Study on Treatment Method of Expansive Soil Embankment in Expressway Reconstruction and Extension
In order to fully utilize expansive soil as filler in highway reconstruction and expansion projects,this paper draws on the successful experience of using expansive soil directly in road construction.It proposes an embankment treatment scheme that involves the use of geogrid-reinforced expansive soil with edge wrapping,based on the reconstruction and expansion project of the Hefei to Dagudian section of the G40 Shanghai-Shaanxi Expressway.Through laboratory tests,the road performance and swelling characteristics of the expansive soil filler were investigated to determine the applicable scope and compaction control indices of the filler.Then,the feasibility of the embankment treatment scheme was demonstrated through the prediction of the embankment swelling,stability analysis of geogrid-reinforced slopes,and economic effect analysis.The results show that the total swelling-shrinkage ratio of the filler is 1.12% ,and its RCBR is greater than 3% ,preliminarily verifying the feasibility of using physically treated expansive soil filler,such as edge wrapping and reinforcement,as lower embankment material.If the compaction control index determined by the wet compaction test is used,the estimated value of the embankment swelling will be an order of magnitude smaller than that determined by the dry compaction method.The anti-pullout safety factors of the geogrids at each layer meet the standard requirements of not less than 2.0,avoiding the risk of pullout.Compared to the lime improvement scheme,this scheme can significantly shorten the construction period and reduce costs.
road engineeringexpansive soilembankment reconstruction and extensionswellinggeogrid
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