膨胀土化学改良效果及其在边坡工程中应用的试验研究

Experimental Research on Chemical Modification of Expansive Soil and Its Application in Slope Engineering

对膨胀土边坡进行化学改良,具有良好的工程应用前景。根据膨胀土的胀缩机理,选择十八烷基三甲基氯化铵和KCl共同作用,用于膨胀土尤其是膨胀土边坡的渗透改良,并从微观层面阐述了改良剂的作用机理。无荷膨胀率试验及无侧限抗压强度试验结果表明:相对于膨胀土素土,经改良剂作用后的膨胀土膨胀性有较大程度的降低,水稳定性也明显增强,泡水后不发生崩解。颗分试验及离心机试验结果表明:改良后膨胀土的比表面积减小,与水的作用减弱,吸着水含量较素土明显减少。模拟渗透改良试验结果表明,通过喷洒改良剂可使边坡表层一定深度内的膨胀土得到有效改良。

The expansive soil slope improved through chemical methods has the broad prospect for development. The oc- tadecyl-trimethyl ammonium chloride and potassium chloride were choosen to improve the expansive soil especially the ex- pansive soil slope based on the swell-shrink mechanism, and the modification mechanism was stated on the microscopic level. The free swelling rate test and unconfined compression strength test on expansive soil were conducted. The test re- suits show that the expansion of the modified soil would be considerably restrained, the water-stability would also be im- proved, and the sample would not be damaged when soaked into water. The grain size analysis test and the centrifugal test show that the volume-to-surface ratio would be reduced, the water-soil interaction would be weakened, and the hy- groscopic moisture content would also be decreased. The simulative penetration improvement test shows that the expansive soil in a certain depth range could be effectively improved after the sprinkling of improver.