Research Of Factors Influencing The Deformation Joint Set In Open-cut Underground Structures And Engineering Applications

ABSTRACT:With the development of Chinese economy and traffic cause, urban rail transit is playing an important role in city’s development. At this stage,our country has skills and experience to build long tunnels and underground railways, but from the point of the waterproof requirement to structure, the waterproof performance is not ideal despite considering in the design. Deformation joint is a generic name of expansion joint and settlement joint, its main function is to adapt the deformation and settlement of engineering structure, which avoids the damages to the structure. Although the deformation joint set can solve the non-uniform deformation of tunnel, optimize the stress condition of structure, it also increases the difficulty of the tunnel structure waterproof. Based on this, this paper studies on factors influencing the deformation joint set, optimizes the distance of the deformation joint with the specific engineering, the main achievement and conclusion of this paper is as follows:(1) Through the research of design specifications and specific engineering about deformation joint, China is a country with a vast territory, its climate and geographical features are various. From the point of the waterproof requirement, the deformation joint should be less set or not set;(2) With numerical simulation methods,3-D load-structure model of tunnel construction is set up in different factors to analyse the influence mechanism of geological factor, temperature factor and structural change factor, which can provide the theory basis for optimizing the distance of deformation joint;(3) The specific projects are applied in optimizing the distance of deformation joint, combining the Dongxiaoying open-cut station of Beijing Subway and Gongbei open-cut tunnel. According to the actual situation of engineering, the main affecting factors in Dongxiaoying open-cut station are geological factors and structural change factors; the main affecting factors in Gongbei open-cut tunnel are temperature factor and structural change factors;(4) With numerical simulation methods, the specific projects are applied in optimizing the distance of deformation joint. It is verified to set the deformation joint only in mutation position in Dongxiaoying open-cut station;the distance of deformation joint is optimized from the original design of the22m to100m by calculation in Gongbei open-cut tunnel.