疏浚硬质黏性土制作室内试验研究

Laboratory study on dredging hard clay production

基于疏浚工程中硬质黏性土挖掘困难和生产效率低的问题,为原状土进行刀齿的切削试验,需要制备硬质黏性土土质。针对疏浚吹填淤泥含水率大和压缩性强等特征,开发了一套底部抽真空的"真空+堆载"制备技术。试验研究表明:1)制备装置效果良好,制备土质标准贯入击数达到13击,液性指数达到0.36,疏浚岩土工程特性级别为4级,性质接近疏浚工程中给施工带来困难的黏性土质,为硬质黏性土的切削试验提供了合格的模型土质。2)制备土质含水率W与无侧限抗压强度R、标准贯入击数N、土体承载力F存在较好的相关性,回归系数均在0.72以上,为流塑等状态的软弱淤泥处理处置研究提供基础技术支撑。

To counter the problem of difficult digging and low production efficiency of hard cohesive soil in the dredging project,we carry out the cutting test of the original soil,for which the hard clay soil sample needs to be produced.In view of the characteristics of the hard clay, we develop a ＂vacuum ＋ stack loading＂ technology for vacuum pumping at the bottom of the dredged silt with high moisture content and high compressibility. The experimental research shows that： 1） The preparation device works well,the standard penetration number of clay soil produced is 13 hits, the liquidity index reaches 0. 36, the dredging geotechnical engineering level is 4, and the properties are close to the sticky soil which is difficult for construction in dredging project,thus it provides qualified model soil quality for the hard clay cutting test. 2） There is a good correlation for moisture content W and unconfined compressive strength R,standard penetration number N,soil bearing capacity F of preparation soil, the regression coefficients are all above 0. 72.The results provide the basic technical support for the researches on the disposal of soft silt in the state of flow plastic.