洗砂泥浆压滤脱水性能及快速检测方法

Pressure filtration dewatering performance of sand-washing slurry and rapid test method

工程渣土在水洗砂过程中产生的洗砂泥浆存在脱水效果差、不稳定的问题,这与泥浆的脱水性能密切相关。通过模拟现场洗砂工艺获得不同脱水性能的洗砂泥浆,开展了改进滤失试验及模拟压滤试验,研究了洗砂泥浆脱水性能受洗砂工艺的影响规律,获得了一种能够快速表征泥浆脱水性能的指标,用以指导优化渣土洗砂工艺。结果表明:洗砂泥浆脱水性能受洗砂粒径和加水量影响明显,滤失量及渗透系数与脱水性能有较好的相关关系;而30min滤失量与最终滤失量、最终泥饼含水率呈现较好的相关性,能够较准确地反映泥浆脱水性能;经模拟压滤试验进一步验证,30 min滤失量可以作为洗砂泥浆脱水性能的快速表征指标。基于此提出了一套洗砂泥浆脱水性能的快速检测及工程渣土洗砂工艺优化方法,能够及时为洗砂工艺参数调整提供指导,以获得脱水性能较优的洗砂泥浆,最终使脱水效果得以改善和稳定。

The slurry produced by sand-washing engineering of excavated soil has the problems of poor dewatering property and instability, which are closely related to the dewatering performance of slurry. In this study, sand-washing slurry samples with different dewatering performances were obtained by simulating the field sand-washing process, then the modified filtration loss test and simulated pressure filtration test were carried out to study the influence of sand-washing process on the dewatering performance of sand-washing slurries, so as to find an index for rapid characterization of the dewatering performance of slurries, which can be used to guide the optimization of the sand-washing process. The results show that the dewatering performance of sand-washing slurry was significantly affected by the mesh size and the amount of water added. The filtration loss and hydraulic conductivity indicated a good correlation with the dewatering performance. In particular, the filtration loss at 30 minutes was nicely correlated with the final filtration loss and the final water content of filter cake, which can accurately reflect the dewatering performance. The results of simulated pressure filtration test further verify that the filtration loss at 30 minutes can be used as an index to quickly characterize the dewatering performance of slurries. Based on the above results, a method is put forward for rapid detection of sand-washing slurry dewatering and optimization of field sand-washing process. The method can provide guidance for the adjustment of sand-washing process parameters in time to obtain the sand-washing slurry with better dewatering performance, which can effectively improve and stabilize the dewatering effect.