Applied Mechanics and Materials Vols. 97-98

Abstract: Stochastic User Equilibrium (SUE) model is equivalent to the problem of Stochastic User Equilibrium, and the solution is unique, so SUE model could be applied to traffic diverging during highway expanding construction. In this paper, SUE model is used with the expanding construction of Tongji highway(G010). Firstly transverse interference and parameters of travel time are adjusted according to the actual situation. And then the linear growth rule is used to predict the current theory traffic, based on which we use SUE model to divert the traffic in Tongji highway(G010) during expanding construction. Through the comparison between the calculation results and the actual traffic, we have validated the reliability of the calculation results and the rationality of the model.

Abstract: One of the main factors that influence the analytic results of slope stability is the determining of mechanical parameters. When the least square method is adopted as the method for determining the rock shear strength parameters, its precondition that the observation errors exist only in one observation variable is always being neglected. By analysis, the calculating of shear strength parameters is divided into three kind of situations, and a new approach to calculate the shear strength parameters is obtained according to the fact that the quadratic sum of distance between line and points in minimum, and the calculating formulae and applying scopes of three different calculating methods are also put forward. A calculating case shows that there are obvious differences among different calculating methods for determining the strength parameters, and it is necessary to select the calculating method based on the observation errors.

Abstract: To study the traffic characteristic and axles load spectra of Jaozhou bay expressway, WIM data was collected, axle configuration and vehicles classification was determined. The characteristic of truck traffic monthly distribution and the truck hourly distribution was studied and axle load spectra for major tuck class groups were developed. The results show that there were more than 22 truck types running on the expressway, the peaks of truck traffic monthly distribution was in December and the rush hour of the hourly distribution was at noon. All major axles had a bimodal pattern of load spectra.

Abstract: This study is focused on the heavy duty sleeper using steel fiber reinforced concrete (SFRC) material to substitute wooden material and on the analysis of the performance of such sleeper. The purpose is mainly to develop heavy-duty prestressed concrete sleeper (HPCS) with high strength and good ductility, and to meet the needs of heavy load for the railroad engineering. The results show that all the properties of designed SFRC conform to design requirement and by using pozzolanic materials, steel fiber and low water content as well as cement content can increase strength, toughness and durability of concrete. The ultimate flexural load of HPCS is 3 times higher than wooden sleeper (WS), and after 3,000,000 cycles repeat loading it shows no failure. This implies that HPCS has better service life than WS and can reduce life cycle cost as replace WS.

Abstract: As a lightweight, fast, airtight, flexible foundation pit supporting structure, lasson steel sheet pile has obvious advantages of short-cycle and low-cost during the construction of double track railway abutment. However, the influence of insertion and extraction of steel sheet pile to original lines is also very big. Therefore, timely backfill grouting, settlement displacement observation and propermaintenance are needed.

Abstract: According to “The Classification Criteria for Casualty Accidents of Enterprise Staff and Workers", the paper statistic and analyzed crew labor accidents occurred in a large state-owned shipping company in recent years, put forward on how to prevent the occurrence of such labor accidents from the angle of management，pointed out management measures preventing crew labor injury accidents occurred. And it included: seeing the crew labor safety as a systematic engineering, and carrying out security research on the systematic engineering according to security theory of it; setting up crew occupational health and safety management system and providing a healthy, hygienic and safe workplace for them; fully implement of the basic principle of safety at the process of production activity on board, attaching great importance to the five elements of crew labor safety; carrying risk identification on board about labor security, drawing up risk control measures about crew labor safety; instituting corresponding safety rules and regulations about crew labor for main operating activities on board; strengthening the safety education of crew working; establishing labor safety supervision organization, strengthening ship safety supervisor’s responsibility in term of crew labor safety; doing better for management of organization and supervision of on-scene work; carrying out human-based management on board; investigating and analyzing labor safety injury accidents that had occurred, drawing lessons from the accident to avoid similar incidents from happening again and so on.

Abstract: Iron ore tailings as a kind of waste products after ore dressing is one of the major industrial solid wastes. Iron ore tailings not only cover huge land and pollute environment, but also give rise to security risks. The comprehensive utilization of iron ore tailings need to be studied systematically. According to the method in Test Methods of Materials Stabilized with Inorganic Binders for Highway Engineering, the technical performances of cement stabilized iron ore tailing gravel in highway application were studied by systemic experiments in this paper. These include the strength, modulus, and frost resistance property, water stability. And the influencing factors of the mixture strength were analyzed, too. The results show that the mixture of cement stabilized iron ore tailing gravel has higher strength and modulus, good frost resistance property and water stability. The technical performances of cement stabilized iron tailing gravel conform to the current specification, so it can be used as sub-base course or base course material.

Abstract: In order to solve the snowing and anti-icing problems, the electric heating asphalt concrete program was proposed. Conductive asphalt concrete samples, with copper mesh electrodes, with its size 20cm × 10cm were made, which was tested by three kinds of voltage heating temperature, and using natural snow to verify the hot performance. Experiments showed that the different points on surface have the different heating performances. When voltages are respectively in 12V, 24V, 36V, the temperature are at the range of 14.6~16°C, 11.7~29.6°C, 15~55°C. Natural snow melting experiments outside showed that the conductive asphalt concrete has a good effect, which becomes significant the sample is keeping with the power for 20 ~ 40 min. With time going on, the snow tends to disappearing completely, and the temperature of snow sample is always lower than the ambient temperature.

Abstract: Despite of the fact that the traffic control zone for maintenance work (work zone) has been recognized as one of major priorities to guarantee the traffic safety, only one conventional posted speed limit (PSL) strategy is applied into the organization and management. This article presents the strategy of the variable speed limit (VSL) on highway work zones that brings about gradual deceleration and low speed variance. To evaluate the safety of the proposed VSL strategy, this study uses the microscopic simulation software VISSM to estimate the traffic flow and adopt transversal and longitudinal coefficients of safety (MSDE and cv) to compare the different speed limit strategies. The results of simulation and analysis confirm that VSL yield a substantial decrease the traffic turbulence caused by speed limit and increase the traffic safety throughout work zones.

Abstract: To study the reserve capacity of city road network under ice and snow condition，the upper programming model was build on the basis of travelers’ demands on level of service, which was incarnated on capacity of links, and travel time reliability, while user equilibrium (UE) was set up in the lower programming model. Then, sensitivity analysis was applied to solve the bi-level programming model under ice and snow condition. At last, one simulation network example was given to demonstrate the practicality of the given model, and the result showed that the ice and snow condition and the travelers’ demands on level of service had great impact on the road network reserve capacity. The methodology is useful and applicable to evaluate road network under ice and snow condition and lays the foundation for capacity reliability.