Research On Design And Construction Technology Of Expansive Soil Roadbed In Guangzhou Xi'er-huan Freeway

Based on extensive foreign or domestic existing research achievements, combined with Guangzhou Xi'er-huan Freeway engineering projects, engineering characteristics of expansive soil were researched. In paper, mineral components of expansive soil on site were analyzed, and classified. By chemical analysis of representative soil samples on site,80% of mineral components were alpha quartzes, 10% were mixtures of kaolinite and turface,8-11% were galapectite. Then dilatability was determined as middle-week. Techniques of design and construction were brought forward. Mortar masonry facing wall or with TBS vegetative protection+facing wall1 were used in cutting. To above-mentioned methods, advisable structural style should be adopted according to cutting height. Multilevel and right slope ratio was used when cutting height was above 8m. Single stage and 1:1.5 ratios were adopted in filled embankment. Grass planting were used when height was under 4m. Seeding grass in 3D Geomat was used when height was 4-6m. Seeding grass in arch-framework and 3D Geomat was used when height was above 6m. Mortar masonry protection would be used when filled embankment past through ponds, reservoirs, paddy fields.In the end, combined research results of existing and the paper, control technical manual of expansive soil was received in many ways as punishment techology, design and construction key technology.