考虑流固耦合效应的砂土注浆加固机理分析

Analysis of Grouting Mechanism Considering the Natural Structure of Sandy Soil

砂土层具有典型的非均质性和原位变异性,注浆过程存在浆液与砂层的流固耦合效应。将随机性与分形理论结合,基于Diamond-square算法构建考虑砂土力学性能参数空间变异性的物理模型,采用精细化的流固耦合多物理场模型,对浆液在砂土介质中的扩散规律进行分析,并探讨注浆前后砂土在荷载作用下的应力和变形特性。研究表明构建的砂土随机分形模型,能够反映地层地质信息条件的差异性,可以准确揭示复杂应力、结构状态下,砂土注浆的基本规律和特征。浆液沿孔深呈不规则形状扩散,不同深度处浆液有效扩散半径各不相同,浆液扩散变化、有效填充范围,与砂土分形结构呈现高度一致性。注浆加固前砂土结构松散,应力传递方式单一,加固后砂土胶凝形成二次结构,荷载传递过程中产生应力集中现象,砂土承载潜力得到充分发挥。注浆加固减小了砂土层的沉降变形,显著提升了砂土的物理力学性能。

The sand layer has typical heterogeneity and in-situ variability,and there is a fluid solid coupling effect between the slurry and the sand layer during the grouting process.Combining randomness with fractal theory,a physical model considering the spatial variability of sand mechanical performance parameters was constructed based on the Diamond square algorithm.A refined fluid solid coupling multi physical field model was used to analyze the diffusion law of slurry in sand media,and the stress and deformation characteristics of sand under load before and after grouting were discussed.Research has shown that the sand random fractal model constructed in this article can reflect the differences in geological information conditions of the strata,and accurately reveal the basic laws and characteristics of sand grouting under complex stress and structural states.The slurry diffuses in an irregular shape along the depth of the hole,and the effective diffusion radius of the slurry varies at different depths.The diffusion changes and effective filling range of the slurry are highly consistent with the fractal structure of sand.Before grouting reinforcement,the sand soil structure was loose and the stress transmission method was single.After reinforcement,the sand soil cemented to form a secondary structure,causing stress concentration during the load transfer process,and the bearing potential of the sand soil was fully utilized.Grouting reinforcement reduces the settlement deformation of the sandy soil layer and significantly improves the physical and mechanical properties of the sandy soil.