Construction method for cathode protection device for underground pipeline system

Abstract

The invention discloses a construction method for a cathode protection device for an underground pipeline system. The construction method comprises the following steps of: 1, drilling downwards from the ground surface (101) above the outer part of an underground pipeline (1); 2, mounting a hollow external protection pipe (2) in a hole which is drilled in the step 1 to ensure that the front end of the external protection pipe (2) contacts the outer wall of the underground pipeline (1); 3, lowering down a waterproof sleeve (5), ensuring that a feed connector (402) which is fixedly arranged at the front end of the waterproof sleeve (5) closely contacts the outer wall of the underground pipeline (1) without moving, and welding; 4, welding the feed connector (402) which is fixedly arranged at the front end of the waterproof sleeve (5) and a metal part of the underground pipeline (1) together; and 5, constructing a sacrificial anode (7). The construction method is comprehensive in technology, has an obvious effect and is convenient to construct and operate. The invention relates to systematic engineering, so that a great number of contents are involved. The construction method is high in technical maturity and has predictable extremely high economic values and social values.

Description

technical field [0001] The invention relates to the scientific field of underground pipeline protection technology, and in particular provides a construction method for a cathodic protection device for an underground pipeline system. Background technique [0002] In the prior art, the use of large-diameter steel water delivery pipelines has the advantages of safety, reliability and short construction period, and is a relatively common method in current water delivery projects. This process is mainly to carry out pipe jacking and burying through the operation between the working shafts. Except for the working shafts, other pipelines pass through the ground without ground excavation. It is difficult to completely solve the durability problem of pipe jacking by using the traditional corrosion protection technology, which affects the durability of the pipeline. Innovative design and construction techniques bring new challenges. Judging from the situation of the pipe jacking pip...

AI Technical Summary

Problems solved by technology

[0010] 1) Reserve corrosion allowance: use thick-walled large-diameter steel pipes, and rely on the corrosion allowance of the steel itself to meet the design life requirements. This method requires a lot of steel resources, and the manufacturing and installation costs are high, and the construction period is long. Professional pipe-making equipment, there are still many mechanical problems for large-diameter steel pipe jacking

In addition, the steel pipe jacking with only corrosion allowance may produce unpredictable damage due to localized corrosion and stress corrosion in soil corrosion environment

At the same time, at present, my country rarely has the ability to mass produce large-diameter ultra-thick-walled steel pipes.

[0011] 2) Corrosion-resistant alloy steel: In the past 50 years, material scientists have developed a variety of corrosion-resistant low-carbon alloy steel and stainless steel, including 10CrMoAl, 304, 316L and 00Cr26Ni7Mo2Ti, etc., although its corrosion rate is more than 2 times lower than that of ordinary carbon steel, However, the welding process is complicated, and it is easy to cause serious pitting corrosion, galvanic corrosion, stress corrosion, etc. in the welding part and heat-affected zone, thereby reducing the overall safety of the structure used, and the cost is also high

[0023] 2. Problems faced by corrosion protection of steel pipe jacking

However, the traditional sacrificial anode cathodic protection method follows the burying of the sacrificial anode during the pipeline laying process, but this method cannot be implemented for the grass-sand top pipeline of the non-excavation construction

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