石灰改良膨胀土路基施工控制参数

Subgrade construction control parameters for lime-treated expansive soils

为了解决石灰改良膨胀土最优施工含水率现行确定方法存在不足的问题，以某边坡膨胀土为研究对象，在对现行石灰改良膨胀土施工控制参数常用方法分析的基础上，进行了石灰改良膨胀土的强度和膨胀性能的相关试验。研究结果表明：石灰改良膨胀土的最优施工含水率在wop＋（2％～4％）之间，石灰改良膨胀土的强度在7d内增长最快，以后逐渐趋于稳定，合理地掺加石灰对石灰改良膨胀土的强度增长影响较大；随着石灰掺量的增加塑性指数减小，自由膨胀率先减小后增大，掺石灰对膨胀土膨胀性质的改善作用非常迅速，在最初的24h内就已基本完成，继续增加龄期对其影响不大。结合强度及膨胀性试验的结果，提出了以膨胀性指标作为主要控制指标，强度指标作为验证指标的路基施工拳数确定方法。

Taking the slope of expansive soil as the research object, based on the analysis of construction control parameters of lime-treated expansive soil, this paper did relevant tests on the strength and expan- sive properties of the soil. The results show that the optimal construction water content of lime-treated expansive soils should be within wop, 2 % ~4%. The strength of lime-treated expansive soil increase fast in 7 days, and after 7 days it tends to be stable, the reasonable lime rate has great influence on the strength improvement of lime-treated expansive soil. The results show that with the increasing of llime rate the plasticity index decreases, and the free swelling ratio decreases first and then increases. The properties of expansive soil mixed with lime will be improved rapidly, which will be finished in first 24 h, and increasing curing of time has little influence on it. Combined with the results of strength and ex- pansive properties tests, the method for the determination of the subgrade construction control parame- ters with the expansive properties as the main control indexes, and the strength as the confirmation index is proposed. 3 tabs, 8 figs, 19 refs.