The Design And Optimization Research Of Deep Freezing Bedrock Double Shaft Lining In West Area

Since2000,with the implementation of the western development strategy in our country, the largest ever new shaft began to build in the region.The engineering and hydrogeologic conditions is very different between the north China plain in eastern region and the western region for the Jurassic cretaceous strata.The current design and construction of freezing method sinking (discipline) are based on the condition of the eastern region, can’t simply copy.In western region, freezing method sinking mostly through the Jurassic cretaceous to frozen deep bedrock, frozen pressure is small, frozen is given priority to with pore water seepage field, the Jurassic cretaceous rock with water sand, mud is characterized.Although using single layer shaft lining can reduce costs, but the shaft lining summer-planting leaking badly.Engineering practices show that the grouting between the internal and external shaft structure., which can effectively block shaft leakage.If we simply uses the current specification, it is bound to cause the inner shaft thickness.Therefore, based on the condition of the western region, the double shaft structure characteristics, to optimize the design of the inner wall, effectively reduce its thickness, is the deep freeze presses for solution of technical problems.Based on the characteristics of the western region, revealing the deep bedrock freezing method sinking double shaft structure characteristics, and providing a basis for optimizing design of shaft wall.First of all, we see shaft cross section as the plane problem, sidewall mechanics model is set up, the internal stress calculation formula is given, analysis its stress state.Then, through the similar model test, we studied shaft lining structure stress-strain relationship which under the action of uniformly distributed confining pressure, it is concluded that the lining inside, the lateral margin of maximum stress and the ultimate bearing capacity.Followed by using ABAQUS finite element analysis software, the establishment of shaft lining structure calculation model, the numerical simulation of structure stress, comparing the simulation results and test results, verify the validity of the model test results.Finally,root theory and experimental results, It is concluded the deep freeze double wall structure concrete strength coefficient which adapt to the western region of bedrock, provides important parameters for casing optimization design.The research results show that concrete strength heightened coefficient formula calculating the ultimate bearing capacity of the wall is feasible.At the same time, To optimize the wall thickness is right, because the wall is actually under multiaxial stress effect.So the optimization measures provides reference for the design of the sidewall.