The special and complex nature of rock strata in tunnel construction requires the use of Steel Arch Support to support the tunnel and ensure its stability. The actual construction of the I-beam connection is often a weak link in the Support Arch construction, mainly due to processing irregularities, transport deformation and site technical management personnel do not pay enough attention to, thus generating some initial support deformation, cracking and other uncontrollable phenomena, which increases the risk of tunnel construction.
The connection of Steel Arch Support is divided into bolt connection and material butt joint.
Bolt connection main drawbacks: nut is not tightened, less nut; Connection plate eyes can not be; Workers construction arbitrarily, check is not in place; Lower excavation machinery collision to make the upper arch foot deformation and so on.
Arch docking drawbacks: the standard I-beam length is 9 metres a, processing machinery in shorter than 1.45 metres can not be processed arc, in an I-beam processing a unit or two units will produce the remaining material in the processing in order to make better use of the material, according to the unit of the unavoidable need to join the length of the I-beam after the material. This creates a connection problem, after the connection also need to over machining arc, in the construction of the use of butt joints, become a connection weak link, so the best way is to add steel plate on the basis of butt joints to help weld reinforcement. Increase the stiffness of the I-beam connection.
Strengthen the technical requirements of arch processing, the Underground Roof Support processing must be accepted according to 1:1 sample before installation. The arch before installation should be according to the large sample drawing for trial assembly, the same batch of the arch can be a few bays for trial assembly, at the same time in the processing of a certain number of arches need to be re-tested after a trial assembly, so that you can continue to adjust to improve the processing of Support Arch processing technology workers in the processing of technical workers in the trial assembly in the processing of technical workers continue to sum up the experience of the processing technology.
Shorten the distance between the arch processing factory and the tunnel entrance, so as to avoid the deformation of the arch in the process of transport.
Strengthen the welding technical requirements of the arch frame connecting plate, on-site technicians and inspectors should strengthen the construction quality and safety management.
Adopt multi-point control when the arch frame is erected, and each connection unit should have a point for controlling the headroom of the arch frame.
All the bolts and nuts are welded firmly after the completion of I-beam erection.
Strengthen the Support Arch construction technical briefing, technical briefing content should be from the arch processing and installation of two aspects.
