In the preliminary design of steel joints, the inner and outer ring panel is divided into many parts. Taking a section of the top wall of steel joints as an example, on the length of 2.2 meters (the net distance between the two partitions), the inner and outer ring plate is divided into parts as shown in Figure 2. There are six steel plates in the outer ring of the steel joint, which are welded in situ through T ribs, and in the lo
ngitudinal direction of the tunnel, they are welded with the cap of the adjacent pipe joints and the steel structure of the final joint. There are also six steel plates in the inner ring of the steel joint, which are joined in situ through L ribs. In the length direction of the tunnel, they are welded with the caps of the adjacent pipe joints and the steel structure of the final joint. According to the statistics, the length of the weld is a
bout 25 meters in the range of 2.2 meters. The total length of the weld of the whole steel joint is 4200 meters by calculation.
After preliminary evaluation, on the premise of ensuring that the mechanical properties of the whole steel structure do not decline, we adopt the following methods to re-divide the steel joint connection plates, so as to reduce the workload of field welding and ensure that the welding quality is more controllable.
(1) The connecting steel plate of the steel joint, the key geometric positioning dimensions of the diaphragm and the thickness and material of the diaphragm remain unchanged.
(2) The key geometric locating dimensions of steel joints in tunnel cross section, including connecting steel plates and partitions, remain unchanged.
(3) Reduce the inner ring of steel joint, the outer ring is connected with steel plate, and T-rib and L-rib are replaced by flat steel.
