Abstract:

The vertical mechanical behavior of composite shaft lining of high strength concrete and double steel cylinder is researched by model test and theoretical analysis. According to the similarity theory, the model of composite shaft lining of high strength concrete and double steel cylinder is designed and manufactured first. Afterward, through loading test, the vertical stress, strain and strength characteristics of the composite shaft lining of high strength concrete and double steel cylinder are gained. The results indicate that the concrete compressive strength increases 1.73－1.92 times under triaxial compressive stresses state because of inner and outer steel plate cylinder restriction, and the concrete utmost compressive strain reached -3900με. The shaft lining is fairly plastic when it was damaged. By mutual restriction between steel plate and concrete, their mechanical performances are improved; and shaft lining vertical bearing capacity increased evidently, which are far greater than sum of vertical ultimate bearing capacity of steel cylinder and middle concrete. Then a formula for calculating the shaft lining ultimate bearing capacity is given on the basis of the theoretical research and experimental results. Thus, the studied results can provide a reference for the theoretical study and engineering application of this kind of shaft lining structure.

Key words: super-deep alluvium, vertical additional force；steel plate, high strength concrete, shaft lining, vertical bearing capacity