Pipe-jacking pipe-soil structure detection method for buried concrete pipeline

Abstract

The invention relates to a method for detecting a pipe-jacking pipe soil structure of a buried concrete pipeline, which comprises the following steps of: setting N measuring points and a load center point on the same bus at the top of the inner wall of the buried concrete pipeline, and arranging a contact type displacement sensor on each measuring point, a knocking device is used for applying impact load to the inner wall of the buried concrete pipeline at the position of a load center point, a contact type displacement sensor records the maximum deflection value L of each measuring point, and the position s of each measuring point on the same bus and the maximum deflection value L of the measuring point serve as coordinate points to be drawn in a rectangular coordinate system. Connecting to form a deflection curve graph, and judging the health state of the pipe-jacking pipe-soil structure of the buried concrete pipeline according to the form of the deflection curve graph; the device and the method can realize nondestructive detection of non-uniformity and void of a soil layer covering the top of the buried concrete pipeline and pipeline crack defects, and are high in identification capability, high in detection precision and good in detection reliability.

Description

TECHNICAL FIELD

[0001] The application relates to a buried concrete pipeline pipe-soil structure detection method, in particular to a buried concrete pipeline pipe-top pipe-soil structure detection method. BACKGROUND

[0002] With the continuous development of municipal infrastructure, the number of buried concrete pipelines is increasing day by day. Due to various environmental factors and complex geological conditions, and the vibration caused by the flow of liquid in the pipeline, unevenness, void and pipeline cracks of the concrete pipeline topsoil layer are caused, which is easy to cause ground subsidence and seriously threatens the safety of the concrete pipeline. The existing detection methods of the pipe-top pipe-soil structure of the concrete pipeline mainly include the pipeline closed-circuit television method (CCTV), the sonar method and the ground penetrating radar method. The pipeline closed-circuit television method (CCTV) can directly observe the signs of pipeline cracks and corrosion from the inside of the pipeline, such as silt leakage and joint opening. The sonar method is used for pipelines filled with water, and the sonar can detect the deformation and deposition inside the pipeline to indirectly assist in judging the loss of external soil. The ground penetrating radar can quickly scan the ground to find the discontinuous surface of the underground medium (possible void). However, the results are greatly affected by the medium, and it is difficult to determine whether the void is "inflated" or "water-filled". These methods can effectively detect the pipe-top pipe-soil structure defects of the buried concrete pipeline under certain conditions, but still have the disadvantages of large signal interference, inaccurate detection, limited detection depth and high equipment cost. Moreover, these methods mainly focus on signal feature analysis, and it is difficult to reflect the true mechanical response of the structure, so it is impossible to analyze the overall health condition of the pipe-top pipe-soil structure of the buried concrete pipeline through mechanical response analysis. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a buried concrete pipeline pipe-top pipe-soil structure detection method, which can realize non-destructive testing of unevenness, void and pipeline crack defects of the buried concrete pipeline topsoil layer, has strong recognition ability, high detection precision and improved detection reliability.

[0004] The technical scheme of the present application is as follows: A buried concrete pipeline pipe-top pipe-soil structure detection method comprises the following steps: Selecting a section of buried concrete pipeline, the buried concrete pipeline being located below the soil layer, Step 1, according to the dynamic response principle of structural mechanics, N measuring points are arranged on the inner wall of the buried concrete pipeline, the N measuring points being located on the same generatrix at the top of the buried concrete pipeline, the N measuring points being distributed at a certain interval, the leftmost measuring point being taken as a measurement reference point, the distance from each measuring point to the measurement reference point being s, and N being a natural number greater than or equal to 3; Step 2, arrange a contact displacement sensor at each measuring point, N measuring points correspond to N contact displacement sensors; Step 3, set a load center point on the inner wall of the buried concrete pipeline, the load center point and the measuring point are located on the same parent line at the top of the concrete pipeline, and the load center point is located on the left side of the measuring reference point; Step 4, set a knocking device in the buried concrete pipeline, move the knocking device to the preset position, raise the knocking device to the predetermined height through the hydraulic system, and ensure that the device is stable, so that the weight of the knocking device is aligned with the load center point. Use the knocking device to apply impact load to the inner wall of the buried concrete pipeline at the load center point; Step 5, N contact displacement sensors respectively record the displacement of N measuring points, that is, the maximum deflection value L of N measuring points; Step 6, according to the measurement data of each contact displacement sensor, draw a deflection curve graph using the maximum deflection value L: take the distance s from the measuring point to the measuring reference point as the abscissa and the maximum deflection value L as the ordinate to establish a rectangular coordinate system. The distance s from each measuring point to the measuring reference point and the recorded maximum deflection value L of the measuring point are taken as coordinate points (s, L) and plotted in the rectangular coordinate system. Connecting the coordinate points (s, L) of N measuring points forms a curve to obtain a deflection curve graph; Analyze the deflection curve graph and use the following method to identify abnormal points on the deflection curve graph. The judgment method is as follows: Absolute value judgment: the maximum deflection value L of one or more consecutive measuring points is much larger than the values of adjacent measuring points and the average value of the whole line; Morphology judgment: the deflection curve appears a sudden, sharp "peak" or "concave"; Change rate judgment: calculate the change gradient of the maximum deflection value L between adjacent measuring points. The gradient at the void boundary will increase sharply; Step 7, judge the health status of the pipe-top-soil structure of the buried concrete pipeline through the morphology of the deflection curve graph: Normal and healthy pipe-soil structure: the deflection curve graph presents uniform attenuation, and the maximum deflection value L decreases smoothly with the increase of the distance s from the measuring point to the measuring reference point, indicating that the pipe-soil structure is uniformly loaded and in good health; Uneven pipe-soil structure: the deflection curve graph presents abnormal fluctuations or local protrusions, indicating that the pipe-soil structure has uneven overburden soil, void, and pipeline cracks; Weak pipe-soil structure: the maximum deflection value L decays very quickly, and the maximum deflection value L at the measuring reference point is large, indicating that the pipe-soil structure may have a relatively serious weak soil layer and needs to be repaired or reinforced.

[0005] The deflection curve shape of the buried concrete pipeline in a healthy state is normal, the maximum deflection value L attenuates gently with the increase of the distance from the measurement point to the measurement reference point, indicating that the structural quality distribution of the buried concrete pipeline is uniform; if the deflection curve shape has abnormal fluctuations, it indicates that the structural quality distribution of the buried concrete pipeline is not uniform, and there is a void or other diseases around the buried concrete pipeline; For different deflection curves under the same position and the same load condition, comparative analysis can be carried out to evaluate the structural differences of different pipe sections, for example, comparing historical data: comparing the current deflection curve data with the previous measurement results to analyze the changes of the pipe-soil structure; The deflection curves under the same load condition of different pipe sections can also be compared, and the bearing capacity of which pipe section is stronger or weaker can be evaluated by measuring the deflection curve shape of different pipe sections.

[0006] In step 4, the knocking device is an electric knocking hammer.

[0007] A rigid bearing plate is arranged at the load center point position of the inner wall of the buried concrete pipeline, the rigid bearing plate is circular, the center of the rigid bearing plate is concentric with the load center point, and the rigid bearing plate is tightly attached to the inner wall of the buried concrete pipeline, so that the inner wall of the buried concrete pipeline is uniformly stressed and the pipe wall is protected, and the knocking device applies impact load to the inner wall of the buried concrete pipeline through the rigid bearing plate.

[0008] The time history curve style of the impact load is a half-sine pulse loading curve.

[0009] Advantages of the present application: 1. According to the dynamic response principle of structural mechanics, the present application applies transient impact load to the inner wall of the buried concrete pipeline, detects the deflection response of the inner wall surface of the buried concrete pipeline, determines the health state of the pipe-soil structure of the buried concrete pipeline according to the attenuation law of the maximum deflection value with distance, and analyzes the deflection curve shape and abnormal points, so as to realize nondestructive testing of the unevenness, void and crack defects of the cover soil layer of the buried concrete pipeline.

[0010] 2. The pipe-soil structure detection method of the buried concrete pipeline of the present application is not limited by the buried depth of the buried concrete pipeline, the detection value can be quantified, and not only has strong identification ability and high detection precision, but also improves the detection reliability. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a schematic diagram for detecting the pipe-soil structure of the buried concrete pipeline; Figure 2 It is a deflection curve diagram of the buried concrete pipeline in a healthy state; Figure 3The deflection curve chart for the buried concrete pipeline and the surrounding soil layer when there is an abnormal problem.

[0012] In the figure, 1 is a rigid top layer, 2 is a soil layer, 3 is a buried concrete pipeline (pipe top pipe wall), 4 is a contact displacement sensor, 5 is a load center point, 6 is a knocking device, 7 is a rigid bearing plate, 8 is a measurement reference point, and g is the acceleration of gravity. DETAILED DESCRIPTION

[0013] The pipe top pipe soil structure detection method of the buried concrete pipeline 3 contains the following steps: A section of the buried concrete pipeline 3 is selected, the buried concrete pipeline 3 is located below the soil layer 2, the soil layer 2 is covered with a rigid top layer 1 on the top, and the pipe soil structure profile of the buried concrete pipeline 3 is as shown in Figure 1 The material parameters of the buried concrete pipeline 3 and the soil layer 2 are as shown in Table 1; Table 1 Material parameters Meaning Number of layers Young's modulus (Pa) Poisson's ratio Density (kg / m³) Damping ratio Thickness (mm) PCC pipe DN600 1 30E9 0.2 2500 0.03 Wall thickness 70 Soil 2 0.05E9 0.25 2000 0.04 1000 Step 1, according to the dynamic response principle of structural mechanics, 7 measurement points are arranged on the inner wall of the buried concrete pipeline 3, the 7 measurement points are located on the same generatrix at the top of the buried concrete pipeline 3, the 7 measurement points are distributed at a certain interval within a range of 1000 mm, the leftmost measurement point is taken as the measurement reference point 8, the distance from each measurement point to the measurement reference point 8 is s, and the specific positions of the measurement points are as shown in Table 2; Table 2 Measurement point positions Measurement point number 1 2 3 4 5 6 7 Distance s of measurement point to measurement reference point (mm) 0 250 375 500 625 750 1000 Step 2, a contact displacement sensor 4 is arranged on each measurement point, and 7 contact displacement sensors 4 correspond to 7 measurement points; Step 3, a load center point 5 is arranged on the inner wall of the buried concrete pipeline 3, the load center point 5 and the measurement points are located on the same generatrix at the top of the concrete pipeline, and the load center point 5 is located on the left side of the measurement reference point 8; Step 4, a knocking device 6 is arranged in the buried concrete pipeline 3, the knocking device 6 is moved to a predetermined position, the knocking device 6 is raised to a predetermined height through a hydraulic system, and the device is ensured to be stable, so that the weight of the knocking device 6 is aligned with the load center point 5, the knocking device 6 is used to apply an impact load to the inner wall of the buried concrete pipeline 3 at the load center point 5, the impact load amplitude is 4kN, the duration is 30ms, the loading area radius is 0.01m, and the spatial distribution is circular distribution; Step 5, the 7 contact displacement sensors 4 respectively record the displacement of the 7 measurement points, that is, the maximum deflection values L of the 7 measurement points, and the maximum deflection values L are transmitted to the ground terminal for analysis; Step 6, draw the deflection curve according to the measured data of each contact displacement sensor 4: establish a rectangular coordinate system with the distance s of the measurement point to the measurement reference point 8 as the abscissa and the maximum deflection value L as the ordinate, plot each measurement point to the measurement reference point 8 Distance s and the recorded maximum deflection value L of the measurement point as coordinate points (s, L) in the rectangular coordinate system, and connect the coordinate points (s, L) of the 7 measurement points to form a curve to obtain the deflection curve, as shown in Figure 2 or 3; Analyze the deflection curve and identify abnormal points on the deflection curve using the following method. The judgment method is as follows: Absolute value judgment: The maximum deflection value L of one or more consecutive measurement points is much larger than the values of adjacent measurement points and the average value of the entire line; Morphology judgment: The deflection curve appears a sudden, sharp "peak" or "dip"; Change rate judgment: Calculate the change gradient of the maximum deflection value L between adjacent measurement points. The gradient will increase sharply at the void boundary; Step 7, judge the health status of the pipe-soil structure of the buried concrete pipeline 3 through the morphology of the deflection curve: Normal pipe-soil structure without disease: The deflection curve presents uniform attenuation, and the maximum deflection value L decreases smoothly with the increase of the distance s of the measurement point to the measurement reference point 8, indicating that the pipe-soil structure is uniformly loaded and has good health status; Non-uniform pipe-soil structure: The deflection curve presents abnormal fluctuations or local protrusions, indicating that the pipe-soil structure has diseases such as uneven overburden soil, void, and pipeline cracks; Weak pipe-soil structure: The maximum deflection value L decays very quickly, and the maximum deflection value L at the measurement reference point 8 is large, indicating that the pipe-soil structure may have a relatively serious weak soil layer and needs to be repaired or reinforced.

[0014] The buried concrete pipeline 3 in a healthy state has a normal deflection curve shape, and the maximum deflection value L decreases smoothly with the increase of the distance s of the measurement point to the measurement reference point 8, as shown in Figure 2 , indicating that the structural quality of the buried concrete pipeline 3 is uniformly distributed; if the deflection curve shape has abnormal fluctuations, as shown in Figure 3 , indicating that the structural quality of the buried concrete pipeline 3 is not uniformly distributed, and the soil layer around the buried concrete pipeline 3 has voids or other diseases; For different deflection curves under the same position and same load conditions, comparative analysis can be performed to evaluate the structural differences of different pipe sections, for example, comparing historical data: compare the current deflection curve data with previous measurement results to analyze the changes in the pipe-soil structure; It is also possible to compare the deflection curves of different pipe sections under the same load conditions. By measuring the shape of the deflection curves of different pipe sections, it is possible to assess which pipe section has a stronger or weaker bearing capacity.

[0015] In step 4, the striking device 6 is an electric striking hammer, which is a device that uses a hydraulically driven hammer to apply transient impact load to the inner wall of the buried concrete pipe 3.

[0016] A rigid bearing plate 7 is provided at the load center point 5 on the inner wall of the buried concrete pipe 3. The rigid bearing plate 7 is circular with a radius of 10mm and a thickness of 30mm. The center of the rigid bearing plate 7 is concentric with the load center point 5. The rigid bearing plate 7 is tightly attached to the inner wall of the buried concrete pipe 3, so that the inner wall of the buried concrete pipe 3 is subjected to uniform force and the pipe wall is protected. The striking device 6 applies an impact load to the inner wall of the buried concrete pipe 3 through the rigid bearing plate 7.

[0017] The time history curve of the impact load is a half-sine pulse loading curve.

Claims

1. A method for inspecting the soil structure above the buried concrete pipeline, comprising the following steps: Step 1: Set up N measuring points on the inner wall of the buried concrete pipe. The N measuring points are located on the same generatrix at the top of the buried concrete pipe. The N measuring points are distributed at intervals. The leftmost measuring point is taken as the measuring reference point. The distance from each measuring point to the measuring reference point is s, and N is a natural number greater than or equal to 3. Step 2: Place a contact displacement sensor at each measurement point, and N measurement points correspond to N contact displacement sensors; Step 3: Set a load center point on the inner wall of the buried concrete pipe. The load center point and the measurement point are located on the same generatrix at the top of the concrete pipe, and the load center point is located to the left of the measurement reference point. Step 4: Install a hammering device inside the buried concrete pipe and use the hammering device to apply an impact load to the inner wall of the buried concrete pipe at the load center point. Step 5: N contact displacement sensors record the displacement of N measurement points, i.e., the maximum deflection value L of the N measurement points; Step 6: Plot the deflection curve using the maximum deflection value L: Establish a rectangular coordinate system with the distance s from each measurement point to the measurement reference point as the abscissa and the maximum deflection value L as the ordinate. Plot the distance s from each measurement point to the measurement reference point and the recorded maximum deflection value L of that measurement point as coordinate points (s, L) in the rectangular coordinate system. Connect the coordinate points (s, L) of N measurement points to form a curve and obtain the deflection curve. Step 7: Determine the health status of the soil structure above the buried concrete pipeline by analyzing the shape of the deflection curve. Normal, disease-free pipe-soil structure: The deflection curve shows a uniform attenuation. The maximum deflection value L decreases steadily with the increase of the distance s from the measurement point to the measurement reference point, indicating that the pipe-soil structure has uniform bearing capacity and is in good health. Uneven pipe-soil structure: The deflection curve shows abnormal fluctuations or local protrusions, indicating that the pipe-soil structure has uneven overburden, voids, and pipe cracks.

2. The method for detecting the pipe-top soil structure of buried concrete pipelines according to claim 1, characterized in that: In step 4, the striking device is an electric striking hammer.

3. The method for detecting the pipe-top soil structure of buried concrete pipelines according to claim 1, characterized in that: in A rigid bearing plate is provided at the load center point of the inner wall of the buried concrete pipe. The rigid bearing plate is circular, and its center is concentric with the load center point. The rigid bearing plate is tightly attached to the inner wall of the buried concrete pipe. The striking device applies an impact load to the inner wall of the buried concrete pipe through the rigid bearing plate.

4. The method for detecting the pipe-top soil structure of buried concrete pipelines according to claim 1 or 3, characterized in that: The time history curve of the impact load is a half-sine pulse loading curve.

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