The large-scale stockpiling of construction waste and industrial solid waste poses a severe threat to the ecological environment, necessitating the development of economically and efficient pathways for resource utilisation. In order to validate the efficacy of industrial solid waste as a solidification agent, this study employs a slag-alkali slag-phosphogypsum (SAP) solid waste system in conjunction with waste tire particles (TPs) for the synergistic solidification of construction waste. The strength of the resulting solidified material is compared with that of conventional cement-stabilised soil. Response surface experiments determined the optimal ratio of SAP solidification agent as m (slag)u2236m (alkali slag)u2236m (phosphogypsum)=16.2%u22363.8%u22364.6%. On this basis, 2.5%, 5% and 7.5% of the tire particles were added to investigate their impact on solidified soil properties. It indicates that the SAP-solidified soil exhibits unconfined compressive strengths of 3 412 kPa and 11 893 kPa at 7 days and 28 days respectively, with water stability coefficients of 0.85 and 0.90. A tire particle content of 2.5% can increase soil strength, comparing to cement-stabilized soil. However, if the proportion exceeds 5%, both the strength and stability of solidfied soil are decline. Microscopic analysis reveals that the SAP system generates a calcium silicate hydrate (C-S-H) gel with spatial network structure and acicular-rod-shaped ettringite (AFt). Excessive tire particle content can disrupt this structure. This research demonstrates that SAP solidification agent can effectively substitute cement, and incorporating a small amount of tire particles enhances soil stabilisation strength. This provides a viable pathway for resource utilisation of industrial solid waste and disused tires in soil stabilisation applications.
Intertidal zone is a transitional area between land and sea, where environmental dynamics is significantly influenced by the periodic tides and spatiotemporal heterogeneity is notable. Based on a 12-month ecological survey of the rocky intertidal level of Qingdao, we systematically analyzed the monthly variation and vertical stratification pattern of macrobenthic communities across different tidal zones and their responses to environmental factors in this study. The benthic community structure exhibited an obvious seasonal fluctuation. The species richness was high in spring and summer and significantly low in autumn and winter. Vertically, the high tidal level was characterized by a community structure with low diversity, low richness and high evenness whereas the middle tidal level was marked by high diversity, high richness and low evenness, being significantly different between two tidal levels. Temperature was the key environmental driver of community structure change. The factors like salinity, precipitation and chlorophyll a played also important roles in shaping community distribution. Our findings provided the insights into understanding the dynamic pattern of intertidal biological communities and the theoretical basis for the conservation and management of intertidal ecosystems.
When seismic waves propagate through underground media, the multi-scale fluid flow in the porous media will cause attenuation and dispersion of seismic waves. However, the existing seismic wave equations rarely consider the influence of capillary pressure on fluid flow. We introduce the capillary pressure parameter into Johnson's formula for calculating the bulk modulus, and substitute the improved calculation method of the bulk modulus into the P-wave equation in the partially saturated porous medium. As a result, an improved P-wave equation in the partially saturated porous medium that considering capillary pressure is obtained. In order to better explore the propagation characteristics of the P-waves in the partially saturated porous media, we derive a high-order finite-difference scheme of the improved P-wave equation in the partially saturated porous media. We also conduct forward modeling, and obtain clear snapshots of the wavefield. Furthermore, we analyze the influence of capillary pressure on the velocity of fast P-wave. At the same time, it is proved that the seismic wave equation can describe the attenuation phenomenon of waves in the seismic frequency band, by means of the analysis of the seismic traces with and without oil in the thin layer and the thick layer models. It also shows that the higher the capillary pressure, the more significant amplitude attenuation in the seismic frequency band.
When cone penetration testing is used to evaluate the undrained strength of cohesive soils, the conventional cone factor shows considerable dispersion and is not suitable for partially drained penetration. To address this problem, an inversion method for undrained strength based on physics-informed neural network was proposed. Spherical cavity expansion theory provides the physical constraint. Separate neural networks were constructed for the elastic and plastic zones. We incorporated the cavity wall limit pressure into the loss function as observational data, enabling direct inversion of undrained strength. The method was then applied to silty clay and clayey silt using the relationship between cone tip resistance and normalized penetration rate. Comparisons with analytical solutions from spherical cavity expansion theory confirmed the numerical reliability of the proposed method. Centrifuge and field tests were conducted on four cohesive soils. The inverted undrained strength showed errors generally within 20%. These results validate the method's applicability across different soil types and drainage conditions.
Fresh water is the fundamental resource for human survival and social development. With global population growth and rapid economic development, the demand for clean water resources has increased significantly, and the supply of fresh water resources is facing severe challenges. Boron is an essential micronutrient for organisms. Excessive or insufficient concentration of boron will both have adverse effects on vital activities. Therefore, controlling the boron concentration in domestic water within standard range is of great significance for ensuring the safety of water resources. In recent years, to improve the efficiency and applicability of boron removal technologies, researchers have made remarkable progress in the development of efficient boron removal materials and the optimization of related technigues. Based on the strict standards for boron content in aqueous solutions, this paper systematically summarizes the latest research advances in boron removal materials and membrane separation technologies. Meanwhile, it further analyzes the improvement potential of membrane separation technologies in practical applications, in light of their core advantages and current limitations. Finally, it propects the research directions of next-generation high-efficiency and low-consumption boron removal materials and technologies, providing scientific basis and technical support for optimization and industrial application of boron removal technologies in water.
