A construction method of underground pipeline after shield construction is developed as the pipe jacking construction, it does not need the excavation surface layer, and the ability to cross the roads, railways, rivers, buildings, underground structures and various kinds of underground pipeline construction, water supply and drainage, gas, electricity, communications and other pipelines are more widely used in the. However, the construction equipment, technology and management level of pipe jacking construction units are uneven, and some problems often appear in construction, which affect the quality of construction.
I. characteristics and technology of pipe jacking construction
1, pipe jacking construction characteristics
(1) in the construction of advanced pipe jacking, no road closure is required, and the selected working wells and receiving wells are located at the unused places.
(2) it needs no excavation, backfill and pavement repair, so it can reduce the total cost of the project compared with the large excavation.
(3) to avoid the bad phenomenon. Chaos stacked mud slurry hexini cycle construction method, ensure that the natural environment is not polluted, can do the construction of civilization.
(4) advanced pipe jacking method is fully automatic remote control, a worker does not need to work in the pipeline, so that not only eliminates the heavy manual workers, the workers also have enough to ensure safety.
(5) to promote the process of advanced pipe jacking boring machine and around the pipeline between the active earth pressure and passive earth pressure, the soil disturbance is few, so it will not lead to the crack of pavement settlement, avoid resurfacing.
2 、 pipe jacking construction technology
The pipe jacking construction technology is a kind of pipeline paving technology, without digging the ground, with a large thrust hydraulic jack used in pipe jacking machine with remote control device in the rear, the heading machine followed by a pipeline through soil, reach the pre designed position, this is called the top of pipe engineering. The excavation takes place in front of the pipe jacking machine, and the excavated material is pumped out through the mud circulation system to reach the surface. The basic principle of pipe jacking construction from the ground excavation pit two wells, then the tube section from work well placed by the main roof jack or relay between pushing machine of the top, the push pipe section from the well reserved hole piercing through the soil reaches the receiving well reserved port side, then through the reserved hole piercing the receiving well, the formation of pipeline construction.
At present, the construction method of pipe jacking construction used is divided into open artificial hand dug type mechanical seal and pipe jacking construction method, including mechanical pipe jacking construction method commonly used and slurry type and soil pressure balance type of two kinds of commonly used pipe jacking construction, concrete pipe, steel pipe, glass sand pipe.
Now more commonly used for pipe jacking construction of slurry balanced pipe jacking construction method, the construction principle: the guiding head cutting rotation function of clay, sand and stone will be broken by a steel pipe, injection of water, mix slurry, slurry sucked out by another pipe, the slurry in a centrifuge centrifugal dehydration, then the dry in the car to dump to spoil the place, the separated water back to the storage tank is used repeatedly. The main equipment used in the construction is information-based and fully automatic slurry balance pipe jacking machine.
