The study on dispersion mechanism of dispersive soil has attracted attention in water conservancy project. In order to investigate the main dispersive influencing factors of soil, grey correlation degree method was used to analysis the relation between dispersion degree and exchanging sodium percentage, clay particles content, organic matter, PH, specific surface area, structure damage rate, cation exchange capacity. The results show that the cation exchange capacity and exchangeable sodiuma do the best contribution to the dispersion of soil, and the specific surface area and the structure damage rate influenced the dispersion slightly.

Laterite has high void ratio, low density, high moisture content, high plasticity, but it does not match with their physical nature, which has the relatively high strength and low compressibility. In order to improve the strength of laterite and increase its compactness, we usually use the method of dynamic compaction in some large engineering projects. Its easy to find that soil compaction degree increased with the moisture content When the content of moisture is low, but soil compaction decreased after reaching the highest. Multiple compaction can effectively improve the maximum dry density and reduce optimum moisture content, but after compaction number is too much that optimum moisture content dont increase obviously.

Rainstorm weather systems and storm flood characteristics were studied to explore the relationship between the rainstorm weather system, the type of rainstorm, the cause of the flood and the time of occurrence, and some basic characteristics law of storm floods are summarized in the Second Songhua River Basin (Northeastern China). Then, the periodicity of catastrophic years was identified using the commensurability method and is shown to have an average of 11 years. Compared with simple flood forecasting, forecasting of flood-causing precipitation has a longer forecast period, which can gain the requisite time to discharge a reservoir and regain storage capacity, lower the limitation level, and manage the occurrence of flooding.