城市河道淤泥固化土干湿耐久性试验研究

Experimental Study on Drying-wetting Durability of Solidified Urban River Sludge

淤泥固化土的干湿耐久性是其资源化利用中长期服役性能的重要指标。本文选取有机质含量分别为7.7%(S淤泥)和11.7%(Z淤泥)的两种典型城市河道淤泥,掺入水泥及新型固化剂进行固化处理,通过干湿循环试验及无侧限抗压强度试验研究了不同种类的固化剂及其掺量对淤泥固化土干湿耐久性的影响。试验结果表明:在水泥掺量较低条件下(S淤泥对应5%、Z淤泥对应5%和10%),淤泥固化土的抗压强度随干湿循环次数增加逐渐下降,且第1次循环的下降幅度最大,随后下降幅度明显减小;在水泥掺量较高条件下(S淤泥对应10%以上、Z淤泥对应15%以上),淤泥固化土的抗压强度随干湿循环次数增加先增大后下降,且峰值强度对应的循环次数具有随水泥掺量的增加和有机质含量的减少而增加的趋势,淤泥固化土抗压强度随干湿循环作用的变化规律是劣化效应和养生修复效应协同作用的结果。总体来说,淤泥固化土随着水泥掺量的增加,其干湿耐久性显著提高。新型固化剂达到掺量10%时淤泥固化土的干湿耐久性介于水泥掺量15%~20%淤泥固化土之间,显然新型固化剂处理城市河道淤泥优于水泥固化的效果。这一研究为城市河道淤泥固化处理提供了一种新的处理技术。

The drying-wetting durability of solidified sludge is an important indicator of long-term per-formance during resource utilization.In this study,two typical urban river sediments with organic mat-ter contents of 7.7%(S sludge)and 14%(Z sludge)were selected,and solidified with Portland ce-ment and a new curing agent.The drying-wetting cycle test and unconfined compressive strength test were conducted to study the effect of the curing agent content on the drying-wetting durability.The re-sults show that under the condition of low cement content(S sludge corresponding to 5%,Z sludge corresponding to 5%and 10%),the compressive strength of solidified sludge gradually decreases with the increase of drying and wetting cycles,and the decrease of the first cycle is the largest,and then the degree of declining is significantly reduced.Under the condition of higher cement content(S sludge corresponding to more than 10%,Z sludge corresponding to more than 15%),with the in-crease of drying-wetting cycles,the compressive strength of solidified sludge increases first,and then decreases.The number of cycles corresponding to the peak strength tends to increase with the increase of the cement content and the decrease of the organic matter content.The law is the comprehensive re-sult of the deterioration effect and curing restoration effect.In general,the solidified sludge has a sig-nificant increase in drying-wetting durability as the cement content increases.When the new curing agent reaches 10%,the drying-wetting durability of the solidified sludge is between 15%-20%of the cement solidified soil.Obviously,the new curing agent is better than cement in curing urban river sludge.This research provides a new treatment technology for the solidification of urban river sludge.