Abstract:

The technologies for the design and construction of the reservation of piles and columns of interchange nodes of interchange stations constructed by coverandcut method are studied and summarized by means of structure analysis,theoretical calculation and practical validation,in order to find solutions for the reservation of piles and columns of the interchange nodes of interchange stations constructed by coverandcut method.The contents of the paper are as follows: 1)The stressing conditions of the interchange node under different construction conditions are analyzed by means of FEM structure calculation software in consideration of the construction conditions of the longterm station,and the internal force variation trend and the control conditions of the structural elements of the interchange nodes along with the construction of the longterm station are obtained; 2)The connection between the support columns of the stations constructed by topdown method and the structural elements of the shortterm and longterm stations are studied systematically and the details of the connections between the vertical columns and piles and the structural elements are obtained; 3)The solution to support the interchange nodes by the retaining structure is discussed,so as to reduce the cost and to facilitate the construction; 4)The construction program of the longterm station,as well as the points to which attention should be paid during the construction,is proposed under the consideration of the working step conversion,so as to control the settlement and deformation of the interchange nodes.

Key words: coverandcut method, interchange station, interchange node, reservation of piles and columns, stressing condition, vertical piles and columns, retaining structure