A device and method for detecting the compactness of the soil around a PCCP pipeline

Abstract

The application discloses a kind of PCCP pipeline peripheral soil density detection device and detection method, belong to major water network engineering construction and safety field.A kind of PCCP pipeline peripheral soil density detection device and detection method, including the following steps, PCCP pipeline soil collection area demarcation, PCCP pipeline peripheral soil is overall sampling, field calibration processing of soil sample, elastic wave tomography processing of soil sample and using calibration curve formula calculation PCCP pipeline peripheral soil density value, PCCP pipeline soil collection area demarcation specific operation flow is as follows: measurement release line gives pipeline longitudinal axis position, mark at the position of distance axis one times pipeline diameter, as subsequent soil collection drilling point.In existing pipeline soil density detection, the soil sample in specific area of pipeline periphery cannot be collected in all directions under the premise of ensuring volume, and the original soil is directly measured for density in the later stage, with poor measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of water network engineering construction and safety, and more specifically, to a device and method for detecting the compaction of soil around a PCCP pipeline. Background Technology

[0002] Prestressed concrete cylinder pipe (PCCP) is a commonly used water conveyance structure in major water network projects. Assuming the construction quality of PCCP pipelines meets specifications and design requirements, the key concern during operation is leakage. Leakage occurs because foundation deformation alters the density of the surrounding soil, leading to uneven stress and inconsistent deformation. This can cause the pipe sections to separate, rubber waterstops to fail, and ultimately, leakage. The causes are mainly twofold: first, uneven settlement of the foundation along the pipeline route results in the relative allowable rotation angle of the pipe sections exceeding the allowable value specified in the specifications; second, excessive load on the pipeline structure alters the density of the surrounding soil.

[0003] Therefore, it is urgent to accurately and promptly determine the soil compaction around key locations along long-distance PCCP pipeline projects to prevent abnormal deformation and leakage caused by uneven stress on the pipeline, which could affect water supply safety. During the operation of the project, PCCP pipelines are buried deep underground, and using excavation methods to test the soil compaction around the pipeline is time-consuming and costly. On-site sampling methods damage the in-situ soil around the pipeline, and the results of laboratory tests have large errors compared to the actual environment. Furthermore, sudden unloading of the soil around the pipeline may affect the stress state of the pipeline structure. If traditional vertical drilling sampling methods are used, it is difficult to drill into the soil in the 180° area below the pipeline circumference, making it impossible to obtain the soil compaction of this most important area. At the same time, there is a lack of non-destructive and quantitative testing methods for the original soil compaction around in-service pipelines both domestically and internationally. Summary of the Invention

[0004] 1. The technical problem to be solved by the present invention

[0005] Embodiments of the present invention provide a solution to the problems mentioned in the background art above:

[0006] The invention is based on the artificial directional drilling process and the self-bending characteristics of the borehole, which enables autonomous directional drilling to drill to any position around the pipeline and obtain the original soil, thus solving the problem of "not being able to detect".

[0007] Secondly, we will establish a detection technology and quantitative evaluation method for the compaction of soil around pipelines based on elastic wave tomography to solve the problem of "inaccurate measurement" of soil compaction.

[0008] 2. Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution: a device and method for detecting the compaction of soil surrounding a PCCP pipeline, comprising the following steps.

[0010] (1) Delineation of the area for soil sampling by PCCP pipeline;

[0011] (2) Comprehensive sampling of the soil surrounding the PCCP pipeline;

[0012] (3) On-site calibration treatment of soil samples;

[0013] (4) Elastic wave tomography processing of soil samples;

[0014] (5) Calculate the density value of the soil around the PCCP pipeline using the calibration curve formula.

[0015] Preferably, the specific operation process for delineating the area for soil collection by the PCCP pipeline is as follows: measuring and setting out the longitudinal axis position of the pipeline, and marking a position at a distance of one pipe diameter from the axis as the drilling point for subsequent soil collection.

[0016] Preferably, the specific operational procedure for comprehensive sampling of the soil surrounding the PCCP pipeline is as follows:

[0017] (A) A fixed directional drilling system is installed with a directional drill rod of diameter D / n. Vertical drilling and hole making are carried out from the starting point until the pipeline is buried at depth z.

[0018] (B) Insert an artificial angled drill rod into the created position hole. The two are connected by a spring locking device. The spring can be controlled at the end of the drill rod to lock or separate it.

[0019] (C) Use a directional drilling rig to press the first section of the artificial directional drill bit into the soil. The artificial directional drill bit squeezes the original soil into the straight drill rod. Activate the spring to separate the hollow straight drill rod from the artificial directional drill bit and remove the straight drill rod and the original soil inside.

[0020] (D) Install the second section of the artificial directional drill bit, insert it into the hole, connect it to the first section of the artificial directional drill bit using the spring lock, and then start the directional drilling machine to press the second section of the artificial directional drill bit into the soil;

[0021] (E) Repeat step C until n sections of artificial directional drill bit are driven in, reaching the area below the pipe at °.

[0022] Preferably, the artificial directional drill rod consists of a hollow straight drill rod with a diameter of D / 2n and an artificial directional drill bit with a front end radius of D / 4n and an arc of 90°. The two are connected by a spring locking device, which can control the spring at the tail of the straight drill rod to lock or separate them. The front end of the drill rod has a controllable magnetic switch, which is located at the end of the drill rod. When the switch is open, the front end of the drill rod is magnetically connected to the first section of the artificial directional drill bit, and the connection is tight. When the switch is closed, the magnetism of the first section of the artificial directional drill bit disappears, the straight drill rod can be pulled out of the soil, and the second section of the artificial directional drill bit can be reinstalled on the ground and drilled into the soil again, so that the second section of the artificial directional drill bit is spring-connected to the first section of the artificial directional drill bit, finally achieving the effect of connecting section by section.

[0023] Preferably, the upper and lower ends of the artificial directional drill bit are a female end and a male end, respectively. The female end of the first artificial directional drill bit generates magnetism with the front end of the directional drill rod, making the two firmly connected. The male end of the artificial directional drill bit is connected to the female end of the next artificial directional drill bit by spring insertion.

[0024] Preferably, the field calibration treatment of the soil sample includes placing the soil sample into a field calibration system. The field calibration system includes a soil sample trough for placing the original soil sample, an eccentric vibrator, and a test trough. First, the original soil sample is added into the soil sample trough, and the eccentric vibrator is started to compact the original soil sample. The compacted soil sample is then added into the test trough, and the relative density of the soil sample is tested using the sand filling method.

[0025] Preferably, the specific process of elastic wave tomography processing of the soil sample is as follows: according to the steps, a second hole is made around the pipe. The second hole is located one to two meters along the radial end of the pipe from the first hole. The first hole and the second hole are used as the excitation hole and the receiving hole for actual measurement, respectively. The elastic wave tomography system is used to carry out the test. The longitudinal wave (transverse wave) velocity measurement results are compared with the calibration curve. The relative density of the part or area is quantitatively calculated using the difference method.

[0026] Preferably, the elastic wave tomography system includes an elastic wave tomography machine body, a transmitter, a receiver, and connecting wires.

[0027] 3. Beneficial effects

[0028] (1) By using a directional drilling system in conjunction with multiple artificially inclined drill rods connected by springs, it is possible to sample and completely cover the directional area around the outer surface of the pipeline. Moreover, the horizontal and vertical errors of the final drilling point and the theoretical position are controlled within ten centimeters, with small deviations, thereby improving the accuracy of the soil sampling location. This makes the final results more accurately reflect the real situation of the specific area around the pipeline, and the subsequent test results are more consistent with the actual situation.

[0029] (2) In the test of relative compaction of land, the original soil sample was compacted by an eccentric vibrator and divided into multiple test samples. The relative compaction of multiple samples was tested by the sand-filling method. Finally, the relative compaction was obtained by the effective average value method.

[0030] (3) The transmitter and receiver of elastic wave tomography are used in conjunction with the first and second boreholes. Based on the sound wave echo values ​​at the same depth, the corresponding data of soil density and wave velocity are obtained. The operation is repeated until the design relative density is reached and then the calibration operation is stopped. The standard calibration curves of different relative densities and longitudinal (transverse) wave velocities are plotted. Finally, the error between the measured value and the true value of the relative density of the land is within five percent. Attached Figure Description

[0031] Figure 1 This is a schematic diagram showing the connection between the straight drill rod and the first section of the artificial directional drill bit of the present invention.

[0032] Figure 2 This is a schematic diagram of the artificially created slanted drill rod of the present invention.

[0033] Figure 3 This is a diagram showing the positional relationship between two interconnected artificial inclined drill bits of the present invention.

[0034] Figure 4 This is a schematic diagram of the field calibration system of the present invention.

[0035] Figure 5 This is a diagram showing the relationship between the elastic wave tomography system of the present invention and the test tank.

[0036] Explanation of the labels in the diagram:

[0037] 1. Directional drill rod, 2. Artificial inclined drill rod, 21. Straight drill rod, 22. Artificial inclined drill bit, 3. Switch, 4. Field calibration system, 41. Soil sample trench, 42. Eccentric vibrator, 43. Test trench, 5. Elastic wave tomography system, 51. Elastic wave tomography machine body, 52. Transmitter, 53. Receiver, 54. Connecting wires. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1:

[0040] Please see Figure 1A device and method for detecting the compaction of soil surrounding a PCCP pipeline, characterized by comprising the following steps:

[0041] (1) Delineation of the area for soil sampling by PCCP pipeline;

[0042] (2) Comprehensive sampling of the soil surrounding the PCCP pipeline;

[0043] (3) On-site calibration treatment of soil samples;

[0044] (4) Elastic wave tomography processing of soil samples;

[0045] (5) Calculate the density value of the soil around the PCCP pipeline using the calibration curve formula.

[0046] The specific operational process for delineating the area for soil sampling of the PCCP pipeline is as follows: the longitudinal axis of the pipeline is measured and laid out, and a mark is made at a distance of one pipe diameter from the axis as the drilling point for subsequent soil sampling. From this point, the soil in a specific area around the pipeline can be sampled by continuously connecting artificial directional drill bits 22. Moreover, the overall original soil sample volume is small, saving time, reducing the energy consumption of mining and the wear and tear on equipment, thereby reducing the overall testing cost.

[0047] The specific operational procedures for comprehensive sampling of the soil surrounding the PCCP pipeline are as follows:

[0048] (A) A fixed directional drilling system is installed with a directional drill rod 1 of diameter D / n. Vertical drilling and hole making are carried out from the starting point until the pipeline is buried at depth z, ensuring that the soil depth can reach the specific area around the pipeline and improving the comprehensiveness of soil sampling.

[0049] (B) Insert the artificial slant drill rod 2 into the created position hole. The two are connected by a spring locking device. The spring can be controlled at the end of the drill rod to lock or separate it. The spring design can quickly complete the connection and disassembly of the two, which is convenient for collecting soil and removing the soil in the straight drill rod 21 later.

[0050] (C) Use a directional drilling rig to press the first section of the artificial directional drill bit 22 into the soil. The artificial directional drill bit 22 squeezes the original soil into the straight drill rod 21. Activate the spring to separate the hollow straight drill rod 21 from the artificial directional drill bit 22. Take out the straight drill rod 21 and the original soil inside.

[0051] (D) Install the second section of the artificial directional drill bit 22, insert it into the hole, connect it to the first section of the artificial directional drill bit 22 using the spring lock, and then start the directional drilling machine to press the second section of the artificial directional drill bit 22 into the soil;

[0052] (E) Repeat step C until n sections of the artificial directional drill bit 22 are pressed in, reaching the area 180° below the pipe.

[0053] Example 2:

[0054] Please see Figure 2-3 The difference from the previous embodiment lies in that the artificial directional drill rod 2 is divided into a hollow straight drill rod with a diameter of D / n and an artificial directional drill bit 22 with a front end radius of D / n and an arc of 90°. The two are connected by a spring locking device, which can control the spring at the tail of the straight drill rod 21 to lock or separate them. The front end of the drill rod has a controllable magnetic switch 3, which is located at the end of the drill rod. When the switch 3 is open, it generates magnetism at the front end of the drill rod and connects and secures it to the first section of the artificial directional drill bit 22; when the switch 3 is closed, the first section of the artificial directional drill bit 22... When the magnetism disappears, the straight drill rod 21 can be extracted from the soil. The second section of the artificial directional drill bit 22 is then reinstalled on the ground and drilled into the soil again, so that the second section of the artificial directional drill bit 22 is spring-connected to the first section of the artificial directional drill bit 22, finally achieving the effect of connecting section by section. The upper and lower ends of the artificial directional drill bit 22 are the female end and the male end, respectively. The female end of the first section of the artificial directional drill bit 22 generates magnetism with the front end of the directional drill rod 1, so that the two are firmly connected. The male end of the artificial directional drill bit 22 is then connected to the female end of the next artificial directional drill bit through spring insertion.

[0055] Example 3:

[0056] Please see Figure 4 The field calibration of soil samples includes placing the soil sample into the field calibration system 4. The field calibration system includes a soil sample trough 41 for placing the original soil sample, an eccentric vibrator 42, and a test trough 43. First, the original soil sample is added into the soil sample trough 41, and the eccentric vibrator 42 is started to compact the original soil sample. The compacted soil sample is then added into the test trough 43, and the relative density of the soil sample is tested using the sand cone method. This improves the accuracy of the relative density test value of the soil sample and facilitates the comparison with the calibration curve to obtain the relative density of the chambers later.

[0057] Example 4:

[0058] Please see Figure 5The specific process for elastic wave tomography processing of soil samples is as follows: Following the steps, a second hole is created around the pipe. This second hole is located one to two meters radially from the first hole, thus covering a certain detection range. To ensure the accuracy of the test results, the number of tests is reduced. The first and second holes serve as the excitation and receiving holes for actual measurement, respectively. The elastic wave tomography system 5 is used for testing. The longitudinal (transverse) wave velocity measurement results are compared with the calibration curve. The relative density of the location or area is quantitatively calculated using the differential method. The elastic wave tomography system 5 includes the main body 51 of the elastic wave tomography machine, the transmitter... The instrument 52, receiver 53, and connecting wire 54 utilize the elastic wave tomography processing method. When there are abnormal bodies such as cavities or loose bodies in the underground rock and soil, the density, elastic modulus, and Poisson's ratio are significantly different from those of normal rock and soil. The longitudinal wave velocity of the elastic wave will decrease accordingly, and the amplitude and frequency will also decrease (the high-frequency part will attenuate even more). The location of cavities or loose bodies can be determined by using the changes in elastic wave parameters. Since there is a difference in wave impedance between cavities / loose bodies and normal rock and soil, when the elastic wave encounters a change in wave impedance during propagation in the medium, a reflection phenomenon will occur. This can accurately obtain the density of the original soil around the pipeline.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for detecting the compactness of the soil around a PCCP pipeline, characterized in that: The system comprises a directional drilling machine system, a field calibration system (4) and an elastic wave tomography system (5); The directional drilling machine system is used for sampling the peripheral soil bodies at different depths equidistantly around the lower side of the PCCP pipeline, and the diameter of the PCCP pipeline is D; The directional drilling machine system comprises a directional drilling machine, a directional drilling rod (1) and a manually-made angle drill rod (2), the manually-made angle drill rod (2) is divided into a straight drill rod (21) with a hollow shape with a diameter of D / 2n and a manually-made angle drill head (22) with a front end radius of D / 4n, and the manually-made angle drill head (22) has an arc of 90° after splicing, and n is the number of the manually-made angle drill heads (22); the straight drill rod (21) and the manually-made angle drill head (22) are connected through a spring lock buckle device, and a control spring is arranged at the tail of the straight drill rod (21) to make the straight drill rod (21) and the manually-made angle drill head (22) lock or separate; the straight drill rod (21) and the manually-made angle drill head (22) are both hollow structures, a plurality of the manually-made angle drill heads (22) are arranged, and the axes of the plurality of the manually-made angle drill heads (22) are parallel to the quarter arc line of the PCCP pipeline to be detected after splicing; a switch (3) is arranged on the outer side of the upper end of the straight drill rod (21), an electromagnet is arranged on the outer side of the lower end of the straight drill rod (21), the switch (3) is used for controlling the electrification of the electromagnet, a spring is arranged on the inner side of the upper end of the manually-made angle drill head (22), one end of the spring is connected with the inner side of the manually-made angle drill head (22), and the other end of the spring abuts against the lower end of the straight drill rod (21) or the lower end of another manually-made angle drill head (22); the manually-made angle drill head (22) is made of iron material; The field calibration system (4) is used for tamping the soil bodies at different depths sampled and detecting the relative compactness by using the sand pouring method; The elastic wave tomography system (5) is used for quantitatively calculating the relative compactness of the soil body at the depth position by using the difference method. The position with a distance of one pipeline diameter from the axis left side or right side of the longitudinal axis of the PCCP pipeline is taken as a drilling point for collecting the soil body, a plurality of the manually-made angle drill heads (22) are connected in sections at the drilling point to sample in turn, the manually-made angle drill head (22) with an arc of 90° after splicing is formed, and finally the region of 180° under the pipeline is sampled.

2. The device for detecting the compactness of the soil around the PCCP pipeline according to claim 1, characterized in that: The switch (3) on the outer side of the upper end of the straight drill rod (21) has controllable magnetism, when the switch (3) is opened, the magnetic connection between the front end of the straight drill rod (21) and the first section of the manually-made angle drill head (22) is fastened, when the switch (3) is closed, the magnetic connection between the first section of the manually-made angle drill head (22) and the straight drill rod (21) is disconnected, the straight drill rod (21) is pulled out of the soil body, the second section of the manually-made angle drill head (22) is reinstalled on the ground and drilled into the soil body again, so that the second section of the manually-made angle drill head (22) is connected with the first section of the manually-made angle drill head (22) through the spring, and finally the effect of connecting in sections is achieved.

3. The device for detecting the compactness of the soil around the PCCP pipeline according to claim 1, characterized in that: The field calibration process of the soil sample includes placing the soil sample into a field calibration system (4) including a soil sample groove (41) for placing the soil sample, an eccentric vibrator (42) and a test groove (43), adding the soil sample into the soil sample groove (41), starting the eccentric vibrator (42) to compact the soil sample, adding the compacted soil sample into the test groove (43), and detecting the relative density of the soil sample by the sand replacement method.

4. The device for detecting the compactness of the soil around the PCCP pipeline according to claim 1, characterized in that: The elastic wave tomography system (5) includes an elastic wave tomography machine body (51), a transmitter (52), a receiver (53) and a connecting wire (54). The specific process of the elastic wave tomography processing of the soil sample is as follows: a second hole is made around the pipeline, the second hole is located at a position of one to two meters along the radial end of the first hole, the first hole and the second hole are respectively used as the excitation hole and the receiving hole for actual measurement, the elastic wave tomography system (5) is used for testing, the longitudinal wave or transverse wave velocity measurement result is compared with the calibration curve, and the relative density of the soil region between the two holes is quantitatively calculated by the difference method.

5. A method for detecting the compactness of the soil around a PCCP pipe by using the detection device according to any one of claims 1-4, characterized in that: The method comprises the following steps: Step (1), demarcating the area of collecting soil around the PCCP pipeline; Step (2), overall sampling of the soil around the PCCP pipeline; Step (3), field calibration processing of the soil sample; Step (4), elastic wave tomography processing of the soil sample; Step (5), calculating the density value of the soil around the PCCP pipeline by using the calibration curve formula.

6. The method of claim 5, wherein: The specific steps of demarcating the area of collecting soil around the PCCP pipeline include: Step 1.1, recording the PCCP pipeline data to be detected, the PCCP pipeline data including the pipeline radius r, the pipeline diameter D and the pipeline burial depth z; Step 1.2, measuring the position of the PCCP pipeline longitudinal axis by setting out the line; Step 1.3, marking a position one pipeline diameter D away from the left or right side of the PCCP pipeline longitudinal axis as a drilling point for subsequent soil collection.

7. The method of claim 6, wherein: The specific steps of overall sampling of the soil around the PCCP pipeline include: Step 2.1, (A) fixing the directional drilling machine system, installing a directional drilling rod (1) with a diameter of D / n, and starting vertical drilling and hole making from the marked drilling point as the starting point until the hole making length reaches the pipeline burial depth z position; Step 2.2, (B) selecting n artificial build angle drill bits (22), placing a straight drill rod (21) and an artificial build angle drill bit (22) into the position hole, and connecting the two through a spring lock buckle device, controlling the spring at the tail of the straight drill rod (21) to make it lock or separate; (C) using the directional drilling machine to press the first section of the artificial build angle drill bit (22) into the soil, the artificial build angle drill bit (22) extrudes the undisturbed soil into the straight drill rod (21), the spring is started to separate the hollow straight drill rod (21) from the artificial build angle drill bit (22), and the straight drill rod (21) and the internal undisturbed soil are taken out; (D) installing the second section of the artificial build angle drill bit (22), extending into the hole, and connecting it with the first section of the artificial build angle drill bit (22) by using the spring lock buckle, and then starting the directional drilling machine to press the second section of the artificial build angle drill bit (22) into the soil. (E) Repeat the artificial build-up drill bit (22) step until the artificial build-up drill bit (22) is spliced after n artificial build-up drill bits (22) are pressed in, the axis thereof is parallel to the quarter arc line of the PCCP pipeline to be detected, and finally the area below the pipeline reaches 180°.

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