Study of dispersive identification and treatment with lime of dam soil in Majiushu Reservoir

The water-retaining structures built of dispersive clay are so easily destroyed to occur the safety accidents. Considering the safety, the dispersivity and treatment with lime of soil for the Majiashu dam are studied using double-hydrometer test, pore water salts test, pinhole test, crumb test and exchangeable sodium percent test. The results are that the dam soil belongs in the low liquid limited clay; and it has a lot of sodium ions in the easily soluble salt and the saturation pore water; and its pH is the stronger alkalescence or even the strongest alkalescence. Those soil samples had more illite and a few of kaolinite and chlorite and montmorillonoid. The soil samples are transition clays and dispersive clays; and the lime is the effective additive when the content of lime is the 0.25 % with mass ratio the dispersive clay becomes to the non-dispersive clay. It is shown that the key reasons of dispersivity are that the soil of dam has the more sodium ions and the pH is the stronger alkalescence. The lime is the effective additive of the dispersive soil.