基于Box-Behnken法的合肥湖积软土固化配方优化的试验研究

选择CaO和纯碱作为激发剂掺入GGBS(粒化高炉矿渣微粉)制备GGBS+CaO+纯碱固化合肥湖积软土,通过无侧限抗压强度试验研究固化黏土的强度变化规律。以GGBS、CaO和纯碱的掺量作为影响因子,以7d和28d固化土的无侧限抗压强度作为响应值,基于Box-Behnken法确定3种外添剂的最佳配合比。研究表明:GGBS掺量的变化对强度响应影响最大,且其敏感程度随龄期的增大而增大;而对于CaO和纯碱,情况则相反。养护7d后,各因素对强度的线性效应和曲面效应均显著,CaO与纯碱的交互作用显著;养护28d后,GGBS与纯碱的交互作用显著。最终得出:GGBS、CaO和纯碱三掺量固化黏土最佳配比分别为13.08%、4.89%和1.25%;在最佳配合比下,7d和28d的预测强度分别达到550.904kPa和665.953kPa。最后对实测值与预测值进行了对比分析。研究成果可为在合肥滨湖地区应用矿渣类软土固化剂提供理论依据。

Experimental Study of formula Optimization for Lacustrine Soft Soil Consolidation in Hefei City based on Box-Behnken method

Selecting calcium oxide (CaO) and sodium carbonate (soda powder) as activators,mixture made of ground granulated blast-furnace slag (GGBS),CaO and soda powder was prepared to solidify lacustrine soft soil in Hefei city.Unconfined compressive strength experiment was carried out to study the variation of solidified clay strength.Taking the amount of GGBS,CaO and sodium carbonate as impact factor,unconfined compressive strength of 7 days and 28 days solidified soil was used as response value,the optimum proportion of three additive agents was determined based on BoxBehnken method.Experimental results show that the amount of GGBS has maximum influence on strength,its sensitivity increases with the increase of solidication age.However,for CaO and soda powder,the situation is contrary.After curing for 7 days,the linear effect and surface effect of three additives on strength are obvious;the interaction between CaO and sodium carbonate is significant.After curing for 28 days,the interaction between GGBS and sodium carbonate is significant.Finally,it is found that the optimum proportion of GGBS,CaO and soda powder are 13.08％,4.89％ and 1.25 ％ respectively.Under the optimum proportion condition,the prediction strength of solidified soil can reach 550.904kPa and 665.953kPa after 7 days curing and 28 days curing,respectively.Finally,the actual strength values are compared with the prediction strength values.Above results may provide theoretical evidence for GGBS solidifying lacustrine soft soil in lakeside area of Hefei city.