Construction of Weak Expansive Red Clay on Dongxin Expressway in Hunan Province, China

Abstract

Red clay is a common roadbed filler in China. In southern China, because of the high natural moisture content, it is hard to make enough compact clay in the process of roadbed filling construction, and it shrinks and cracks when dehydrated. This article compares the domestic regional soil properties of red clay in China, analyzing its physical properties, composition, chemical properties, and water characteristics, and the filler used in the construction of the Dongxin expressway. Swelling of the red clay packing was also observed. According to laboratory tests, field test analyses, and settlement observation tests, when using red clay as road filler, the use of a smooth bump grinding wheel and rolling of subgrade compaction works best for controlling moisture content, with the wet compaction test method within the range of ±5% of optimum moisture content. This method can ensure the strength and stability of the subgrade to provide guidance for the use of red clay in construction.