To study the spatiotemporal evolution process of particle wakes behind the impeller in the centrifugal pump, this paper utilized high-speed photography to capture the particle motion characteristics under different solid-phase particle concentrations (1%, 1.5%, and 2%). First, this paper studies the changes in hydraulic performance of the centrifugal pump under solid–liquid two-phase flow conditions. It then introduces the evolution process of the impeller particle wake, comparing the differences in particle wake evolution under varying solid-phase concentrations. Finally, the impact of the solid-phase concentration on the wear of the volute's partitions is investigated. This study found that as the solid-phase particle concentration increases, the hydraulic performance of the pump gradually declines. Under the design conditions, when the solid-phase concentration increases by 0.5%, the efficiency of the centrifugal pump decreases by 0.56% and 0.35%. There is mutual transport of particles between adjacent wakes, and the movement of particle wakes within the volute passage is not equidistant over time. As the solid-phase particle concentration increases, wake cutting occurs at the volute partitions, and there is a significant solid–liquid separation between the particle wakes. The spatial evolution of the particle wakes is significantly influenced by the solid-phase concentration. Wear at the volute partitions intensifies with increasing solid-phase concentration and is also affected by changes in the particle wakes. The research results provide a basis for further exploration of the solid–liquid two-phase flow dynamics within centrifugal pumps.

Fragile ancient buildings are recognized as an eloquent testimony to human civilization, and their safety should arouse more attention. According to the special case of adjacent blasting construction, the assessment model should be essentially built to assess the effect of tunnel blasting on the safety of the ancient buildings. To analyze the structural safety of ancient buildings under blasting vibration and to protect the precious ancient buildings, a risk assessment model of ancient buildings with 20 relevant assessment indexes was initiatively built in this study. To be specific, the relative factors of blasting, the factors of ancient buildings, and other factors (e.g., religion) were comprehensively considered in the model. Subsequently, the risk level and weight were calculated more systematically and quantitatively by adopting the optimized optimal comprehensive method integrating the G1 method and the entropy method. Lastly, the overall risk value was determined by applying the fuzzy gray method. Afterward, the value was adopted to assess the safety of the Asoka Temple, the only existing temple named after the Indian King Asoka in China, as an attempt to verify the feasibility of this model. Besides, the Asoka tunnel was around it. As demonstrated from the results, the age of the buildings maximally impacted the safety of ancient buildings, and the safety level of the Asoka Temple was “relatively safe.” The present study built an effective model to assess the safety of ancient buildings under adjacent subway blasting construction, which could help improve the efficiency and accuracy of assessments.

The coastal areas are the most economically developed, and they need to build many infrastructures such as airports, ports, and subways. However, the complex geological conditions in the coastal areas pose risk issues to the construction. In response to the characteristics of the high risk of subway shield tunneling, we proposed a new method to evaluate the safety of subway shield tunneling by using the entropy weight method and the matter-element theory. In addition, we built a safety evaluation index system with 52 evaluation indexes, including workers, machinery, materials, technology, environment, etc. Accordingly, using the entropy value method, we calculated the weight of each index and built the classical domain with the matter-element theory. Then, combining the joint domain with the evaluation of the main factors, we calculated the risk correlation degree. Moreover, we established the safety assessment model. Taking the coastal tunnel between the Hujing Station and Wanshou Station of Fuzhou metro line 6 as an example, we validated the evaluation model and assessed the risk of the coastal tunnel. The result demonstrates that the total construction safety risk level is low. But the environmental factors are very crucial; the highest is the embankment collapse C523, and its proportion is 8.14%. It is necessary to measure deformation and reduce the environmental risks of construction. The case study can provide a very valid reference for some similar coastal projects.

Based on the construction of Wufengshan Tunnel on Jintai Railway, in order to study the propagation law of vibration wave when the tunnel meets the special stratum of upper soft and lower hard, the obtained vibration velocity is fitted and analyzed by field monitoring and numerical simulation. The analysis results show that the traditional Sadowski formula is suitable for the study of vibration velocity law in single stratum and has a good fit. For the study of vibration velocity propagation law in complex stratum such as upper soft and lower hard, the modified Sadowski formula V=KQ^a R^b is more suitable; through tunnels in upper soft and lower hard stratum, the peak value of vertical vibration velocity of blasting is higher. Because of the existence of soft-hard interface, the attenuation velocity of vertical vibration velocity is the sharpest relative to the radial and tangential vibration velocities. At the same time, the feasibility of numerical software to simulate such engineering blasting construction is verified.

Provenance analysis of aeolian sediments is key for understanding its origin, transportation and climatic significance. The ability to identify and quantify source contributions of aeolian sediments remains challenging. This study applies a discriminant function analysis (DFA) method to analyze the geochemistry of five different types of sediments (mobile dunes, vegetated dunes, fluvial sands, sandy loess and loess) in the Taklamakan desert and quantify the relative contribution of sediment sources. The geochemical compositions of sediments are influenced by the source rock compositions, chemical weathering and grain size. We analysed the effects of these three factors on the geochemical characteristics of sediments in detail and identified seven source tracers. The seven tracers of potential source areas and target sediments were compared by DFA, to obtain a series of discriminant functions which could identify the sources and their relative contributions. The results show that the aeolian sediments in the Taklamakan Desert are primarily sourced from the Kunlun Mountains and the Tianshan Mountains, with different grain sizes having different sources. The provenance of different types of sediments within the same grain size fractions were found to remain unchanged. The contribution of sediments sourced from the Kunlun Mountain and Tianshan Mountain to the > 63 μm fractions are 60% and 40% respectively, while the contribution to the < 63 μm fractions are 40% and 60% respectively. The findings are valuable for further understanding the source and transport mechanism of sediment in arid and semi-arid areas.