Subgrade Strength Based On The Attenuation Of The Road Under The Conditions Of Structural Mechanics Analysis And The Recommendation Of A Typical Structure

Yellow-River alluvial silt is peculiar silt of china, because of its complex characters, such as easy to scour, low intensity, bad stability in water, strength decrease swiftly after drinking, roads filled with the silt soil is instability and produces much disease easily, which seriously affects the performance of the highway and its life. Study the rule of subgrade strength decrease and analysis the impaction on mechanical feature of semi-rigid pavement structure, then select the pavement structure in heavy repair and the prevention of the road breakage, has been very urgent.Firstly, uneven settlement and water distribution in roadbed have been surveyed in detail aiming at Dong-gang highway. And according to much test and numerical simulation results, the reason of early road breakage even under normal traffic load has been confirmed, which include strength decay and uneven settlement of roadbed. What's more, heavy traffic load would speed up the time of road breakage.Secondly, according to the diseases investigation, the test and numerical simulation were carried on to determine the rule of strength decay and the impaction on the semi-rigid structure. Firstly, by adopting a lot of experiments, such as water survey, rebound modulus test, water infiltration test and shear strength test, characteristics of the silt soil and the infiltration rule were determined.Thirdly, the BISAR Code was used to analysis the impaction on mechanical feature of semi-rigid pavement structure because of the strength decay and the heavy traffic. And the general impaction of both factors was computed too, which could reveal the short life of the road in the Yellow River alluvial plain.What's more, by considering of the general influence of the strength decay, it is proved that the traditional semi-rigid structure can't fit to the roadbed diseases characters of the silt soil distributing in the Yellow River alluvial plain. The structure of the LSPM flexible base can control the development of the reflecting cracks because of the special feature of flexible base. Therefore, numerical simulation was done aiming at the structure of the LSPM flexible base. Results showed that the structures could be suitable to those road diseases aroused by the strength decay and the heavy traffic loading.Finally, the silt subgrade common diseases, such as subgrade strength degradation, sideslip, such as uneven settlement of the control techniques were studied.In one word, the roadbed strength decay and the character of the pavement structure in the Yellow River alluvial plain have been definitude, which can produce important theoretical and practical significance for the highway construction and maintenance.