CN102493490A - Inspection shaft cover capable of sensing resistance variation of inspection shaft cover - Google Patents

Abstract

The invention discloses a manhole cover capable of sensing the change of its own resistance, which belongs to the manhole cover. Including the base of the manhole cover, two electrodes are buried in the base of the manhole cover, and the electrodes are fixedly connected with wires protruding from the base of the manhole cover; the base of the manhole cover is made of the following mass ratio raw materials mixed with water and then poured into the mold for curing : Steel slag: 30-40%, cement: 10-12%, fly ash: 20-25%, gravel: 20-35%, steel fiber: 1.5-2%, silicon powder: 6%-12%; The volume percentage of cement + fly ash is 1:1. The beneficial effect is that the structure is simple, and the manufacture and use are very convenient. By testing the change of the electrical conductivity of the manhole cover, the stress, strain, fatigue and damage degree inside the manhole cover can be monitored. Form a large inspection manhole cover Internet of Things, combined with the construction of digital urban management, real-time monitoring and supplementary maintenance of urban manhole covers to prevent accidents.

Description

A manhole cover that senses changes in its own resistance

technical field

The invention relates to an inspection shaft cover, in particular to an inspection shaft cover capable of sensing changes in its own resistance. A manhole cover that can sense damage by itself.

Background technique

Inspection wells are widely used in urban roads, natural gas pipelines, inspection wells of chemical bases, wells for electric power and telecommunication facilities, etc. However, the theft and damage of inspection well covers has become a social security problem. Personal casualty accidents and major traffic accidents have caused immeasurable losses to the society, and administrative departments in various places have also made efforts for it. The main reason is that the traditional cast iron manhole cover is easy to break and has the value of recycling, which is the coveted item of many "trash kings". Composite material and concrete manhole covers are easy to be crushed by cars, and the personal injury and social disputes caused by managers who cannot be replaced in time have been on the rise in recent years, which has brought great trouble to urban management.

Contents of the invention

In order to improve the level of urban management, the invention provides a manhole cover that can sense the change of its own resistance. By measuring the change of the resistance of the manhole cover, the damage of the manhole cover can be known, which is convenient for timely replacement.

The present invention is realized by the following technical scheme: a manhole cover capable of sensing the change of its own resistance, including a manhole cover base body, two electrodes are embedded in the manhole cover base body, and a protruding manhole for connecting external equipment is fixedly connected to the electrodes The wire outside the base of the cover; the base of the manhole cover is made by mixing the following volume ratio of raw materials with water and then pouring them into a mold for curing:

Steel slag: 30-40%

Cement: 10-15%

Fly ash: 20-25%

Stones: 20-35%

Steel fiber: 1.5～2%

Silica fume: 6% to 12%;

Among them, the volume percentage of steel slag and cement + fly ash must also be 1:1.

The fineness modulus of the steel slag is 2-3.

Among the above-mentioned raw materials, steel slag contains relatively high metal iron and its oxides, the content of FeO is generally above 20%, and the resistivity of FeO at room temperature is 5×10-2Ω·cm. The function is to increase the strength of the manhole cover as the aggregate of concrete on the one hand, and to improve the conductivity of the manhole cover on the other hand, so that the manhole cover becomes a weak conductor. Cement and fly ash are used as cementitious materials. For example, when the manhole cover breaks, the resistance between the two electrodes changes. By testing the change of the conductivity of the concrete manhole cover, the stress, strain, fatigue and damage inside the manhole cover are monitored.

The beneficial effect of the invention is that the structure is simple, and the manufacture and use are very convenient. Through online real-time measurement, a large inspection manhole cover Internet of Things can be formed, combined with the construction of digital urban management, real-time monitoring and supplementary maintenance of urban manhole covers can be carried out to prevent accidents.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a structural representation of the present invention;

Figure 2 is a diagram of the electrode structure.

In the figure: 1, inspection well cover substrate, 2, electrode, 3, lead wire, 4, small through hole.

Detailed ways

As shown in Figure 1 and Figure 2, the manhole cover that can sense the change of its own resistance has two electrodes 2 buried in the manhole cover base 1, and the electrodes 2 are fixedly connected with wires 3 protruding out of the base for connecting external devices; The base 1 is made by adding water and mixing the following volume ratios of raw materials and then pouring them into a mold for curing:

Steel slag: 35%

Cement: 13%

Fly Ash: 20%

Pebbles: 24%

Steel fiber: 2%

Silica fume: 6%;

The volume percentage of steel slag and cementitious material (cement + fly ash) is 1:1 (dry ratio). Steel slag contains Fe025%.

The electrode 2 is made of a conductive metal plate with a thickness of 0.3-2mm, such as thin copper plate, stainless steel plate, aluminum plate and other materials. A plurality of small through holes 4 are drilled on the electrode 2, and the diameter of the small through holes is larger than the maximum particle size of the steel slag, so as to ensure that the concrete on both sides of the electrode can communicate with each other. The connecting wire 3 is welded on the electrodes, and two electrodes are installed on each manhole cover, and the size of the electrodes 2 is: thickness 0.3-2mm, length 50-70mm, width 30-50mm. The distance between the two electrodes is 400-600mm. The size of the electrodes should be smaller than the cross-section of the manhole cover, so as to ensure that the electrodes will not be exposed on the outer surface of the manhole cover, so that the manhole cover will not easily appear cracks at the electrodes when the manhole cover is subjected to external force. The reinforcement ribs of the manhole cover are in contact.

The principle is: under the action of external load, the steel slag manhole cover will have two interactive processes inside:

First, under the action of external force, the interior of the specimen becomes more and more compact, which increases the chance of contact between adjacent steel slag particles and forms a new conductive network, which increases the conductivity of the specimen, that is, reduces the resistivity. ;

The second is that the external load causes damage to the inside of the specimen, resulting in cracks, increasing the interval barrier of steel slag, causing damage to the existing conductive network, and causing an increase in the resistivity of the specimen. Before the failure load of the manhole cover is reached, after the external force is removed, the resistivity of the manhole cover returns to the state without stress. If the manhole cover is damaged, the resistivity cannot be restored to the state without force. By measuring the resistivity of the manhole cover Changes, you can know the damage of the manhole cover, which is convenient for timely maintenance.

Claims (5)

1. the inspection shaft lid of an ability perception self-resistance variation comprises inspection shaft lid matrix (1), it is characterized in that, in inspection shaft lid matrix (1), is embedded with two cube electrodes (2), is connected with the lead (3) outside the inspection shaft lid matrix that stretches out that is used to connect external equipment on the electrode (2); Described inspection shaft lid matrix (1) is that the raw material by following mass ratio adds and pours the mould maintenance into after water mixes and process:

Slag: 30～40%

Cement: 10～15%

Flyash: 20～25%

Stone: 20～35%

Steel fibre: 1.5～2%

Silica flour: 6%～12%;

Wherein the percent by volume of slag and concrete and coal ash is 1: 1;

The fineness modulus of said slag is 2-3.

2. the inspection shaft lid that ability perception self-resistance according to claim 1 changes is characterized in that described electrode (2) is the conductive metal sheet of thickness 0.3～2mm, length 50-70mm, width 30-50mm.

3. the inspection shaft lid that ability perception self-resistance according to claim 1 changes is characterized in that described electrode (2) is provided with the hole, and the diameter in hole is greater than the maximum particle diameter of slag.

4. according to claim 1 can perception the inspection shaft lid that changes of self-resistance, it is characterized in that, described two interelectrode apart from 400-600mm.

5. the inspection shaft lid that ability perception self-resistance according to claim 1 changes is characterized in that, on described electrode (2), is drilled with a plurality of small through hole (4).

Images