CN205712211U - Prestressed pipe pile body internal force device implanted with fiber bragg grating sensor - Google Patents

Abstract

The utility model relates to a prestressed pipe pile internal force device implanted with a fiber grating sensor. The main structure includes a prestressed pipe pile, a tube cavity center fixing device, a fiber grating sensor, an armored optical cable, a fiber grating string, a clamping support, Additional reinforcement, fiber grating data demodulator, computer. Compared with the prior art, the utility model solves the problem that the internal force of the prestressed pipe pile cannot be accurately tested on site. The burial of the fiber grating string is simple and the operability is strong. The technology provides an effective test method for studying the mechanical characteristics and stress transfer mechanism of prestressed tubular piles.

Description

An internal force device for prestressed pipe piles implanted with fiber grating sensors

technical field

The invention belongs to the field of pile foundation engineering and relates to the problem of testing the internal force of a prestressed pipe pile body, in particular to an internal force device of a prestressed pipe pile body implanted with an optical fiber grating sensor.

Background technique

Prestressed pipe piles have high bearing capacity, industrial production, convenient transportation, no noise and no pollution during on-site construction, and are widely used in the southeast coastal areas of my country. At present, the pile driving methods of prestressed pipe piles mainly include hammering method, vibration method and static pile pressing method. Among them, the static pile pressing method has no noise and no vibration during the construction process, and is widely used in urban areas with high environmental protection requirements. . During the penetration process of prestressed tubular piles, the mechanical characteristics and stress transfer mechanism of piles are not completely clear, and the distribution of side friction resistance and the magnitude of end resistance of piles cannot be accurately determined. Therefore, the distribution along the pile body under load can be obtained more accurately. The size of the internal force is beneficial to separate the pile sinking resistance in the penetration process of prestressed pipe piles. At present, the methods for testing the internal force of prefabricated tubular piles mainly include the steel bar stress gauge method and the optical fiber test method. The method of embedding steel bar stress gauges in prefabricated piles and embedding optical fiber sensors in grooves on the surface of prefabricated piles is gradually popularized and used. However, due to the special manufacturing process of prestressed pipe piles, the embedding of steel bar stress gauges in the production of pipe piles is relatively complicated. Due to the high temperature in the production process of pipe piles, the cost of high-temperature stress gauges is high and the survival rate is low; optical fiber sensors are carved on the surface of pipe piles. Groove implantation will cause some damage to the elastic modulus of the pile body, and the friction properties and integrity of the pile-soil interface will also be different after packaging, resulting in changes in the friction coefficient of the pile-soil interface. The distribution of pile side frictional resistance and the magnitude of pile tip resistance can be calculated accurately. Therefore, based on field tests, developing a more accurate method and device for testing the internal force of prestressed tubular piles, and accurately measuring the internal forces of the pile during the penetration and rest stages is of great importance to the research on the resistance and long-term bearing characteristics of prestressed tubular piles. It can also better improve the research theory of the penetration mechanism and bearing characteristics of prestressed pipe piles.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies and defects of the prior art, and propose a prestressed pipe pile body internal force device, before the prestressed pipe pile is made, the additional steel bar with the optical fiber grating sensor is pre-implanted in the steel cage, Put the reinforcement cage implanted with the additional reinforcement with the fiber grating sensor into the steel mold made of the prestressed pipe pile, and make the prestressed pipe pile according to the normal production process.

In order to achieve the above object, the main structure of the internal force device of a prestressed pipe pile implanted with a fiber grating sensor in the present invention includes a prestressed pipe pile, a tube cavity center fixing device, a fiber grating sensor, an armored optical cable, a fiber grating string, a clamping Support, additional steel bars, fiber grating data demodulator, computer; it is characterized in that: the fiber grating sensors are connected in series with the armored optical cables to form the fiber grating strings, and the distance between the fiber grating sensors and the quantity are determined according to the soil layer at the construction site; the clamping support is welded to the additional steel bar, and each of the fiber grating sensors of the fiber grating string is installed on the clamping support on the additional steel bar On the seat, the additional reinforcement is bound to the position to be measured of the reinforcement cage; the armored optical cable connected to the fiber grating sensor is guided to the near end of the reinforcement cage along the additional reinforcement, and introduced into the center of the lumen for fixation On the pre-set central fixing device of the lumen, that is, all the armored optical cables of each section of the prestressed pipe pile pass through the wall of the pipe pile and are temporarily fixed on the section near the top of the prestressed pipe pile. On the fixing device at the center of the lumen; all the armored optical cables are led out from the top of the pile, and connected with the fiber grating data demodulator, and the fiber grating data demodulator is connected with the computer.

The additional reinforcement is a prefabricated reinforcement with a diameter of 20mm and a length of 400mm, and the grade of the reinforcement is the same as that of the stressed reinforcement; the fiber optic grating sensor on the additional reinforcement is bound at intervals of 500mm on the reinforcement cage.

The fixing device at the center of the pipe cavity is a cross steel bar, which is welded with the stress bars of the steel cage, and anchored in the concrete on the inner wall of the pipe pile after the concrete is poured; The fixing device in the center of the cavity is 1m away from the top of the pile.

The optical fiber grating data demodulator has high resolution, good repeatability, fast acquisition speed, high reliability, strong processing capability, small transmission loss, large transmission capacity and wide measurement range.

The present invention has the advantages of: compared with the prior art, it solves the problem that the internal force of the prestressed pipe pile cannot be accurately tested, the fiber grating string is easy to embed, and the operability is strong. The force field test technology provides an effective test method for studying the mechanical characteristics and stress transfer mechanism of prestressed tubular piles.

Description of drawings

Fig. 1 is the principle schematic diagram of main body structure of the present invention;

Fig. 2 is a schematic diagram of the present invention relating to the structure of additional steel bars;

Fig. 3 is a schematic diagram of the structural principle of the pipe pile central fixing device involved in the present invention.

1. Prestressed pipe pile; 2. Lumen center fixing device; 3. Optical fiber grating sensor; 4. Armored optical cable; 5. Optical fiber grating string; 6. Clamping support; Demodulator; 9. Computer.

detailed description

The present invention will be further described below in conjunction with accompanying drawing:

As shown in the figure, a prestressed pipe pile body internal force device implanted with a fiber grating sensor, the main structure includes a prestressed pipe pile 1, a tube cavity center fixing device 2, a fiber grating sensor 3, an armored optical cable 4, and a fiber grating string 5. Clamping support 6, additional steel bar 7, fiber grating data demodulator 8, computer 9, characterized in that: the fiber grating sensor 3 is connected in series with the armored optical cable 4 to form the fiber grating string 5. The spacing and quantity between the fiber grating sensors 3 are determined according to the soil layer at the construction site; the clamping support 6 is welded to the additional steel bar 7, and each of the optical fibers of the fiber grating string 5 The grating sensor 3 is installed on the clamping support 6 on the additional steel bar 7, and the additional steel bar 7 is bound on the position to be measured of the steel cage; the armored optical cable 4 connected to the fiber grating sensor 3 is along the The additional steel bar 7 is introduced to the near end of the steel cage, and introduced to the center of the lumen to be fixed on the pre-set fixing device 2 at the center of the lumen, that is, all the prestressed pipe piles 1 of each section The armored optical cable 4 passes through the wall of the pipe pile and is temporarily fixed on the described lumen center fixing device 2 near the top of the prestressed pipe pile 1 described in this section; all the armored optical cables 4 are drawn out from the pile top, and The fiber grating data demodulator 8 is connected, and the fiber grating data demodulator 8 is connected with the computer 9 .

The additional reinforcement 7 is a prefabricated reinforcement with a diameter of 20 mm and a length of 400 mm. The grade of the reinforcement is the same as that of the stressed reinforcement; the fiber grating sensor 3 on the additional reinforcement 7 is bound at intervals of 500 mm on the reinforcement cage.

The center fixing device 2 of the tube cavity is a cross steel bar, which is welded with the stress bars of the steel cage 3, and anchored in the concrete on the inner wall of the tube pile after pouring concrete; Concentration, the lumen center fixing device 2 is at a position 1m away from the pile top.

The fiber grating data demodulator 8 has high resolution, good repeatability, fast acquisition speed, high reliability, strong processing capability, small transmission loss, large transmission capacity and wide measurement range.

Claims (3)

1. A prestressed pipe pile body internal force device implanted with a fiber grating sensor, the main structure includes a prestressed pipe pile, a tube cavity center fixing device, a fiber grating sensor, an armored optical cable, a fiber grating string, a clamping support, an additional steel bar, fiber grating data demodulator, computer; it is characterized in that: the said fiber grating sensor is connected in series with said armored optical cable to form said fiber grating string, and the distance and quantity between said fiber grating sensors are based on construction The soil layer on site is determined; the clamping support is welded to the additional steel bar, and each fiber grating sensor of the fiber grating string is installed on the clamping support on the additional steel bar, so The above-mentioned additional steel bars are bound to the position to be measured in the steel cage; the armored optical cable connected to the fiber grating sensor is led to the near end of the steel cage along the additional steel bars, and is introduced into the center of the lumen and fixed at the preset position. On the fixing device at the center of the lumen, that is, all the armored optical cables of each section of the prestressed pipe pile pass through the wall of the pipe pile and are temporarily fixed in the lumen near the top of the prestressed pipe pile in this section On the central fixing device; all the armored optical cables are led out from the top of the pile, connected with the fiber grating data demodulator, and the fiber grating data demodulator is connected with the computer. 2. A kind of internal force device of a prestressed pipe pile implanted with a fiber grating sensor as claimed in claim 1, wherein said additional reinforcement is a prefabricated reinforcement with a diameter of 20mm and a length of 400mm, the grade of the reinforcement and the stress of the reinforcement Same; FBG sensors on additional rebar lashed at 500mm intervals on the rebar cage. 3. a kind of prestressed pipe pile body internal force device implanted with fiber grating sensor as claimed in claim 1, is characterized in that the center fixing device of the pipe cavity is a cross steel bar, which is welded with the stress bar of the reinforcement cage, After the concrete is poured, it is anchored in the concrete on the inner wall of the pipe pile; in order to avoid the stress concentration caused by the armored optical cable during the piling process, the center of the pipe cavity is fixed at a position 1m away from the pile top.