Online automatic monitoring of urban integrated pipe gallery
Introduction of integrated pipe gallery
The integrated pipe gallery system is mainly composed of the pipe gallery body, auxiliary systems and control center. Among them, the main body of the integrated pipe gallery includes: prefabricated assembly of standard sections, substations, pipeline branch ports, hoisting ports, ventilation ports, and intersections; the auxiliary systems of the pipe gallery include fire protection systems, ventilation systems, power supply and lighting systems, and monitoring and alarm systems. , drainage system and identification system, etc.
The comprehensive pipe gallery is classified according to the different section forms: rectangular section, circular section, semicircle, arched section and special-shaped section. requirements and factors of the external engineering environment.
Figure 1-2 Cross-sectional form of integrated pipe gallery
According to the number of cabins, it is classified into: single-cabin integrated pipe gallery, double-cabin integrated pipe gallery, and multi-cabin integrated pipe gallery. Among them, Section 4.3.5 of "Technical Specifications for Urban Comprehensive Pipe Gallery Engineering" ( GB50838-2015 ) stipulates that when the thermal pipeline uses steam medium and natural gas pipeline, separate compartments must be set up; Section 4.3.6 stipulates that the thermal pipeline cannot be installed in In the same compartment; Section 5.4.1 stipulates that each compartment must be provided with personnel entrances, emergency escape openings, vents, etc.; Section 5.4.7 stipulates that the distance between the natural gas pipeline vents and other compartments must be greater than or equal to 10m , and Each port in the natural gas tank shall not be connected with other tanks, and warning signs shall be provided.
Figure 1-2 Classification of integrated pipe gallery cabins
Analysis of common structural diseases
The underground comprehensive pipeline corridor is long in length, buried in the ground, has a complex structure, and is easily affected by various factors such as surrounding geological conditions, buildings, and foundation pits. The following diseases are prone to occur in the actual operation of the integrated pipe gallery
( 1 ) Uneven settlement
The various plots of the integrated pipe gallery in the business district are usually constructed by different developers, and the construction period may differ by several years, while the various plots of the municipal integrated pipe gallery must be completed in advance. If effective protection measures are not taken during the underground excavation and construction of the plots to be built later, it is easy to cause serious settlement to the integrated pipe gallery that has been put into use.
( 2 ) Horizontal dislocation
The horizontal dislocation of the pipe gallery structure is generally caused by external factors such as stratum disturbance, and usually occurs in the weak parts of the pipe gallery, such as the expansion joints and splicing joints of the pipe gallery.
( 3 ) Cracks
Due to the large longitudinal length of the pipe gallery, if the spacing between the expansion joints is too large, cracks will easily occur in the integrated pipe gallery. Cracks in the pipe gallery structure will accelerate chemical erosion, freeze-thaw cycles, carbonization, steel corrosion, alkali-aggregate reaction, etc., resulting in secondary damage, which will seriously damage the concrete structure. Water seepage seriously affects all kinds of pipelines inside the pipe gallery, especially may lead to short circuit of electrical cables and blockage of network communication.
When the above diseases occur, it is easy to cause deformation of the pipes in the pipe gallery, and even lead to direct damage to the pipes in severe cases. The splicing seam of the pipe gallery is the connection place of each section of the duct gallery, which is the weak part of the duct gallery, and various diseases are more likely to occur here, especially the change of the horizontal displacement at the splicing seam is more likely to occur. Therefore, monitoring the displacement at the joints of the pipe gallery is an indispensable work for the monitoring of the pipe gallery.
Pipe gallery deformation monitoring technology
The integrated pipe gallery may have deformations such as uneven settlement, cracks, and horizontal dislocation during service. The existing measurement methods and technologies mainly include the following.
( 1 ) Electric displacement monitoring method
Electrical sensors cannot be connected in series and are not suitable for humid environments. The pipe gallery structure is buried underground, the environment is humid, and the longitudinal length is long , generally ten to dozens of kilometers. Each sensor consumes a lot of cables. The entire monitoring project may require multiple demodulation equipment, and the monitoring cost is relatively high. High, not suitable for monitoring of integrated pipe gallery.
( 2 ) FBG displacement monitoring method
FBG is a quasi-distributed sensor, and the sensors can be connected in series, with high precision, long transmission distance, and good long-term stability. For the entire pipe gallery structure, only a few or even one optical cable may be needed to meet the monitoring needs, and the required cost is low. . Therefore, the monitoring of the pipe gallery structure generally uses fiber grating sensors.