武汉东湖淤泥早强固化试验研究

Experimental study of early solidification of sludge in East Lake,Wuhan

利用传统淤泥主固化材料水泥与辅助固化材料粉煤灰和石膏,通过组合配比对武汉东湖疏浚淤泥分别进行固化,基于无侧限抗压强度试验和三轴剪切试验,确定不同材料组合及配比下淤泥固化强度和特点。试验研究表明:在疏浚淤泥固化过程中水泥占主导地位,对固化效果影响最为显著;粉煤灰起到的作用相当于降低了淤泥初始含水率,表现在固化淤泥早期强度的快速提高;石膏有利于固化淤泥早期强度的形成,其作用持续于整个淤泥固化过程。随着含水率的增大,单纯水泥固化淤泥试样的应力-应变关系曲线由应变软化逐渐过渡到应变硬化模式,围压对固化淤泥强度的影响程度也随着含水率的增大而逐渐减弱,辅助固化材料的添加使原单纯水泥固化淤泥的应变硬化型曲线变为应变软化模式。不同含水率东湖疏浚淤泥固化材料最佳配比为水泥掺入比20%,粉煤灰为3倍的水泥量,石膏为30%的水泥量,该研究成果有助于武汉东湖底泥的治理以及疏浚淤泥排放场地的地基处理和环境整治。

Traditional main solidified materials （cement） and auxiliary materials （fly ash and gypsum） are used for solidifying sludge of East Lake of Wuhan. Based on the results of unconfined compressive strength test and triaxial shear test, the strength and characteristics of sludge solidified by the combination of different materials and mixture ratios are determined. Experimental results show that the role of cement is the dominant additive during solidification of sludge. The role of fly ash is equivalent to reducing the initial water content of sludge, and the early strength of solidified silt has been increased rapidly. The gypsum is conducive to the early strength formation of solidified sludge; and its role is shown throughout the solidifying process continuously. The model of stress-strain curve has been transitioned gradually from strain softening to strain hardening with the increase of water content of sludge samples which are solidified by cement only. Also the effect of the changing confining pressure on strength of solidified silt has been weakened gradually with the increasing water content. The model of stress-strain curve has been transitioned from strain softening to strain hardening because of adding auxiliary solidified material to sludge. The 20% cement, fly ash for 3 times the cement volume, and gypsum for 30% of the cement volume are the optimum mixture ratio for different water content sludge of East Lake. The research results will be contributed to the sediments treatment of East Lake as well as the foundation treatment and environmental renovation of the sludge stock yard.