Abstract: Due to the shortage of non-expansive soil resources in the Jiang-Huai section of the project of Yangtze River to Huaihe River water diversion, the study on the reclamation of weak expansive soil and slaking sandstone from the excavated and abandoned slag in the river course is carried out based on the experimental project, and the production technology of non-expansive soil is developed. According to the experiment of reducing water content of weak expansive soil, the optimal method of reducing water content of weak expansive soils is determined. Based on the properties of natural low moisture content, weak expansion and easy powder formation of slaking sandstone, a composite modified soil comprising "primarily of weak expansive soil, slaking rock powder and modifier (cement)" is developed. The study shows that compared with road mixer and plough, rotary tiller have a higher efficiency in reducing soil moisture content. The desired effect is not achieved by using cement and industrial salt as admixture to accelerate the reduction of water content. Slaking rock powder with less than 30% of the incorporation amount of weak expansive soil as the raw material of modified soil can meet the permeability and compaction requirements of non-expansive soil finished products and can improve relevant technical indexes. The moisture content of the expansive soil is negatively correlated with the degree of compaction of modified soil. The degree of compaction can however be increased by additional compaction of soil. The test results of cement distribution uniformity of the modified soil are related to the sampling interval. The sampling interval should not exceed 40m, and the corresponding uniformity index should be 0.7-0.8.

Key words: water diversion project from Yangtze River to Huaihe River, non-expansive soil, modification of weak expansive soil, slaking rock powder, detection index