Engineering pile body quality evaluation method under urban update background

Abstract

The invention discloses an engineering pile body quality evaluation method under an urban updated background, and belongs to the technical field of engineering pile body quality evaluation.The method comprises the following steps that S1, detection equipment is arranged, and the detection equipment for receiving vibration wave velocity signals is arranged on the periphery of an engineering pile body; s2, the wave velocity is detected, an excitation hammer is used for knocking the upper structure of the engineering pile body, and the wave velocity of the complete section of the engineering pile and the average wave velocity of the engineering pile are received through detection equipment; s3, quality evaluation: comparing the wave velocity of the complete section of the engineering pile with the average wave velocity of the engineering pile, and analyzing and evaluating the quality of the engineering pile; the method comprises the following steps: receiving transmitted wave signals along a side detection hole and two reflected wave signals descending along a pile body at one time through detection equipment, determining the wave velocity of a complete section of a to-be-detected pile through the two reflected wave signals, determining the average wave velocity of the whole pile according to the time from the side detection hole transmitted wave head to the wave travel time, and determining the wave velocity of the whole pile according to the comparison of the average wave velocity of the pile body and the wave velocity of the complete section. The pile body quality can be evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of quality assessment of engineering pile bodies in urban renewal projects, and specifically to a method for assessing the quality of engineering pile bodies under the background of urban renewal. Background Art

[0002] Quality assessment of engineering pile bodies under the background of urban renewal is an important link to ensure the safety of building foundations. Its core lies in the detection and assessment of the integrity and bearing capacity of pile bodies. As an important part of the building foundation, the quality inspection of engineering pile bodies can detect potential quality problems, such as defects like cracks, cavities, and mud inclusions, so as to take corresponding remedial measures to avoid the risks of building settlement, inclination, and even collapse caused by pile body quality problems.

[0003] Under complex geological conditions, quality problems are prone to occur during the construction of pile foundations. For example, bored cast-in-place piles may have problems such as excessive sediment at the pile bottom and low concrete strength due to changes in geological conditions. Through pile body detection, these problems can be discovered in time and measures can be taken to ensure the bearing capacity and stability of pile foundations under complex geological conditions.

[0004] For example, the patent with the publication number CN108104179B discloses a method for inspecting and assessing the bearing capacity of inclined pipe piles, including: conducting a general survey using the low-strain method to detect the integrity of the pile body of concrete piles, determining the degree and location of pile body defects, and obtaining the low-strain method curve of each foundation pile; based on the low-strain method test results, L / c strengthening the piles with obvious and serious co-directional reflection wave signals before a certain time, and obtaining the horizontal displacement change amount of the top position of each foundation pile since the pile was formed by using a measurement method; classifying the foundation piles based on the low-strain method results and the magnitude of the horizontal displacement change amount of the pile top, and statistically analyzing the bearing capacity of each type of foundation pile through high-strain method tests on the basis of classification, so as to effectively evaluate the bearing capacity of all foundation piles in a unit project and provide a design basis for the optimization and selection of the reinforcement and strengthening plan for inclined pipe piles.

[0005] As disclosed in the patent with publication number CN119574701A, an underwater pile foundation detection method, system, device, and storage medium are disclosed, which solve the technical problem of failing to effectively integrate the information of multiple key parameters and lacking a scientific and reasonable comprehensive evaluation method to accurately judge the overall state of the pile foundation. By comprehensively obtaining various parameters and conducting in-depth analysis, a complete pile foundation quality evaluation system is constructed. In the propagation speed analysis link, after accurately locating the abnormal points, through the calculation and assignment of the speed difference and the proportion of the abnormal area length, in terms of amplitude analysis, by comprehensively considering the amplitude mutation, the discreteness of the difference between adjacent points, and the proportion of the abnormal area length, the abnormal characteristics and range of the pile body amplitude are detected in all directions, significantly improving the detection accuracy of local non-uniform defects. During frequency analysis, the abnormal points are locked by comparing the emitted frequencies, and combined with regional analysis for assignment, fully considering its impact on the pile foundation quality. Finally, the pile foundation state value is calculated and matched with the state interval to generate information.

[0006] Again, as disclosed in the patent with publication number CN108625409B, a building foundation pile quality detection and evaluation system and an evaluation method are disclosed, including: by setting a first stress wave sensor and a second stress wave sensor on the foundation pile, detecting the stress wave of the first frequency and the stress wave signal of the second frequency emitted by the excitation source assembly, and determining the position of the foundation pile defect through the first arrival time difference, so that it is not necessary to make a time-depth waveform diagram, and at the same time, pile body defects can be found in real time during a single detection process, thereby improving the detection efficiency; as an important component of the foundation, part of the engineering pile is located below the ground surface and part is located above the ground surface, its overall length is relatively large, and the wave velocities generated at different positions during the excitation detection are different. Incomplete acquisition of the wave velocity on the surface of the engineering pile will affect the accuracy of data acquisition, thereby affecting the quality evaluation of the engineering pile.

[0007] In view of the above problems, there is an urgent need to innovate and design on the basis of the original engineering pile body quality evaluation method. Summary of the Invention

[0008] The purpose of the present invention is to provide an engineering pile body quality evaluation method under the background of urban renewal in the field of urban renewal, so as to solve the problem raised in the above background technology that as an important component of the foundation, part of the engineering pile is located below the ground surface and part is located above the ground surface, its overall length is relatively large, and the wave velocities generated at different positions during the excitation detection are different. Incomplete acquisition of the wave velocity on the surface of the engineering pile will affect the accuracy of data acquisition, thereby affecting the quality evaluation of the engineering pile.

[0009] To achieve the above purpose, the present invention provides the following technical solution: An engineering pile body quality evaluation method under the background of urban renewal, including the following steps: S1. Arrange detection equipment. The lower section of the engineering pile column is embedded in the ground, and the upper structure of the engineering pile is higher than the ground. Detection equipment for receiving vibration wave velocity signals is arranged around the engineering pile body.

[0010] S2. Detect the wave velocity. Use a hammer to strike the upper structure of the engineering pile, and receive the wave velocity of the complete section of the engineering pile and the average wave velocity of the engineering pile through a detection device.

[0011] S3. Quality assessment. Compare the wave velocity of the complete section of the engineering pile with the average wave velocity of the engineering pile, and analyze and evaluate the quality of the engineering pile.

[0012] Preferably, the hammer is connected to a signal analyzer through a cable to receive the force signal of the hammer.

[0013] Preferably, in S1, the detection device includes a side hole opened in the ground. The side hole is located around the embedded position of the engineering pile column. A plurality of geophones are arranged in the side hole, and the plurality of geophones are connected to each other through a cable.

[0014] Preferably, the distance between the plurality of geophones is maintained at 0.5 - 2 m.

[0015] Preferably, the geophone is used to receive the transmitted wave of the side hole, and the average wave velocity of the whole engineering pile is determined according to the first arrival time of the transmitted wave in the side hole; the average wave velocity is set to v 0.

[0016] Preferably, the detection device further includes two sensors installed on the side of the engineering pile column, namely sensor 1 and sensor 2.

[0017] Preferably, the distance between sensor 1 and sensor 2 is maintained at 0.5 - 2 m.

[0018] Preferably, sensor 1 and sensor 2 are used to receive two reflected wave signals traveling downward along the pile body, and the wave velocity of the complete section of the engineering pile is determined through the two reflected wave signals; the wave velocity of the complete section is set to v .

[0019] Preferably, the peak time difference of the velocity signals obtained by sensor 1 and sensor 2 is ∆ t .

[0020] The distance between sensor 1 and sensor 2 is ∆ l .

[0021] Wave velocity of the complete section of the engineering pile v = 2∆ l / ∆ t .

[0022] Preferably, the specific method of quality assessment in S3 includes: (1) When the average wave velocity v 0 and the wave velocity of the complete section vIf the difference is less than 10%, it can be judged that the pile quality is good.

[0023] (2) When the average wave speed v 0 less than 0.9 v , indicating that the concrete strength of the pile body has decreased, there are general quality problems, and the bearing capacity needs to be reduced.

[0024] (3) When the average wave speed v 0 less than 0.8 v , indicating that the concrete strength of the pile body is very low and there are serious quality problems, and it needs to be reinforced before use.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: in the method for evaluating the quality of engineering pile bodies under the background of urban renewal, detection equipment is arranged around the engineering piles, and the detection equipment can receive the transmission wave and the reflection signal wave generated when the engineering piles are excited, and the complete section wave velocity of the engineering piles is determined by the two reflection wave signals, and the average wave velocity of the whole engineering pile is determined according to the travel time from the head of the transmission wave to the wave in the side measuring hole, and the quality of the engineering piles can be quickly analyzed by comparing the complete section wave velocity and the average wave velocity, and the method can realize one-time excitation and obtain the complete section wave velocity of the pile body and the average wave velocity of the whole pile at the same time, thereby realizing the evaluation of the quality of the existing engineering pile body, and the test is simple and fast, and the test results are reliable.

[0026] Furthermore, the detection equipment includes a side-test hole opened in the ground, in which a plurality of detectors are arranged. The plurality of detectors are correspondingly distributed at the pre-buried positions of the lower section of the engineering pile, and can effectively receive the transmitted waves at different positions when the engineering pile is excited, thereby obtaining a more accurate wave velocity of the complete section of the engineering pile, thereby improving the accuracy of analyzing and evaluating the quality of the engineering pile.

[0027] Furthermore, the distance between sensor 1 and sensor 2 is maintained at 0.5-2m, which can respectively receive the reflected signal waves of the upper end of the engineering pile located above the ground. Based on the two reflected signal waves, the complete section wave velocity of the engineering pile can be calculated, thereby improving the accuracy of analyzing and evaluating the quality of the engineering pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the detection equipment of the present invention.

[0029] Figure 2 This is a schematic diagram of the speed signal obtained by the sensor of the present invention.

[0030] Figure 3 It is a schematic diagram of the test results of the side test hole transmission wave of the present invention.

[0031] Figure 4 It is a schematic diagram of the engineering pile excitation test results of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1: Please refer to Figure 1 , the present invention provides the following technical solutions: A method for evaluating the quality of engineering pile bodies in the context of urban renewal in the field of urban renewal, including the following steps: S1. Arrange detection equipment. The lower section of the engineering pile column is embedded in the ground, and the upper structure of the engineering pile is above the ground. Detection equipment for receiving vibration wave velocity signals is arranged around the engineering pile body.

[0034] The detection equipment includes side holes opened in the ground. The side holes are located around the embedded position of the engineering pile column, and multiple geophones are arranged in the side holes. The multiple geophones are connected to each other through cables.

[0035] The distance between the multiple geophones is kept at 0.5 - 2 m.

[0036] The geophones are used to receive the transmitted waves in the side holes, and the average wave velocity of the entire engineering pile is determined according to the travel time of the transmitted first arrival waves in the side holes; the average wave velocity is set to v 0.

[0037] The detection equipment also includes two sensors installed on the side of the engineering pile column, namely sensor 1 and sensor 2.

[0038] The distance between sensor 1 and sensor 2 is kept at 0.5 - 2 m.

[0039] Sensor 1 and sensor 2 are used to receive two reflected wave signals traveling downward along the pile body, and the wave velocity of the complete section of the engineering pile is determined through the two reflected wave signals; the wave velocity of the complete section is set to v .

[0040] S2. Detect the wave velocity. Use an impact hammer to strike the upper structure of the engineering pile, and receive the wave velocity of the complete section of the engineering pile and the average wave velocity of the engineering pile through the detection equipment.

[0041] The impact hammer is connected to a signal analyzer through a cable to receive the force signal of the impact hammer.

[0042] S3. Quality evaluation. Compare the wave velocity of the complete section of the engineering pile with the average wave velocity of the engineering pile, and analyze and evaluate the quality of the engineering pile.

[0043] The peak time difference of the velocity signals obtained by sensor 1 and sensor 2 is ∆t .

[0044] The distance between sensor 1 and sensor 2 is ∆ l .

[0045] Wave velocity of the complete section of the engineering pile v = 2∆ l / ∆ t .

[0046] The specific methods for quality assessment include: (1) When the difference between the average wave velocity v 0 and the wave velocity of the complete section v is less than 10%, it can be judged that the pile body quality is good.

[0047] (2) When the average wave velocity v 0 is less than 0.9 v , it indicates that the concrete strength of the pile body has decreased, there are general quality problems, and the bearing capacity needs to be reduced for use.

[0048] (3) When the average wave velocity v 0 is less than 0.8 v , it indicates that the concrete strength of the pile body is very low, there are serious quality problems, and it needs to be strengthened before use.

[0049] By applying an impact hammer to the surface of the upper structure of the engineering pile, after one excitation of the hammer, two reflected wave signals traveling along the side hole and two reflected wave signals traveling downward along the pile body are received at one time. Sensor 1 and sensor 2 can receive the two reflected wave signals on the engineering pile, and multiple geophones inside the side hole around the engineering pile can receive the transmitted waves at different positions in segments. The wave velocity of the complete section of the pile to be measured is determined by the two reflected wave signals, the average wave velocity of the whole pile is determined according to the first arrival time of the transmitted wave in the side hole, and the quality of the pile body can be evaluated according to the comparison between the average wave velocity of the pile body and the wave velocity of the complete section.

[0050] This method can achieve one excitation and simultaneously obtain the wave velocity of the complete section of the pile body and the average wave velocity of the whole pile, so as to realize the assessment of the quality of the existing engineering pile body. The test is simple, fast, and the test results are reliable.

[0051] Example 2: Please refer to Figures 1-4 , for the transformation of a certain existing project, in order to determine the quality of the engineering pile of this project, the above method is used to evaluate the quality of the engineering pile.

[0052] Sensor 1 and sensor 2 are respectively arranged at heights of 0.2 m and 0.8 m at the exposed section of the pile to be measured. A side hole is arranged at a distance of 2 m from the pile side, the hole depth is 15 m, and the interval between multiple geophones on the geophone string is 0.5 m. An impact hammer is used to excite on the upper structure of the pile top of the engineering pile, and the velocity signals obtained by the two sensors are as Figure 2 shown.

[0053] Figure 2 The travel time difference ∆ at the signal peaks 1 and 2 in the middle t = 0.32 ms. According to the distance ∆ between the two sensors l = 0.8 m - 0.2 m = 0.6 m, the wave velocity of the intact section of the pile can be calculated as v = 2∆ l / ∆ t = 3750 m / s.

[0054] The test results of the side-hole transmission wave method are as Figure 3 shown. According to the linear fitting of the arrival times of the first arrival waves of the transmission waves, the fitting line of the pile side section is determined as Figure 3 the dashed line in the middle, and its slope represents the average wave velocity of the pile body v 0 is 3352 m / s.

[0055] According to v 0 < 0.9 v , it can be inferred that there are general quality defects in the pile body and it needs to be used with reduced bearing capacity.

[0056] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for evaluating the quality of engineering pile bodies under the background of urban renewal, characterized in that, It includes the following steps: S1. Install detection equipment. The lower section of the engineering pile column is embedded in the ground, and the upper structure of the engineering pile is above the ground. Detection equipment for receiving vibration wave velocity signals is arranged around the engineering pile body. S2. Detect wave velocity. Use an impact hammer to strike the upper structure of the engineering pile, and receive the wave velocity of the complete section of the engineering pile and the average wave velocity of the engineering pile through the detection equipment. S3. Quality assessment. Compare the wave velocity of the complete section of the engineering pile with the average wave velocity of the engineering pile, and analyze and evaluate the quality of the engineering pile.

2. The method for evaluating the quality of engineering pile shafts under the background of urban renewal according to claim 1, wherein: The impact hammer is connected to a signal analyzer through a cable to receive the force signal of the impact hammer.

3. A method for evaluating the quality of engineering pile bodies under the background of urban renewal according to claim 1, characterized in that: In S1, the detection equipment includes a side hole opened in the ground. The side hole is located around the embedded position of the engineering pile column, and multiple geophones are arranged in the side hole. The multiple geophones are connected to each other through cables.

4. A method for evaluating the quality of engineering pile bodies under the background of urban renewal according to claim 3, characterized in that: The distance between the multiple geophones is maintained at 0.5 - 2 m.

5. A method for evaluating the quality of engineering pile shafts under the background of urban renewal according to claim 3, characterized in that: The geophone is used to receive the transmitted wave of the side hole, and determine the average wave velocity of the entire engineering pile according to the travel time of the transmitted first arrival wave in the side hole. Set the average wave velocity to v 0.

6. The method for evaluating the quality of engineering pile shafts under the background of urban renewal according to claim 3, characterized in that: The detection equipment further includes two sensors installed on the side of the engineering pile column, namely sensor 1 and sensor 2.

7. A method for evaluating the quality of engineering pile shafts under the background of urban renewal according to claim 6, characterized in that: The distance between sensor 1 and sensor 2 is maintained at 0.5 - 2 m.

8. A method for evaluating the quality of engineering pile shafts in the context of urban renewal according to claim 6, characterized in that: Sensor 1 and sensor 2 are used to receive two reflected wave signals traveling downward along the pile body, and determine the wave velocity of the complete section of the engineering pile through the two reflected wave signals. Set the full - segment wave velocity to v .

9. A method for evaluating the quality of engineering pile shafts under the background of urban renewal according to claim 8, characterized in that: The peak time difference of the speed signals obtained by the sensor 1 and the sensor 2 is ∆ t ; The distance between sensor 1 and sensor 2 is ∆ l ; Wave velocity of the complete section of the engineering pile v =2∆ l / ∆ t 。 10. A method for evaluating the quality of engineering pile bodies under the background of urban renewal according to claim 8, characterized in that: The specific method of quality assessment in S3 includes: (1) When the average wave velocity v is less than 10% different from the wave velocity of the intact section v , it can be judged that the pile body quality is good. (2)When the average wave velocity v is less than 0.9 v , it indicates that the concrete strength of the pile body has decreased, there are general quality problems, and it is necessary to use it with a reduced bearing capacity; (3) When the average wave velocity v is less than 0.8 v , it indicates that the concrete strength of the pile body is very low, there are serious quality problems, and it needs to be strengthened before use.

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