基于浸水载荷试验的粗粒填土地基工程特性研究

以贵州省凯里市某建筑场地的大区域粗粒填土地基土为例,对填土的物源组成、粒度级配、最大干密度、最优含水率、压实度、密实度等物理力学指标进行了室内实验和原位测试研究的基础上,选择3个代表性试验点开展了初始浸水压力为200 k Pa的浸水载荷试验研究。研究发现粗粒填土地基浸水载荷试验的荷载与沉降关系曲线表现出四个不同变形特征的变形阶段,即细颗粒压缩变形阶段、细颗粒软化蠕变变形阶段、粗颗粒压缩变形阶段和粗颗粒剪切滑移变形阶段。结合填土地基的粒度组成和结构特征,分析了各变形阶段对应的内在变形机理。研究认为,揭示粗粒填土地基的变形机理对建筑物地基采用变形控制设计具有重要的指导意义,有利于克服填土地基上因填土不均匀性造成建筑物不均匀沉降的传统难题。

Study on engineering properties of soil foundation based on load test for coarse filling soil in the case of immersion

Taking large area of coarse grain filling foundation soil at a project site In Kaili City, Guizhou province as an example, the composition of the source, soil particle size gradation, maximum dry density, optimum moisture content, degree of compaction, density and other physical and mechanical indexes was studied on the indoor experiment and in-situ test. Three representative test points were picked to carry out flooding load test which initial inundation pressure is 200kPa. The authors found that the relationship curve between load(P) and settlement(S) show four deformation stage representing four different deformation characteristics conformably, namely the fine particle compression deformation stage, fine particle softening creep deformation stage, coarse grain compression deformation stage and coarse particle shear slip deformation stage. Combining with the grain size composition and structure characteristics of backfill foundation, authors analyzed the internal mechanism of deformation in different deformation phases respectively. Finally, authors think that to reveal the deformation mechanism of coarse grain filling foundation for building foundation has the important guiding significance in deformation control design, which helps to solve traditional problem of uneven settlement of buildings caused by the heterogeneity of backfill foundation.