Optimization of steel joint structure

Optimization of steel plate partition scheme for steel joint connection

In the preliminary design of steel joint, the inner and outer ring panels are divided into many blocks. Taking a section of steel joint overhead wall as an example, in the length of 2.2m (clear distance between two diaphragms), the inner and outer ring connecting steel plates are divided into blocks, as shown in the upper part of Figure 2. There are six steel plates in the outer ring of the steel joint, which are connected by T-rib field welding; in the longitudinal direction of the tunnel, they are welded with the steel cap of the adjacent pipe section and the steel structure of the final joint. There are also six steel plates in the inner ring of the steel joint, which are connected on site through l-rib; in the length direction of the tunnel, they are welded with the steel cap of the adjacent pipe section and the steel structure of the final joint. According to the statistics, within the range of 2.2 meters, the weld length is about 25 meters, and the total weld length of the whole steel joint is 4200 meters.

After preliminary evaluation, on the premise of ensuring the mechanical performance of the whole structure of the steel structure does not decline, we take the following methods to re divide the steel plates connected by the steel joints, so as to reduce the workload of on-site welding and ensure that the welding quality is more controllable.

(1) The connecting steel plate of the steel joint, the key geometric positioning dimension of the diaphragm, the thickness and material of the plate remain unchanged;

(2) The key geometric positioning dimensions of the steel joint on the cross section of the tunnel, including the connecting steel plate and diaphragm, remain unchanged;

(3) The inner ring of the steel joint is reduced, the outer ring is connected with the steel plate, and the T rib and l rib are replaced by flat steel.

After the steel joint connecting steel plate is partitioned and adjusted, take the connecting steel plate within the 2.2m length of the steel joint as an example, and the partitioned situation is shown in the lower part of Figure 2.

There are two steel plates in the outer ring of the steel joint, which are connected by butt welding; in the longitudinal direction of the tunnel, they are welded with the steel cap of the adjacent pipe section and the steel structure of the final joint.

There is only one steel plate in the inner ring of the steel joint, which is directly butt welded with the adjacent steel plates; in the longitudinal direction of the tunnel, it is welded with the steel cap of the adjacent pipe section and the steel structure of the final joint. It is estimated that within the range of 2.2m in length, the weld length is about 12m (also without considering the welding of diaphragm). Compared with that before the block adjustment of connecting steel plate, the weld length is reduced by more than 50%, and the weld length of the whole project is reduced to 2000m.