Applied Mechanics and Materials Vols. 587-589

Abstract: Through a highway asphalt pavement condition survey and analysis of the main causes of disease, through material selection and grading design, the design of the treatment structure, class structure using the drainage layer, exclude the internal structure of the water surface; focused on solving the asphalt pavement water damage issues, effectively extending the life of the highway.

Abstract: This paper uses Sidoroff damage model to research asphalt concrete (AC) trabecular tensile damage. Damage factor D is used to estimate the damage degree of AC. And the optimum position of grid overlay is obtained. In order to simulate the trabecula without grid and grid in different position, an AC trabecular bending test model is established in ABAQUS. From the analysis of AC damage, it can retard AC damage efficiently when grid overlay is located on the bottom of trabecula. The results of the research can offer the reference of controlling on damage cracking in the process of design and construction of asphalt pavement.

Abstract: Two experimental areas in a highway soft soil ground treatment project in Guangdong Province were designed to investigate the improvement mechanism of geogrid-reinforced and pile-supported embankment(GRPS).The experimental results showed: In End-bearing Pile Area,the differential settlement between pile and soil was bigger than that of Floating Pile Area,so the bearing capacity of soil was exerted to a certain extent in Floating Pile Area. The bearing efficacy of soil below the pile cap was little, so the replacement ratio of composite foundation could be calculated according to the pile cap dimension. The load transfer efficacy of the geogrid was better than that of the soil arch. Five kinds of methods were used to evaluate the soil arch in the fill and it was indicated that the results calculated by the BS8006 method and Carlsson method was close to the experimental data which was smaller than results calculated by Hewlett method and Terzaghi method, bigger than Guido method. Through the analysis of the pile-soil stress ratio, the improvement mechanism of the two types of GRPS were revealed.

Abstract: In this paper, on-the-spot measurement of the subgrade vibration induced by rail transit is con-ducted. According to the data, the power spectrum and 1/3 octave band are analyzed. The re-sults show that when the passenger train drives, the vibration level away from centerline of 30-60 m will increase with the vehicle speed. The main frequency of vibration energy decrease from 50-70 Hz to 25-35 Hz and optimal frequency decrease from 57.98 Hz to 31.25Hz. The attenuating speed of high frequency vi-bration is greater than that of low frequency vibration. The attenuating speed of high frequency vi-bration is greater than that of low frequency vibration. The center frequency that greater than 25Hz decay gradually in 1/3 octave band, but the center frequency vibration level changes within the range 1 to 20 Hz is smaller.

Abstract: Through the construction of cement stabilized macadam and lime-fly ash stabilized macadam road, and strain gauges, vertical stress sensors and temperature sensors were laid in the pavement during construction. Pavement structure dynamic stress, strain, deflection and pavement temperature were collected. The correlation between pavement temperature and structural dynamic response was analyzed. The results showed that, tensile strain of semi-rigid base layer was less affected by temperature; structural deflection was great affected by the thickness of semi-rigid base. After a certain number of repeated loads, the delay rate of tensile strain of semi-rigid base layer increased first and then slowly decreased.

Abstract: The simulation experiment of the vehicle action on pavement was carried on. In the progress of the experiment, HZ-MS48 microseismic monitoring system was used to collect microseismic waves. And these microseismic signals were disposed and analyzed. It introduced the scheme and the process of the data collecting experiment. After that, several types of microseismic waveform were compared and discussed. Also shock waves for transmitting characteristic in pavement base were studied. At the same time, taking a typical microseismic event location as a case, the precision of microseismic event location was confirmed, which put forward a new way for monitoring traffic vehicles.

Abstract: The test methods provided by current related "specifications" do not apply to saline soil soft foundation bearing capacity test. Through discussing the limitations of the related specifications and based on the experience on saline soil soft ground capacity test, the paper made some improvements of test on such aspects: conditions of loading and stopping load, determination of the characteristic value of the ground bearing capacity and evaluation, the paper also put forward the saline soil soft ground capacity test method.

Abstract: Graded broken stone has good road performance and it gradually began to adopt in strengthening the domestic old road or the new road design, because it is the repose of aggregate materials ,can effectively prevent the occurrence of reflection cracking and has good bearing capacity. Graded broken stone material has obvious stress dependent characteristics and the stress strain curve is nonlinear variation. Stress state and its place in the structure of pavement layer, layer thickness and modulus of the structure are directly related. Therefore, the paper has analyzed the thickness of each layer in the design of reinforcement structure impacting on the grading macadam stress state.

Abstract: In order to solve the problem of the artificial detection method of rail abrasion ,which is low efficiency, low precision, not easy to store and so on, design and development of rail profile dynamic acquisition system based on LabVIEW, introduced the hardware and software design method. The system take the laser line on the rail surface as the detection object, which is not easily affected by external factors and high measuring accuracy; testing personnel can continuous push the inspection car to check on the track surface, which is high efficiency. The system can realize side abrasion and vertical abrasion of the rail, and calculate the total abrasion. It also can achieve the function of abrasion limit alarm and complete the data storage. It has the vital significance to improve the present situation of the work department, and guarantee the safety of railway system.

Abstract:

A kind of composite precast pavement system made by two composite and staggered layer panel is put forward, the finite element analysis software ANSYS is used to analyze the pavement system, and the calculation result is compared with the result of common precast pavement system. It shows that the proposed pavement system can greatly reduce the surface earth pressure, thus to improve the bearing capacity of pavement, and provide a new pavement structure system for the construction of site temporary road paving.