Analysis Of The Influence Of Shield Construction On The Force Of Segment Structure

The shield segment is the skeleton of the subway tunnel and the safety performance of the segment has a critical influence on the entire project of the subway. In the process of the construction, the segment structure not only bear the pressure of the surrounding formation, but also need to take the cylinder thrust force and the constantly increasing grouting pressure which is outside the segments of the shield. The change of the factors of the external loads will bring some influences on the segment and the segment joint. With the increasingly widespread application of the tunnel, the stress characteristics of the shield segment during the process of the construction have caused more and more attention of engineers. In the research, taking the background of the interval from Lin Dun Lu station to Chang JIE station of the Su Zhou Nol subway, there is a research to the situation of the equivalent stress of the segments and the mechanical state of the segment joint and so on, the following is the main contents:(1) The commonly used mechanical model of the segment joint is analyzed and the appropriate mechanical mode is optimized and selected. On the base of optimizing a reasonable calculation theory, the external load of the segment suffering is analyzed and calculated.(2) The ANSYS software and the discontinuous model of the beams and joints which were refinemented are used, and the joint structure is considered as surface and bolts to simulate. The different cylinder thrust force, difference angle of the cylinder thrust force, difference grouting pressure and difference angle of break joint assembly assembly are taked to comparative analyed and the stress characteristics of the shield segment is further studied.(3) Through the analysis and arrangement of the measured data, the steel stress states which is in different locations is acquired and the trend of the steel stress during the shield construction process is analyzed.