Advanced Materials Research Vols. 671-674

Abstract: This paper uses the FLAC software to simulate self-settlement of high embankment. Analysis and discussion on the simulation results are performed. The final results indicate that the self-settlement of high embankment can't be ignored, the maximum settlement within the embankment occurs at about （1/3～1/2）embankment height. This conclusion has a reference value for guiding the actual construction.

Abstract: The ATB-25 mixture is optimized design base on the Bailey method. The skeleton embeded crowded structure of ATB-25 is better than that of AC-25 through analyzing the Bailey parameters, and the value of high temperature stability is 17.5% higher than that of AC-25, their water resistance are similar. The ATB-25 mixture is more suitable as pavement base materials. The proposed gradations belong to embedded crowed-solid structure which is verified by the calculated Bailey parameters, and the high temperature stability and water stability can be ensured. Combining with the highway pavement engineering project of Qujiang to Nanxiong, It is researched on the design of the mix proportion for asphalt treated base ATB-25 in the paper, and the suitable gradation design scheme is put out for the design and construction of highway pavement in high temperature and heavy duty area. The high temperature stability and water stability of ATB-25 which is designed based on the Bailey method can meet the requirements, and pavement performance can meet the design requirements.

Abstract: By the scanning electron microscopy and experimental study, curing mechanism of the ZL-1 curing agent was studied in this paper, and the curing mechanism of the traditional curing materials in the soil clay was also analyzed. The study found that ZL-1 has a good curing effect on curing agent to the lime and clay mixture ，cement and clay mixture, and has greatly improved water stability, durability. And the best mix proportion was given.

Abstract: It always is a technical problem about the drying shrinkage cracking of mortar plastering layer and concrete surface layer of building wall in construction field. The influencing factors of cracking have regional climate characteristics, building structures, raw materials, construction standards etc. Analyzed the cracking principle of mortar and concrete pavement in dry areas of North China, and developed the complex additives having five kinds of performances: efficient water conservation, compensated shrinkage, fiber reinforcement, self-repair cracks in the matrix and polymers toughening, which is used to mortar and concrete to alleviate drying shrinkage cracking. The series of processes and product performances of the complex additives has been introduced in this paper.

Abstract: Foundation treatment is necessary when the construction is built on soft ground; Reinforcing is superior to many other methods when embankment is built on soft ground. This paper adopts slide block balance analysis of the composite foundation bearing capacity consisting of the horizontal reinforced and discrete material pile, while considering the level friction resistance from the reinforcement and ground on the foundation bearing capacity influence. and it is applied to practical engineering. The results show that the method is feasible.

Abstract: This paper draws on the successful experience from domestic and abroad researches, testing repeatedly of powder subgrade with load triaxial tests, analyzing the relationship between the subgrade soil resilient modulus, deviatoric stress, water content and degree of compaction. At the same time, conducting corresponded roadbed soil resilient modulus forecast model, and qualifying its correctness of test data model.

Abstract: The false joint of bearing layer is one of the engineering measures to guide the crack development, in unit double-block ballastless track, it’s usually designed in staggered arrangement with expansion joint of track concrete layer. According to the actual situation, this seam layout is unreasonable. So the thorough study on the design scheme of false joint is presented. The distribution of stress in bearing layer, under temperature load, is first computed, the result shows the bearing layer under expansion joint is more prone to cracking than that at other positions. Then compares the theoretical response got from two different kinds of seam layout under train load. Finally, the false joint design is optimized on the basis of project experience. A conclusion is drawn as follows: the false joint and the expansion joint ought to be aligned in general case, and the false joint setting in the middle of the unit should be canceled. But, when the railway is built on a unstable the lower foundation or in a area with plenty of rainfall, the false joint design ought to adopt the optimized arrangement of break joint.

Abstract: Due to the impact of train load, temperature force and foundation deformation, high-speed railway track disease becomes more and more serious. The existing track maintenance mode can’t meet the requirement of the modern tack structure. Track quality state and its evaluation ways was analyzed, and a method to predict track maintenance cycle based on the track quality deterioration rule was put forward. The track maintenance cycle could be forecasted scientifically by TQI deterioration rule, which is of great significance to high-speed railway maintenance in the future.

Abstract: Dynamic response tests were developed on CRTS Ⅱslab ballastless track subgrade of Beijing-Tianjin intercity high-speed railway.The relationship between vibration response and the speed, the vertical and horizontal distribution law of vibration response along lines, the effect of axle load on vibration response were researched.Test results are as follows: The vibration displacement of the extreme value caused by a single axle load is not obvious;Train axle load significantly affects the vibration response;Despite the vertical connection between two track slab, but the end of track slab vibration response is still significantly greater than the middle and the vertical multi-storey line structure vibration response decreases rapidly along the depth;Speed has no significant effect on the vibration displacement, but vibration acceleration and vibration velocity is sensitive to speed.

Abstract: In recent years, the phenomenon of vehicle overload in highway transportation is more and more serious. The three-dimensional dynamic FEM was adopted and a three-dimensional simulative model for asphalt pavement with subgrade based on cross-anisotropy under moving load was established by the large-scale finite element analysis software ABAQUS. The response of the stress in the pavement structure was got by using ABAQUS/Standard code. During deceleration, The simulation analysis results under the rated load were compared with those under the different overload ratio. The results show that, under moving load, the surface course of pavement is mainly in three dimension compressive stress state. The horizontal load caused by deceleration has a remarkable effect on the longitudinal stress and the horizontal shearing stress. The stress of the pavement structure under overload is much greater than that caused by the rated load. And the greater the overload ratio, the greater the deviation between them.