In order to investigate the feasibility of applying solidified shield muck in road construction, the shield muck from Nanjing Metro was taken as the research object, and the green polymer composite curing agent developed independently was used to solidify the shield muck. The impact of the curing agent dosage and maintenance age on the road performance indicators of the shield muck was analysed using various tests-unconfined compressive strength, direct shear test, California bearing ratio (CBR), resilient modules, and freeze-thaw cycle test. In addition, the micro-characteristics and solidification mechanism of the solidified soil were investigated by scanning electron microscope and X-ray diffraction. The results indicate that the composite curing agent can effectively improve the strength of solidified muck, and with the increase of curing agent dosage and maintenance age, the strength of solidified muck also increases. The CBR and resilient modulus of solidified shield muck substantially improve as the dosage of the curing agent elevates, and the solidified soil can well meet the requirements of the Specifications for Design of Highway Subgrades (JTG D30—2015) and Specifications for Design of Highway Asphalt Pavement (JTG D50—2017). The freeze-thaw resistance of shield muck is poor, while it can be effectively improved after curing treatment. The strength loss and mass loss of solidified soil are less than 20% and 1% respectively. The anti-freezing performance indicators meet the requirements of the specification. After the curing agent has been added to the soil body, the polymer components will absorb water and dissolve, creating a static chelating effect with the mineral ions in the soil, initially reducing the water content of soil and promoting the agglomeration between the soil particles. Meanwhile, the other components of the curing agent generate hydration reaction to form hydrated calcium silicate gel, ettringite and other substances to fill the internal pores of soil, making the soil structure denser and greatly improving the strength.

In order to facilitate the counting of turning traffic flow and to enhance the detection speed and accuracy of turning traffic flow at intersections, a deep learning-based method was suggested for detecting, tracking, and counting turning traffic flow at urban crossings. Initially, the YOLOv5s, which was lightweight and efficient, was chosen as the target detection framework after conducting a comparative analysis. Unmanned aerial vehicle (UAV) aerial photography was utilized to record video footage of traffic movement at urban intersections, resulting in the development of a dataset of vehicle aerial photography photos. The pre-training weights and the most recent weight files were utilized to conduct training and testing on the self-constructed dataset. The model evaluation shows that the vehicle detection model using YOLOv5 exhibits great detection speed and accuracy. The model’s box_loss value declines rapidly and stabilizes at 0.038, while the mAP_0.5 value climbs swiftly and stays near 0.91.After that, the DeepSORT model was used as the backend multi-vehicle tracking technique, and a corner-to-centroid coordinate transformation was used to simplify the extraction of vehicle trajectories. The precision of the driving trajectory line was evaluated thereafter. To improve the robustness of trajectory points’ coordinate information, a corner-point-center-of-mass point coordinate transformation was suggested to tackle the issue of corner points in the detection frame. A sixth-degree polynomial was used to model the vehicle trajectory. Unsuitable trajectory lines were rotated and optimized to meet the function mapping requirements and ensure good fitting of all trajectories. Turning vehicles were detected and counted by using a predetermined threshold to determine the turning angle. Ultimately, to validate the performance of the proposed turning vehicle flow detection method, vehicle detection experiments were conducted at a city intersection as an illustration. The manual counting values were compared and analyzed against the detection results obtained using this method. The results show that the average detection accuracy for the four flow directions is 92.9%, with a maximum of 95.7%, meeting the standard detection requirements for turning vehicle flow in real intersection scenarios.

In order to improve the engineering characteristics of silty soil in yellow plain area with low strength, easy deformation and poor bonding ability, mechanical testing and scanning electron microscope (SEM) were used to add different contents of xanthan gum(XG), The mechanical properties and improvement mechanism of XG, lignin fiber (LF) and curing age were studied. The results show that both XG and LF as improved materials can increase the compressive strength of silty sand. With the increase of XG content, the compressive strength of silty sand first increases and then decreases. With the increase of LF content, the compressive strength of silt will increase, and the improvement effect will be weakened by adding too much LF. When the two materials are added to the silt simultaneously, the compressive strength of the silt is higher than that of one material alone. XG produces high viscosity gel when it encounters water, the loose silty soil is tightly cemented together, and the strength of the soil is improved. LF contains large molecular groups, forming a spatial network structure with surrounding soil particles, which strengthens the joint force between soils. The research results can provide reference values for the silty soil subgrade improvement project in the yellow plain area.

In order to study the influence of the tank environment on the results of the seaplane model test, for the first time in this field, a series of whole aircraft model tests were conducted using the same seaplane model in two towing tanks to study the aerodynamic and hydrodynamic characteristics of the whole aircraft model in the two towing tanks, the test results and environmental differences were analyzed. The results show that the towing tank environment has a significant impact on the aerodynamic characteristics of the seaplane model, but by compensating the aerodynamic characteristics of the seaplane model in each towing tank during the test, the interference of the test environment on the water resistance results could be avoided, so as to obtain a more satisfactory water resistance test result. Among the boundary effects of the towing tank, the blockage effect has the greatest impact on the aerodynamic characteristics of the seaplane model. Compared with 2.51% relative blockage ratio 0.67%, the aerodynamic drag coefficient of the seaplane model is 0.1~0.2 larger, and the lift coefficient is at least 0.2.Because the typical high-speed coasting state is used for aerodynamic compensation to calculate, so the compensation effect is only achieved at the corresponding speed and produce some deviation at other speeds, resulting in a certain deviation in the test result, but it will not have a significant impact on the test result because the deviation is so small. The research findings provide guidance for model hydrodynamic tests and performance analysis of seaplanes in China.

To explore the formation mechanism of safety working style among flight cadets, a hypothetical model was constructed based on the theory of planned behavior, incorporating organizational safety culture as an extended variable. Six questionnaires, including behavioral attitude, subjective norms, perceived behavioral control, behavioral intention, safety working style and organizational safety culture, were compiled and distributed to 160 flight cadets. The feasibility of the theoretical model was analyzed through direct path effects, indirect path effects, and moderation effect analysis. The results indicate that the behavioral intention of flight cadets has a significant positive impact on their safety working style. Behavioral attitude, subjective norms, and perceived behavioral control influence safety working style primarily through behavioral intention. Additionally, subjective norms and perceived behavioral control can indirectly enhance behavioral intention through behavioral attitude, ultimately leading to a positive impact on safety working style. Furthermore, organizational safety culture plays a positive moderating role in the impact of behavioral intentions on flight cadets’ safety working style. These findings give new perspectives that it is significant to enhance flight cadets’ strong sense of safety responsibility, impose strict adherence to regulations and foster the integration of safety culture within civil aviation institutions which could effectively elevate their safety working style and ultimately ensure flight safety.

Dynamic graph link prediction aims to predict the formation or disappearance of links between nodes in a graph based on their historical interactions. To address the issue of high energy consumption associated with modeling dynamic networks using recurrent neural networks at fine-grained temporal graphs, a dynamic graph link prediction model optimized by spiking neural networks was proposed. By the node memory updater incorporated spiking neural networks and the spiking update process of node memory, the evolving dynamics of dynamic graphs were learned by graph neural networks and the model achieved link prediction. The results on three publicly available classic datasets show that the proposed model exhibits improved runtime efficiency while maintaining accuracy, showcasing favorable performance in dynamic graph link prediction tasks.

When utilizing double skin composite shear walls as the primary components for resisting lateral forces in buildings, it is crucial to ensure proper horizontal connection of the walls. Currently, traditional bolt connections and welding are the main methods used for horizontal connection of these walls. However, these methods present significant challenges during construction and do not fully exploit the structural advantages of the wall. Based on the structural characteristics of this type of wall, a new type of horizontal joint connection node was designed for the upper and lower layers of the wall. This new design featured a socket-type square semi-grouted sleeve connection. The influence of steel bar diameter, sleeve length, grouting material strength, and sleeve form on the tensile performance of this new connection node was explored using finite element simulation. The results indicate that this new node effectively connects the horizontal joints of double skin composite shear walls with several advantages including convenient construction and reliable performance. Furthermore, it is observed that failure mainly occurs on connecting steel bars which achieves an “equivalent cast-in-place” goal for prefabricated double skin composite shear walls.

Affected by the continuous rainfall in the rainy season, the Taihe Town moraine soil paleolandslide is a giant soil-rock complex paleolandslide with a volume of about 1 200×10⁴ m³, which began to be resurrected in 2021 and entered the creep stage. By 2022, the growth rate began to decline in the rainy season, which seriously threatened the normal mining inside the pit. Based on field investigation, drilling exposure, field monitoring, and physical and mechanical tests, the influencing factors and resurrection mechanism of ancient landslides were explored on the basis of identifying the micro-topography, geological structure characteristics and deformation instability stages of ancient landslides. The results show that the accumulation of rock and soil and topography are the basis of ancient landslide resurrection, and rainfall infiltration and mining excavation are the inducing factors of landslide resurrection. The analysis shows that under the influence of long-term rainfall leaching, fine particulate matter accumulates at the base-cover interface to form a sliding zone, and mining excavation causes an effective free face at the leading edge. Under the long-term influence of groundwater, the strength of the sliding zone soil is gradually reduced. Rainfall leads to increased seepage and reduced shear strength, which induces the revival of ancient landslides. The research results have certain reference value for similar engineering problems.

The problem of inaccurate evaluation of the clamping performance of the spiral angle type slip will be effectively overcome, which is caused by the unclear contact characteristics between the slip and the pipe string. The forces acting on the interaction between slip and columns were analyzed by the theoretical method. A full-scale finite element model of the interaction between the slip, pipe column, and slip seat was established using the numerical simulation method. The mises stress and contact stress distribution patterns of the slip and pipe column under different axial loads and friction coefficients were studied. The mises stress and contact stress gradually decreases from the bottom to the top in the axial direction. They are an imperfect symmetric distribution in the circumferential direction. And there are stress concentration locations. The slip is subjected to higher mises stress and lower contact stress than the pipe column. As the axial load increases, the mises and contact stress increase. As the friction coefficient increases, the mises and contact stress decrease. In design and practical use, emphasis should be placed on components and locations with high-stress levels. Under high load conditions, increasing the friction coefficient by changing the material and shape of the slip teeth is recommended. Further the clamping performance of the slip under high load conditions is improved. It also prevents damage to the pipe column caused by excessive clamping force. The research results can provide theoretical guidance for the design of slips and the evaluation of clamping performance.

CO₂ foam fracturing can reduce reservoir damage and contribute to the stimulation of unconventional oil and gas reservoirs. However, there needs to be more quantitative methods to evaluate the influence of the CO₂-H₂O ratio of foam fracturing fluid on the conductivity, and the optimization of foam fracturing fluid system is insufficient. To select the CO₂ foam fracturing fluid system suitable for the conglomerate reservoir in the Mahu Basin, proppant embedment experiments were carried out with the treatment of foam fluid with different CO₂-H₂O ratios at simulated reservoir conditions, and each interval of embedment depth was obtained. A conductivity model considering the heterogeneous proppant embedment was established to calculate the effects of different foam fluids on improving the conductivity and analyze its mechanism. The results show that using CO₂ to replace part of the water-based fracturing fluid can reduce the degree of proppant embedment. With the increase of the CO₂-H₂O ratio, the effect of improving the conductivity weakens and reaches the upper limit gradually, increasing by about 12% compared with that of water-based fracturing fluid. When the ratio is 7∶3, the conductivity of samples with low clay content (<20%) increases to the upper limit. However, the conductivity of samples with high clay mineral content (≥20%) is more sensitive to the influence of the CO₂-H₂O ratio, and the upper limit is lower. CO₂ foam fracturing fluid can improve the hydrological capacity of the propped fracture-formation system. The research results can reference the CO₂-H₂O ratio optimization of the CO₂ foam fracturing fluid system.