Installation method steps and principles of ductile iron pipe jacking method

The ductile iron pipe jacking method can be used to install pipelines underground without digging trenches, and can also be used to lay pipelines in tunnels. The ductile iron pipe jacking method has the following advantages:

(1) Since the interface protrusion is small and all connection work can be performed from inside the pipe, the space between the inside of the tunnel and the outside of the pipe can be made smaller.

(2) Since there is no need to consider fire or electricity when connecting pipes in a tunnel, the work can be performed safely.

(3) Due to the mechanical interface, the installation work is simple and fast.

Due to the high flexibility of the mechanical interface of ductile iron pipes, this kind of pipe can also be used to lay pipes in curved parts of tunnels.

The installation steps of ductile iron pipe jacking method are as follows:

(1) Before inserting the socket (socket), apply thick soapy water on the outside of the socket, the inside of the socket and the rubber ring.

(2) After insertion, put the rubber ring on the socket and push it with your fingers to a position where you can gently insert it.

(3) Insert the opening ring (divided into 3 arc-shaped pieces) from the bottom in sequence, first install two I's on the bottom, then slide H towards the tube axis and rest it on top of the I's to assemble. When inserting the three arc pieces of the opening ring into the socket, if there is a large gap between the arc pieces, insert an arc piece that fills the gap between I and I on the arc piece ( Same cross-section as the opening ring, same material, thickness 6mm).

(4) Insert the compression ring (divided into 4 arc pieces) screwed into the bolt from the bottom in sequence. In order to prevent the II from falling off, it is fixed with a fixing piece. The fixing piece is to prevent the upper compression ring from falling off during the installation operation.

After installation, due to the rebound force of the rubber ring and the arching effect of the cement mortar filled between the gland ring and the bottom of the socket, the risk of the upper gland ring falling off no longer exists and can be removed. However, it is also possible to leave the fixings as they are. For the sake of caution, they are usually galvanized.

(5) Use a wrench or ratchet wrench to rotate part of the bolts of the compression ring (approximately 1 out of 3 bolts) so that it is screwed out by 35-40mm from the compression ring, thereby removing the rubber. The circle pushes people deep.

(6) Install the fixing pin on the flat cap of the bolt head that has not yet been unscrewed.

(7) Slightly unscrew the bolts with the fixing pins installed, tighten the starting bolts one at a time, and install the fixing pins on their heads (all the bolts have been installed with the fixing pins).

While making sure that the unscrewed gaps are equal up, down, left, and right, unscrew all the bolts. When the gap between the compression ring and the bottom of the socket reaches the specified length, the installation is complete.

General principles for the installation of ductile iron pipes:

(1) Water supply and gas pipeline projects should be constructed in accordance with design documents and construction drawings. Ductile iron pipes and fittings should comply with the relevant national product standards (GB1329) or the current international standards (ISO 2531), and should be factory-qualified. Certificate, the materials of pipes used for domestic drinking water must not pollute water quality. The construction of water supply and gas pipeline projects should comply with relevant national and local regulations, and project acceptance should comply with relevant national standards and specifications.

(2) Before the construction of water supply and gas pipeline projects, the design unit should conduct design briefings, conduct investigations and studies according to construction needs, and master the following conditions and information along the pipelines.

(3) The conditions of the site topography, landforms, buildings, various pipelines and other facilities.

(4) Engineering materials, hydrogeology, engineering land and construction water, drainage conditions, power supply conditions, etc.

(5) Supply conditions of engineering materials and construction machinery.

(6) When constructing in surface water bodies or on the shore, the hydrology and navigation data of the surface water should be mastered; when constructing in cold areas, the data on surface water freezing and drifting ice should be mastered.

(7) Other information and information based on project characteristics and site conditions.

(8) If drainage is required, a drainage construction design should be prepared. Construction drainage should consider a series of drainage issues such as drainage not affecting traffic and not damaging roads, farmland, riverbanks and other structural buildings.