Li Y.,Beijing Jiaotong University |
Wang L.,Beijing Jiaotong University |
Ding G.,Beijing institute of Geology |
Ge B.,Beijing Jiaotong University |
Li D.,Beijing Jiaotong University
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2012
Bridge-subgrade transition section is a weak link between roadbed and bridges or culverts in existing heavy haul railway. To detect and evaluate the roadbed bearing capacity is the key to ensure the smooth of railway and comfort of moving train. In this article, Number 170 Bridge's bridge-subgrade transition section of Shuo-Huang railway is detected by K 30 plate loading test, light dynamic penetration test and laboratory test. The results indicate that 1, Foundation coefficient K 30 can intuitively characterize the subgrade stiffness and bearing capacity. The reinforced roadbed's foundation coefficient K 30 has increased from 15% to 40% in different positions of bridge-subgrade transition section. 2, There is good correlation between foundation coefficient K 30 and Light Dynamic Penetration N 10. Compaction coefficient and foundation coefficient K 30 has no correlation. 3, The bridge-subgrade transition section detecting of existing heavy haul railway should do enough light dynamic penetration test, and complementary with foundation coefficient K 30 standard. It has important significance for improving the detection efficiency and reducing detection cost and the disturbance of detection to existing railway operation.
Liu S.C.,Chinese Research Institute of Highway |
Ding G.L.,Beijing institute of Geology |
Chen G.,Xinjiang Beixin Road and Bridge Group Co.
Applied Mechanics and Materials | Year: 2013
This project is aiming at the high water content clay in seasonally frozen ground region, based on the expressway program in Heilongjiang province. By applying laboratory test, field test, field monitoring and theoretical analysis, research has been proposed to understand the deformation law and long-term performance of high water content clay subgrade in freeze-thaw condition. From the comparison test of soil and soil treated with lime, road properties of high water content clay has been found out. It is a very necessary and effective method using lime to treat the high water content clay in subgrade construction. Laboratory freeze-thaw experiments uncover the strength weakening law of soil treated with lime. With theoretical analysis and numerical calculation, the interaction between clayey subgrade and pavement structure layer under effect of vehicle dynamic load is analyzed. According to this result, control standards of subgrade frost heave in seasonally frozen ground region and subgrade resilience modulus in spring have been proposed. © (2013) Trans Tech Publications, Switzerland.
Ding G.,Beijing institute of Geology
Advanced Materials Research | Year: 2012
Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.
Han M.-D.,Beijing University of Chemical Technology |
Han C.-Y.,Beijing University of Chemical Technology |
Zhang L.-D.,Beijing University of Chemical Technology |
Qi G.,Beijing institute of Geology
Advanced Materials Research | Year: 2011
An Environmental friendly sand-fixing agent of water-borne polymer(graft copolymer of starch with acrylic acid and acrylamide)was synthesized. The influences of monomer dosage ratio, initiator dosage, the temperature and reaction time on the properties were discussed. The structure, thermal stability and morphology was characterized by IR spectra, TG-DTA and SEM, respectively. With the sand soil as research object, the tolerance of high temperature and compressive strength of the sand-fixing agent were studied preliminarily. The results show that when the mass ratio of acrylic acid to acrylamide is 15:10, the mass content of initiator is 4%, the reaction temperature is 50°C and time is 6h, the product has a good sand fixation performance for practical application. © (2011) Trans Tech Publications, Switzerland.
Liu S.,Chinese Research Institute of Highway |
Ding G.,Beijing institute of Geology
Advances in Environmental Vibration - Proceedings of the 5th International Symposium on Environmental Vibration, ISEV 2011 | Year: 2011
For roadbed and the transition section easily lead to problems of high-speed railway, dynamic response tests of the high embankment, low embankments, cuttings, half cutting roadbed and filling and excavation of transition section between bridge and subgrade are earned out when high-speed train passes. Through analyzing large amounts of data, the conclusions are made that dynamic displacement changes of different forms of embankment are not obvious as the train speed, and acceleration increase significantly with the continuous improvement of train speed. Dynamic response of the cut is greater than that of the high embankment and half-filled and hah-dug embankment, and dynamic response of low embankment is the minimum. In addition, the dynamic response of filling transition section is significantly larger than the cut transition section. The main reason is that the construction quality of the filling transition section is difficult to guarantee test by ground penetrating radar. Moreover, it is also found that the dynamic response of transition section increases with the train speed improvement. And in a certain distance to the abutment which is 31m in this article, the dynamic response of the transition section decreases with the increase of the distance from bridge abutment.