Stability Study On Vertical Reducible Joint

In the recent years, more than one hundred coal mine shaft rupture accidents have been taken place in many parts of the coal mine areas.The vertical additional force problem did not recapture people’s attention until recently.When in the special stratum conditions, the shaft lining will bear not only the weight of gravity includes equipment, but also the vertical additional force from the aquifer dewater.When the displacement of shaft lining is greater than the downward displacement of stratum, the outside surface of shaft lining will be affected by the upward vertical additional force; On the other hand, it will be affected by the vertical additional force downward effect.The reason of the most shaft rupture accident is that the soil consolidation settlement around the shaft leads to the shaft accepts a considerable downward vertical additional force, and causes the vertical load of the shaft increase, eventually leads to the shaft damage due to insufficient strength. The best way to solve this problem is to reduce the vertical stiffness of the shaft; And that is to set a number of vertical expansion joints in shaft.Most of the mine contractible shaft joints are combination of steel structures, and the steady performance of steel structure is an important factor to determine its bearing capacity; Therefore the stability study of reducible joint has become an important research topic.This thesis will take the Qinan mine skip shaft and Taohu main shaft of Huaibei Mining (Group) Co., Ltd for example, and has researched the ultimate bearing capacity and the vertical stability of the reducible joint by the method of combining theoretical analysis and numerical simulation This thesis has comparative analysed the mechanical properties of the reducible joint structure in the different size and structure.Studies show that the ultimate bearing capacity of the reducible joint is less affected to the height, primarily related to the cross-section of the upright plate and location; when the vertical ultimate bearing capacity of reducible joint less than the corresponding non-linear bucklingcritical load, the structure will not occur vertical instability and failure, and the vertical ultimate bearing capacity of the structure is the vertical design calculation control load.On the contrary, the structure will occur vertical instability and failure, and the structure of the non-linear buckling vertical design load is calculated to control the load. And the nonlinear buckling critical load of the structure is the vertical design calculation control load.