Advanced Materials Research Vols. 1065-1069

Abstract: Direct shear tests by laboratory to study the red sandstone aggregate mixture under the action of water intensity decay law, got red sandstone aggregate mixture, fill high subgrade compaction experimental study, tests showed that dynamic compaction compacted earth and rock mix fill embankment feasible, Rayleigh Wave test results show that the effect of dynamic compaction compaction good.

Abstract: Reinforcement with longitudinal and cross beams is one of the frequently employed methods for reinforcement of railway. Regarding the special case of box culvert going rightly under the railway switch, this paper conducts feasibility analysis of the reinforcement method by numerical simulation with the assistance of finite element software. It offers important theoretical guidance for similar railway switch reinforcement projects.

Abstract: In order to meet the requirements of the use of aircraft, improve mechanical properties of pavement concrete, the steel fiber mixed basalt hybrid fiber reinforced concrete technical route was proposed, by using the method of orthogonal experiment, steel fiber with 1.2%,1.5%,1.8% these 3 volume fraction and basalt fiber in 0.05%,0.1%,0.15% these 3 volume fraction mixed, research the rules of its effect on the performance of airport pavement concrete.

Abstract: This paper mainly studies the index system and application method of highway alignment design conformance verification. Based on the actual conditions of vehicle running on the plane curve, straight section and curved slope combination section, the speed verification model formula is proposed. The results can be referred by the engineering and technical personnel in the design of highway engineering proposal in plain terrain.

Abstract: Much research work about tunnel fire focused on a single temperature field of tunnel lining structures, and ignored the thermoelastic coupling effects in concrete pavement. Normally, the simplified heating curve sush as the environment temperature curve was adopted, therefore, a mathematical model of the thermoelastic coupling field was established based on finite element method, and the solving algorithm using finite difference method was proposed to analyze tunnel fire problem. Moreover, the results by the above method was also compared to those without considering thermoelastic coupling effects. In addition, the influences of material parameters, such as heat conductivity coefficient, specific heat capacity, elastic modulus and so on, were studied respectively to give the sensitivity of the problem. Through this research, the following conclusions were obtained: the thermoelastic coupling has a certain impact on the temperature field, and it appears the hysteresis phenomenon along the depth direction. Furthermore, when considering the thermoelastic coupling, the temperature of tunnel pavement under fire decreases with the increment of each material parameter respectively, i.e. all the material parameters have similar effects on the temperature field.

Abstract: A laboratory ice-breaking test was employed for an asphalt pavement with different dosage of rubber crumbs to study the ice-breaking effects by a self-developed road ice-breaking simulating tester. The mesoscopic model of rubber crumbs asphalt pavement structure with 2mm ice layer was established using the discrete element method, and the mesoscopic responses of rubber crumbs asphalt pavement structure were simulated under the standard axle loading. The results indicate that the weighted average rebound amounts of BPN with 3% rubber crumbs increase by 11.45% and 1.46%, respectively, compared with that of 2% and 4% rubber crumbs. The weighted average rebound rates of BPN with 3% rubber crumbs increase by 11.22% and 3.06%, respectively, compared with that of 2% and 4% rubber crumbs. For 3% rubber crumbs, the maximum contact forces in this pavement structure are the biggest which are 2.705×10³N before loading and 2.706×10³N after loading, and its strain energy is 1.34 times that of 2% rubber crumbs, 1.25 times that of 4% rubber crumbs. In addition, the results of numerical simulation are consistent with the results laboratory test.

Abstract: On the basis of the GPR method principle, data acquisition and processing, this paper mainly discusses two-dimensional GPR profiles and three-dimensional GPR images through GPR detection example about the voids of highway bridge head subgrade and the grouting distribution. Three-dimensional images accurately and directly evaluate the grouting effect. Thus it illustrates that GPR used to detect the voids of highway bridge head roadbed and the grouting distribution is an effective method.

Abstract: The growth rates of stress in the hexagon , square and octagon cement blocks under different vehicle loads were analyzed using the finite element method (FEM). The growth rate of bottom layer stress of the hexagon is the smallest among them when vehicle loads increase. Under the 400kN loads, the growth rate of bottom layer stress of the hexagon significantly reduced as the thickness increase. When its thickness is up to 28cm,the bottom layer stress is the smallest among the three kinds of shapes. The results show that the hexagon cement block is the most suitable for overload vehicles obviously when compared to the square and octagon cement block. Therefore, hexagon cement block is the most suitable for the roads which are always under heavy and overload vehicles .

Abstract: An analysis based on questionnaire was conducted to study the technology of highway subgrade disaster prevention and maintenance. A serial of questions related to the subgrade maintenance management, maintenance technique, and existing problems were consulted with 39 experts from local highway administrations, highway management and maintenance centers, highway construction Co. Ltd, road maintenance companies in Guangdong Province. The investigation and analysis results provide a valuable scientific reference for further formulating “the technical specification of the highway subgrade maintenance”.

Abstract: Loose deposit is widely distributed along the south route of Sichuan-Tibet highway (in Tibet). Slope disasters often occur because of the broken loose deposit and the low grade highway without complete safeguards for the slope. The paper proposed the integrated treatment technology with micro steel pipe piles and soil nailing frame beam and its work theory and structure design. The slope stability was simulated numerically with Midas-GTS on typical sections to verify the effectiveness of the technology. During simulation, the stable coefficient of slope with or without the integrated treatment technology was calculated. Results showed that the technology with micro steel pipe piles and soil nailing frame beam can improve the stability of loose deposit cutting slopes greatly.