Role of iron oxide content on mechanical properties of granite residual soil in full suction range.

Granite residual soil is a widely encountered clayey soil with unique microscopic soil structures. Its soil structures mainly stem from the presence of interparticle cementation by iron oxide. An attempt is made herein to experimentally quantify the impact of interparticle iron oxide cementation on soil's mechanical properties, particularly in the high suction range. The amount of interparticle cementation is artificially generated by mixing soil samples with varying mass fractions of iron hydroxide colloid. The mechanical behavior of these soil samples in the full suction range is measured via the drying cake test. Preliminary experimental results demonstrate that interparticle iron oxide cementation can significantly decrease soil shrinkage (by up to 52%), and substantially increase soil elastic modulus (by up to 1.83 times) and negative suction stress change (by up to 0.82 times). [ABSTRACT FROM AUTHOR]