ISSN 1000-3665 CN 11-2202/P

    基于增温加热技术的淤泥真空预压现场试验研究

    A field experimental study of sludge vacuum preloading based on the temperature increasing heating technology

    • 摘要: 增温加热联合真空预压技术是一种新型淤泥脱水固结技术,尚未开展有关的现场试验研究。以白洋淀底泥为研究对象,采用一种间歇式温致相变汽化发生器联合真空预压技术进行淤泥脱水固结的现场试验,从热动力学和渗透固结理论方面阐述了增温加热联合真空预压的技术原理,并将处理效果与常规真空预压进行对比分析。结果表明:增温加热联合真空预压技术可大幅度提高底泥的固结沉降,体积压缩率约为常规真空预压的3倍,底泥含水率为34.59%,较常规真空预压降低了18.6%,十字板强度提高了约2倍,处理61 d后的固结度达83.3%~85.4%,但处理后的底泥表面存在不均匀沉降现象,在平面上表现为距增温装置越远,沉降量越小。根据饱和土的有效应力理论,距离增温装置越近,孔隙水压力消散的越快,当停止增温加热时,孔隙水压力产生了明显的回弹现象,距离增温装置越近,回弹量越大,这主要与增温装置的埋设深度、加载时长和温度加载模式有关。同时,根据底泥含水率和沉降变化规律,初步厘定了该增温装置的有效半径为2~3 m。研究结果可为该技术的工程应用提供技术指导。

       

      Abstract: Temperature increasing heating combined with vacuum preloading is a new sludge dewatering and consolidation technology, and relevant field experimental research has not been carried out. The Baiyangdian sediments are taken as the research object in this study, an intermittent temperature mass phase change vaporizer combined with vacuum preloading is used to conduct field experimental research on sludge dewatering and consolidation. The technical principle of temperature increasing heating combined with vacuum preloading is expounded from the aspects of thermodynamics and osmotic consolidation theory, and the treatment effect is compared with conventional vacuum preloading. The results show that the technology of warming and heating combined with vacuum preloading can greatly improve the consolidation settlement of sediments. The volume compression rate is about 3 times that of the conventional vacuum preloading, the water content of the sediments is 34.59%, which is 18.6% lower than that of the conventional vacuum preloading, the strength of vane is about 2 times higher, and the degree of consolidation after 61 d of treatment is 83.3% to 85.4%. However, there is uneven settlement on the surface of sediments after treatment, showing that the farther away from the warming device on the plane, the smaller the settlement. According to the effective stress theory of saturated soil, the closer to the temperature increasing device, the faster the pore water pressure dissipates. When the temperature increasing heating stops, the pore water pressure has an obvious rebound phenomenon. The closer to the temperature increasing device, the greater the rebound, which is mainly related to the buried depth, loading time and temperature loading mode of the temperature increasing device. At the same time, according to the variation law of sediment moisture content and settlement, it is preliminarily determined that the effective radius of the temperature increasing device is 2 m to 3 m. The results may provide technical guidance for the engineering application of this technology.

       

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