Mechanism Analysis Of Middle Pillar In The Simple Reverse Construction

As China’s economic development, there are more and more high-rise buildings,the foundation pit of these buildings are in many forms. The reverse method has itsunique features and reflects a distinct advantage high-rise building construction. Then,The reverse method has been widely used in civil air defense projects, subway and otherunderground structures construction. With the use of reverse construction cases in Chinaincreasing, reverse construction technology is maturing. However, the process ofreverse construction engineering mechanics theory to be further in-depth. The studies ofinteraction of soil, middle pillar piles and Concrete diaphragm wall are insufficient.The SHUYUAN road air defense project is the first case of the reverse method.The reverse method which this project utilized is different from the classic reverseconstruction technology. There are not pre-built Concrete diaphragm wall, The middlepillar pile and soil take the upper load, set up temporary vertical support after theexcavation, and construct the steel reinforced concrete structure columns at the sametime. After the column structure to achieve capacity requirements, removed temporaryvertical support. We call this construction method being known as the simple reversemethod.In this article, studied the interaction of soil and middle pillar piles in the absenceof the conditions underground continuous wall. Derive the joint effect of pile-soilstiffness matrix. Obtained the common equation of the pile, the soil and upper structurefor simple reverse construction.The SHUYUAN road air defense project in Qingdao was taken as an example.ANSYS finite element software was used for the simulation analysis of the typicalrange of three-dimensional modeling. ANSYS could not only accurately simulate theconstruction of pit excavation, but also effectively analysis the distribution of pressurebetween the middle pillar pile and soil. The research in the article described the changerule of axial force of the middle pillar pile in different excavation sequence, when themiddle pillar pile and soil taking the upper loads together. This article also explores the load sharing ratio between the middle pillar pile andsoil when the pillar pile take the type of1000mm concrete bored piles or800mm steelpipe pile.