聚丙烯酰胺改善流态固化处理效果的试验研究

Experimental Study on Improving the Effect of Flow State Solidification Treatment with Polyacrylamide

为研究聚丙烯酰胺(PAM)对流态固化土的改善作用,针对长江中下游河漫区广泛分布的软土,研究了PAM掺量、液固比、灰土比对流态固化土的影响,结果表明:PAM可以快速降低含水泥流态固化土的流动度、提高黏滞性,减缓水泥土前期的固化速度,且可用净流动度定量描述PAM对流态固化土流动性的改善效果。由此得出,不同初始液固比的流态水泥土在添加一定比例的PAM后其净流动度降低比例处于相同水平;针对液固比为70%~80%的软土,PAM掺量建议控制在0.02%~0.03%,使得流动度满足回填要求,现场施工效果较佳;同时PAM有效地提高了施工流程的自由度;在此基础上,获得了该土体动切力和流动度的关系,可以较好地拟合实测数据。

In order to study the improvement effect of polyacrylamide(PAM) on the flow state solidification soil,the effects of PAM dosage,liquid-solid ratio,and ash soil ratio on the widely distributed soft soil in the middle and lower reaches of the Yangtze River were studied.The results showed that PAM can quickly reduce the flowability of cement-based flow state solidification soil,improve viscosity,and slow down the early solidification speed of cement-based soil.The improvement effect of PAM on the flowability of fluidized solidification can be quantitatively described by net flow rate.It can be concluded that the net fluidity of fluid cement soil with different initial liquid-solid ratios decreases at the same level after adding a certain proportion of PAM.For soft soil with a liquid-solid ratio of 70% to 80%,it is recommended to control the PAM content at 0.02% to 0.03% to ensure that the flowability meets the backfill requirements and the on-site construction effect is better.At the same time,PAM effectively improves the freedom of the construction process.On this basis,the relationship between the dynamic shear force and fluidity of the soil was obtained,which can better fit the measured data.