Research on the Optimization of Pavement Thickness andConstruction Depth of Modified Subgrade Soil Basedon the California Bearing Ratio
About the author:
Beijing No. 1 Municipal Construction Engineering Co., Ltd., Beijing 100083, China
Abstract:
This study conducts research on the optimization of pavement thickness and construction depthof modified subgrade soil based on the California bearing ratio （CBR）。 Three types of subgrade soils withdifferent quality ratios were prepared,which are 25% expansive soil + 75% kaolin, 35% expansive soil +65% kaolin, 75% expansive soil + 25% kaolin, and chemically treated with a mixture of 20% cementand 8% lime. The engineering properties of the subgrade soil were studied through Atterberg limit tests,Proctor compaction tests, California bearing ratio tests, and expansion tests. The research results showthat the liquid limit, plastic limit, plasticity index, moisture content and expansion rate of unmodifiedsubgrade soil all increase with the increase of expansive soil content. The California bearing ratio ofunmodified subgrade soil does not meet the specification requirements,while that of modified subgradesoil significantly increases, meeting the requirements of road construction. The modified subgrade soilreduces the pavement thickness and construction depth,with the mixture of 25% expansive soil + 75%kaolin having the smallest pavement thickness and construction depth, both at 30mm and 80mmrespectively. In road construction,when encountering expansive soil subgrade, it is preferred to usechemical stabilizers for treatment rather than removal and replacement. During construction, closelymonitor key indicators of subgrade soil, especially in rainy areas, strengthen drainage design to ensurethe long?term stability and durability of the road.
