Basic requirements for pipe jacking construction of concrete precast components

Basic requirements for pipe jacking construction of precast concrete components:

1 When the jacked steel pipe uses steel mesh cement mortar and rib plate protection layer, the external anti-corrosion layer at the welding joint should be made up after welding.

2 When using reinforced concrete pipes, the interface treatment should comply with the following regulations:

Before the pipe joint enters the soil layer, the outside of the joint should be padded with flax, linoleum or wooden pads, and a gap of 10 to 20mm should be left inside the pipe opening; the gap between the two pipes after tightening should be 10 to 15mm; after the pipe joint is put into the soil, when installing an internal expansion ring at the adjacent interface of the pipe joint, the pipe joint interface should be located in the middle of the internal expansion ring, and the gap between the internal expansion ring and the pipe should be plugged with a wooden wedge.

3 When using T-shaped steel collar and rubber ring waterproof interface for pipe jacking construction, the following regulations should be met:

The surface of the concrete pipe joints should be smooth and flat, without blisters or bubbles; the interface size should meet the regulations; the appearance and cross-sectional structure of the rubber ring should be dense and uniform, without defects such as cracks, pores or dents; it should be kept clean and free of oil stains before installation, and should not be exposed to direct sunlight; the steel collar interface should have no defects, the welded joints should be flat, the ribs should be perpendicular to the plane of the steel plate, and anti-corrosion treatment should be carried out in accordance with the design regulations; the thickness of the wooden liner should be compatible with the design jacking force.

Prefabricated reinforced concrete structure is a reinforced concrete structure that is mainly composed of reinforced precast concrete components and is assembled, connected and partially cast in place. Compared with traditional cast-in-place reinforced concrete components, precast concrete components can speed up construction through standardized production and mechanized construction, ensure project quality, significantly reduce construction waste, dust and wastewater emissions, reduce construction noise, and truly be green and environmentally friendly.

The external wall insulation system mainly consists of the base layer (reinforced concrete wall), bonding layer (bonding mortar), insulation layer, plastering layer (alkali-resistant mesh cloth + plastering glue + anchor bolts), and facing layer. It can effectively avoid thermal and cold bridges in buildings and has become a widely used thermal insulation system.

Under normal use and maintenance, the service life of the exterior wall insulation system should not be less than 25 years [1]. However, in actual use, accidents of the insulation layer falling off are common. Therefore, the safety of the external wall insulation thin plastering system is particularly important. There are many factors that affect safety. Take the EPS exterior wall insulation and thin plastering system as an example.