, 1, 3, 5, and 7) using a split Hopkinson pressure bar apparatus were conducted. The experimental results revealed that the impact dynamic strength of the frozen-soil was related to the number of FTC and MC. A threshold exists for the number of FTC for the frozen-soil. Before reaching this threshold, the impact dynamic strength of the frozen-soil progressively decreased with an increasing number of FTC. Further, the threshold decreased as the MC decreased. Analyzing the energy of frozen-soil during impact process, an expression for the FTC damage in frozen-soils with different MCs was established using the energy density. The reinforcing effect of ice particles on the impact dynamic mechanical properties of frozen-soil was examined, and the elastic constants for the frozen-soils with different MCs were evaluated using micromechanical theory. Furthermore, a finite element numerical model of frozen-soil was developed by integrating cohesive elements into solid elements via Python scripting using the cohesive zone model. The impact dynamic mechanical behavior and crack evolution behavior of frozen-soils with different MCs following varying numbers of FTCs were simulated by considering the mechanisms of FTC degradation and ice particles reinforcement. The validity of the model was confirmed by comparing simulation and experimental results.