Study Of Silt Subgrade Filling Technology In Taizhou Area

Recently, along with the rapid development of Chinese economy, road construction in our country is also booming. However, highway distress, particularly in silt areas, keeps cropping up due to increasing traffic volume and car axle load as well as problems concerning road design and construction. It is widely proved that effective compaction of subgrade helps enlarge road service life. Therefore, effectively compacting subgrade plays a significant role in road construction.Taizhou city, located in the middle and lower reaches of the Yangtze River, abounds in low liquid limit silt. Silt is different from clay and sand and has its unique engineering properties. As silt is characteristic of poor gradation, cohesion and water-retention ability, ideal compaction is hard to achieve by employing conventional compacting technique. So it is significant to study roadbed filling using low liquid limit silt in Taizhou area while ensuring sufficient compactedness. For this purpose, this thesis, focusing on rolling compaction technique of low liquid limit silt, has carried out the following tasks.(1) Laboratory test has been conducted to get the physical properties of silt in Taizhou area like gradation, liquid plastic limit, optimum moisture content and optimum dry density, based on which various rolling compaction techniques are put forward and field compaction experiments are conducted. The best compaction technique is found after comparing the compactedness under different techniques.(2) Dynamic test scheme is designed and formulated on the basis of field rolling compaction experiments to test the acceleration of vibrating roller in the subgrade. Signal analysis is conducted on the acceleration to study the distribution of acceleration along the depth and attenuation law of dynamic energy.(3) Three-dimensional finite element model on roadbed rolling compaction is established on the basis of ABAQUS large scale finite element analysis tool. Numerical simulation results are contrasted with real test results to validate the model. By virtue of the established finite element model, influences of different rolling compaction techniques, loose laying depths and rolling compaction speeds on compactedness are studied.(4) With the help of ABAQUS finite element software, numerical simulation test is conducted on silt side-slope rainfall infiltration, in an effort to study the slope deformation after rainfall and the protective effect of vegetation against the slope rainfall infiltration.