| With the rapid development of China’s railway, the train operating speed and axle load are improved gradually, embankment retaining structures, especially the studies of whether the design of the shoulder retaining structures takes the impact of dynamic load trains into consideration are worth studying. Combined with the construction of the central south Shanxi railway channel, the author selects typical gravity shoulder retaining wall worksite and carries out static and dynamic mechanics field tests of embankment and the back part of the retaining wall, makes the analysis of the data of 76 test trains by using classical theory to calculate and analyze the static and dynamic soil pressure in of wall back and finally discusses the calculation, size and distribution of dynamic soil pressure of the back of gravity road shoulder retaining wall of heavy haul railways. The main contents and conclusions are summarized as follows:(1) The central south Shanxi railway channel DK551+859.62～DK551+877.00 is chosen as the test section. The routine laboratory soil test section of fill of roadbed segment is carried out and the basic physical-mechanical indices are obtained.(2) Combined with gravity road shoulder retaining wall construction of filed worksite, the author puts forward reasonable test methods and test programs of soil pressure of the back of gravity road shoulder retaining wall. The dynamic soil pressure box of the particular positions between embankment and the back part of the retaining wall, static soil pressure box, vibration displacement meter, vibration velocity meter, vibration accelerometers as well as other sensors are buried on the spot.(3)Having ehicle dynamic test on embankment and gravity retaining wall on condition of different velocity-stage and train formation, collected filed data of 76 test trains and five kilometers included at different speed level and analyzed the earth pressure, vibration displacement, vibration velocity, vibration accelerated speed, dynamic response range and the impact of train speed. (when the train travels at speed of 60-100km/h, the average dynamic stress of embankment surface is 132-156kPa, vibration displacement is 0.31～0.50mm, vibration velocity is 5.8-9.1 mm/s, vibration accelerated speed is 1.98～3.39 m/s2. Average earth pressure of wall is 0.09～3.81kPa, vibration displacement is0.005-0.013mm, vibration velocity is 0.27～0.62 mm/s, vibration accelerated speed is 0.04～0.11 m/s2). Analysis shows that the speed of train has minor influence on vibration displacement, especially the top of wall. Otherwise vibration velocity and vibration acceleratedspeed have linear relationship with that. Attenuation of vertical dynamic response of sleeper via the embankment surface to the top of the wall is clear which has became very small influenced by the load of the train when it passes to top of the wall.(4) Through elastic theory "Boussinesq solution" as well as four axis axle load distribution, the author calculates the dynamic soil pressure of the back part of retaining wall and compared results of the spot. The author analyses train speed, train load quantity and train pulling quality which make impact of dynamic soil pressure of the back part of the retaining wall, and discusses of the unevenness of the dynamic soil pressure along the channel length, and the distribution and calculations of dynamic soil pressure under train load. The analysis shows that the soil pressure of longitudinal wall back is in uneven distribution in the range between two adjacent four-axis load. The farther away from the axis load, the smaller soil pressure of the wall back. When double loading works, the heavy trucks of Ⅱ line has a certain influence on the retaining wall and vice versa. The dynamic soil pressure of wall back increases with the increase of train axle load and speed. The increase of train pulling quality has little influence on the soil pressure of wall back in short time periods. |
