Installation method for drilling and embedding thermometer on in-service concrete member

Abstract

The invention provides an installation method for drilling and embedding a thermometer on an in-service concrete member, and relates to the technical field of concrete member temperature measurement. The method comprises the steps that firstly, the drilling position, the inclination angle and the hole depth are determined on a concrete member, and then drilling is conducted on the determined surface drilling position; and finally, a thermometer is placed in the drilled hole, depth positioning is carried out by binding the thermometer on a glass fiber rod, grouting is carried out, and thermometer installation is completed. According to the method, the internal temperature of the existing in-service concrete member can be effectively measured, and the grouting compactness is ensured through an improved grouting mode, so that the accurate measurement value of the internal temperature of the concrete is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of temperature measurement of concrete components, in particular to an installation method of drilling and embedding a thermometer on an in-service concrete component. Background Art

[0002] In order to evaluate the operating status of concrete engineering structures in real time and ensure their safe operation, many large bridges, super high-rise buildings, and hydraulic structures have installed structural health monitoring systems. In these monitoring systems, temperature monitoring is an essential part.

[0003] However, most of the current temperature sensors are only installed on the surface of the structure, and can only obtain temperature data on the surface of the concrete structure. For thicker concrete components, the surface temperature cannot accurately reflect the changes in the internal temperature. In order to determine the temperature variation characteristics along the thickness direction of the component, most studies rely on heat transfer finite element analysis. However, since heat transfer analysis involves many parameters and the calculation model is often too idealized, the accuracy of the internal temperature data obtained by numerical analysis is difficult to guarantee.

[0004] The most direct way to obtain the internal temperature of a concrete component is to install a thermometer inside the actual component. For new structures, embedded thermometers are usually embedded before concrete pouring. For existing concrete structures, the installation of embedded thermometers requires drilling holes on the surface of the structure, placing the sensor inside the structure, and finally filling the void between the embedded thermometer and the wall of the borehole to ensure the accuracy of temperature measurement. However, the boreholes required for embedded thermometers are generally between 12 and 25 mm, with a small hole diameter. When the depth of the borehole is large, it is not easy to fill the hole densely. The current "Construction and Acceptance Standards for Structural Health Monitoring Systems" proposes recommendations for the construction of drilled embedded sensors, requiring that fine stone concrete or mortar should be used to fill the gap after the sensor is buried. However, the above regulations have limited guidance for actual construction. First, fine stone concrete is suitable for larger diameter boreholes (such as 40 mm or more), but using large diameter boreholes to install thermometers is not only unnecessary, but may also cause significant damage to the concrete structure. Secondly, ordinary mortar has poor fluidity and is prone to form gaps in the pores after water loss and shrinkage, which may affect the accurate measurement of the internal temperature of the structure. On the other hand, the installation parameters of existing embedded thermometers are generally determined by experience or even by construction personnel according to their own convenience, which often results in excessive borehole diameter and greater damage to the original structure. At the same time, some installation methods do not pay attention to the selection of filling materials and filling density, which causes significant changes in the thermal conductivity of the concrete structure and distorts the measured temperature field. In some installation methods, the strength of the filling material in the borehole is much lower than that of the original concrete, which may reduce the bearing capacity of the structure.

[0005] In general, the existing literature still lacks research on the specific construction method of drilling and embedding thermometers in in-service concrete components. The details of thermometer installation directly affect the reliability of temperature data. Therefore, the reasonable installation of embedded thermometers has become an urgent problem to be solved in the temperature monitoring of in-service concrete structures. Summary of the invention

[0006] In order to solve the above technical problems existing in the prior art, an embodiment of the present invention provides a method for installing a thermometer by drilling a hole in an in-service concrete component. The technical solution is as follows:

[0007] A method for installing a drilled embedded thermometer on an in-service concrete bridge, the method comprising:

[0008] S1. Positioning:

[0009] Determine the drilling position, inclination and depth of the holes on the concrete elements;

[0010] S2. Drilling and hole cleaning:

[0011] According to the drilling inclination angle obtained in step S1, the drilling diameter is calculated, and the component surface is drilled; a vacuum cleaner or high-pressure air is used to penetrate into the drilling hole through a conduit to clean the debris in the drilling hole, and a cotton ball dipped in clean water is used to wet the hole wall;

[0012] S3. Place the thermometer and grout:

[0013] When the design requires the use of no less than two thermometers, the thermometers shall be fixed to the fiberglass rods with thin iron wires according to the designed burial depth and placed in the drilled holes;

[0014] When the design requires the use of a thermometer, place the thermometer directly into the bottom of the borehole;

[0015] After the thermometer is placed in the drilled hole, the high-position funnel method is used for grouting to complete the installation of the thermometer.

[0016] In step S1, the drilling position is determined on the surface of the concrete component according to actual needs, the angle between the line connecting the drilling position and the thermometer embedding position required by the test and the horizontal plane is the drilling inclination angle, and the drilling depth does not exceed 50 cm.

[0017] The surface of the drilling position of the in-service concrete member must be exposed to the air and cannot be immersed in water.

[0018] In step S1, the drilling direction is inclined or vertically downward, the drilling inclination angle is not less than 5 degrees, and the hole mouth is higher than the hole bottom.

[0019] In step S2, the diameter D of the borehole and the inclination angle of the borehole , the diameter of the thermometer and the diameter of the signal line:

[0020] ① If the thermometer is not located at the bottom of the hole, then the maximum cross-sectional area of ​​the thermometer and the signal line perpendicular to the drilling direction is set to A, and the cross section is equivalent to the diameter circle;

[0021] ② If the thermometer is only located at the bottom of the hole, the equivalent circle diameter d of the cross section of the thermometer and the signal line perpendicular to the drilling direction is the diameter of the signal line;

[0022] ③ When the drilling angle When the angle is greater than 10 degrees, the minimum drilling diameter D is 3.5d;

[0023] ④ When the drilling angle When the angle is 5-10 degrees, the minimum drilling diameter D is 4.0d.

[0024] During the grouting in step S3, grouting is performed through a high-position funnel, the borehole and the funnel are connected by a soft rubber hose, and the grouting material is injected through the funnel.

[0025] The length of the soft rubber hose does not exceed 15 cm.

[0026] The grouting process is specifically as follows:

[0027] ① When the inclination angle of the borehole does not exceed 80 degrees, after placing a thermometer in the borehole, when the catheter is inserted into the hole, the signal line of the thermometer is led out from the top of the hole to form an exhaust hole; during the grouting process, one end of the cable tie is placed into the borehole through a funnel and a soft rubber hose, and the other end is held by hand or connected to a reciprocating motion device to make the cable tie move back and forth along the direction of the slurry movement at a frequency of about 1Hz (generally 0.5~2Hz), thereby promoting the slurry to flow in the borehole and increasing the grouting speed.

[0028] ② When the borehole inclination angle is 80~90 degrees, after placing the thermometer in the borehole, directly connect the funnel to the borehole and use gravity for irrigation; at the same time, the signal line is directly led out from the funnel mouth.

[0029] The grouting material adopts high-strength non-shrinkage cement-based grouting material with a maximum aggregate particle size not exceeding 1 mm, and the strength of the grouting material stone body is not lower than the original concrete strength.

[0030] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0031] This method can improve the density of grouting, achieve high-precision measurement of the internal temperature of existing in-service concrete structures, and reduce the problem of large structural damage caused by traditional installation methods. In particular, when measuring the temperature change of the vertical web of the box girder of a long-span bridge along the thickness direction, it is necessary to install an embedded thermometer in a nearly horizontal borehole. This method can ensure the quality of grouting and the accuracy of temperature measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 It is a schematic diagram of drilling a hole in an in-service concrete component and embedding a thermometer provided by an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of installing a thermometer by drilling a hole and embedding the thermometer in an in-service concrete member according to an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the drilling and cleaning process for drilling a hole in an in-service concrete member and embedding a thermometer in an embodiment of the present invention, wherein (a) is high-pressure air cleaning, and (b) is vacuum cleaner cleaning;

[0036] Figure 4 The figure is a schematic diagram of the grouting process of drilling a hole and embedding a thermometer in an in-service concrete member according to an embodiment of the present invention.

[0037] Among them: 1-concrete component; 2-drilling hole; 3-thermometer; 4-thin iron wire; 5-sensor signal line; 6-glass fiber rod; 7-conduit; 8-high-pressure air pump; 9-vacuum cleaner; 10-soft rubber hose; 11-funnel; 12-grouting material. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0039] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0040] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0041] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0042] An embodiment of the present invention provides a method for installing a drilled embedded thermometer on an in-service concrete bridge.

[0043] A method for installing a drilled embedded thermometer on an in-service concrete bridge, the method comprising:

[0044] S1. Positioning:

[0045] Determine the drilling position, inclination and depth of the holes on the concrete elements;

[0046] S2. Drilling and hole cleaning:

[0047] According to the drilling inclination angle obtained in step S1, the drilling diameter is calculated, and drilling is performed on the surface of the concrete component 1, such as Figure 1 ; Connect a vacuum cleaner 9 or a high-pressure air pump 8 through a conduit 7, and clean the debris in the borehole 2 through the conduit, such as Figure 3 And use absorbent cotton balls dipped in clean water to wet the hole wall;

[0048] S3. Place the thermometer and grout:

[0049] When the design requires the use of no less than two thermometers 3, the thermometers 3 are fixed to the glass fiber rods 6 with thin iron wires 4 according to the designed embedding depth and placed in the borehole 2. Figure 2 ;

[0050] When the design requires the use of a thermometer, place the thermometer directly into the bottom of the borehole;

[0051] After the thermometer 3 is placed in the borehole 2, the high-position funnel method is used for grouting to complete the thermometer installation. Specifically, Figure 4 After placing the thermometer 3 in the borehole 2, the sensor signal line 5 is led out from the top of the hole when the soft rubber hose 10 is inserted into the hole to form an exhaust hole; during the grouting process, one end of the cable tie is placed into the borehole 2 through the funnel 11 and the soft rubber hose 10, and the other end is held by hand or connected to a reciprocating motion device to make the cable tie move back and forth along the slurry movement direction at a frequency of about 1 Hz (generally 0.5~2 Hz), thereby pushing the grouting material 12 to flow in the borehole 2 and increasing the grouting speed.

[0052] This will be described below with reference to specific embodiments.

[0053] Example 1

[0054] For a concrete box girder bridge in service, the box girder has construction conditions inside, the bottom plate thickness is 60cm, and the internal temperature change at the midpoint of its thickness (30cm from the upper and lower surfaces) needs to be measured. A thermometer is designed to be placed in the drill hole. The diameter of the thermometer signal line is selected to be 3.2 mm.

[0055] By adopting the method of the present invention, according to the measurement requirements, the drilling position is determined on the upper surface of the bridge bottom plate opposite to the preset thermometer placement position, and a hole is drilled from the drilling position to the preset thermometer placement position. The drilling inclination is 90 degrees (vertical drilling), the drilling depth is 30 cm, and the drilling diameter is determined according to the following process: since the thermometer is only located at the bottom of the hole, the equivalent circle diameter d of the cross section of the thermometer and the signal line perpendicular to the drilling direction is taken as the diameter of the signal line 3.2 mm; and since the drilling inclination is The angle is greater than 10 degrees, so the drilling diameter D is not less than 3.5×3.2=11.2mm. Considering the drill modulus, the drilling diameter D can be 12mm.

[0056] After drilling, connect the conduit through a high-pressure air pump, go deep into the borehole to clean the debris, and use a cotton ball dipped in clean water to moisten the hole wall. Finally, place the thermometer directly at the bottom of the borehole, connect the funnel directly to the borehole, grout through the high-position funnel, and lead the signal line directly from the funnel mouth.

[0057] Among them, the grouting material adopts high-strength non-shrinkage cement-based grouting material with a maximum aggregate particle size not exceeding 1mm, and the strength of the grouting material stone body is not lower than the original concrete strength.

[0058] Example 2

[0059] For a concrete box-shaped pipe gallery in service, the interior of the pipe gallery has the construction conditions. The wall thickness of the pipe gallery is 30 cm. It is necessary to measure the internal temperature change at a depth of 15 cm from the inner surface at half the height of the side wall. The design is to insert a thermometer into the drill hole. The diameter of the thermometer signal line is selected to be 3.2 mm.

[0060] According to the method of the present invention, a hole with an inclination of 5 degrees is used according to the measurement requirements, and the hole mouth is located above the sensor height. The drilling position is determined at 15×tan(5°)=1.31cm above the sensor height on the inner surface of the corridor side wall, and a hole is drilled from the drilling position to the preset thermometer placement position. The drilling inclination is 5 degrees downward, and the drilling depth is 15÷cos(5°)=15.06cm. The drilling diameter is determined according to the following process: Since the thermometer is only located at the bottom of the hole, the equivalent circle diameter d of the cross section of the thermometer and the signal line perpendicular to the drilling direction is taken as the diameter of the signal line 3.2mm; and because of the drilling inclination Less than 10 degrees, so the drilling diameter D is not less than 4.0×3.2=12.8mm. Considering the drill modulus, the drilling diameter D can be 14mm.

[0061] After drilling, connect the conduit through a high-pressure air pump, go deep into the borehole to clean the debris, and use a cotton ball dipped in clean water to moisten the hole wall. Finally, place the thermometer directly at the bottom of the borehole, grout through a high-position funnel, connect the borehole and the funnel through a soft hose, and inject the grouting material through the funnel. When the soft hose is inserted into the hole, lead the signal line of the thermometer from the top of the hole to form an exhaust hole; during the grouting process, put one end of the cable tie into the borehole through the funnel and soft hose, and the other end is held by hand or connected to a reciprocating motion device, so that the cable tie moves back and forth along the slurry movement direction at a frequency of about 1Hz, pushing the slurry to flow in the borehole and increasing the grouting speed.

[0062] Among them, the grouting material adopts high-strength non-shrinkage cement-based grouting material with a maximum aggregate particle size not exceeding 1mm, and the strength of the grouting material stone body is not lower than the original concrete strength.

[0063] Example 3

[0064] For a concrete floor panel in service, the upper surface of the floor panel is ready for construction. The thickness of the floor panel is 20cm. It is necessary to measure the internal temperature change at the depth of 5cm, 10cm and 15cm from the upper surface in the thickness direction of the panel. The design is to insert 3 thermometers in the drilled holes. The diameter of the thermometer signal line is 3.5mm, and the cross section of the sensor probe is 6×4mm.

[0065] By adopting the method of the present invention, according to the measurement requirements, the drilling position is determined on the upper surface of the floor panel opposite to the preset thermometer placement position, and a hole is drilled from the drilling position to the preset thermometer placement position. The drilling inclination angle is 90 degrees (vertical drilling), the drilling depth is 15 cm, and the drilling diameter is determined according to the following process: Since the thermometer is not located at the bottom of the hole, and the maximum cross-sectional area of ​​the thermometer and the signal line perpendicular to the drilling direction is A=6×4=24mm 2 , so the equivalent circle diameter of the section of the thermometer and the signal line perpendicular to the drilling direction is ; Due to the inclination of the drilling The angle is greater than 10 degrees, so the drilling diameter D is not less than 3.5×5.53=19.36mm. Considering the drill modulus, the drilling diameter D can be 20mm.

[0066] After drilling, connect the conduit through a high-pressure air pump, go deep into the borehole to clean the debris, and use a cotton ball dipped in clean water to moisten the hole wall. Finally, fix the thermometer to the designed buried depth with a thin wire on the fiberglass rod and place it in the borehole. Connect the funnel directly to the borehole, use gravity grouting through the high-position funnel, and lead the signal line directly from the funnel mouth.

[0067] Among them, the grouting material adopts high-strength non-shrinkage cement-based grouting material with a maximum aggregate particle size not exceeding 1mm, and the strength of the grouting material stone body is not lower than the original concrete strength.

[0068] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for installing a thermometer by drilling a hole in an in-service concrete member, characterized in that: The method comprises: S1. Positioning: Determine the drilling position, inclination and depth of the holes on the concrete elements; S2. Drilling and hole cleaning: According to the drilling inclination angle determined in step S1, the drilling diameter is calculated, and the component surface is drilled; a vacuum cleaner or high-pressure air is used to penetrate into the drilling hole through the conduit to clean the debris in the drilling hole, and a cotton ball dipped in clean water is used to wet the hole wall; S3. Place the thermometer and grout: When the design requires the use of no less than two thermometers, the thermometers shall be fixed to the fiberglass rods with thin iron wires according to the designed burial depth and placed in the drilled holes; When the design requires the use of a thermometer, place the thermometer directly into the bottom of the borehole; After the thermometer is placed in the drilled hole, the high-position funnel method is used for grouting to complete the installation of the thermometer.

2. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 1, characterized in that: In step S1, the drilling position is determined on the surface of the concrete component according to actual needs, the angle between the line connecting the drilling position and the thermometer embedding position required by the test and the horizontal plane is the drilling inclination angle, and the drilling depth does not exceed 50 cm.

3. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 2, characterized in that: The surface of the drilling position of the in-service concrete member must be exposed to the air and cannot be immersed in water.

4. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 1, characterized in that: In step S1, the drilling direction is inclined or vertically downward, the drilling inclination angle is not less than 5 degrees, and the hole mouth is higher than the hole bottom.

5. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 1, characterized in that: In step S2, the diameter D of the borehole and the inclination angle of the borehole , the diameter of the thermometer and the diameter of the signal line: ① If the thermometer is not located at the bottom of the hole, then the maximum cross-sectional area of ​​the thermometer and the signal line perpendicular to the drilling direction is set to A, and the cross section is equivalent to the diameter circle; ② If the thermometer is only located at the bottom of the hole, the equivalent circle diameter d of the cross section of the thermometer and the signal line perpendicular to the drilling direction is the diameter of the signal line; ③ When the drilling angle When the angle is greater than 10 degrees, the minimum drilling diameter D is 3.5d; ④ When the drilling angle When the angle is 5-10 degrees, the minimum drilling diameter D is 4.0d.

6. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 1, characterized in that: During the grouting in step S3, grouting is performed through a high-position funnel, the borehole and the funnel are connected by a soft rubber hose, and the grouting material is injected through the funnel.

7. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 6, characterized in that: The length of the soft rubber hose does not exceed 15 cm.

8. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 6, characterized in that: The grouting process is specifically as follows: ① When the inclination angle of the borehole does not exceed 80 degrees, after placing a thermometer in the borehole, when the soft rubber hose is inserted into the hole, the signal line of the thermometer is led out from the top of the hole to form an exhaust hole; during the grouting process, one end of the cable tie is placed into the borehole through a funnel and a soft rubber hose, and the other end is held by hand or connected to a reciprocating motion device, so that the cable tie moves back and forth along the slurry movement direction at a frequency of 0.5~2Hz, promoting the slurry to flow in the borehole and increasing the grouting speed; ② When the borehole inclination angle is 80~90 degrees, after placing the thermometer in the borehole, directly connect the funnel to the borehole and use gravity for irrigation; at the same time, the signal line is directly led out from the funnel mouth.

9. The method for installing a thermometer by drilling a hole in an in-service concrete member according to claim 6, characterized in that: The grouting material adopts high-strength non-shrinkage cement-based grouting material with a maximum aggregate particle size not exceeding 1 mm, and the strength of the grouting material stone body is not lower than the original concrete strength.

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