A secondary contact zone (SCZ) is an area where incipient species or divergent populations may meet, mate, and hybridize. Due to the diverse patterns of interspecific hybridization, SCZs function as field labs for illuminating the on-going evolutionary processes of speciation and the establishment of reproductive isolation. Interspecific hybridization is widely present in avian populations, making them an ideal system for SCZ studies. This review exhaustively summarizes the variations in unique traits within avian SCZs (vocalization, plumage, beak, and migratory traits) and the various movement patterns of SCZs observed in previous publications. It also highlights several potential future research directions in the genomic era, such as the relationship between phenotypic and genomic differentiation in SCZs, the genomic basis of trait differentiation, SCZs shared by multiple species, and accurate predictive models for forecasting future movements under climate change and human disturbances. This review aims to provide a more comprehensive understanding of speciation processes and offers a theoretical foundation for species conservation.

In the process of grading and dynamically optimizing the design and construction parameters of the surrounding rock mass of a rock tunnel face, efficiently and accurately acquiring the geometrical parameters of the rock discontinuities is an important basic task. To address the problems of time consuming, low accuracy, and high danger associated with traditional methods of obtaining the structural information of rock mass, this paper proposes a method for three-dimensional reconstruction and intelligent information extraction of tunnel face based on binocular stereo vision (BSV). First, the parallel binocular device with a single camera was improved, calibrated using the checkerboard calibration method. By integrating with the semi-global matching algorithm, the BSV based method for the three-dimensional reconstruction of the rock mass of the tunnel face was optimized. Furthermore, based on the results from on-site engineering applications, this study leveraged two parameters, point cloud density and algorithm runtime, to determine the optimal values for the disparity range and window size parameters within the semi-global stereo matching algorithm. This enhancement improved the performance of the 3D reconstruction method based on binocular stereo vision. Finally, efficient and refined intelligent methods for extracting structural parameters of the rock mass were proposed based on k-nearest neighbor search and kernel density estimation. The research results can provide reliable technical support for the intelligent and efficient acquisition of rock mass structural information in rock tunnel engineering faces.

In this study, the chemical shrinkage of calcium carbide residue-waste red brick powder cementitious materials pastes (CWCP) was tested using two different methods, and the shrinkage mechanism of drying shrinkage and chemical shrinkage was analyzed. The products at different stages of material shrinkage were studied by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric (TG). The results indicated that the chemical shrinkage test method was more accurate after the pastes was sealed. The chemical shrinkage of CWCP can be mainly divided into four stages, shrinkage, expansion, re-shrinkage, stability. An increase in calcium carbide residue (CCR) during the initial shrinkage stage will enhance the alkali concentration, promote the dissolution of the raw materials, and improve the shrinkage value. As the alkali in CCR and the active ingredient in WRBP were consumed, the chemical shrinkage decreased and then increased with the increase of CCR doping in the reshrinkage stage. Dry shrinkage was manifested as monotonic shrinkage. The increase of CCR content will produce more amorphous gel with high Ca/Si, thus slowing down the drying shrinkage of samples. The drying shrinkage of CWCP accounted for the main part of shrinkage, and the chemical shrinkage value was about 10 %-22 % of the drying shrinkage value after 28 days.

There are three primary methods for highway driving safety analysis and prediction, namely, mathematical statistical analysis, risk factor simulation, and vehicle and road pattern analysis. The major problem of these methods is believed to be the lack of verification by real data. And safety governance measures lack of implement in actual project to verify its effectiveness. In order to integrate road safety research more closely with real road conditions, Digital Twin (DT) is proposed in this study for realising highway driving safety analysis, management and verification. The methodical realisation process involves the following steps. First, a drone was flown to acquire the traffic data, which was then segmented and mapped onto different lanes using Yolo, DeepSORT, and Savitzky-Golay. After rebuilding the missing road parameters and traffic data using Prescan, Matlab/Simulink was employed to formulate the road network DT for vehicle localisation and driving pattern representation and forecasting. Next, the vehicle speed and trajectory prediction model of the actual road was generated from the developed long short-term memory network (LSTM). Last but not least, a number of safety measures were formulated out of the DT system and validated through the experimental analysis.

In deep rock engineering, evaluating the likelihood of rock burst is imperative to ensure safety. This study proposes a new metric, the post-peak dissipated energy index, which accounts for strain rate and size effects in assessment of the rock burst proneness of a rock mass. To investigate rock burst proneness, conventional compression tests were conducted on limestone and slate samples with different length to diameter (L/D) ratios (ranging from 0.3 to 1.5) at four different strain rates (0.005, 0.01, 0.5, and 1.0 s−1). Based on the testing observations, the actual rock burst proneness was classified into three categories (no risk, low risk, and high risk). A new criterion was also established using the post-peak dissipated energy index, which is the ratio of elastic energy to total dissipated energy. The impact of the strain rate and L/D ratio on rock burst proneness was analyzed. The results indicated that increased strain rates cause a strong hardening effect, leading to staged growth of rock burst proneness. However, the rock burst proneness decreases non-linearly with the increasing L/D ratio. The accuracy of the proposed criterion was validated by comparison with existing criteria, demonstrating that the energy-based index ensures a reliable evaluation of the rock burst proneness of a rock mass. The proposed method has excellent potential for practical application in deep rock engineering.

Polyurethane (PU), with excellent physical and chemical properties and high designability, is one of the ideal materials for asphalt modification in the future. In this paper, based on the limitations of traditional asphalt modifiers, the preparation process, relative advantages and development prospects of PU as asphalt modifiers are described. Subsequently, the spatial structure, physical and chemical properties of PU synthetic raw materials were combined with the modification properties of PU to analyze the effect and influence of PU on asphalt modification. Specifically, polyurethane modified asphalt (PUMA) is divided into thermoplastic polyurethane modified asphalt (TP-PUMA) and thermosetting polyurethane modified asphalt (TS-PUMA). The gain effect of TP-PUMA in high-temperature performance, low-temperature performance, aging resistance, fatigue resistance, weathering performance and bonding performance is obvious. In addition, it has good storage stability. With excellent road performance, TS-PUMA makes up for the shortcomings of epoxy asphalt in terms of low-temperature performance and compatibility. Finally, due to the development trend of functional diversification of modified asphalt, the research basis and status of several new modified asphalts based on PU properties are described. Because the systematic study of PUMA is insufficient, this paper proposes corresponding research. To provide guidance and ideas for the research of PU modified asphalt.

As a result of the complex geological conditions of sand-cobble stratum, various types of problems may arise during construction of tunnels crossing sand-cobble stratum, the most prominent of which is the stability problem of the face. In order to study the stability of the tunnel face in sand-cobble stratum, first, a continuous medium model of sandstone soil is established, and numerical simulation is carried out on the three-axis compression test of sandstone soil to analyze its micro-mechanical characteristics. Second, a calculation model of simulated sandstone strata excavation is established by FLAC3D finite difference software. Then, the safety factor K calculated by the strength reduction method is introduced as the evaluation index of the face stability, and the face stability of sand-cobble tunnels with a series of stone content, tunnel burial depth and tunnel diameter are analyzed. The results show that the macro stress-strain curve of sand-cobble soil in the three-axis compression test can be divided into linear stage, elastic-plastic stage and ideal plastic stage, and the shear strength of sand-cobble soil increases with the increase of stone content. In the process of tunnel excavation, the stability of tunnel face increases with the increase of stone content in the stratum; while the tunnel buried depth and diameter increase, the stability of tunnel face decreases. These results provide a reference for predicting the instability and failure of sand-cobble tunnels, which is critical for the construction and safety of tunnels in sand-cobble stratum.

During the drilling process, high-strength rock can lead to various issues such as drilling suppression, bit wear, and increased operational costs. To ensure safe and efficient drilling operations, it is crucial to accurately predict the strength parameters of the rock and recommend modifications to operational procedures. This paper proposes a low-cost and fast measurement method for predicting the strength parameters of rock in the field. To evaluate the effectiveness of this method, a drilling process monitoring experiment was conducted on sandstone, limestone, and granite. The experiment studied the effect of confining pressure on the response of cutting with an impregnated diamond bit. By analyzing the relationship between the thrust force, torque force, and penetration depth under different confining pressures, the researchers developed an analytical model for drilling that considers confining pressure, compressed crushed zone, and bit geometry. The results show that the confining pressure has a significant effect on the cutting response. As the confining pressure increases, the thrust force, torque force, and penetration depth at the cutting point also increase. Furthermore, a new measurement method was proposed to determine the strength parameters, such as cohesion, internal friction angle, and unconfined compressive strength. The estimated strength parameters for the three rock types using the drilling method were in good agreement with those of the standard laboratory test, with an error range of 10%. This method of estimating rock strength parameters is a practical tool for engineers. It can continuously and quickly obtain the drilling parameters of in-situ rocks.

A real-time adaptive energy management strategy (EMS) used a model-based predictive control algorithm that continuously adapted to the changing driving patterns and traffic conditions. With battery degradation in an operation being considered, the algorithm was designed to minimize the total cost of electricity consumed by vehicles with hybrid energy storage systems (HESSs) while ensuring that the battery and supercapacitor cell were not overcharged or overdischarged. First, the objective function was taken as the instantaneous minimization of the comprehensive cost. Second, a hierarchical instantaneous optimal control EMS (HIOC-EMS) was suggested to solve the optimal power coupling coefficient of the supercapacitor that satisfied the constraints at any moment. Third, the HIOC-EMS was proven to be an efficient and robust method for optimizing the energy management system of HESSs. The experimental results of three different driving cycles showed that the HIOC-EMS, when compared to the particle swarm-optimized fuzzy EMS (PFZY-EMS), achieved reductions in battery losses of 18.41%, 13.94%, and 20.37% and comprehensive cost reductions of 11.16%, 7.37%, and 9.61%, respectively, in the three cycles. Furthermore, compared to the dynamic programming EMS (DP-EMS), the HIOC-EMS resulted in increased battery losses of 14.87%, 10.77%, and 4.87% and increased comprehensive costs of 8.48%, 2.98%, and 1.55%, respectively. These results proved the effectiveness of the HIOC-EMS in reducing the usage cost of electric vehicles with HESSs.

Excavating tunnels in sandy cobble strata carries a high risk of ground collapse caused by instability of the tunnel face. In order to prevent instability at the tunnel face during excavation, this paper focuses on studying the effects of various pre-reinforcement method on the stability of tunnel in the sand-cobble strata. Firstly, pre-reinforcement projects suitable for these tunnels are proposed. Then, using FLAC3D to established numerical models, then simulate the excavation process under six different working conditions: non-reinforced, pre-reinforcement with advance small pipes, pre-reinforcement with pipe-roof, pre-reinforcement with GFRP bolts, pre-reinforcement with advance small pipes and GFRP bolts, and pre-reinforcement with pipe-roof and GFRP blots. The displacement and stress fields of the soil behind and in front of the tunnel face under each condition are obtained. The results show that the use of GFRP bolts for pre-reinforcement can effectively control the deformation of the surrounding rock in front and behind the tunnel face, and pre-reinforcement with advance small pipes or pipe-roof can reduce the settlement of the tunnel crown. Pre-reinforcement by the combination of GFRP bolts with advance small pipes or pipe-roof can better ensure the stability of the tunnel during the excavation process.

Full-scale fatigue tests were performed on three composite decks with the MCL (modified clothoid) connectors to investigate their fatigue performance. Fatigue life and failure mode of the composite bridge decks were explored by measuring the specimens with three different stress amplitudes. The deflection, strain, carrying capacity, and stiffness degradation of the composite decks were measured and analyzed in the test. In addition, parameter analysis was performed using finite-element method in this study. Results showed that the mechanical performance of the composite decks accorded with the plane-section assumption under constant amplitude load, and the fatigue failure mode of the composite decks was the local fracture of the bottom steel plate. The stiffness degradation law and S-N curve were obtained in this study. Moreover, the concrete slab depth had a remarkable effect on the fatigue performance of the composite decks.

To quantitatively characterize and evaluate the morphological features of coarse aggregate particles, 2D images of coarse aggregate particles were processed by using Image Pro-Plus software in this paper. Through image enhancement, correction, segmentation, and retrieval, six morphological indicators such as axial coefficient, rectangularity, roundness, roughness, angular parameters, and fractal dimension were obtained. Further statistical analysis of the distribution pattern of each morphological characteristic parameter was carried out in a large sample to provide a basis for the quality control of coarse aggregates processing. What’s more, further statistical analysis of the distribution pattern of each morphological characteristic parameter was carried out in a large sample to provide a basis for the quality control of coarse aggregates processing. The axial coefficient of coarse aggregates of different particle sizes, decreases with increasing particle size. The roundness decreases with increasing particle size, and the fractal dimension decreases with increasing particle size; the axial coefficient and rectangularity can be used to characterize the shape of coarse aggregates without the influence of angles. Roughness and fractal dimension can be used to characterize coarse aggregate angles independent of shape; angular parameters, roughness or angular parameters, and fractal dimension can be chosen when characterizing angles only. This study can provide a fast and efficient quantitative basis for the optimization of the coarse aggregate processing and process control of incoming quality.

针对货车利用躲避摄像头等手段在城市道路中不按规定时间、规定线路行驶,使得车辆不能被准确识别的问题,提出基于改进Faster RCNN的城市道路货车检测方法.该方法以Faster RCNN为基础模型,通过对传入主干网络的车辆图片进行卷积和池化等操作来提取特征,其中增加特征金字塔网络(FPN)提升对多尺度目标检测的精度;同时将K-means聚类算法应用在数据集上以获取新的锚点框;利用RPN(region proposal network)生成建议框;并使用CIoU(complete-IoU)损失函数代替原算法的smoothLi损失函数以提升检测车辆的精确性.实验结果显示,改进后的Faster RCNN相比原算法对货车检测的平均精度(AP)提高7.2％,召回率(recall)提高6.1％,减少了漏检的可能,在不同场景下具有良好的检测效果.

In permafrost areas, the degradation of permafrost greatly affects the stability of concrete pile composite foundations. Hence, direct shear tests were carried out to analyze the effect of the rising frozen temperature, moisture content, and normal stress on the mechanical properties of the frozen soil-pile interface during the thawing process of permafrost. A constitutive model was established to describe the shear stress-displacement variation law of interface, considering the hydrothermal coupling effect. The results show that the frozen strength of the interface was provided by the ice crystal structure formed at the interface, and its area increases with increasing water content. The whole shear process can be divided into three stages: the prepeak stage with growing shear stress, the postpeak stage with deep dropping shear stress, and the shear stress reconstruction stage. The peak frozen strength was positively correlated with water content and normal stress, however, it was negatively correlated with the rising frozen temperature. The residual frozen strength has a linear relationship with normal stress and water content, however, it shows different regularity with rising frozen temperature at different water content. Moreover, the Gompertz model prediction results are in good agreement with the experimental results. This model can describe well the stress-displacement variation law of interface with different rising frozen temperature and water content.

Abstract Geological disasters damage highways and disrupt traffic, which reduces the service level of roads. We collected 15,435 geohazards in Guangxi Province. The geohazards within 1km of the highway buffer were selected to study its spatial distribution characteristics and risk assessment methods. Geohazard intensity index and sensitivity index are proposed to establish the highway geohazards assessment model. Based on the weights of evidence (WOE) method, the influencing factors of the sensitivity index and the weight of each factor are obtained. By analyzing the spatial distribution characteristics of geohazards, collapses, landslides, ground collapse and unstable slopes are identified as major geohazards along the highway. Based on the Getis-Ord Gi* statistic methods, the hotspot map of four disasters was drawn, and the intensity index along the highway was calculated. The relationship between slope, aspect, topographic relief, annual average rainfall, land use, lithology type and geohazards was analyzed. The sensitivity index was calculated using the WOE method. The intensity index and the sensitivity index were superimposed to obtain the geohazard index, and the geohazard risk of the highway is divided into five levels. The model accuracy-test based on the receiver operating characteristic (ROC) curve shows that Area Under Curve (AUC) equals 0.71, indicating high reliability for the risk assessment.

针对处在恶劣的天气、严重遮挡、过暗或过亮的光照等复杂环境下,现存的目标检测算法对车辆的检测准确度不高,针对该问题提出了基于YOLOv4的改进算法来检测目标车辆.使用图像处理算法处理数据集,模拟复杂环境,以增强算法的鲁棒性;使用K-means++聚类算法优化先验框参数,提高先验框与目标的匹配度;在骨干网中加入空洞卷积(Dilated Convolution)模块,使骨干网络能更好地提取车辆特征;使用Focal Loss损失函数代替交叉熵损失函数,解决检测过程中正样本数和负样本数相差过大的问题.通过实验可得mAP为86.13％,相较原YOLOv4算法提高了7.31％,检测精度在一定程度上优于原YOLOv4检测算法.

On the Qinghai–Tibet Plateau area, the permafrost and the wetlands are interdependent to form a symbiotic system, called permafrost wetlands (PWs). Due to the extremely complex hydrothermal conditions, the PWs greatly impact road stability. Thus, it is necessary to classify PWs in terms of engineering characteristics and evaluate their engineering stability. In this study, the typical diseases of subgrade in permafrost wetland areas are analyzed based on field investigation. Then, the permafrost type, waterlogged area ratio, and meadow development degree are used as the main indicators for classifying PWs by a three-level division method. Finally, a scheme for the engineering stability evaluation of PWs was established based on the fuzzy comprehensive theory and used for the pre-evaluation of the engineering stability for the proposed Qinghai 224 highway. The results indicate that the longitudinal cracks and uneven deformation are the main road diseases in this area, caused by the combined effect of permafrost, waterlogged areas, and meadow development. The PWs are divided into 15 types according to the engineering characteristics. Waterlogged area ratio and meadow development degree are proven to represent the development of underlying permafrost. The influencing factors include climatic environment, permafrost property, and wetland conditions, which have decreased influence on the engineering stability of PWs. The engineering stability of k230 + 100 and k255 + 400 is evaluated as basically stable and less stable, and the corresponding measures are adopted. At present, no significant damage occurred on the two road sections. The results suggest that the evaluation model in this article can be used to pre-evaluate the engineering stability of PWs.

In order to meet the travel needs of inhabitant, buses as a travel mode of “low-carbon, environmental protection and green travel” have been widely used, so the statistics of public transport passenger flow has gradually become an important reference data source for rational traffic planning and optimization of public vehicle route scheduling. Aiming at the impact of incorrect counting caused by complex conditions such as movement, crowding and occlusion in the actual bus surveillance video scene, this paper adopts the passenger flow statistics system with the passenger's head area as the target detection. The algorithm proposed in this paper mainly uses the head area of the passengers getting on and off as the target feature to be extracted, and on this basis, the image processing and recognition operations are performed. Then input the above results into the target tracking algorithm to be used to estimate and preprocess it, and then use the data information obtained by the algorithm to achieve the association matching between multiple targets. Finally, the counting is completed by analyzing the target motion trajectory, so as to realize the statistics of boarding and alighting passenger flow. The experimental results show that the passenger flow statistics have strong robustness, track and count the target passengers accurately, and meet the needs of actual passenger flow statistics.