In order to solve the problem of difficulty in determining the optimal measurement points for bearing signal acquisition. Taking the NU306 bearing-housing system as the research object, the bearing housing to carry out multi-measurement points vibration test experiment. The local linear embedding algorithm was used to linearly reduce the multi-dimensional space data of the bearings to obtain the sensitivity matrix of the measurement point. The optimal position of the measuring point under varying load and rotation speed was studied when the inner or outer ring are defective. The results show that for bearings with outer ring failures, the optimal measurement point is the one closest to the location of the failure when the load or rotational speed increases. For bearings with inner ring failures, the optimal measurement point is the one at lower loads far from the center of the housing when the load or rotational speed increases. The results can provide an effective reference for the selection of measurement points under different operating conditions.

In order to study the influence of overlying load on the internal deformation of soil outside the foundation pit, a transparent soil test chamber with controllable deformation mode of retaining structure was designed and combined with particle image velocimetry technology to analyze the influence of different deformation modes of retaining structure and overlying load on the internal deformation of soil. The reliability of the test results was verified by comparing the data obtained from the transparent soil test with the prediction curve and the engineering example. The results show that the overlying load has a significant effect on the displacement field of the soil outside the pit. Increasing the overlying load or reducing the distance between the overlying load and the retaining structure will make the influence area of soil displacement outside the pit expand to the deep soil layer, and the maximum vertical settlement and horizontal displacement will also increase. The soil depth of the soil outside the cantilever type and the convex type is significantly affected by the overlying load pressure and distance. The displacement of the upper soil is significantly affected by changing the pressure and distance of the overlying load in the cantilever deformation mode, but the displacement of the middle and lower soil is more significantly affected by changing the pressure and distance of the overlying load in the convex deformation mode. Compared with reducing the distance of the overlying load in the same proportion, increasing the overlying load has a greater impact on the displacement. It can be seen that in the actual project, it is necessary to combine the local building distribution with the underground engineering environment, and take appropriate measures to avoid the most unfavorable deformation mode of the retaining structure.

In response to the problem of insufficient analysis of the risk impact on system components and inadequate classification management in civil aircraft maintenance, which leads to sudden failures during component operation, a comprehensive risk impact factor was introduced to accurately evaluate the importance and potential hazards of civil aircraft system components, and a component preventive maintenance strategy considering the comprehensive risk impact of multiple factors was established. A chance maintenance decision model for civil aircraft systems was established with the objective of optimizing the maintenance cost of components, taking into account the comprehensive risk impact of multiple factors on components. The model comprehensively considers the time correlation between system components and the cost generated by the comprehensive risk impact of multiple factors on components. Example verification shows that compared to preventive maintenance decisions that do not consider the impact of component risks, the maintenance decision proposed in this article reduces the total maintenance cost of civil aircraft systems by about 20.20%, and the reduction rate of preventive maintenance and replacement frequency is about 41.23%.

Aiming at the problem of poor model accuracy caused by poor stability and strong randomness of wind power output. A short-term prediction model of wind power based on quadratic decomposition error compensation was proposed. Firstly, BiLSTM (bidirectional long short-term memory) prediction model is established to predict wind power and output prediction errors. Secondly, an IDBO (improved dung beetle optimizer) algorithm was used to initialize the population by using chaotic mapping, update the position of rolling dung beetles by introducing golden sine strategy, and update the position of thieving dung beetles by adding dynamic adaptive weight coefficient to optimize the parameters of the prediction model. Prevent the network from falling into the local optimal solution, and adaptively search the optimal parameter combination. Then, using the decomposition-reconstruction-decomposition strategy, CEEMDAN (complete ensemble empirical mode decomposition with adaptive noise) was used for the first decomposition. In addition, SE(sample entropy) and K-means are introduced to reconstruct the sequence according to frequency, and the high-frequency error sequence was decomposed into error sequences of different frequency bands by VMD(variational mode decomposition). Improve the prediction efficiency and accuracy of subsequent models. Finally, the input error compensation model of each component was used to predict and the Attention mechanism was introduced to learn the feature relationship of different time steps and give different weight values to enhance the attention to key information. Through the measured data of a wind farm in Xinjiang, the prediction accuracy of the proposed model is proved to be high and has significant advantages.

For the research on the characteristics and main controlling factors of volcanic rock reservoirs, core observation, casting thin section identification, physical property testing and logging data analysis were utilized to conduct the study on the characteristics, distribution and main controlling factors of the Carboniferous volcanic rock reservoirs in the Junggar Basin. The results show that in the Chepaizi uplift, the Carboniferous volcanic rock reservoirs mainly developed volcanic effusion facies, explosive facies, tuffaceous facies and volcanic sedimentary facies, and the lithologies are mainly andesite, basalt, volcanic breccia, tuff and tuffaceous sandstone. The reservoir spaces are classified into connected pore type, fracture type, fracture-pore type and pore-cavity-fracture type according to the configuration relationship between pores and fractures. Affected by lithology and lithofacies, weathering and leaching effects and tectonic actions, the reservoir properties have strong heterogeneity. The dominant reservoir lithologies are andesite, volcanic breccia and tuff. A three-layer weathering crust structure composed of clay layer, hydrolysis layer and weathering and leaching layer is developed at the top of the Carboniferous, which significantly improved the reservoir physical properties. Fractures are an effective supplementary factor for reservoir development. Different from the previous studies that mainly focused on characterizing the characteristics of the dominant volcanic rock reservoirs, based on the coupled controlling effects of lithology and lithofacies, weathering and leaching, and strike-slip faults on the reservoirs, it is innovatively recognized that two dominant volcanic rock reservoir development models, namely fault-block body and fault-fracture body, are mainly developed in the study area. The research results have certain guiding significance for the exploitation of the Carboniferous oil and gas resources from east to west in the Chepaizi uplift.

In order to study the erosion behaviour of the gooseneck pipe in the drilling fluid environment and the evaluation of the surface strengthening effect, the influence of the drilling fluid density on the erosion behaviour of the gooseneck pipe and the evaluation method of the surface strengthening of the inner lumen were investigated by the finite element simulation and analysis method. The results show that: the erosion rate of gooseneck pipe is the largest in the inner diameter of the bend, and the maximum erosion rate becomes larger with the density of drilling fluid becoming higher, but the maximum erosion rate still occurs in the inner diameter of the bend. The maximum deformation displacement can be effectively reduced by 34.23% after surface strengthening of the inner lumen of the gooseneck pipe. It can be seen that the effect of drilling fluid density on the erosion behaviour of the gooseneck pipe cannot be ignored, and surface strengthening can effectively reduce the maximum deformation displacement.

Aiming at the problems of anti-noise, anti-high resistance and complex threshold setting of traditional pole selection methods, a fault selection method of flexible DC distribution line based on Res-BiLSTM network was proposed. Firstly, the original fault signal was subjected to complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), and then the reconstructed signal was obtained by using the correlation coefficient and Shannon entropy for reconstruction. Secondly, the Res-BiLSTM network model was constructed for the pole selection. In order to improve the network accuracy and the convergence speed, the channel attention module was introduced into the split-attention network. The reconstructed signal features were extracted using the convolutional bidirectional long short-term memory and the improved split-attention network at the same time. The extracted features were fused using the attention feature fusion module, and the fused features are classified. Finally, PSCAD/EMTDC was employed to construct the model and to verify the proposed methodology. The simulation results show that the proposed pole selection method is highly accurate, anti-interference, and independent of fault distance.

The construction of the shield tunnel for the high-speed railway will impact the settlement of railway tracks, roadbeds, and other structures, potentially affecting the railway’s operation. In order to study the influence of shield tunnel underneath the high-speed railroad in Guiyang area on the settlement pattern of frame box culvert, roadbed and high-speed railway track and the shield construction parameters suitable for Guiyang area, relying on Guiyang Rail Transit Line 3, the model of soil layer-frame culvert-roadbed-track was established to analyze the settlement law of shield construction in limestone on frame culvert, existing high-speed railroad track and roadbed, and to optimize the parameters of shield construction. The results indicate that the settlement of the frame culvert exhibits a “W” shaped transverse and longitudinal settlement pattern, with a peak settlement value of 1.805 mm during the tunneling process. The shield machine’s crossing causes a sudden change in subgrade settlement, with the peak value reaching 1.753 mm. High-speed rail track settlement shows a single peak with excavation, with a peak value of 1.41 mm. Analysis of eight types of shield tunneling pressure and grouting pressure reveals that grouting pressure has a better control effect on settlement than excavation pressure. Increasing grouting pressure leads to a decrease in the peak value of subgrade surface settlement, with the peak value reaching 1.355 mm at 800 kPa grouting pressure. The maximum deformation rate is 20.7%, with grouting pressure set at 800 kPa and tunneling pressure at 100 kPa for the shield machine.

In the absence of accurate transit demand information, a demand responsive transit(DRT) route planning method based on taxi trajectory data was proposed to predict the “potential demand” of demand responsive transit and provide a feasible plan for route planning before transit operation. Firstly, taxi trajectory data in the study area was obtained through data mining, representing the “potential demand” for passenger travel in the area, and candidate station were determined using the K-means clustering algorithm. Secondly, a benchmark station network was established using these candidate station, with edge benchmark stations designated as the starting and ending points of routes. Utilizing the K-shortest pathes(KSP) algorithm constrained by route length, benchmark chains were generated. Finally, after determining the sub-chain set of the benchmark chains, demand response stations within each sub-chain were searched based on circumferential critical value constraints. Using this algorithm, alternative routes were generated repeatedly within specific time periods, and an initial optimal route was selected based on comprehensive evaluation indices for each alternative route.

In the condition of engineering surcharge near the existing pipeline, the pipeline produce subsidence deformation and further threaten the normal operation of the existing pipeline. Most of the research in this area stays in the finite element and indoor tests, and few theoretical solutions are used to analyze the stress and deformation response of existing pipelines under adjacent engineering surcharge. Based on this, the pipeline-soil interaction under this working condition was investigated by using theoretical analysis. Firstly, the Boussinesq solution was used to analyze the additional stress at the axis of the existing pipeline. Then, the pipeline was simplified as an infinite beam rest on the Pasternak model to further obtain the total energy of the system during the deformation of the pipeline. Finally, the stress and deformation response of the pipeline can be obtained according to the energy variation theory. By comparing with the existing experimental data, the correctness of the proposed method was verified. Compared with the degradation analysis of the proposed method, the proposed method is closer to the measurements. The parameter study shows that the stress deformation of the pipeline wills decrease nonlinearly with the increase of the buried depth of the pipeline. Increasing the diameter of the pipeline would increase the deformation response of the pipeline, the deformation of the pipeline is not sensitive to the angle between the pipeline and the loading area. Increasing the horizontal distance between the pipeline and the loading area can effectively reduce the stress and deformation response of the pipeline, and the deceleration increases first and then decreases. A series of analysis results can be used to analyze the influence of engineering surcharge on the stress and deformation of existing pipelines in practical engineering.