考虑颗粒破碎的固化泥粒-砂土混合填料压缩特性研究

Study on Compression Characteristics of Solidified Mud-Sand Mixed Fillers Considering Particle Breakage

固化泥粒与砂土的混合填料为废弃工程泥浆的资源化处置提供了理想解决方案,而填方工程的压缩特性与混合填料的强度特性及颗粒破碎特征密切相关。该文通过开展不同颗粒级配的混合填料大尺寸压缩试验,建立考虑颗粒破碎的固化泥粒‒砂土混合填料的侧限压缩试验离散元(DEM)模型,探究了压实过程中混合填料压缩模量变化和固化土颗粒破碎量,重点分析了固化泥粒掺入比与初始孔隙比等因素对混合填料的压缩特性和应力‒应变关系的影响规律,并论证了混合填料用于填方工程的可行性。结果显示:密实条件下固化泥粒‒砂土混合填料的压缩性与泥粒掺入比呈正相关,而与泥粒强度呈负相关,并且一定固化泥粒的掺入可有效降低松砂在低应力水平下的压缩性,而高应力水平下受泥粒破碎的影响导致混合填料压缩性稍有提升;混合填料在压缩过程中,其颗粒破碎度随泥粒掺入比和砂土初始孔隙比的增加而提高,且在压缩终态破碎率均趋近于80%。

The mixed filler of solidified mud and sand provides an ideal solution for the resourceful disposal of wasted engineering mud,and the compression characteristics of filling engineering are closely related to the strength characteristics and particle breakage characteristics of mixed fillers.This study conducted large size compression tests on mixed fillers with different particle gradations and established a discrete element method(DEM)model that incorporated particle breakage for the side-limited compression tests of solidified mud-sand mixed fillers.The changes in the compression modulus of the mixed fillers and the amount of solidified soil particle breakage during compaction were investigated.The study placed a special focus on analyzing the impact of factors such as the solidified mud mixing ratio and the initial void ratio on the compression properties and the stress-strain relationship of the mixed fillers.It also demonstrated the feasibility of using mixed fillers in filling engineering.The results show that under compacted conditions,the compressibility of the solidified mud-sand mixed fillers is positively correlated with the mixing ratio of clay particles,but negatively correlated with the strength of mud particles.The addition of a certain amount of solidified mud particles can effectively reduce the compressibility of loose sand at low stress levels.However,the compressibility of the mixed fillers slightly improves due to the breakage of mud particles at high stress levels.In the compression process,the degree of particle breakage in the mixed filler increases with the increase in mud mixing ratio and sand initial void ratio,and the final breakage rate tends to approach 80%at the end of compression.