To research the influence of the contact condition between a semi-rigid base and asphalt surface course on the mechanical responses of the pavement structure and on fatigue life, a typical pavement structure is chosen and a shear spring compliance from the software Bisar 3.0 is used as the evaluation index of the interlayer contact condition to conduct the mechanical response calculation of the pavement structure and to analyze the change law of the stress, strain, and deflection under different contact conditions. and then the fatigue life of the pavement structure is calculated under different contact conditions. The results show that the shear spring compliance can quantitatively characterize by the interlayer contact conditions between the base and surface course. The interlayer conditions have a significant impact on tensile stress and shearing force. When the interlayer contact pattern changes from a continuous state into a sliding state, the growth rate of the tension stress of the bottom of the asphalt layer is 528.25% and growth rate of shear stress is 157.3% while the interlayer conditions have a smaller impact on deflection.

The autogenous shrinkage of pavement concrete with different water to cement ratios are measured in an experimental setup, and these samples' gradation and pore structure characteristics are analyzed by a mercury intrusion method and an optical microscope with the Image Pro-Plus software package. The autogenous shrinkage model of pavement concrete with 0.38-0.44 water to cement ratio is established. The results of the shrinkage mechanism analysis show that pores with a diameter less than 100 nm play a vital role in autogenous shrinkage, varying the water supply volume only changes the number of capillary pores, and varying the cement volume changes the capillary number, the total porosity of the mixture, the average pore diameter, and the pore space factors.

Expansive soils in cut slopes are prone to sliding for a period of time after excavation. They are commonly found during construction in expansive soil subgrade. Their sliding is not directly affected by the height and ratio of the slope. To understand the evolution of their deformation and the consequences of failure to implement effective engineering treatment, the finite difference procedure FLAC is used to analyze the regularity of the excavation process of expansive soil slopes and obtain the displacement, stress, and strain. The safety factor for slope cutting calculated by using the strength reduction method decreases as the slope depth increases, but is still stable after the complication of excavation. In addition, the thermodynamics module of the finite difference procedure FLAC is used to simulate the humidity field of the atmospheric effects for the expansive soil slope and to obtain the variability of the displacements, stresses, and strains of the cut slope after wetting and drying cycles. The numerical simulation results are basically in accordance with field observation results during and after the construction of cut slopes in the Sitang interchange ramp of the Bailong expressway in Guangxi Zhuang Autonomous Region, China. The four stages of evolution of expansive soil cutting slopes are summarized. It is proposed that flexible supporting structure technology should be used.

To cope with the phenomenon of moisture imbalances in subgrades due to excavation, the resistivity of different excavation subgrades (deep excavation section, shallow excavation section, and cut-and-fill transition section) at different vertical depths pre- and post- excavation of blind drains were measured using temperature and resistance sensors laid in test sections of the Zhangjiakou-Zhuozhou expressway project.The moisture migration characteristics in excavation subgrades were analyzed by developing the relation between resistivity and moisture content from laboratory experiments.The analysis results show that (1) the moisture contents in subgrades in late autumn and early spring increases with an increased excavation depth, which is due to the combined effect of the temperature and water supply from excavation slopes; (2) blind drains and the roadbed replacement depth contribute to the suppression of moisture migration in excavation section subgrades, which can improve the work state of the subgrade; (3) summer rainfall significantly influences moisture migration in deep excavation section subgrades and cut-and-fill transition section subgrades; the moisture content in summer significantly increases compared with that in the other seasons; the influence of seasonal factors on moisture migration in deep excavation section subgrades is significantly stronger than that in cut-and-fill transition section subgrades.

The bearing capacity of soils under highway engineering differs from that of soils under the building foundation as a result of different superstructure types and foundation forms. Determining the characteristic value of highway bearing capacity by directly adopting the evaluation method from building codes is conceptually indefensible because such codes do not represent the real bearing capacity of highway foundations. By analyzing the superstructure types and foundation forms of highway subgrade, bridge, culvert, and building, the evaluation methods of highway foundation, bridge, and culvert are determined. Furthermore, a three-level classification system of highway foundations is presented and a highway engineering bearing capacity evaluation system based on Geographical Information Systems (GIS) is established. By using the spatial data management and spatial data analysis platform of GIS and by combining the plate-loading testing data and engineering properties of different soils, the system accomplishes the effective evaluation of the bearing capacity beneath the highway subgrade, bridge, and culvert, and provides a theoretical basis and practical reference for the evaluation of the bearing capacity and the choice of ground improvement in engineering design and construction.

To solve the problem of identification damage in a cantilever retaining wall, a damage identification method for such a wall, based on the flexibility-difference mean curvature, is proposed. The concept of mean curvature in differential geometry is introduced to calculate the flexibility-difference mean curvature. First, the flexibility difference matrix is calculated using the change in the modal flexibility matrix of the before and after damage in the retaining wall, and each column average value of the flexibility difference matrix is used as an element of the modal flexibility-difference column vector. Then, the flexibility-difference mean curvature (FDMC) is obtained using the central difference method, as a new index of damage identification. The result of a numerical simulation of the cantilever retaining wall indicates that (1) the damage location in a retaining wall, single damage or multiple damages, can be detected accurately using FDMC and (2) the unit damage extent can be accurately detected via the relation between the damage extent and the index FDMC with high precision. Further, the effectiveness and advantages of FDMC as compared to the Gauss curvature modal difference are proven.

The finite element software ABAQUS is used to analyze the influence of hinge joint crack on transverse load distribution of prefabricated concrete hollow core slab bridge, including single-side crack and two-side crack. The relationship between hinge joint crack length and load transverse distribution was built by using the Regression Analysis. Equivalent Area Method was adopted to bring out the critical crack length. The paper introduced a correlative method to illustrate single plate phenomenon and suggested the critical hinge joint crack lengthens for prefabricated concrete hollow slab bridge, which provided a technical basis for the quantitative assessment of single plate phenomenon in the technical inspection practice of bridges. In the end, critical crack lengths of hinge joint were determined based on a criterion of the "Single Plate Load Effect", that is, the critical crack length of single-side crack is 100% of the total span length of the bridge, while that of the two-side cracks is 67%. This result will lead to further research on the failure mechanics of prefabricated hollow core concrete slab beam bridges and their retrofit techniques.

The effect of friction at movable supports on the elasto-plastic seismic responses of continuous girder bridges was analyzed on the basis of three aspects including stiffness contribution, friction energy dissipation of the movable supports, and kinetic interaction between the girders and movable piers. Finite element models were established, which considered the friction nonlinearity of the movable supports and the material nonlinearity of the reinforced concrete piers. In addition, nonlinear time history analysis was performed to analyze the effects of friction at the movable supports on the pier bottom curvature, girder displacement, velocity, and acceleration. The results indicated that the frictional effect at movable supports is not always favorable. In some cases, the friction at these points must be considered. For the nonlinear time history analysis, the effect of natural vibration characteristics of the bridge and the response spectrum of the ground should also be considered. For some complicated continuous bridges, particularly those with the heights and stiffness of the fixed and movable piers, the friction at movable supports should be considered in seismic analysis.

When the two excavation faces of a tunnel constructed from both the entrance and exit simultaneously in soft surrounding rock approach, the excavation surface disturbance areas are superimposed,stress and deformation in the surrounding rock become extraordinarily complex, which results in substantial deformation and instability. By combining the study of the surrounding rock stress and displacement caused by both unidirectional and face-to-face excavation in the Shizilong Tunnel, the stability of the tunnel face with two excavation faces approaching one another in a bidirectional construction is analyzed by numerical analysis. It is shown that, with the reduction in the length of the unexcavated soil between the two excavation faces, the plastic zone and deformation significantly increase, and the arching effect gradually weaken, resulting in greatly reduced tunnel stability. When the distance between the two excavation faces is less than the limiting distance, an extended range of the surrounding rock approaches plastic failure, and only effective countermeasures can guarantee the safety of the tunnel construction. Further, bamboo anchor pipe grouting is adopted to reinforce tunnel faces with the initial support strengthened, when those two excavation faces in the construction of the Shizilong Tunnel are approaching. Field implementation indicates that the tunnel is excavated safely.

To protect the environment and to minimize the water pressure on a tunnel lining, the controlled drainage principle is proposed for deep mountain tunnels below high water tables. The mechanical characteristics of tunnel supports and linings with respect to seepage and pressure are studied by using numerical methods and a test model based on the tunnel mechanics and seepage mechanics. The results show that the pressure exerted on primary supports is unrelated to surrounding drainage conditions. The pore water pressure on primary supports diverts to tunnel linings when the drainage system moves from the interface between rock mass and primary supports to the interface between primary supports and tunnel linings, and the primary supports are unloaded and the pressure moves outwards to the rock mass. The water pressure on tunnel linings can be neglected if the ground water can be discharged smoothly. When a tunnel drainage system malfunctions and leads to poor drainage, the flow gradient in the ground decreases, the effective radial stresses decrease, the radial flow of tunnel decreases and the ground deformations decrease.

To evaluate the performance of a traffic signal control system quickly and efficiently, a hardware-in-the-loop simulation system of multi-intersection traffic signal is developed. With the hardware-in-the-loop approach, a simulation model based on the microscopic traffic simulation software is established, and the real-time communication between the simulation software and the traffic signal controllers is achieved, altogether providing a realistic traffic control simulation environment to evaluate the performance of a multi-intersection traffic signal control system. A case study of Zhongguancun East Road along with the corresponding simulation results demonstrates that the hardware-in-the-loop system can evaluate not only the performance of various signal controllers, but also the performance of the traffic signal control system for multi-intersections quickly and efficiently.

The sharp variation of illumination at the entrance and exit of highway tunnels causes difficulty in the visual adaptation of drivers and may even lead to accidents. Therefore, ascertaining the light and dark adaption time is a basic task to promote the safety of tunnel transportation. Took 26 typical tunnels as experimental settings and used the IViewX HED Laptop eye tracker system, the light and dark adaption of drivers in highway tunnels had been experimentally investigated. The relation between pupil area and its variation velocity was presented based on many experimental data and the ratio k of the variation velocity to its critical variation velocity was used to evaluate the visual load in highway tunnels and thus ascertained the visual adaption time, whereby the relation between tunnel length and visual adaptation time was thus obtained. Experimental results indicated that the dark and light adaption time of tunnels was less than 23 s and 13 s for medium and long length tunnels, respectively.

A single release method for four-leg roundabouts is proposed. To completely use the time and space resources of roundabouts from the aspects of adjacent entrances and T-type storage spaces of the circulating lane, two types of optimized single release signal control models for a four-leg roundabout are presented. The coordination of signal phase design on the two types of optimized control models is presented, the phase coordination calculation is described in detail, and the original cycle length model is improved. By comparing the delays of the two optimized signal control models, the applicable conditions for optimized signal control models are discussed. Finally, considering the Tanxi Road/Changhong Road Roundabout in Xiangcheng, Xiangyang, as an example, the effectiveness of the presented optimized control models is evaluated. Simulated results show that the traffic flow at this roundabout is improved when the optimization methods are applied.

To realize real-time and reliable transportation path planning for improving the efficiency of a traveler in a highway transportation network, this paper presents a fast traveler demand clustering algorithm based on simulated annealing particle swarm optimization (SAPSO). First, we apply fast clustering according to the traveler demand obtained by a cooperative vehicle system, and then integrate the results with the planning destination target and traveling vehicle information to realize the optimized highway transportation path. Based on an experiment and comparison results, this method has better performance than two algorithms and has high effectiveness and should increase traveler satisfaction.

This study aims to analyze the theory mechanism behind MFOZ(main functional areas zone) and investigates MFOZ's effect on high ways and transportation. This study adopts the classic theory of increasing returns to scale of regional economies, draws lessons from the experience of world cities' development presented in a World Bank paper, and deconstructs the theory mechanism behind MFOZ and its effect on highways and transportation. MFOZ is a big achievement in spatial planning and territorial development, as through increasing returns to scale, the economic zone will attain more agglomeration and improved area integration. Zones with social and ecological functions through public service equalization will realize regional coordinated development. To respond to MFOZ's requirements, the economic zone should develop and realize transportation integration, while in the limited development zone and prohibited zone, we should realize equal transport service.

IEEE 802.11p, which is a fundamental protocol of dedicated short-range communication in intelligent transportation systems, is evaluated in this work. The relationship of IEEE 802.11p with other protocols in the layered architecture for DSRC, as well as the standard framing process for wireless transmission, is studied. The common problems of the orthogonal frequency division multiplexing vehicular communication system and their solutions, such as channel estimation, carrier frequency offset, and symbol time offset, are analyzed by simulation. Analysis results indicate the acceptable reliability and performance of IEEE 802.11p. Simulation results confirm the viability of the design of related applications.

To cope with the problem that less-than-truckload (LTL) logistics network design for certain origin-destination (OD) flow demands often fails to utilize the network resources in a balanced manner, the characteristics of OD flow uncertainties and network design difficulties are analyzed, and a mixed integer programming model is devised by considering the OD flow uncertainties based on inventory theory. An example study demonstrates that design of a logistics network with OD flow uncertainties based on optimizing the network operation and construction costs, and the network resources utilization ratio comprehensively has a significant improvement in balancing the utilization degree of network resources compared to only considering minimizing the network operation and construction costs. The result contributes to adjustment of the logistics network structure to improve the balancing utilization degree of network resources for uncertain OD flow demands.