Abstract: Nowadays, hydraulic dredging is a common way to dredge urban river channels, but its generated silt has high water content, large volume and difficult separation of mud and water. The frame vacuum preloading method was put forward, and its dehydration effect and influencing factors were explored through experimental research. The technology of frame vacuum preloading dewatering could effectively solve many problems of traditional vacuum preloading and had a good effect of sludge dewatering. The sludge drainage rate decreased sharply from the maximum value, the drainage volume increased rapidly, the final drainage rate was low, and the drainage volume finally tended to be stable. The smaller the spacing of the filter pipes in the frame structure, the larger the initial drainage rate of the test tank and the larger the drainage. When the size of the test model increased, the dehydration effect was improved. The volume of silt decreased obviously, and the smaller the spacing of filter pipes in the frame structure was, the larger the reduction of volume decreased. With the increase of size, the reduction of sludge volume increased gradually. The smaller the spacing of the filter pipes in the frame structure, the greater the shear strength of the cross plate of silt. With the increase of model size, the shear strength of cross plate of silt decreased gradually. The change law of moisture content of silt was opposite to that of shear strength of cross plate.

Key words: waterway engineering; hydraulic dredging; sludge; dehydration; framework; vacuum preloading

摘要： 水力冲挖是时下一种常用的城市河道疏浚方式，但产生的淤泥含水量高、体积大、泥水分离困难。提出框架真空预压法，通过试验研究，探究其脱水效果及其影响因素。框架真空预压脱水技术可有效解决传统真空预压的诸多问题，具有良好的淤泥脱水效果。淤泥排水速率由最大值急剧减小，排水量迅速增加，最终排水速率较低，排水量趋于稳定。框架结构内滤管间距越小，试验槽的初始排水速率越大，排水量越大；当试验模型尺寸增大时，脱水效果有所提高。淤泥的体积缩减明显，滤管间距越小，体积缩减幅度越大；随着模型尺寸的增大，淤泥体积缩减幅度亦逐渐增大。框架结构内滤管间距越小，淤泥的十字板剪切强度越大；随着模型尺寸的增大，淤泥的十字板剪切强度逐渐减小。淤泥的含水率变化规律与十字板剪切强度的规律相反。

关键词: 航道工程；水力冲挖；淤泥；脱水；框架；真空预压