Engineering and geological characteristics of granite weathering profiles in South China

Granite weathering profiles are widely distributed in South China. Their engineering and geological characteristics are major geotechnical subjects that are important in the design and construction of civil engineering projects. This paper presents a summary of the weathering characteristics and zoning of granite weathering profiles in South China and discusses their engineering and geological properties. A five-grade scheme has been adopted in the zoning of a granite weathering profile. Studies have shown that the completely weathered granites (CWG) in South China have the following characteristics: low moisture content, low to medium plasticity (W_L = 22.5-39.0% I_p =6.5-11.8%), medium void ratio (0.36-1.29), weak shrinkage and medium compressibility (a_1-2 = 0.24-0.8 MPa^-1) and high shear strength (φ = 20-30°; c = 20-40 KPa). The CWGs are usually at a low or high plastic state and most of them are over-consolidated soils. A majority of the physical and mechanical properties have good statistical correlations with the degree of weathering. The data presented in the paper are important in geotechnical engineering projects such as slope stability evaluation in China.