Mechanical property and economic effect of contractible concrete filled steel tube support

The finite models of U-steel support,grid steel frame,hollow steel tube support and concrete filled steel tube support were established,of which mechanical properties and influencing factors such as bearing capacity and support effect were analyzed.Comparative analysis of economic benefit was carried out through research of material dosage and support effect index.A contractible joint for concrete filled steel tube was designed,and its mechanical characteristics were analyzed through testing.The results showed that the supporting performance of the concrete filled steel tube support is related to the confinement coefficient.Compared with traditional support,the concrete filled steel tube support has high bearing capacity,intensive later strength,good ductility,various standards and good economic benefits,and in conjunction with the contractible joint,it is able to implement functions of quantitatively increasing resistance and yielding.Properly designed through optimization analysis on associated effects,the concrete filled steel tube support can meet the support demand of deep soft rock and joint broken rock.