Research on setting method of fatigue warning sign on desert expressway based on driver's heart and myoelectric index.

Drivers are more likely to feel fatigue when driving on the desert highway due to its single line, monotonous road side landscape, and small traffic volume, etc., so the method of setting fatigue warning signs on desert highway should be studied for. In this paper, field investigation and field test are carried out on the section of Uma Expressway crossing Tengger Desert, and the same road scene and line shape as the actual one are constructed by using uc-win road. Driving simulation experiments were carried out by using driving simulation cabin, collecting heart and muscle electric indexes and analyzing fatigue characteristic law. On this basis, simulation experiments of different fatigue warning signs and stimulation intervals were carried out in multiple groups, and the pattern of cardiac and electromyographic indexes and the interaction law were analyzed based on the artifact correction method after denoising the measured data, so that the optimal setting method was obtained according to the stimulation effect. Based on the artifact correction method, the measured data were de-noised and analyzed the changes of ECG and EMG indexes and the interaction law, and the best setting method was obtained according to the stimulation effect. Finally, the fatigue level was classified based on the cohesive hierarchical system cluster analysis method to verify the rationality of the fatigue warning sign setting scheme. The results show that the driver's psychological fatigue and physiological fatigue both show obvious fluctuation growth, and the growth trend exists in four stages, namely, smooth fluctuation (0-30min), initial fatigue (35-85min), adjustment stage (85-160min), and severe fatigue (after 160min), and psychological fatigue is earlier than physiological fatigue, and the driver's regulation effect on physiological fatigue is better than psychological fatigue. Analysis of the psychological indexes of the four groups of traffic signs shows that the fatigue warning signs with black characters on a white background and set at an interval of 60-80 km have the most obvious effect on driver stimulation in a desert highway with a design speed of 80-100 km/h.

Analysis of the impact of expressway construction on soil moisture in road areas.

To reveal the effect pattern of expressways on regional soil moisture, in this study, using trend analysis and buffer zone analysis methods, the data of VSWI (vegetation supply water index) in central Zhejiang Province from 2005 to 2016 were extracted from landsat7 satellite data using a single window algorithm, and spatial analysis was used to investigate the law of its differentiation. The results show that the multi-year average is 0.01879, between 0.01035-0.02774, showing a gentle decreasing trend, and there are obvious regional variations in space. We found that the impact of the new expressway and interchange on the VSWI in the buffer zone lasted for more than two years, and the VSWI increased in space farther away from the road, and this trend returned to normal at 8 km. Finally, the development patterns of the VSWI in the buffer zone of the newly established expressway and the interchange are approximately the same.

Analysis of the driving role and impact of road construction on carbon stock.

Road construction will have a large impact on the ecosystem in the road area, and carbon stock, as an important indicator to measure the scale and quantity of primary productivity of the ecosystem, will also change, but the specific pattern is not clear. It is important to study the impact of road construction on carbon stock for regional ecosystem protection and sustainable economic and social development. Based on the InVEST model, this paper quantifies the spatial and temporal changes of carbon stocks in Jinhua, Zhejiang Province, from 2002 to 2017, using remote sensing image classification data land cover types as model driving data, geodetector, trend analysis, and buffer zone analysis methods, explores the driving effect of road construction on carbon stocks, and analyzes the spatial and temporal impacts of road construction on carbon stocks within the buffer zone. Results indicate that the total carbon stock in the Jinhua area showed a decreasing trend during the 16 years, decreasing by about 8.58 × 106 t. The spatial changes in the areas with higher carbon stocks were not significant. The explanatory power of road network density on carbon stock reaches 37%, and the anisotropic effect of road construction on carbon stock is strong and had a significant driving effect on carbon storage reduction. The new highway construction will accelerate the rate of carbon stock decline in the buffer zone, and the spatial situation is generally "the farther away from the highway, the higher the carbon stock."

Three-dimensional characterization and calculation of highway space visual perception.

To quantify the impact of three-dimensional highway spatial characteristics on drivers' visual perception, this study analyzes the measurement points of highway spatial visual perception from the perspectives of spatial visual depression and spatial visual continuity based on spatial perception theory. Based on the hemispherical field of view, a spatial enclosure calculation method improved by "Distance/Height value" is proposed. A three-dimensional quantification model of the build-to-line ratio, including the vertical direction, was established using the relative relationship between the maximum section plane and the road area. Finally, a 3D real-scene model of the demonstration highway section was established, the proposed three-dimensional quantization method of visual perception of highway space was applied, and the road area landscape construction and promotion strategy is proposed based on the quantitative calculation results. The results show that: the overall landscape space of the highway section is undulating and that there is a lack of visual continuity. It is advisable to plant an appropriate amount of vegetation on the side of the road at 0 m-250 m and 500 m-700 m of the road section to reduce the fluctuation of its enclosure and enhance its spatial continuity. The improved quantitative results of the spatial enclosure degree and the three-dimensional build-to-line ratio can well characterize the spatial visual depression and the spatial visual continuity and can provide a basis and support for road space reorganization and the improvement of landscape construction.

Simulation analysis of the effect of single-chamber double-line pipe jacking through different soil materials on surface uplift and subsidence.

This article is based on the relocation project of the 330 kV overhead line in Xi'an, China. In this paper, the soil settlement under different jacking depths was calculated by using the modified Peck's formula. Meanwhile, by modeling in ABAQUS, the jacking process of a single-chamber double-line large diameter pipeline under different soil conditions was simulated, and the ground deformation data under the different simulated working conditions were obtained. The results of the two methods were compared with the construction monitoring results, and it was found that the finite element simulation results were closer to the actual results. The control variable method was used in the analysis of the surface soil deformation law to analyze the effect of different soil parameters and pipe jacking depths on surface soil deformation. Finally, the best soil conditions applicable to single-chamber double-line large diameter pipe jacking construction were obtained through comparative analysis. The results show that (1) when using double-line construction, the maximum surface settlement under different soil conditions is located 11-15 m from the centerline of the soil above the pipeline, the minimum settlement location is inside the isolation pile, and with the increase in jacking distance, the settlement at the same section of the surface will gradually decrease and finally produce a small uplift. (2) In the first jacking, the settlement of powder clay is the largest, and the maximum settlement points in the surface section are more distributed. The maximum settlement value is approximately 11.66 mm. The settlement of powder soil is the smallest but produces a certain uplift deformation, and its maximum settlement is more concentrated in the surface section. After the comparison of deformation and soil parameters, loess-like soil is more suitable for single-compartment double-line large diameter pipe jacking construction. (3) When the top pipe burial depth changes, the greater the burial depth is, the smaller the settlement but the greater the lateral influence range. In the soil parameters, the modulus of elasticity only changes 3 MPa, and the settlement change value is approximately 5 mm. By changing the parameters, it can be obtained that the larger the modulus of elasticity of the soil is, the smaller its deformation. The larger the internal friction angle of the soil is, the smaller its deformation, but the maximum value of settlement change is only 1.7 mm, which means that the change in the internal friction angle has little effect on the soil deformation.