Study On Axial Compression Mechanical Behavior Of Ice Filled Steel Tubular Stub Columns

Concrete is widely used in the engineering construction field in its source of raw materials, simple process, low production cost. But in permafrost regions, especially in the polar regions, the use of concrete is limited, so the ice is a material that shows its advantages. Because of its low strength and poor deformation ability, it can not be widely applied to the engineering field. Refering to working principle of concrete filled steel tubular structure, we propose a combined structure of ice filled steel tubular column in this paper and carry on some related mechanics experiment research. The specific research contents are as follows:(1) A total of 9 circular ice filled steel tubular short column whose steel tube wall thickness were 2mm,3mm,4mm, respectively and a total of 9 square ice filled steel tubular short column whose steel tube wall thickness were 2mm,3mm,4mm, respectively were test under monotonic axial compression. The test parameter is steel tube wall thickness. The test results show that The core ice compression strength and deformation ability have been greatly improved because it is in the triaxial stress state; Because of the low strength of ice, the axial bearing capacity of the steel tube accounts for the majority of the bearing capacity of the specimen. With the increase of the thickness of steel tube, The lateral restraint of core icicles confined is more and more strong; Compared with the square steel tube, circular steel tube have a better lateral restraint on core icicles, so the bearing capacity and deformation capacity are higher.(2) Based on the test data, the stress analysis was carried out on the test piece. We finally get axial stress-axial strain relation curves, lateral stress-axial strain relation curves, equivalent stress-axial strain relation curves, restraint stress-axial strain relation curves of steel tubes and axial stress-axial strain relation curves of core icicles.The above analysis separates the complex stress state of steel tubes and concrete, which in turn intensify the understanding and knowledge about the interaction of steel tubes and icicles.(3) Based on the stripping analysis, we get the stress-strain data of core icicles. Through regression analysis, we obtain the constitutive models of the core icicles which are in complex stress fields under the condition of this experiment. By comparing with the experimental data, the results are in good agreement with the experimental data. Because of the single test parameter, further study is needed to verify the correctness of the constitutive model. In addition, the formula of the ultimate bearing capacity of the steel tube icicles is established.