阅读说明：本技术 一种建筑物基础灌注桩缺陷检测方法 (Defect detection method for building foundation cast-in-place pile ) 是由 庞莹莹 于 2020-06-21 设计创作，主要内容包括：一种建筑物基础灌注桩缺陷检测方法,包括：(1)在灌注桩轴线均匀设置发热元件；在灌注桩周向均匀设置分布式热感光纤；(2)对所有发热元件使用相同的加热过程；(3)根据分布式热感光纤检测的发热元件对应深度的温度数据,确定该深度是否存在灌注桩缺陷；(4)获取发热元件相邻分布式热感光纤的温度数据；(5)根据步骤(4)获取的温度数据,判断相邻的发热元件深度之间是否存在灌注桩缺陷。(A method for detecting defects of a building foundation cast-in-place pile comprises the following steps: (1) heating elements are uniformly arranged on the axis of the cast-in-place pile; uniformly arranging distributed thermal sensing optical fibers in the circumferential direction of the cast-in-place pile; (2) using the same heating process for all heating elements; (3) determining whether the depth has a cast-in-place pile defect according to temperature data of the corresponding depth of the heating element detected by the distributed thermal sensing optical fiber; (4) acquiring temperature data of distributed thermal sensing optical fibers adjacent to the heating element; (5) and (4) judging whether the depth of the adjacent heating elements has the defect of the cast-in-place pile or not according to the temperature data acquired in the step (4).)

1. A method for detecting defects of a building foundation cast-in-place pile comprises the following steps: (1) n heating elements are uniformly arranged on the axis of the cast-in-place pile; uniformly arranging distributed thermal sensing optical fibers in the circumferential direction of the cast-in-place pile; (2) using the same heating process for all heating elements; (3) determining whether the depth has a cast-in-place pile defect according to temperature data of the corresponding depth of the heating element detected by the distributed thermal sensing optical fiber; (4) for the ith heating element from shallow to deep, the following operations are performed in sequence: (4.1) determining whether i is equal to 1 or i is equal to N; if i is equal to 1, then i is added by 1, and step (4.2) is carried out; if i is equal to N, entering the step (5); (4.2) heating the ith heating element; (4.3) acquiring temperature data of the distributed thermal sensing optical fiber with the depth corresponding to the (i-1) th heating element and the (i + 1) th heating element; (4.5) after the heating is finished, the room temperature is recovered, i is automatically added by 2, and the step (4.1) is returned; (5) and (4) judging whether the depth of the adjacent heating elements has the defect of the cast-in-place pile or not according to the temperature data acquired in the step (4).

Technical Field

The invention relates to the technical field of building foundation detection, in particular to a method for detecting defects of a building foundation cast-in-place pile.

Background

The cast-in-place pile is a common and important building foundation type, has the characteristics of relatively simple and mature construction process, strong adaptability, stable working performance, small construction interference, high construction efficiency and the like, and is widely applied to multiple engineering fields of buildings, traffic, water conservancy, energy sources and the like.

The cast-in-place pile foundation belongs to hidden engineering, is difficult to monitor in the whole process of pile forming, is difficult to detect after pile forming, and is easy to have quality problems of hole collapse, inclined hole, diameter shrinkage, pile breakage, pile body segregation, floating slurry and the like. The quality detection of the cast-in-place pile mainly aims at detecting the integrity of the pile body, detecting the quality defect of the pile body, the position and the size of the pile body, determining the influence degree of the pile body on the quality of the pile body, further determining whether the quality of the pile body meets the standard, and simultaneously repairing some defects to ensure the service life and the safety of the pile body.

Common pile quality detection methods include an ultrasonic transmission method, a core drilling sampling method, a high-strain dynamic pile testing method, a low-strain reflection wave method, a static load test and the like. The different detection methods have the advantages and the disadvantages, the ultrasonic transmission method is not limited by the pile length and the field, the data is visual and reliable, the anti-interference capability is strong, but the acoustic pipe needs to be pre-embedded in advance, and if the acoustic pipe is not protected properly, the acoustic pipe is easy to block and cannot be tested; the detection result of the core drilling sampling method is visual and reliable and is not interfered, but the core drilling sampling method has the defects of long time consumption, high cost, area by area, erroneous judgment or missed judgment and the like due to the fact that the detection is destructive; the reliability of detecting the integrity of the pile body by the high-strain dynamic pile testing method is higher than that of the low-strain dynamic pile testing method, but the method has heavy equipment, high cost and low efficiency, a blind area exists in shallow defect judgment, and the test error is large; the low strain reflection wave method is convenient, quick, economical and applicable to detection, but is easily interfered by various factors, and the waveform is difficult to identify and distinguish.

Disclosure of Invention

The invention provides a further improvement and provides a method for detecting the defects of the building foundation cast-in-place pile, which can further determine the defects among different depths of heating elements.

As an aspect of the present invention, there is provided a method for detecting a defect of a cast-in-place pile of a foundation of a building, including: (1) n heating elements are uniformly arranged on the axis of the cast-in-place pile; uniformly arranging distributed thermal sensing optical fibers in the circumferential direction of the cast-in-place pile; (2) using the same heating process for all heating elements; (3) determining whether the depth has a cast-in-place pile defect according to temperature data of the corresponding depth of the heating element detected by the distributed thermal sensing optical fiber; (4) for the ith heating element from shallow to deep, the following operations are performed in sequence: (4.1) determining whether i is equal to 1 or i is equal to N; if i is equal to 1, then i is added by 1, and step (4.2) is carried out; if i is equal to N, entering the step (5); (4.2) heating the ith heating element; (4.3) acquiring temperature data of the distributed thermal sensing optical fiber with the depth corresponding to the (i-1) th heating element and the (i + 1) th heating element; (4.5) after the heating is finished, the room temperature is recovered, i is automatically added by 2, and the step (4.1) is returned; (5) and (4) judging whether the depth of the adjacent heating elements has the defect of the cast-in-place pile or not according to the temperature data acquired in the step (4).

Preferably, in the step (3), the type and the position of the defect in the cast-in-place pile are determined based on the following steps: (3.1) acquiring the peak value of temperature data of each distributed thermal sensing optical fiber at the depth of each heating element; (3.2) drawing histograms of all temperature data peak values by taking a certain temperature difference as a group interval; (3.3) selecting the group with the highest frequency number in the histogram, and calculating a first mean value T and a first mean square error delta T of the temperature data peak value; (3.4) determining that the first temperature data peak value threshold is equal to T-3 Δ T according to the first mean value T and the first mean square error Δ T of the temperature data peak value; (3.5) sequentially judging the depth of each heating element as follows: if the temperature data peak values of all the distributed thermal sensing optical fibers at the depth are greater than or equal to the first temperature data peak value threshold value, the cast-in-place pile has no defects at the depth; if the temperature data peak values of all the distributed thermal sensing optical fibers at the depth are smaller than the first temperature data peak value threshold value, pile breakage exists in the cast-in-place pile at the depth; if the temperature data peak value of the single distributed thermal fiber at the depth is smaller than the peak value threshold value, a cavity exists at the connecting line position of the single distributed thermal fiber and the central axis of the cast-in-place pile; if the temperature data peak value of the distributed thermal fibers smaller than all the heating fibers is smaller than the peak value threshold value, a cavity exists in a fan-shaped area formed by the adjacent distributed thermal fibers and the central axis of the filling pile in the distributed thermal fibers.

Preferably, in the step (5), (5.1) determining the temperature data peak value of all thermal sensing optical fibers; (5.2) drawing a histogram of all temperature data peak values by taking a certain temperature difference as a group interval; (5.3) selecting the group with the highest frequency number in the histogram, and calculating a second mean value T1 and a second mean square error delta T1 of the temperature data peak; (5.4) determining that the second temperature data peak threshold is equal to T1-3 Δ T1 according to the second mean value T1 of the temperature data peaks and the second mean square error Δ T1; (5.5) judging the temperature data peak value of the ith heating element depth, (5.5.1) judging the temperature data peak value of the ith-1 heating element depth, if the temperature data peak values of all the distributed thermal sensing optical fibers of the ith-1 heating element depth are greater than or equal to a second temperature data peak value threshold value, judging that the filling pile has no defect in the depth from the ith heating element to the ith heating element; if the temperature data peak values of all the distributed thermal sensing optical fibers at the depth of the (i-1) th heating element are smaller than the second temperature data peak value threshold value, pile breakage exists in the depth from the (i-1) th heating element to the (i) th heating element of the cast-in-place pile; if the temperature data peak value of the single distributed thermal sensing optical fiber at the (i-1) th heating element depth is smaller than the second temperature data peak value threshold value, a cavity exists at the connecting line position of the (i-1) th heating element depth of the single distributed thermal sensing optical fiber and the ith heating element depth of the central axis of the cast-in-place pile; if the temperature data peak value of the distributed thermal sensing optical fibers with the i-1 th heating element depth smaller than the number of all the heating optical fibers is smaller than a second temperature data peak value threshold value, a cavity exists in a fan-shaped area formed between the adjacent distributed thermal sensing optical fibers in the distributed thermal sensing optical fibers with the i-1 th heating element depth and the ith heating element depth of the central axis of the filling pile; (5.5.2) judging the temperature data peak value of the depth of the (i + 1) th heating element, if the temperature data peak values of all the distributed thermal sensing optical fibers of the depth of the (i + 1) th heating element are greater than or equal to a second temperature data peak value threshold value, the cast-in-place pile has no defect in the depth from the i +1 th heating element to the (i + 1) th heating element; if the temperature data peak values of all the distributed thermal sensing optical fibers at the depth of the (i + 1) th heating element are smaller than the second temperature data peak value threshold value, pile breakage exists between the depth of the (i + 1) th heating element and the depth of the cast-in-place pile; if the temperature data peak value of the single distributed thermal sensing optical fiber at the (i + 1) th heating element depth is smaller than the second temperature data peak value threshold value, a cavity exists at the connecting line position of the (i + 1) th heating element depth of the single distributed thermal sensing optical fiber and the ith heating element depth of the central axis of the cast-in-place pile; if the temperature data peak value of the distributed thermal sensing optical fibers with the (i + 1) th heating element depth being less than the number of all the heating optical fibers is less than the second temperature data peak value threshold value, a hollow hole exists in a fan-shaped area formed between the adjacent distributed thermal sensing optical fibers in the plurality of distributed thermal sensing optical fibers with the (i + 1) th heating element depth and the ith heating element depth of the central axis of the cast-in-place pile.

Preferably, in the step (1), N heating elements extend from the top of the pouring shaft to the bottom of the pouring pile and are uniformly arranged in the mounting hole, and N is an integer greater than 8.

Preferably, in the step (1), the N heating elements are uniformly arranged at a distance of 0.5-1 m.

Preferably, in the step (1), the number of the distributed thermal sensing optical fibers is 4 or 6 or 8.

Preferably, in the step (2) and the step (4.2), the heating temperature is less than 200 ℃, and the heating time is 1-5 min.

Preferably, the group distance in the step (3) and the step (5) is set to be between 0.5 ℃ and 3 ℃.

Preferably, the distributed thermal fiber determines the temperature at different locations based on raman scattering.

Preferably, a steel reinforcement cage is arranged in the cast-in-place pile.

Drawings

Fig. 1 is a schematic diagram of a heating element and a distributed thermal sensing optical fiber in the method for detecting the defects of the cast-in-place pile in the constructional engineering.

FIG. 2 is a flow chart of the method for detecting the defects of the cast-in-place pile in the constructional engineering.

Detailed Description

In order to more clearly illustrate the technical solutions of the present invention, the present invention will be briefly described below by using embodiments, and it is obvious that the following description is only one embodiment of the present invention, and for those skilled in the art, other technical solutions can be obtained according to the embodiments without inventive labor, and also fall within the disclosure of the present invention.

The method for detecting the defects of the cast-in-place piles of the building foundation is used for detecting the defects of holes and broken piles in the cast-in-place piles provided with the reinforcement cages, and referring to fig. 1, mounting holes 1 located on a central axis and a plurality of mounting holes 2 located on the periphery are preset in cast-in-place piles 100. And the distributed thermal sensing optical fibers 3 are uniformly and vertically arranged in the mounting holes 2 in the circumferential direction of the cast-in-place pile. Wherein, the number of the plurality of distributed thermal sensing optical fibers 3 can be set to be 4, 6 or 8. The distributed thermal fibre 3 is capable of determining the temperature of the fibre at different locations along the fibre based on raman scattering of the laser pulses as they propagate through the fibre.

And the central heating assembly 10 is vertically arranged in the mounting hole 1 of the central axis of the cast-in-place pile. The central heating assembly 10 extends from the top of the bored concrete shaft mounting hole 1 to the bottom of the bored concrete pile mounting hole 1, and includes a plurality of vertically and uniformly arranged heating elements 11. In a single bored concrete pile, the number of heating elements 11 is set up to more than 8, also can evenly set up according to certain interval, for example evenly set up in bored concrete pile mounting hole 1 with 0.5~1m as the interval. The heating element 11 may be a metal heating element, and the heating temperature thereof is lower than 200 ℃. The heating element 11 is heated for the same time at the same temperature when defect detection is performed. Wherein, the heating time can be, for example, 1 to 5 min.

And a data acquisition unit which acquires temperature data of different depth positions of the plurality of distributed thermal sensing fibers 3. And a defect analysis unit which determines the type and position of the defect in the cast-in-place pile based on the temperature data of the plurality of distributed thermal sensing fibers 3 corresponding to the depth of the heating element 11, which is acquired by the data acquisition unit.

The method for detecting the defects of the cast-in-place pile in the constructional engineering, disclosed by the embodiment of the invention, is shown in figure 2 and comprises the following steps of: (1) n heating elements 11 are uniformly arranged on the axis of the cast-in-place pile 100; uniformly arranging distributed thermal sensing optical fibers 3 in the circumferential direction of the cast-in-place pile 100; wherein N is a natural number of 8 or more; (2) the same heating process is used for all the heating elements 11; (3) according to the temperature data of the corresponding depth of the heating element 11 detected by the distributed thermal sensing optical fiber 3, determining whether the depth has a cast-in-place pile defect; (4) for the ith heating element 11 from shallow to deep, the following operations are performed in sequence: (4.1) determining whether i is equal to 1 or i is equal to N; if i is equal to 1, then i is added by 1, and step (4.2) is carried out; if i is equal to N, entering the step (5); (4.2) heating the i-th heating element 11; (4.3) acquiring temperature data of the distributed thermal sensing optical fiber 3 with the depth corresponding to the (i-1) th heating element 11 and the (i + 1) th heating element 11; (4.5) after the heating is finished, the room temperature is recovered, i is automatically added by 2, and the step (4.1) is returned; (5) and (4) judging whether the depth of the adjacent heating elements 11 has a cast-in-place pile defect or not according to the temperature data acquired in the step (4).

In step (3), the type and location of the defect in cast-in-place pile 100 is determined based on the following steps: (3.1) acquiring the peak value of the temperature data of each distributed thermal sensing optical fiber 3 at the depth of each heating element 11; (3.2) drawing histograms of all temperature data peak values by taking a certain temperature difference as a group interval; the group distance can be set to be between 0.5 and 3 degrees; (3.3) selecting the group with the highest frequency number in the histogram, and calculating a first mean value T and a first mean square error delta T of the temperature data peak value; (3.4) determining that the first temperature data peak value threshold is equal to T-3 Δ T according to the first mean value T and the first mean square error Δ T of the temperature data peak value; (3.5) the following judgment is made for the depth of each heating element 11 in turn: if the temperature data peak values of all distributed thermal sensing fibers 3 at the depth are greater than or equal to the first temperature data peak value threshold value, the cast-in-place pile 100 has no defect at the depth; if the temperature data peak values of all the distributed thermal sensing optical fibers 3 at the depth are smaller than the first temperature data peak value threshold value, the cast-in-place pile is broken at the depth; if the temperature data peak value of the single distributed thermal sensing optical fiber 3 at the depth is smaller than the peak threshold value, a cavity exists at the connecting line position of the single distributed thermal sensing optical fiber 3 and the central axis of the cast-in-place pile 100; if the peak value of the temperature data of the plurality of distributed thermal sensing fibers 3 which is less than the number of all the heating fibers is less than the peak threshold value, a hollow exists in a fan-shaped area formed by the adjacent distributed thermal sensing fibers 3 in the plurality of distributed thermal sensing fibers 3 and the central axis of the cast-in-place pile 100.

Preferably, in the step (5), (5.1) determining the temperature data peak value of all the thermal sensing optical fibers 3; (5.2) drawing a histogram of all temperature data peak values by taking a certain temperature difference as a group interval; (5.3) selecting the group with the highest frequency number in the histogram, and calculating a second mean value T1 and a second mean square error delta T1 of the temperature data peak; (5.4) determining that the second temperature data peak threshold is equal to T1-3 Δ T1 according to the second mean value T1 of the temperature data peaks and the second mean square error Δ T1; (5.5) judging the temperature data peak value of the ith heating element 11, and (5.5.1) judging the temperature data peak value of the ith-1 heating element 11 depth, wherein if the temperature data peak values of all the distributed thermal sensing fibers 3 of the ith-1 heating element 11 depth are greater than or equal to a second temperature data peak value threshold value, the cast-in-place pile 100 has no defect in the depth from the ith-1 heating element 11 to the ith heating element 11; if the temperature data peak values of all the distributed thermal sensing optical fibers 3 at the depth of the (i-1) th heating element 11 are less than the second temperature data peak value threshold value, the bored concrete pile 100 is broken at the depth from the (i-1) th heating element 11 to the (i) th heating element 11; if the temperature data peak value of the single distributed thermal fiber 3 at the depth of the (i-1) th heating element 11 is smaller than the second temperature data peak value threshold value, a hollow hole exists in the connecting position of the depth of the (i-1) th heating element 11 and the central axis of the cast-in-place pile 100 at the depth of the (i) th heating element 11 in the single distributed thermal fiber 3; if the temperature data peak value of the distributed thermal sensing optical fibers 3 with the depth of the (i-1) th heating element 11 being less than the number of all the thermal sensing optical fibers is less than the second temperature data peak value threshold value, a hole exists in a fan-shaped area formed between the adjacent distributed thermal sensing optical fibers 3 in the distributed thermal sensing optical fibers 3 with the depth of the (i) th heating element 11 in the central axis of the pouring pile 100; (5.5.2) judging the temperature data peak value of the depth of the (i + 1) th heating element 11, if the temperature data peak values of all the distributed thermal sensing fibers 3 with the depth of the (i + 1) th heating element being 11 degrees are greater than or equal to the second temperature data peak value threshold value, the cast-in-place pile 100 has no defect in the depth from the (i) th heating element 11 to the (i + 1) th heating element 11; if the temperature data peak values of all the distributed thermal sensing optical fibers 3 at the depth of the (i + 1) th heating element 11 are less than the second temperature data peak value threshold value, the bored concrete pile 100 has pile breakage at the depth from the (i) th heating element 11 to the (i + 1) th heating element 11; if the temperature data peak value of the single distributed thermal fiber 3 with the depth of the (i + 1) th heating element 11 is smaller than the second temperature data peak value threshold value, a cavity exists at the connecting position of the depth of the (i + 1) th heating element 11 of the single distributed thermal fiber 3 and the depth of the ith heating element 11 of the central axis of the cast-in-place pile 100; if the peak value of the temperature data of the distributed thermal fibers 3 at the depth of the (i + 1) th heating element 11, which is less than the number of all the thermal fibers, is less than the second peak value threshold value of the temperature data, a hollow exists in the sector area formed between the adjacent distributed thermal fibers 3 in the distributed thermal fibers 3 at the depth of the (i + 1) th heating element 11 and the depth of the ith heating element 11 at the central axis of the cast-in-place pile 100.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The particular features, structures, materials, or characteristics described in this disclosure may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.