固化淤泥结构性力学特性的试验研究

Experimental Study on Structural Mechanical Properties of Solidified Sludge

以完全扰动重塑的泥浆作为评价基准,从土结构性的角度考察了水泥固化淤泥的力学特性,发现固化淤泥是一种典型的结构性土,存在明显的固结屈服应力,屈服前后固化淤泥的力学性质显著不同。固化淤泥的压缩曲线位于淤泥的固有压缩曲线的上方,屈服之前固化淤泥的压缩性很小,屈服后压缩性迅速增大。水泥添加量越高,固化淤泥的固结屈服应力越大。固结不排水剪切试验中,若固化淤泥未在固结围压下屈服,剪切时表现出超固结土的性质,若在围压下屈服,固化淤泥则表现出正常固结土的性质。屈服之前,固化淤泥的不排水强度基本不随围压改变,屈服后的强度随围压线性增大。水泥的加入会使黏聚力和内摩擦角都增大,屈服前阶段固化淤泥的强度由胶结作用所控制,屈服后阶段由组构作用所控制。在固化淤泥的实际工程应用中,应考虑到它所特有的结构性力学特性。

Based on the completely disturbed and remolded mud,the mechanical properties of cement solidified sludge are studied from the perspective of soil structure.It is found that the solidified sludge is a typical structural soil with obvious consolidation yield stress,and the mechanical properties of the solidified sludge are significantly different before and after yielding.The compression curve of solidified sludge is located above the inherent compression curve of sludge.The compressibility of solidified sludge before yielding is very small,and the compressibility increases rapidly after yielding.The more cement is added,the greater the consolidation yield stress of the solidified sludge is.In the consolidated undrained shear test,if the solidified sludge does not yield under the confining confining pressure,it exhibits the properties of overconsolidated soil when sheared.If it yields under confining pressure,the solidified sludge will show the properties of normal consolidated soil.Before yielding,the undrained strength of solidified sludge basically does not change with the confining pressure,and the strength after yielding increases linearly with the confining pressure.The cohesion and internal friction angle increase with the addition of cement.The strength of solidified sludge is controlled by cementation before yield and by fabric after yield.In the practical engineering application of solidified sludge,its unique structural mechanical properties should be considered.