CN109029338A - A kind of embedded type concrete strain gauge means and its construction method - Google Patents

Abstract

The invention relates to a concrete strain gauge, in particular to an embedded concrete strain measuring device and a construction method thereof. The embedded concrete strain measuring device includes a first backing ring and a second backing ring, and the first backing ring and the second backing ring are fixed on the air side of the rock and soil body through a fixed rod, so as to avoid the erection of auxiliary swivel steel bars With welding, it takes up less space and is easy to use; the concrete strain gauge is installed across the first backing ring and the second backing ring, and end seats and force cakes are provided at both ends to ensure that the concrete strain gauge is longitudinally stressed; The concrete strain gauge is fixed on the first backing ring and the second backing ring through fixing wires, which can effectively eliminate the influence of concentration force and friction force caused by traditional wire binding, and ensure the accuracy of test results.

Description

An embedded concrete strain measuring device and its construction method

technical field

The invention relates to a concrete strain gauge, in particular to an embedded concrete strain measuring device and a construction method thereof.

Background technique

In the field of civil engineering, it is often necessary to use embedded concrete strain gauges to monitor the stress and strain of concrete structures. On the one hand, the use of concrete strain gauges can test the safety of concrete structures, and on the other hand, it can conduct scientific research and analysis on the mechanical behavior of structures. explain. Embedded concrete strain gauges are widely used in engineering fields such as housing construction, tunnels, foundation pits, slopes, and dams, and are widely used components in geotechnical testing.

However, it should be noted that the test structure of the embedded concrete strain gauge is greatly affected by the embedding method. On the one hand, in order to ensure the accuracy of the data of the concrete strain gauge, the components should ensure that the force is applied along the longitudinal direction and should not be subject to large horizontal concentration. Force and friction interference. On the other hand, the embedded concrete strain gauge is greatly affected by the arrangement of steel bars. For reinforced concrete lining, the embedded concrete strain gauge can be bound to the steel bar, but this method will be affected by the friction of the wire and the steel bar. The accuracy of data is affected; for plain concrete structures, embedded concrete strain gauges are difficult to arrange. In this case, field experimenters need to arrange auxiliary steel bars, and use auxiliary steel bars to arrange strain gauges. This method is more complicated, especially for tunnels The high top position and little standing space make testing work difficult. On-site testing often requires simple and rapid layout of components at any location, without affecting the construction progress of the building.

Contents of the invention

In order to solve the above problems, the present invention provides an embedded concrete strain measuring device and its construction method. The present invention has the advantages of simple structure, easy manufacture, low cost, convenient use and accurate measurement results.

The technical solution adopted in the present invention is: an embedded concrete strain measuring device, including a concrete strain gauge embedded in the concrete, characterized in that it also includes a first pad ring and a second pad for installing the concrete strain gauge ring, the first backing ring and the second backing ring are fixed on the air side of the rock and soil body through a fixed rod, the concrete strain gauge is installed across the first backing ring and the second backing ring, and the concrete One end of the strain gauge extends out of the first backing ring, and the other end extends out of the second backing ring, and the ends are provided with end seats and force cakes; the concrete strain gauge is provided with electronic components for measuring concrete strain, The electronic component is arranged between the first grommet and the second grommet, and the test line of the electronic component protrudes out of the concrete.

As a preference, both the first backing ring and the second backing ring adopt a half-cut metal circular tube structure with an open upper end and a closed lower end, and the first backing ring and the second backing ring are provided with connecting holes through which the fixing wire passes The attachment holes secure the concrete strain gages to the first backing ring and the second backing ring.

Further, the vertical distance between the connection hole and the bottom of the corresponding first backing ring or second backing ring is between the outer diameter of the end seat of the concrete strain gauge and the diameter of the stress cake.

Preferably, the upper end of the fixing rod is fixedly connected to the corresponding first backing ring or the second backing ring through threads, the lower end is fixedly connected to the rock and soil body through threads, and the middle part is the optical axis.

Preferably, the lower end of the fixed rod fixedly connected with the rock and soil mass is tapered.

Preferably, the axes of the first grommet and the second grommet are on the same straight line.

A construction method of an embedded concrete strain measuring device, comprising the following steps:

a. Fix the first backing ring and the second backing ring to the air side of the rock and soil body through the fixing rod. The fixing rod is screwed into the rock and soil body to a depth of 5-10cm, and the axes of the first backing ring and the second backing ring are on the same line superior;

b. The concrete strain gauge is placed across the first backing ring and the second backing ring;

c. Fix the concrete strain gauge with the first backing ring and the second backing ring with fixing wires;

d. When pouring concrete, it is required that the test lines of the electronic components leak out of the concrete.

The beneficial effects obtained by the present invention are: both the first backing ring and the second backing ring are fixed on the air side of the rock and soil body through the fixing rod, avoiding the erection and welding of the auxiliary rotating steel bars, occupying a small space, and being convenient to use; The gage is installed across the first backing ring and the second backing ring, with end seats and force cakes at both ends to ensure that the concrete strain gauge is stressed in the longitudinal direction; the concrete strain gauge is fixed on the first backing ring by fixing wires And on the second backing ring, it can effectively eliminate the influence of concentration and friction caused by traditional wire binding, and ensure the accuracy of test results.

Description of drawings

Figure 1 is a schematic diagram of the arrangement of traditional embedded concrete strain gauges;

Fig. 2 is a structural representation of the present invention;

Fig. 3 is a structural schematic diagram of fixing the first backing ring to the rock and soil body;

FIG. 4 is a side view of FIG. 3 .

Detailed ways

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

As shown in Figure 1, the traditional concrete strain gauge 3 is bound to the steel bar 6 by binding wire 7 before constructing the concrete. This arrangement is greatly affected by the arrangement of the steel bar 6. Without the suspension of the steel bar 6, the concrete cannot be installed. The strain gauge 3, and the effect of the friction between the binding wire 7 and the steel bar 6 will also affect the accuracy of the data.

As shown in Fig. 2-4, a kind of embedded concrete strain measuring device of the present invention, comprises the first backing ring 1, the second backing ring 2 and concrete strain gauge 3, the first backing ring 1 and the second backing ring 2 They are all fixed on the air-side of the rock and soil body through the fixing rod 4. Taking the tunnel test as an example, if the concrete strain of the arch of the tunnel is measured, the first backing ring 1 and the second backing ring 2 are under the rock and soil body; Concrete strain on the side wall, the first backing ring 1 and the second backing ring 2 are located beside the rock and soil mass; if the concrete strain at the bottom of the tunnel is measured, the first backing ring 1 and the second backing ring 2 are above the rock and soil mass .

In order to ensure that the concrete strain gauge 3 is embedded in the concrete and only bears force along the longitudinal direction as much as possible, in this embodiment, when the first backing ring 1 and the second backing ring 2 are installed, the axes are on the same straight line, and the measured concrete strain position, adjust the relative position of the first backing ring 1 and the second backing ring 2, one end of the concrete strain gauge 3 extends out of the first backing ring 1, and the other end extends out of the second backing ring 2, and the ends are equipped with The end seat 31 and the force cake 32, the concrete strain gauge 3 is provided with an electronic assembly 33 for measuring the strain force of the concrete, the electronic assembly 33 is arranged between the first backing ring 1 and the second backing ring 2, the test of the electronic assembly 33 Wires protrude out of the concrete to connect with external devices for data transmission.

As shown in Figure 3-4, the structure of the first backing ring 1 and the second backing ring 2 is the same. The length of steel pipe is 5.2cm, and steel pipe external diameter 35mm, internal diameter 30mm, all are provided with connecting hole (11,21) on the first backing ring 1 and the second backing ring 2, the diameter of connecting hole is 2mm, and connecting hole and corresponding The vertical distance at the bottom of the first backing ring 1 or the second backing ring 2 is between the outer diameter of the end seat 31 of the concrete strain gauge 3 and the diameter of the stressed cake 32. In this embodiment, the distance between the center of the connecting hole and the bottom of the backing ring The vertical distance is 32mm. The fixing wire 5 passes through the connecting holes (11, 21) to fix the concrete strain gauge 3 on the first backing ring 1 and the second backing ring 2. The concrete strain gauge 3 is not in direct contact with the fixing wire 5 (steel wire is used in this embodiment), which avoids affecting the accuracy of data measurement.

In this embodiment, the fixing rod 4 is made of metal material with a diameter of 16 mm and a total length of 30 cm. The upper end is provided with a fine thread 41 , the lower end is provided with a coarse thread 42 , and the middle part is an optical axis 43 . The upper end of the fixing rod 4 is fixedly connected with the threaded hole at the lower end of the first backing ring or the second backing ring through a fine thread 41 , and the lower end is fixedly connected with the rock and soil mass through a coarse thread 42 . The nominal diameter of the fine thread 41 is slightly smaller than the diameter of the fixed rod 4, the nominal diameter is 10mm, and the thread pitch is 1mm; the length of the coarse thread 42 is 5-10cm, the nominal diameter is 16mm, the thread pitch is 2mm, and the end of the coarse thread 42 is a cone Shaped structure, the cone angle is 30°, and there is no thread at the tip of the cone.

Take a specific construction project as an example: the site is in a mountain tunnel, the purpose of the test is to test the strain of the plain concrete lining, and the surrounding rock level is IV. The thread 41 is connected and fixed with the fixed rod 4, and then the coarse thread 42 at the lower end of the fixed rod 4 is screwed into the rock-soil body. During installation, the axes are on the same straight line, the concrete strain gauge 3 is placed on the first backing ring 1 and the second backing ring 2, and finally the concrete strain gauge 3 is fixed with the fixing wire 5, then the installation of the whole device is completed. After the concrete is poured, the test line 331 can be used to read the data.

The basic principles and main structural features of the present invention have been shown and described above. The present invention is not limited by the above examples, and without departing from the spirit and scope of the present invention, the present invention also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (7)

1. An embedded concrete strain measuring device, comprising a concrete strain gauge (3) embedded in the concrete, is characterized in that: it also includes a first backing ring (1) for installing the concrete strain gauge (3) and The second backing ring (2), the first backing ring (1) and the second backing ring (2) are fixed on the air side of the rock and soil body through the fixing rod (4), and the concrete strain gauge (3) is horizontal The straddle is installed between the first backing ring (1) and the second backing ring (2), one end of the concrete strain gauge (3) protrudes from the first backing ring (1), and the other end extends out of the second backing ring (2), the ends are provided with end seats (31) and force cakes (32); the concrete strain gauge (3) is provided with an electronic assembly (33) for measuring concrete strain, and the electronic assembly ( 33) It is arranged between the first grommet (1) and the second grommet (2), and the test line (331) of the electronic component (33) protrudes out of the concrete. 2. The embedded concrete strain measuring device according to claim 1, characterized in that: the first backing ring (1) and the second backing ring (2) have the same structure, and both adopt a half-section with the upper end open and the lower end closed. Metal circular tube structure, the first backing ring (1) and the second backing ring (2) are provided with connecting holes (11, 21), and the fixing wire (5) passes through the connecting holes (11, 21) to fix the concrete The strain gauge (3) is fixed on the first backing ring (1) and the second backing ring (2). 3. The embedded concrete strain measuring device according to claim 2, characterized in that: said connection hole (11, 21) is connected to the bottom of the corresponding first backing ring (1) or second backing ring (2). The vertical distance is between the outer diameter of the end seat (31) of the concrete strain gauge (3) and the diameter of the stressed cake (32). 4. The embedded concrete strain measuring device according to claim 1, characterized in that: the upper end of the fixing rod (4) is fixed to the corresponding first backing ring (1) or second backing ring (2) by threads Connection, the lower end is fixedly connected with the rock and soil body through threads, and the middle part is the optical axis. 5. The embedded concrete strain measuring device according to claim 1, characterized in that: the lower end of the fixed rod (4) fixedly connected with the rock and soil body is tapered. 6. The embedded concrete strain measuring device according to claim 1, characterized in that: the axes of the first backing ring (1) and the second backing ring (2) are on the same straight line. 7. A construction method of an embedded concrete strain measuring device, comprising the following steps: a. Fix the first backing ring (1) and the second backing ring (2) to the free side of the rock and soil body through the fixing rod (4). The fixing rod (4) is screwed into the rock and soil body to a depth of 5-10 cm. The axes of the first backing ring (1) and the second backing ring (2) are on the same straight line; b. The concrete strain gauge (3) is placed across the first backing ring (1) and the second backing ring (2); c. Fix the concrete strain gauge (3) with the first backing ring (1) and the second backing ring (2) with the fixing wire (5); d. When pouring concrete, the test line (331) of the electronic component (33) is required to leak out of the concrete.