On measures of improving subgrade quality for grade 2highway in areas of mountains and hills

Taking for example the subgrade construction of Zhangjiajie section of Zhangluo highway, the measures of improving subgrade engineering quality for grade 2 highway in areas of mountains and hills were discussed, such as strengthening the subgrade clearing,the investigation and treatment of soft soil foundation; Selecting the construction season and the roadbed filling material reasonably; Strictly controlling the quality of filling material; Ramming in lamination strictly in accordance with the specification and requirements of test road section; Rationally selecting the ramming machinery; Actually conducting subgrade protection; setting up perfect waterproof and water drainage system etc.