A device and method for detecting quality of concrete in bored pile hole based on concrete hydration heat

Abstract

The present invention provides a device and method for detecting the quality of concrete in a bored pile expansion hole based on the heat of concrete hydration. The device comprises: a rod assembly, a guide sleeve and a serial temperature sensor. The rod assembly at least comprises a guide rod, an upper arm, a lower arm and an end rod that are sequentially hinged and arranged in the guide sleeve. The guide rod body is provided with at least two pairs of guide wheels, and the guide wheels are in rolling contact with the inner wall of the guide sleeve. The guide sleeve has a cavity for accommodating the rod assembly. The middle side wall of the guide sleeve is provided with a rectangular opening for the upper arm and the lower arm to bend and extend outward. The bottom of the guide sleeve is fixedly connected to the bottom of the end rod. The serial temperature sensor comprises a cable and a plurality of temperature sensors. The cable is integrated with the rod assembly and arranged in parallel in the guide sleeve. The plurality of temperature sensors are fixed on the outer sides of the upper arm and the lower arm, and the cable is externally connected to an external detection device. The present invention solves the problem of testing the temperature of concrete hydration heat in the bored pile expansion hole and detecting the quality of concrete.

Description

Technical Field

[0001] The invention relates to the field of pile foundation engineering technology and geotechnical testing technology, and in particular to a device and method for detecting the quality of concrete in a bored pile hole based on concrete hydration heat. Background Art

[0002] Bored piles are the most commonly used form of pile foundation. As the requirements for foundation bearing capacity of large-scale structures such as high-rise buildings, heavy port terminals, and long bridges continue to increase, traditional uniform-section bored piles are designed to be longer and longer, even reaching more than 100 meters in some projects. Extra-long bored piles have a higher bearing capacity, but their construction quality control is difficult and their long-term settlement after construction is obvious, leading to many engineering problems. Compared with uniform-section bored piles, special-shaped bored piles such as manually expanded and mechanically squeezed bored piles can better exert the soil's anti-compression properties, increase the proportion of end resistance, and thus optimize the pile length. In recent years, as the development of hole expansion equipment has become more mature, special-shaped bored piles have been used more and more.

[0003] However, special-shaped bored piles have similar concrete quality problems as those of uniform cross-section bored piles, such as mud inclusion and segregation. In particular, the concrete quality at the expanded hole position is relatively more risky. At present, there is still a lack of effective technical means for concrete quality detection in the expanded hole section of special-shaped bored piles. Traditional bored pile quality detection methods, including low-strain reflection wave method, cross-hole ultrasonic method, and drilling coring method, are difficult to apply. The insufficiency and lack of quality detection methods restrict the application of special-shaped bored piles. Therefore, it is of great engineering significance to propose an effective method for detecting the quality of concrete in the expanded hole and a feasible detection device. Summary of the invention

[0004] The purpose of the present invention is to provide a device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration, which can be applied to engineering sites and is simple, convenient and easy to operate, so as to effectively solve the problem that the existing bored pile quality detection method cannot detect the quality of concrete in the enlarged hole.

[0005] In order to achieve the above-mentioned object, the present invention provides a device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration, and the device comprises: a rod assembly, a guide sleeve and a serial temperature sensor,

[0006] The rod assembly at least comprises a guide rod, an upper arm rod, a lower arm rod and an end rod which are sequentially hinged up and down and are arranged in the guide sleeve. The guide rod body is provided with at least two pairs of guide wheels, and the guide wheels are in rolling contact with the inner wall of the guide sleeve.

[0007] The guide sleeve has a cavity for accommodating the rod assembly, and a rectangular opening is provided on the middle side wall of the guide sleeve for the upper arm and the lower arm to bend and extend outwards. The bottom of the guide sleeve is fixedly connected to the bottom of the end rod.

[0008] The serial temperature sensor includes a cable and a plurality of temperature sensors connected to the cable. The cable is integrated with the rod and arranged in parallel in a guide sleeve. The plurality of temperature sensors are fixed on the outside of the upper arm and the lower arm, and the cable is connected to an external detection device.

[0009] The rod assembly also includes an extension rod located at the top of the guide rod, the extension rod is detachably fixedly connected to the guide rod, and the top of the extension rod is higher than the top of the guide sleeve.

[0010] The upper arm and the lower arm are hinged by a pin and a pin nut. A pre-biased push rod is arranged on the outer side of the pin nut. The pre-biased push rod is arranged with its back to the rectangular opening of the guide sleeve. The free end of the pre-biased push rod contacts the inner wall of the guide sleeve opposite to the rectangular opening.

[0011] There are multiple sets of devices for detecting the quality of concrete in the enlarged hole of the bored pile based on the heat of concrete hydration, which are respectively arranged at different positions of the cross section of the steel cage.

[0012] A plurality of devices for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration, which are arranged at different positions, have upper arm rods of different lengths and lower arm rods of different lengths.

[0013] A plurality of devices for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration are arranged at different positions, and the upper arm and the lower arm connected thereto have different limit angles, and the limit angle ranges from 180 degrees to 30 degrees.

[0014] Another object of the present invention is to use the above device to detect the quality of concrete in the enlarged hole of the bored pile.

[0015] In order to achieve the above object, the present invention provides a method for detecting the quality of concrete in a bored pile hole based on the heat of concrete hydration, which comprises the following steps:

[0016] S1. Assembling a device for detecting the quality of concrete in a bored pile hole based on the heat of concrete hydration as described in any one of claims 1 to 4;

[0017] S2, tying the device for detecting the quality of concrete in the enlarged hole of the bored pile based on the heat of concrete hydration to the outside of the steel cage along the axial direction of the steel cage, lowering the steel cage into the bored pile hole, so that the elevation of the connecting pin shaft of the lower arm rod and the end rod is higher than the design elevation of the enlarged hole bottom in the bored pile hole, and lower than the design elevation of the enlarged hole top in the bored pile hole;

[0018] S3. After the steel cage is lowered to the design elevation, the temporary fixation of the rod assembly is removed, and a load is applied to the top of the rod assembly to make it move downward until the elevation of the connecting pin shaft between the guide rod and the upper arm is lower than the design elevation of the expansion hole top in the cast-in-place pile hole, and then the top of the rod assembly is temporarily fixed to restrict its movement along the guide sleeve;

[0019] S4. After the concrete is poured, the temperature of each temperature sensor on the serial temperature sensor cable is collected at equal intervals until the temperature value of the temperature sensor on the serial temperature sensor cable changes with time and a clear peak value is observed, and the collection is terminated, and the peak time is recorded;

[0020] S5. After the acquisition is completed, a temperature-time curve of the temperature value of each temperature sensor changing with time is drawn with the same time axis, and a temperature-depth curve of the temperature value of each temperature sensor on the same serial temperature sensor cable changing with the sensor depth at the peak moment is drawn with the same depth axis;

[0021] S6. Analyze the above temperature-time curve and judge the quality of concrete in the following way:

[0022] S6-1. When the temperature value recorded by a temperature sensor or several consecutive temperature sensors on the peak time serial temperature sensor cable is significantly lower than the temperature value recorded by other adjacent temperature sensors, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective;

[0023] S6-2. When the temperature value recorded by a certain temperature sensor or several consecutive temperature sensors on the serial temperature sensor cable changes slightly over time or is significantly smaller than the temperature change amplitude of the adjacent temperature sensor, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective;

[0024] S6-3. If a significant temperature peak is visible in the obtained temperature-depth curve corresponding to the designed hole expansion depth range, the hole expansion is visible, and the starting point of the temperature peak is the actual hole expansion top, and the end point of the temperature peak is the actual hole expansion bottom, and the difference between the two is the actual hole expansion height; if no significant temperature peak is seen, there are defects in the quality of the hole expansion concrete or the hole expansion is not visible.

[0025] Preferably, the buried depth range of the temperature sensor covers a depth of one times the pile diameter above the designed expansion hole top to a depth of one times the pile diameter below the designed expansion hole bottom.

[0026] The beneficial effects of the present invention are:

[0027] (1) This method can detect and analyze the quality of bored pile enlargement concrete without excavation or core drilling. Data collection and analysis can be started after the bored pile concrete is poured, so that concrete quality defects can be identified as early as possible, which is conducive to the implementation of defect treatment measures.

[0028] (2) The device used in this method is easy to operate, and the specifications and dimensions of each component of the device can be flexibly adjusted according to the specific installation location requirements, and it has strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of a device for detecting the quality of concrete in a bored pile expansion hole based on the heat of concrete hydration according to the present invention.

[0030] Figure 2 It is a structural schematic diagram of the connecting portion of the extension rod and the guide rod of the present invention.

[0031] Figure 3a It is a front structural schematic diagram of the guide rod of the present invention.

[0032] Figure 3b It is a schematic diagram of the side structure of the guide rod of the present invention.

[0033] Figure 4a It is a front structural schematic diagram of the upper arm rod of the present invention.

[0034] Figure 4b It is a schematic diagram of the side structure of the upper arm rod of the present invention.

[0035] Figure 5a It is a front structural schematic diagram of the lower arm rod of the present invention.

[0036] Figure 5b It is a schematic diagram of the side structure of the lower arm of the present invention.

[0037] Figure 6a It is a schematic diagram of the front structure of the end rod of the present invention.

[0038] Figure 6b It is a schematic diagram of the side structure of the end rod of the present invention.

[0039] Figure 7a The invention is a schematic diagram of the installation of a device for detecting the quality of concrete in a bored pile expansion hole based on the heat of concrete hydration, with the device being lowered into the hole along with a steel cage.

[0040] Figure 7b The invention is a schematic diagram of the installation of a device for detecting the quality of concrete in a bored pile hole based on the heat of concrete hydration fixed in the hole.

[0041] Figure 8The temperature-depth curve diagram is obtained by testing the device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration when the limit angle is 180 degrees.

[0042] Fig. 9 yes Figure 8 Temperature-time curve obtained from the temperature sensor test at the depth corresponding to the medium temperature peak.

[0043] in,

[0044] Cast-in-place pile equal diameter position 1, cast-in-place pile expansion position 2, steel cage 3, guide rod 4, upper arm 5, lower arm 6, end rod 7, guide sleeve 8, cable 9, upper guide wheel 10, lower guide wheel 11, upper guide wheel pin nut 12, lower guide wheel pin nut 13, guide rod and upper arm connecting pin nut 14, upper arm and lower arm connecting pin nut 15, lower arm and end rod connecting pin nut 16, pre-biased push rod 17, guide sleeve rectangular opening 18, extension rod 19, extension rod screw hole 20, guide rod screw 21, pin hole 22, guide wheel hole 23, upper guide wheel pin 24, lower guide wheel pin 25, guide rod and upper arm connecting pin 26, upper arm and lower arm connecting pin 27, lower arm and end rod connecting pin 28, temperature sensor 29. DETAILED DESCRIPTION

[0045] In order to have a clearer and more intuitive understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings.

[0046] like Figure 1 As shown, a device for detecting the quality of concrete in a bored pile hole based on concrete hydration heat comprises: a rod assembly, a guide sleeve and a serial temperature sensor.

[0047] The rod assembly includes an extension rod 19, a guide rod 4, an upper arm rod 5, a lower arm rod 6 and an end rod 7 which are sequentially connected in the upper and lower directions and are arranged in the guide sleeve. The extension rod 19 is located at the top of the guide rod and is provided with an extension rod screw hole 20. It is detachably fixedly connected to the guide rod 4 through a guide rod screw 21, and the top of the extension rod is higher than the top of the guide sleeve. The guide rod 4 and the upper arm rod 5 are hinged by the guide rod and the upper arm rod connecting pin 26 and the guide rod and the upper arm rod connecting pin nut 14, the upper arm rod 5 and the lower arm rod 6 are hinged by the upper arm rod and the lower arm rod connecting pin 27 and the upper arm rod and the lower arm rod connecting pin nut 15, and the lower arm rod 6 and the end rod 7 are connected by the lower arm rod and the end rod connecting pin 28 and the lower arm rod and the end rod connecting pin nut 16, thereby forming a multi-link assembly in which the guide rod, the upper arm rod, the lower arm rod and the end rod can be movably hinged.

[0048] The guide rod 4 is provided with an upper guide wheel 10 and a lower guide wheel 11, and the upper guide wheel and the lower guide wheel have the same height difference with the upper end of the guide rod and the lower end of the guide rod respectively. The guide rod wall is provided with guide wheel holes 23 and pin holes 22 at the installation positions of the upper and lower guide wheels, and the upper guide wheel pin 24 and the lower guide wheel pin 25 are respectively fixed on the guide rod through the upper and lower pin holes 22. The guide wheel rolls in contact with the guide sleeve through the guide wheel hole 23 to ensure that the guide wheel slides axially in the guide sleeve.

[0049] The guide sleeve 8 is a cylindrical component having a cavity for accommodating the integrated rod components. A rectangular opening is provided on the middle side wall thereof for the upper arm and the lower arm to bend and extend outward. The bottom of the guide sleeve 8 is fixedly connected to the bottom of the end rod 7.

[0050] A pre-biased push rod 17 is provided on the outer side of the pin nut 15 connecting the upper arm and the lower arm. The pre-biased push rod is arranged facing away from the rectangular opening of the guide sleeve, and the free end of the pre-biased push rod contacts the inner wall of the guide sleeve opposite to the rectangular opening.

[0051] The serial temperature sensor includes a cable 9 and a plurality of temperature sensors 29 connected to the cable 9. The cable 9 is integrated with the rod and arranged in parallel in the guide sleeve 8. The plurality of temperature sensors 29 for testing the temperature of the concrete are arranged outside the corresponding positions of the upper arm and the lower arm. The cable 9 is tied from the bottom of the end rod 7 along the side of the rod integration to the top of the extension rod 19, and extends from the top opening of the guide sleeve to connect to the external detection device.

[0052] When a load is applied to the top of the extension rod 19 to cause the extension rod to move downward, since the end rod is fixed to the bottom of the guide sleeve and cannot move downward, the upper arm rod 5 and the lower arm rod 6 move laterally under the action of upper and lower pressures and extend outward from the rectangular opening; when an upward pulling force is applied to the top of the extension rod 19 to pull the extension rod upward, the upper arm rod 5 and the lower arm rod 6 also rotate around the pin shaft and are straightened, and retract from the rectangular opening of the guide sleeve.

[0053] The above-mentioned device for detecting the quality of concrete in the bored pile hole based on the heat of concrete hydration can be installed in multiple sets at the same time, and they are respectively arranged at different positions of the cross section of the steel cage. And the multiple sets of devices for detecting the quality of concrete in the bored pile hole based on the heat of concrete hydration arranged in different positions have upper arms of different lengths and lower arms of different lengths, so that the upper arms and lower arms of the hinged connection have different limit angles.

[0054] The detection method of the present invention comprises the following steps:

[0055] S1. Before lowering the steel cage, assemble the device for detecting the quality of concrete in the bored pile hole based on the heat of concrete hydration according to the present invention, make the pre-biased push rod 17 contact the inner wall of the guide sleeve facing the rectangular opening 18 of the guide sleeve, and then temporarily fix the extension rod 19 to limit the sliding of the rod integrated in the guide sleeve 8;

[0056] S2, tying the above-mentioned device to the outside of the steel cage along the axial direction of the steel cage 3, lowering the steel cage 3, so that the elevation of the lower arm and the end rod connecting the pin 28 is higher than the design elevation of the bottom of the bored pile hole, and lower than the design elevation of the top of the bored hole;

[0057] S3, after lowering the steel cage 3 to the designed elevation, remove the temporary fixation of the extension rod 19, then apply a load on the top of the extension rod 19 to make it move downward until the elevation of the connecting pin 26 of the guide rod and the upper arm rod is lower than the designed expansion hole top elevation. Then temporarily fix the extension rod 19 to limit its movement along the guide sleeve 8;

[0058] At the same time, multiple sets of the above-mentioned devices for detecting the quality of concrete in the expanded hole of the bored pile based on the heat of concrete hydration are arranged at different positions of the cross section of the steel cage. Multiple serial temperature sensors can be arranged at different positions of the pile hole at the same time, so as to more comprehensively cover the concrete quality detection at different positions in the hole.

[0059] For devices for detecting the quality of concrete in bored pile holes based on the heat of concrete hydration in different orientations, upper arms and lower arms of different specifications are set in length so that the upper and lower arms hinged under pressure have different limiting angles of bending in the hole. The position of the limiting angle can vary from a straight angle (the upper and lower arms are straightened toward each other) to an acute angle (for example, 30 degrees), thereby changing the position of the temperature sensors attached to the upper and lower arms to faithfully reflect the temperature conditions in the hole.

[0060] The buried depth range of the temperature sensor covers the depth of one times the pile diameter above the designed expansion hole top to the depth of one times the pile diameter below the designed expansion hole bottom, so as to fully cover the temperature range that needs to be measured.

[0061] S4. After the concrete is poured, the temperature of each temperature sensor on the serial temperature sensor cable is collected at equal intervals until the temperature value variation curve of most temperature sensors on the serial temperature sensor cable with time shows an obvious peak value, then the collection is terminated and the peak time is recorded;

[0062] S5. After the acquisition is completed, a temperature-time curve of the temperature value of each temperature sensor changing with time is drawn with the same time axis, and a temperature-depth curve of the temperature value of each temperature sensor of the same serial temperature sensor cable changing with the sensor depth at the peak moment is drawn with the same depth axis;

[0063] S6. Analyze the above temperature-time curve and temperature-depth curve, and judge the quality of concrete in the following way:

[0064] S6-1. When the temperature value recorded by a temperature sensor or several consecutive temperature sensors on the peak time serial temperature sensor cable is significantly lower than the temperature value recorded by other adjacent temperature sensors, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective;

[0065] like Fig. 9 As shown in the temperature-time curve, curve d reflects that the peak time temperature value of the corresponding temperature sensor is significantly lower than the peak time temperature value recorded by the adjacent temperature sensor (curves a, b, c), indicating that there are defects in the concrete quality at the corresponding temperature sensor location or in the adjacent area.

[0066] S6-2. When the temperature value recorded by a certain temperature sensor or several consecutive temperature sensors on the serial temperature sensor cable changes slightly over time or is significantly smaller than the temperature change amplitude of the adjacent temperature sensor, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective;

[0067] S6-3. If a significant temperature peak is visible in the obtained temperature-depth curve corresponding to the designed hole expansion depth range, the hole expansion is visible, and the starting point of the temperature peak is the actual hole expansion top, and the end point of the temperature peak is the actual hole expansion bottom, and the difference between the two is the actual hole expansion height; if no significant temperature peak is seen, there are defects in the quality of the hole expansion concrete or the hole expansion is not visible.

[0068] like Figure 8 The temperature-depth curve shown in the figure is the temperature-depth curve of the device for detecting the quality of concrete in the bored pile hole based on the heat of concrete hydration when the upper arm and the lower arm limit angle is approximately 180 (i.e. when they are straightened). The figure shows that z1 is the starting point of the temperature peak and is the actual top of the hole, and z2 is the end point of the temperature peak and is the actual bottom of the hole.

[0069] During the solidification process, cast-in-place concrete will generate heat due to hydration reaction. The amount of heat generated is closely related to the volume of concrete, the quality of concrete, and the environment in which the concrete is located. When there are defects such as mud inclusion and segregation in concrete, the heat generated by the hydration reaction of concrete is reduced, and the thermal conductivity of the defective concrete deteriorates, causing the hydration heat temperature of the defective concrete itself and the adjacent areas to be lower than that of the working condition without defects. Based on this, the temperature change law of the hydration heat of concrete can be monitored through a certain temperature measuring point or several adjacent temperature measuring points in the concrete, and then the pouring quality of the concrete at the temperature measuring point or its adjacent area can be analyzed. In addition, when the concrete solidification process is in contact with normal temperature environmental media such as air, water, and soil, due to the obvious heat exchange at the contact interface, the closer the concrete is to the contact interface, the closer the temperature is to the ambient medium temperature. Based on this, the temperature distribution law of the hydration heat of concrete can be monitored through multiple temperature measuring points near the concrete boundary, and then the boundary position of the concrete can be analyzed. In addition, compared with the cast-in-place pile with uniform cross-section, the concrete of the expanded hole section of the cast-in-place pile is equivalent to increasing the concrete volume in the circumferential direction on the basis of the concrete of the cast-in-place pile with uniform cross-section. Therefore, the hydration heat temperature at the position of the cast-in-place pile reinforcement cage corresponding to the expanded hole position is higher than that of the uniform cross-section section, and a temperature peak is formed. The starting point and end point of the temperature peak correspond to the top and bottom of the expanded hole respectively. If the effective expanded hole is not formed, the temperature peak is not obvious. Based on the above principle, by installing temperature sensors in the expanded hole of the cast-in-place pile and on the outside of the reinforcement cage corresponding to the expanded hole to monitor the change law of the hydration heat temperature of the concrete over time and the distribution law over space, the pouring quality of the expanded hole concrete can be analyzed.

[0070] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration, characterized in that include: Rod integration, guide sleeve and serial temperature sensor, The rod assembly at least comprises a guide rod, an upper arm rod, a lower arm rod, an end rod and an extension rod at the top of the guide rod, which are sequentially hinged up and down and are arranged in the guide sleeve. The guide rod body is provided with at least two pairs of guide wheels, and the guide wheels are in rolling contact with the inner wall of the guide sleeve. The extension rod is detachably fixedly connected to the guide rod, and the top of the extension rod is higher than the top of the guide sleeve. The guide sleeve has a cavity for accommodating the rod assembly, a rectangular opening is provided on the middle side wall of the guide sleeve for the upper arm and the lower arm to bend outward and extend, the bottom of the guide sleeve is fixedly connected to the bottom of the end rod, the upper arm and the lower arm are hinged by a pin and a pin nut, a pre-biased push rod is provided on the outside of the pin nut, the pre-biased push rod is arranged with its back to the rectangular opening of the guide sleeve, and the free end of the pre-biased push rod contacts the inner wall of the guide sleeve opposite to the rectangular opening, The serial temperature sensor includes a cable and a plurality of temperature sensors connected to the cable. The cable is integrated with the rod and arranged in parallel in a guide sleeve. The plurality of temperature sensors are fixed on the outside of the upper arm and the lower arm, and the cable is connected to an external detection device.

2. The device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration according to claim 1 is characterized in that: There are multiple sets of devices for detecting the quality of concrete in the enlarged hole of the bored pile based on the heat of concrete hydration, which are respectively arranged at different positions of the cross section of the steel cage.

3. The device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration according to claim 2, characterized in that: A plurality of devices for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration arranged at different positions have upper arms of different lengths and lower arms of different lengths.

4. The device for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration according to claim 2, characterized in that: A plurality of devices for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration are arranged at different positions, and the upper arm and the lower arm connected thereto have different limit angles, and the limit angle ranges from 180 degrees to 30 degrees.

5. A method for detecting the quality of concrete in the enlarged hole of a bored pile based on the heat of concrete hydration, characterized in that: The following steps are involved: S1. Assembling a device for detecting the quality of concrete in a bored pile hole based on the heat of concrete hydration as described in any one of claims 1 to 4; S2, the device for detecting the quality of concrete in the bored pile hole based on the heat of concrete hydration is tied to the outer side of the steel cage along the axial direction of the steel cage, and the steel cage is lowered into the bored pile hole, so that the elevation of the connecting pin shaft of the lower arm rod and the end rod is higher than the design elevation of the bottom of the bored pile hole and lower than the design elevation of the top of the bored pile hole; S3. After the steel cage is lowered to the design elevation, the temporary fixation of the rod assembly is removed, and a load is applied to the top of the rod assembly to make it move downward until the elevation of the connecting pin shaft between the guide rod and the upper arm is lower than the design elevation of the expansion hole top in the cast-in-place pile hole, and then the top of the rod assembly is temporarily fixed to restrict its movement along the guide sleeve; S4. After the concrete is poured, the temperature of each temperature sensor on the serial temperature sensor cable is collected at equal intervals until the temperature value of the temperature sensor on the serial temperature sensor cable changes with time and a clear peak value is observed, and the collection is terminated, and the peak time is recorded; S5. After the acquisition is completed, a temperature-time curve of the temperature value of each temperature sensor changing with time is drawn with the same time axis, and a temperature-depth curve of the temperature value of each temperature sensor on the same serial temperature sensor cable at the peak moment changing with the sensor depth is drawn with the same depth axis; S6. Analyze the above temperature-time curve and temperature-depth curve, and judge the quality of concrete in the following way: S6-1. When the temperature value recorded by a temperature sensor or several consecutive temperature sensors on the peak time serial temperature sensor cable is significantly lower than the temperature value recorded by other adjacent temperature sensors, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective; S6-2. When the temperature value recorded by a certain temperature sensor or several consecutive temperature sensors on the serial temperature sensor cable changes slightly over time or is significantly smaller than the temperature change amplitude of the adjacent temperature sensor, the concrete quality at the location of the temperature sensor or several consecutive temperature sensors or in the adjacent area is defective; S6-3. If a significant temperature peak is visible in the obtained temperature-depth curve corresponding to the designed hole expansion depth range, the hole expansion is visible, and the starting point of the temperature peak is the actual hole expansion top, and the end point of the temperature peak is the actual hole expansion bottom, and the difference between the two is the actual hole expansion height; if no significant temperature peak is seen, there are defects in the quality of the hole expansion concrete or the hole expansion is not visible.

6. The method according to claim 5, characterized in that: The buried depth range of the temperature sensor covers the depth of one times the pile diameter above the designed expansion hole top to the depth of one times the pile diameter below the designed expansion hole bottom.

Images