不同水环境下土石混填地基水平推剪试验研究

Horizontal push-shear test of soil-rock mixture filled foundation under different water environments

为了研究土石混填地基的承载特性与变形机理尤其是不同水环境对其有何影响,在特制的地槽内分别开展正常条件、饱水浸泡、干湿循环作用下的土石混填地基水平推剪试验研究,得到试样在不同条件下更加完整的破裂面、抗剪强度及推剪变形曲线。研究结果表明:土石混填地基的抗剪强度主要源于其内部土石料之间的相互摩擦、咬合等作用;在正常条件下可表现出良好结构性,其破裂面会发展到底面之下一定深度;干湿循环对试样的黏聚力有较大影响,对其破裂面、内摩擦角及推剪变形过程影响有限;饱水浸泡对试样的破裂面、抗剪强度及推剪变形过程均有很大影响,尤其是试样抗剪强度会大幅度降低,故在相关工程实践中须予以足够重视。

In order to study the bearing characteristic and deformation mechanism of the soil-rock mixture filled foundation, especially the impact of different water environments, the horizontal push-shear test of soil-rock mixture filled foundation was carried out under normal condition, rain-fall soak and dry-wet cycling in a special model tank respectively, and then the more complete and real fracture surface, shear strength index and shear deformation curve of samples were gotten in different conditions. The results show that the shear strength of soil-rock mixture filled foundation is mainly caused by mutual friction, mesh and embedding of aggregated rock. The samples has good constitutive property under normal condition, and its fracture surface will exceed the sample＇s height. Dry-wet cycling have great influence on the cohesive force of sample, but it has little impact on the sample＇s fracture surface, internal friction angle and shear deformation process. Rain-fall soak has great influence on the fracture surface, shear strength and shear deformation process of sample. Especially, the samples＇ c（cohesion） and φ（internal friction angle） greatly reduce, and hence enough attention should be paid in the relevant engineering practice.