碱渣-粉煤灰液相吹填混合料试验研究

Experimental study on the liquid-pumping filling mixture with soda waste and fly ash

碱渣与粉煤灰固体拌合制成工程土可用作道路基础或大面积填垫材料,通过原位试验将碱渣与粉煤灰液相混合后进行吹填。研究表明,碱渣与粉煤灰固体含量最优配比为7∶3,此时碱渣土最优含水量与最大干密度分别为63.5%和0.88g/cm^3,渗透性较低,养护7d后无侧限抗压强度约为纯碱渣的6.5倍。现场液相吹填的碱渣土混合较好,沉淀层厚度约为80cm。经5个月自然晾晒后,碱渣土含水量介于160%~180%,深度方向轻型动力触探击数介于1~5,具有一定强度。相比固体拌合碱渣土,液相吹填碱渣土工艺简单,能够大批量、低成本利用碱渣,后期强度可通过真空预压等排水固结措施满足工程需要。

The mixture of soda waste and fly ash is likely to serve as engineering soil for road foundation and large area filling material. By in-situ test,the soda waste and fly ash were mixed in form of liquid mixture and conducted pumping filling. The study indicates that the optimum mixing ratio of solid volume of soda waste versus fly ash is 7∶ 3,corresponding to the optimum water content and the maximum dry density to be respectively 63. 5 % and 0. 88 g / cm^3 for soda waste. The prepared mixture has low permeability and its unconfined compressive strength is about 6. 5 times the original strength after7-day curing period. The pumping filling soda waste was mixed well in field with the deposited layer of about 80 cm. After5-month sun-cure,the water content of the mixture ranges between 160 % ~ 180 % and the blow number of light dynamic penetration test ranges between 1 ~ 5,showing fairly good strength. Compared with the solid-mixing method for soda waste,the liquid-pumping filling method for soda waste is simple in operation and is able to dispose a large amount of soda waste with low cost. The strength of the mixture may be further increased to reach engineering need through some drainage consolidation methods such as vacuum preloading.