膨胀土水泥改性均匀性及长期效果试验研究

Experimental Study on Uniformity and Long-term Effects of Cement Modified Expansive Soil

为了解南水北调中线工程南阳膨胀土试验段水泥改性土的掺拌均匀性及长期改性效果,进行了现场取样和室内试验研究。结果表明,中膨胀水泥改性土采用稳定土拌和机拌合效果相对较好;弱膨胀水泥改性土采用路拌机拌合,试样渗透系数及无侧限抗压强度变化均较大,表明现场拌合不均匀,即水泥改性土的拌合工艺对其均匀性影响很大。水泥改性土现场运行一年多之后,不仅显著降低了膨胀性,而且显著提高了膨胀土的抗剪强度,长期改性效果显著。

In order to understand uniformity and long-term effects of the cement modified expansive soil in Nanyang segment of Middle Route Project of Water Diversion from south China,site sampling and laboratory experiments are performed.The results show that the mixing effect of cement modified middle expansive soil mixing by stabilized soil mixing machine is relatively good.The mixing effect of cement modification for weak expansive soil mixing by Road mixing machine is not good.It is Poor because the variation range of permeability coefficient and unconfined compressive strength of the samples are larger and the uniformity is poor.It is indicated that the mixing technique of cement modified expansive soil has a great influence on the uniformity.The swelling of expansive soil is significantly reduced and the shear strength is significantly improved after cement modified expansive soil at Nanyang section operatedmore than one year.