Abstract: In order to research the road performance of granite residual soil subgrade filling materials, compaction characteristics and mechanical properties of compacted residual soil are researched by using compaction test, California bearing ratio(CBR) test consolidation test and indoor test method for coefficient of subgrade reaction. The deformation properties of the soil under dynamic loads are studied by using cyclic loading test on the optimum moisture content and saturated samples. The results show that compaction works more efficiently with K of 91%-97% for granite residual soil. Improving the degree of compaction is effective to enhance the local deformation resistance of the soil. K30 was obtained from indoor triaxial test, and the value is 188.25 MPa/m. The dynamic stability of granite residual soil is comparatively well under the optimum moisture content. However the plastic deformation increases substantially and dynamic elastic modulus reduced with water content increasing. The increasing water content is not conducive to the deformation stability of the soil. So as filling materials, it shall be considered as spare materials of embankment which suffers low effect of environment. If used as subgrade body and highway roadbed, shall be modified and making choice based on the requirements of deformation. This study may provide technical reference for the construction process of granite residual soil as embankment filling and soil conditioning.

Key words: granite residual soil, California bearing ratio(CBR) test, subgrade coefficient K30, moisture content, cumulative plastic strain, dynamic elastic modulus