淤泥EPS颗粒轻质土单向压缩下渐进性破坏研究

Study on the Progressive Failure of Lightweight EPS-Bead Treated Soil Made from Dredging Silt under Uniaxial Compression

在疏浚淤泥中添加固化材料和轻质材料,将其转化为新型土工材料-轻质土,是疏浚淤泥资源化利用的有效方法之一。通过单轴压缩下宏观、细观力学试验,对疏浚淤泥EPS颗粒轻质土试样的变形特性及破坏机理进行了分析。试验结果表明,在荷载作用下,轻质土试样变形破坏具有明显的渐进性特征。渐进性破坏过程包括细观裂纹产生的线弹性变形阶段、细观裂纹稳定扩展的弹塑性变形阶段、细观裂纹整体贯通的破坏阶段。渐进性破坏产生的主要机理在于:一是在EPS颗粒与固化土结合面处局部存在的原生微裂纹;二是固化土胶结强度的逐渐丧失与固化土摩擦强度的逐渐发挥二者不同步。

One of effective resource utilization measures of dredging silt is light-weight technology by mixing dredged silt with solidification and lightweight materiais. The deformation properties and failure mechanism of lightweight soil were studied by macroscopic experiment and microscopic experiment under uniaxial pressure. The results show that the failure of lightweight soil sample is progressive failure process, including linear elastic deformation stage of meso-craek generation, elastic-plastic deformation stage of stable meso-crack extension and softening stage of meso-crack complete holing-through. There are two main factors influencing progressive failure under load. One factor is the existence of primary micro--cracks at the interface between EPS beads and solidified soil particles, the other is the asynchronous response of gradually loss of cementing strength and gradually getting of solidified soil particles friction strengthening.