河湖清淤吹填土固结硬化及生态处治效果

河湖清淤吹填土含水率高，流动性大，具有污染性。无砂真空排水预压法在固结硬化吹填土，提高其强度和承载力方面效果显著。受环形流道、落淤分选的影响，同一堆泥场内不同区域的地基沉降和超静孔压的变化存在一定差异性。无砂真空预压法具有较好的阻隔、过滤、吸附有机污染物等净化功能，经历堆置沉淀、负压抽吸、尾水沉淀和水生植物过滤吸附后排放的水体中有机质和总磷(TP)含量大幅减小，污染综合指数由0.8~1.0降到0.7，基本满足地表水Ⅲ类水质标准要求。固结后吹填土中的有机质、总氮、总磷含量大幅度降低，有机污染指数提高了1个等级。重金属含量符合土壤环境质量Ⅲ类标准，重金属的浸出毒性指标低，对地表水无污染，重金属污染程度的计算评价结果总体为轻微。

Hardening of hydraulic fill dredged from rivers & lakes and its ecological treatment effect

The hydraulic fill dredged from rivers and lakes is generally characterized by high water content, large fluidity, and greater pollution. The sand-free vacuum preloading method has a remarkable effect in consolidating and hardening the hydraulic fill, and improving its strength and bearing capacity. Due to the influences of the annular channel and the sedimentation separation, there are some differences between the foundation settlement and the change of the excess pore water pressure in the different areas of the same mud pit. This method performs an important purification function in barrier, filtration and adsorption of the organic pollutants. After the stacking and precipitation, the negative pressure suction, the tailwater precipitation, the filtration and adsorption of the aquatic plant, the content of organic matter and total phosphorus (TP) are decreased significantly, and the pollution index P is reduced from 0.8~1.0 to 0.7, which basically meets the requirements of the class Ⅲ water quality standard of the surface water. After consolidation, the content of organic matter, total nitrogen and total phosphorus in the soil had decreased greatly, and the organic pollution index OI is improved by one grade. The content of the heavy metal element in the soil meets the class Ⅲ environment quality standard for soils, and the leaching toxicity of the heavy metals is low, thus producing no pollution to the surface water. The calculation results show that the heavy metals pollution degree is slight.