Study on the Influence and Law of Waterproof System Design Factors on the Typical Stress of Bridge Deck Pavement

To improve the structural design rationality of cement concrete bridge deck pavement systems and reduce diseases such as interlayer displacement and rutting in the early stage of bridge deck use, this paper studies the influence and law of the coupling effect of various factors of the waterproof system on the typical stress of bridge deck pavement and determines the best structure combination for the bridge deck pavement structure. A finite element model was established by using commercial software to simulate the mechanical response of different types of waterproof bonding layer, waterproof leveling layer, and impervious structure layer under different parameters. The simulation results show that when the thickness of the pavement layer was 8 cm, the maximum shear stress of the pavement layer occurred in the middle of the wearing course and the junction between layers. When the pavement layers were continuous, the maximum strain of the waterproof bonding layer with the “rubber asphalt + protective plate” structure in the transverse and longitudinal directions was the largest. When the waterproof leveling layer was cement concrete, the structure bore a large amount of stress and easily produced cracks, resulting in water damage. High-density water-based asphalt concrete with a low permeability coefficient can reduce the interlayer shear stress and effectively ensure the interlayer bonding effect. On this basis, the following bridge deck pavement structure was proposed: waterproof system + multifunctional waterproof layer + load-bearing structure layer + surface functional layer.

Valuable Clues for DCNN-Based Landslide Detection from a Comparative Assessment in the Wenchuan Earthquake Area

Landslide inventories could provide fundamental data for analyzing the causative factors and deformation mechanisms of landslide events. Considering that it is still hard to detect landslides automatically from remote sensing images, endeavors have been carried out to explore the potential of DCNNs on landslide detection, and obtained better performance than shallow machine learning methods. However, there is often confusion as to which structure, layer number, and sample size are better for a project. To fill this gap, this study conducted a comparative test on typical models for landside detection in the Wenchuan earthquake area, where about 200,000 secondary landslides were available. Multiple structures and layer numbers, including VGG16, VGG19, ResNet50, ResNet101, DenseNet120, DenseNet201, UNet−, UNet+, and ResUNet were investigated with different sample numbers (100, 1000, and 10,000). Results indicate that VGG models have the highest precision (about 0.9) but the lowest recall (below 0.76); ResNet models display the lowest precision (below 0.86) and a high recall (about 0.85); DenseNet models obtain moderate precision (below 0.88) and recall (about 0.8); while UNet+ also achieves moderate precision (0.8) and recall (0.84). Generally, a larger sample set can lead to better performance for VGG, ResNet, and DenseNet, and deeper layers could improve the detection results for ResNet and DenseNet. This study provides valuable clues for designing models’ type, layers, and sample set, based on tests with a large number of samples.

Calculation of Pavement Engineering Quantities of Mountainous Highway in Feasibility Study Stage

The reasonable estimation of the number of pavement works in the feasibility study stage of highway engineering construction project is one of the basis for the preparation of investment estimation. The selection of pavement structure layer and the calculation of thickness, the calculation of different terrain and pavement area is the main content of highway pavement quantity calculation in mountainous and hilly area. It is of great significance to select the correct calculation method according to different geological conditions. Through 10 engineering cases analysis, the paper analyzes the thickness and area calculation of the pavement structure of the mountain road. It is concluded that the pavement structure layer can be in the form of subbase + base + seal + surface layer. The influence of shoulder, subgrade retaining wall and middle separation zone should be considered in the calculation of pavement area.

Analysis on cracking of structure layer of cement stabilized graded macadam

Because of its strong bearing capacity, good stability and easy control of construction technology, cement stabilized graded macadam was widely used in highway pavement structure. In order to solve its characteristics of easy cracking, relevant researchers have carried out systematic studies on it, but such studies did not involve the large volume and large scope of the structural layer, and only carried out research on the specimen and small scope. Based on engineering project, the influence of dust content and cement content on the cracking was studied by adjusting the parameters and paving the test section during the production process. At the same time, the cracks in the project were counted, and the influences of exposure time, structural level, traffic load and construction level on the cracks in the cement stabilized graded macadam were analyzed. The relationship between crack spacing and exposure time is established, and through comparative analysis, it is found that construction level is the most important factor affecting crack spacing.

Ecological Engineering Trench Inspection and Foundation Reinforcement in the New Era

The structure layer of geocell reinforced with macadam, as well as effectiveness and practicality of such a method in foundation reinforcement during work progress of civil engineering is studied in this paper. Basic theory and method about foundation reinforcement structure applied in work process of civil engineering have been studied. Physical model of experimental tank built by loaded plates has been established. Experiments have been conducted on the loaded-plate tank for geocells in different specification and filler in the geocell to determine the relationship between loads at various of structure layers and longitudinal travel. Experimental results showed that structure layer of geocell reinforced with macadam could improve vertical deformation in a better way, whose efficiency became smaller along with weld spacing of geocell getting larger within a certain range. Besides, specification of the filler also imposed effects onto the reinforcement efficiency, where filler with larger particle diameter brought about better reinforcement effects. The experimental results demonstrated rationality and effectiveness of structure layer of geocell reinforced with macadam and provided staff members responsible for civil engineering construction with reference on selecting the foundation reinforcement scheme.