A device and method for sampling undisturbed soil in a hydraulic pressure measuring tube

Abstract

The present invention provides a device for sampling undisturbed soil in a hydraulic pressure measuring pipe, comprising a sampling tube, a traveling unit, and a driving unit. The sampling tube and the traveling unit can be driven by independent driving units respectively by positive or negative pressure. The sampling tube has a sampling inlet. The entire device can be placed in the hydraulic pressure measuring pipe from the outside. The traveling unit is driven by a matching driving unit to deform along the pipeline path. The device is displaced outward along the pipeline path in the pipeline by elastic force and externally applied tension. The device is displaced inward along the pipeline path in the pipeline by elastic force of deformation and gravity of the device. When the device is displaced inward to the obstruction site, the sampling tube creates a negative pressure environment in the driving tube of the matching driving unit to penetrate the obstructed soil sample, and the obstructed soil sample is filled in the tube by the negative pressure. The present invention can travel and sample in the pipe, with minimal disturbance to the undisturbed soil sample, thereby greatly reducing damage to the undisturbed soil sample.

Description

Technical Field

[0001] The invention relates to the technical field of research on siltation of pressure measuring tubes of hydraulic structures, and more particularly to a device and method for sampling undisturbed soil blocked in hydraulic pressure measuring tubes. Background Art

[0002] In the study of hydraulic piezometer blockage, it is necessary to collect undisturbed soil samples from the piezometer. Through experimental analysis of the physical and mechanical properties and chemical composition of the collected undisturbed soil samples, the clogging mechanism can be explored. Currently, the following problems exist when sampling undisturbed soil samples for piezometer blockage:

[0003] First, the diameter of hydraulic pressure measuring tubes is generally small, mostly 3-5 cm, while the diameter of the core barrel of existing common drilling rigs is greater than 5 cm, which is not suitable for sampling inside the pressure measuring tube;

[0004] Secondly, the buried depth of hydraulic pressure measuring pipes is generally more than 10m, and most pipelines have horizontal sections, vertical sections, curved sections, etc. The sampling equipment of the general straight rod end sampler is not suitable for sampling operations inside hydraulic pressure measuring pipes;

[0005] Third, the silted soil in the hydraulic pressure measuring tube is generally in a saturated and plastic state, and is easily disturbed by the sampler, causing damage to the original soil sample. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a device for sampling undisturbed soil in hydraulic pressure measuring tubes, which can adapt well to the small-diameter sampling environment of hydraulic pressure measuring tubes, realize sampling in the tube, and can walk in horizontal sections, vertical sections, and curved sections of the pipeline. Sampling has little disturbance to the undisturbed soil samples, which can greatly reduce the damage to the undisturbed soil samples, and provide a strong guarantee for the accuracy of subsequent research results. Based on the device, the present invention also proposes a method for sampling undisturbed soil in hydraulic pressure measuring tubes.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A device for sampling undisturbed soil in a hydraulic pressure measuring tube, the structural features of which are:

[0009] The sampling cylinder comprises a sampling cylinder, a traveling unit, and a driving unit. The sampling cylinder and the traveling unit can be driven by independent driving units respectively by positive or negative pressure. The sampling cylinder is a cylindrical shell cavity structure, wherein one side of the shaft end is open as a sampling inlet, and the other side of the shaft end is used to receive the drive of the matching driving unit.

[0010] The entire device can be placed in a hydraulic pressure measuring tube from the outside, and the walking unit is driven by the matching driving unit to generate deformation along the pipeline path. The elastic force of the deformation and the external pulling force are used together to realize the outward displacement of the device along the pipeline path in the pipeline, and the elastic force of the deformation and the gravity of the device are used together to realize the inward displacement of the device along the pipeline path in the pipeline. When it moves inward to the blockage site, a negative pressure environment is formed in the driving cylinder of the matching driving unit, and the sampling cylinder is penetrated into the blockage site with the sampling inlet facing the blockage site. The penetration depth is increased by continuing to apply negative pressure until the sampling of the original soil sample of the blockage site is completed. The original soil sample is kept stationary in the sampling cylinder by relying on the combined action of negative pressure, friction between the original soil sample and the cylinder wall, side friction resistance and the gravity of the original soil sample, and can be displaced outward with the device to the outside of the pipeline.

[0011] The structural characteristics of the present invention are also:

[0012] The device placed in the hydraulic pressure measuring tube takes the side where the sampling tube is located as the front side, and the walking unit includes a front cavity and a rear cavity with the same appearance, which are arranged at the rear end of the sampling tube with a front and rear interval, and also includes a walking spring tensioned between the front cavity and the rear cavity along the pipeline path. The cavity volume of the front cavity is larger than that of the rear cavity. The front cavity and the rear cavity are independently driven by the matching driving unit based on positive pressure or negative pressure. The structural form is that it has a cavity medium flow port for receiving the cavity medium driven by the driving unit, and a pair of pressure-bearing structures are arranged on both sides of the cavity along the diameter direction of the pipeline. The pressure-bearing structure on each side includes a pressure-bearing structure that is slidably penetrated in the cavity along the diameter direction of the pipeline. The guide rod on the body also includes a piston built into the cavity, a pressure-bearing spring tensioned between the inner wall of the cavity and the piston along the diameter direction of the pipeline, and a pressure-bearing plate placed outside the cavity. The rod section of the guide rod extending into the cavity is sleeved with the pressure-bearing spring, the end is connected to the piston, and the end exposed outside the cavity is connected to the pressure-bearing plate. The driving unit relies on positive or negative pressure to form a positive or negative pressure environment in the cavity. A pair of pistons are displaced back to back or towards each other along the diameter direction of the pipeline by the positive or negative pressure in the cavity, so that a pair of pressure-bearing plates are either pressed against the inner wall of the pipeline on their side along the diameter direction of the pipeline, horizontally supported in the pipeline, or separated from the inner wall of the pipeline.

[0013] The outer shape of the side of the pressure-bearing sheet that contacts the pipeline is adapted to the inner wall of the pipeline, and when pressed against the inner wall of the pipeline on the side, it is tightly attached to the inner wall of the pipeline.

[0014] The device placed in the hydraulic pressure measuring tube has the side where the sampling cylinder is located as the front side. The sampling cylinder is fixedly connected to the front end of the walking unit. The sampling cylinder has a cylinder medium flow port for receiving the drive of the matching driving unit.

[0015] The driving unit uses liquid or gas as a medium and relies on positive pressure or negative pressure to drive the sampling tube and the walking unit.

[0016] The driving unit is a positive and negative pressure micro air pump, and there are three sets in total, two of which are used to drive the front cavity and the rear cavity in the walking unit respectively. The driving unit matching the front cavity is fixedly connected to the cavity medium flow port on the front cavity through a first hose, and the driving unit matching the rear cavity is fixedly connected to the cavity medium flow port on the rear cavity through a second hose. The other set is used to drive the sampling cylinder, and the driving unit matching the sampling cylinder is fixedly connected to the cylinder medium flow port on the sampling cylinder through a third hose.

[0017] The front cavity, the rear cavity and the sampling cylinder are aligned along the pipeline path, and a through channel is formed in the center of the front cavity and the rear cavity for the third hose to pass through. The channel is independent of the cavities of the front cavity and the rear cavity. The cylinder medium flow port is opened in the center of the rear axial end of the sampling cylinder. The cylinder medium flow port is fixedly connected to the bottom end of the rear cavity through a hard connecting pipe, and is threadedly connected to and communicated with the end of the third hose.

[0018] The pipe sections of the first hose and the third hose between the front cavity and the rear cavity are spring hoses.

[0019] The sampling tube is made of metal.

[0020] The present invention also proposes a method for sampling undisturbed soil in a hydraulic piezometer tube, which is implemented using the above-mentioned undisturbed soil sampling device in a hydraulic piezometer tube, and includes the following steps:

[0021] Step 1: Place the device into the hydraulic pressure measuring tube. Under the action of gravity, the device will fall into the hydraulic pressure measuring tube. The matching drive unit is driven by positive pressure to form a positive pressure environment in the front cavity and the rear cavity of the walking unit. The device is supported horizontally in the pipe by its own pressure-bearing plates to keep it stationary.

[0022] In step 2, the rear cavity remains stationary, and the front cavity is driven by the negative pressure of the matching driving unit, and the corresponding pressure-bearing piece is separated from the inner wall of the pipe. Under the action of gravity, the sampling tube and the front cavity are displaced inward along the pipe path relative to the rear cavity, causing the travel spring to deform. Afterwards, the front cavity is driven by the positive pressure of the matching driving unit and is cross-supported in the pipe again at the current position by the pressure-bearing piece. The rear cavity is driven by the negative pressure of the matching driving unit to separate the pressure-bearing piece from the inner wall of the pipe. Under the combined action of its own gravity and the elastic force generated by the deformation of the travel spring, the rear cavity is displaced inward. Afterwards, the rear cavity is driven by the positive pressure of the matching driving unit and is cross-supported in the pipe again at the current position by the pressure-bearing piece.

[0023] Step 3: Referring to step 2, the front cavity and the rear cavity of the traveling unit are alternately moved forward along the pipeline path toward the blocked portion until the sampling tube penetrates the blocked portion;

[0024] Step 4: The sampling inlet of the sampling tube penetrates the blocked soil sample, and a negative pressure environment is formed in the sampling tube through the supporting driving unit, so that a negative pressure area is formed on the top of the soil sample in the sampling tube. If resistance is encountered during the sampling process, negative pressure is continued to be applied to the sampling tube, and the penetration force of the sampling tube is increased until the sampling tube is filled with the blocked soil sample. The negative pressure is continued to be applied to the sampling tube, so that the soil sample in the sampling tube remains stationary under the combined action of negative pressure, friction between the soil sample and the tube wall, lateral friction resistance, and gravity;

[0025] The cam is then pulled out of the way by the spring, and the front and rear cams are moved outwards relative to each other along the path of the pipe, causing the spring to deform. The cam is then pulled back against the spring, and the front and rear cams are moved back and forth along the path of the pipe, causing the spring to deform. The cam is then pulled back against the spring, and the spring is pulled back and forth, causing the spring to deform. The cam is then pulled back and forth, causing the spring to deform, causing the spring to deform, and the spring to deform. The cam is then pulled back and forth, causing the spring to deform, causing the spring to deform, and the spring to deform.

[0026] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0027] The present invention is provided with a sampling cylinder for sampling and a self-propelled walking unit. The sampling cylinder and the walking unit can be driven by independent driving units respectively by positive pressure or negative pressure. The entire device can be driven by the matching driving unit to generate deformation along the pipeline path through the walking unit, or rely on the elastic force of the deformation and the external pulling force to realize the outward displacement of the device along the pipeline path in the pipeline, or rely on the elastic force of the deformation and the gravity of the device to realize the inward displacement of the device along the pipeline path in the pipeline. When the sampling cylinder moves inward to the blocked part, a negative pressure environment is formed in the driving cylinder of the matching driving unit, and the blocked soil sample is inserted into the sampling inlet toward the blocked part, and the blocked soil sample is filled and retained in the cylinder by the negative pressure.

[0028] Since the clogging soil samples in the hydraulic pressure measuring tube are mainly fine particles and have a small permeability coefficient, a good negative pressure area is formed on the top of the soil sample in the sampling tube. Therefore, when the device encounters resistance during its movement in the tube, by continuing to apply negative pressure to the sampling tube, the force of the sampling tube penetrating the clogging soil sample can be increased. After sampling, by continuously applying negative pressure to the cavity in the sampling tube, the soil sample in the sampling tube can be kept stationary under the action of negative pressure, friction between the soil sample and the tube wall, side friction resistance and the soil sample's own gravity. This method mainly disturbs the soil sample at the sampling inlet of the sampling tube and a small area at the interface of the tube body that is connected to the negative pressure. The large middle section of the soil sample in the tube is basically in its original state, achieving a good effect of minimal disturbance to the soil sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of the sampling tube of the present invention when it just penetrates the soil sample;

[0031] Figure 3 This is a schematic diagram of the structure of the sampling tube of the present invention when it penetrates the soil sample;

[0032] Figure 4 This is a schematic diagram of the structure when the traveling unit encounters a curved pipe section;

[0033] Figure 5 It is a structural diagram of the rear cavity;

[0034] Figure 6 It is a structural diagram of the sampling tube;

[0035] Figure 7 Schematic diagram of the structure of the third hose between the front cavity and the rear cavity;

[0036] Figure 8 This is a structural diagram of the side of the pressure-bearing plate that is in contact with the pipe;

[0037] Figure 9 This is a force diagram of the present invention when it is displaced in a hydraulic pressure measuring tube;

[0038] Figure 10 It is a force diagram of the present invention when sampling in a hydraulic pressure measuring tube.

[0039] In the picture:

[0040] 1 sampling cylinder; 11 cylinder medium flow port;

[0041] 21 front cavity; 22 rear cavity; 23 travel spring; 24 cavity medium flow port; 25 pressure-bearing structure; 251 piston; 252 guide rod; 253 pressure-bearing spring; 254 pressure-bearing sheet; 2541 elastic material layer;

[0042] 3 drive unit; 31 first hose; 32 second hose; 33 third hose; 34 controller;

[0043] 41 hydraulic pressure measuring tube; 42 silted soil sample. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] Please refer to Figures 1 to 8 The present embodiment of the present invention relates to a device for sampling undisturbed soil in a hydraulic pressure measuring tube, comprising a sampling tube 1, a traveling unit, and a driving unit 3. The sampling tube 1 and the traveling unit can be driven by independent driving units 3 respectively by positive or negative pressure. The sampling tube 1 is a cylindrical shell cavity structure, wherein one axial end is open as a sampling inlet, and the other axial end is used to receive the drive of the matching driving unit 3.

[0046] The entire device can be placed in the hydraulic pressure measuring tube 41 from the outside, and the walking unit is driven by the matching driving unit 3 to produce deformation along the pipeline path. The elastic force of the deformation and the external pulling force are used to realize the outward displacement of the device along the pipeline path in the pipeline, and the elastic force of the deformation and the gravity of the device are used to realize the inward displacement of the device along the pipeline path in the pipeline. When it moves inward to the blockage site, the sampling tube 1 forms a negative pressure environment in the driving tube of the matching driving unit 3, and penetrates the blockage site with the sampling inlet toward the blockage site. The penetration depth is increased by continuing to apply negative pressure until the sampling of the original soil sample of the blockage site is completed. The original soil sample remains stationary in the sampling tube 1 by relying on the combined action of negative pressure, the friction between the original soil sample and the tube wall, the side friction resistance and the gravity of the original soil sample, and can be displaced outward with the device to the outside of the pipeline.

[0047] In a specific implementation, the corresponding structural setting of the device also includes:

[0048] The device placed in the hydraulic pressure measuring tube 41 takes the side where the sampling tube 1 is located as the front side, and the walking unit includes a front cavity 21 and a rear cavity 22 with the same appearance, which are arranged at the rear end of the sampling tube 1 with a front and rear interval. It also includes a walking spring 23 that is tensioned between the front cavity 21 and the rear cavity 22 along the pipeline path. The cavity volume of the front cavity 21 is larger than that of the rear cavity 22. The front cavity 21 and the rear cavity 22 are independently driven by the matching driving unit 3 based on positive pressure or negative pressure. The structural form is that it has a cavity medium flow port 24 for receiving the drive unit 3 drive, and a pair of pressure-bearing structures 25 are arranged on both sides of the cavity along the diameter direction of the pipeline. The pressure-bearing structure 25 on each side includes a cavity that is slidably penetrated along the diameter direction of the pipeline. The guide rod 252 also includes a piston 251 built into the cavity, a pressure spring 253 tensioned between the inner wall of the cavity and the piston 251 along the diameter direction of the pipe, and a pressure piece 254 placed outside the cavity. The rod section of the guide rod 252 extending into the cavity is sleeved with a pressure spring 253, the end of which is connected to the piston 251, and the end exposed outside the cavity is connected to the pressure piece 254. The driving unit 3 is driven by positive or negative pressure to form a positive or negative pressure environment in the cavity. A pair of pistons 251 are displaced back to back or towards each other along the diameter direction of the pipe by the positive or negative pressure in the cavity, so that a pair of pressure pieces 254 are either pressed against the inner wall of the pipe on the side along the diameter direction of the pipe, horizontally supported in the pipe, or separated from the inner wall of the pipe.

[0049] The side of the pressure-bearing plate 254 that contacts the pipe is shaped to conform to the inner wall of the pipe. When pressed against the inner wall of the pipe on that side, it adheres tightly to the inner wall of the pipe. The side of the pressure-bearing plate 254 that contacts the pipe is provided with an elastic material layer 2541 to increase the friction between the pressure-bearing plate 254 and the inner wall of the pipe, thereby more securely holding the front cavity 21 or the rear cavity 22 in place.

[0050] The device placed in the hydraulic pressure measuring tube 41 has the side where the sampling tube 1 is located as the front side. The sampling tube 1 is fixedly connected to the front end of the walking unit. The sampling tube 1 has a cylinder medium flow port 11 for receiving the drive of the matching drive unit 3.

[0051] The driving unit 3 uses liquid or gas as a medium and drives the sampling tube 1 and the walking unit by positive pressure or negative pressure.

[0052] The driving unit 3 is a positive and negative pressure micro air pump, and there are three sets in total, two of which are used to drive the front cavity 21 and the rear cavity 22 in the walking unit respectively. The driving unit 3 matching the front cavity 21 is fixedly connected to the cavity medium flow port 24 on the front cavity 21 through the first hose 31, and the driving unit 3 matching the rear cavity 22 is fixedly connected to the cavity medium flow port 24 on the rear cavity 22 through the second hose 32. The other set is used to drive the sampling cylinder 1, and the driving unit 3 matching the sampling cylinder 1 is fixedly connected to the cylinder medium flow port 11 on the sampling cylinder 1 through the third hose 33.

[0053] The front cavity 21, the rear cavity 22 and the sampling cylinder 1 are aligned along the pipeline path, and a through channel is formed in the center of the front cavity 21 and the rear cavity 22 for the third hose 33 to pass through. The channel is independent of the cavities of the front cavity 21 and the rear cavity 22. A cylinder medium flow port 11 is opened in the center of the rear axial end of the sampling cylinder 1. The cylinder medium flow port 11 is fixedly connected to the bottom end of the rear cavity 22 through a hard connecting pipe, and is threadedly connected to and communicated with the end of the third hose 33.

[0054] The first hose 31 and the third hose 33 are located in the travel spring 23 , and a distance is kept between them and the travel spring 23 .

[0055] The sections of the first and third hoses 31 and 33 between the front and rear chambers 21 and 22 are spring hoses. These sections have greater deformation than other sections, making them more suitable for navigating curved sections and enabling sampling even in these areas. Threaded connections are used between the sections, as well as between the sections and the medium flow ports 24 of the front and rear chambers 21 and 22, as well as the medium flow port 11 of the barrel.

[0056] The sampling tube 1 is made of metal.

[0057] A controller 34 is configured to control each drive unit 3 .

[0058] The following combination Figure 9 The principle of the process of collecting undisturbed soil samples by this device is further explained:

[0059] The force analysis is conducted on the upper surface of the sampling tube 1. Assuming that the atmospheric pressure is P0, the liquid pressure on the upper surface of the sampling tube 1 is P1, and the internal gas pressure is P2. According to the principle of object motion, in order to ensure the effectiveness of the method, it is necessary to calculate the resultant force (the internal and external pressure difference) that drives the sampling tube 1 to move. This resultant force can be calculated according to the following physical formula:

[0060]

[0061] F=PS Formula (2)

[0062] P 液体 =ρgΔh Formula (3)

[0063] Formula (1) is the pressure formula, formula (2) is the derived formula, and formula (3) is the liquid pressure formula. In formulas (1) to (3), P is the pressure (unit is Pa), F is the pressure (unit is N), and S is the force area (unit is m 2 ).

[0064] Combined with the force on the upper surface of the sampling tube 1, we can get:

[0065] F=(P1+P0-P2)×S Formula (4)

[0066] In formula (4), F is the resultant force on the upper surface of the sampling tube 1 (the difference between the internal and external pressures), P0 is the liquid pressure on the upper surface of the sampling tube 1, P1 is the atmospheric pressure on the upper surface of the sampling tube 1, P2 is the internal gas pressure on the sampling tube 1, and S is the surface area of ​​the upper surface of the sampling tube 1. Among them, P2≤P0; when the sampling inlet of the sampling tube 1 just contacts the soil sample, the inside of the sampling tube 1 is connected to the atmosphere, at this time P2=P0; when the sampling tube 1 has penetrated the soil sample, negative pressure is continuously applied to the inside of the sampling tube 1 through the internal pressure hose, at this time P2 <P0。

[0067] According to the principle of object movement, the sampling tube 1 will be subjected to an upward friction force while penetrating the blocked soil sample 42. When F>f, the sampling tube 1 will continue to penetrate the blocked soil sample 42; f is the friction force.

[0068] The following combination Figure 10 The principle of keeping the soil sample in the sampling tube 1 of the device still is further explained:

[0069] When the soil sample reaches a state of equilibrium in the sampling tube 1, negative pressure can be applied to lift the entire sampling device out of the hydraulic pressure measuring tube 41. Combined with the force on the soil sample in the sampling tube 1, it can be obtained that:

[0070] F 吸 +μF N ≥f t S+G formula (5)

[0071] In formula (5), F 吸 is the suction force from negative pressure on the soil sample (unit: N), μ is the friction coefficient between the soil sample and the sampling tube 1, F N is the support force of the side wall of the sampling tube 1 on the soil sample (unit: N), f t S is the side friction resistance (unit is N), f t is the shear strength of the soil sample (unit: Pa), S is the contact area between the soil sample and the wall of the sampling tube 1 (unit: m 2 ).

[0072] The working principle of this device is as follows:

[0073] The device is based on the principles of atmospheric pressure and the movement of objects. It uses gravity to drop the device to a certain position in the pressure measuring tube. Then, the sampling tube 1 and the travel unit are driven by an independent drive unit 3 based on positive or negative pressure. The elastic force generated by the deformation of the travel spring 23 of the travel unit under the drive, together with the gravity of the device, realizes the inward displacement in the pipeline toward the blockage area, and together with the external tension, realizes the outward displacement in the pipeline. For example:

[0074] When displacing inward, the supporting drive unit 3 fills the medium into the rear cavity 22, forming a positive pressure environment in the cavity. Under the action of the positive pressure, the pistons 251 of the pair of pressure-bearing structures 25 displace backwards. Under the guidance of the guide rod 252, the pair of pressure-bearing plates 254 displace synchronously therewith, and finally press against the inner wall of the pipeline, so that the rear cavity 22 and the pair of pressure-bearing structures 25 carried by it are horizontally supported in the pipeline through the pair of pressure-bearing plates 254, and remain relatively still. At this time, under the action of gravity, the sampling tube 1 will cause the front cavity 21 to displace inward along the pipeline path relative to the rear cavity 22, causing the walking spring 23 to deform. On this basis, the medium is filled into the front cavity 21 by using the supporting driving unit 3. Similarly, the front cavity 21 is horizontally supported in the pipeline and maintained at the current position. Then, the medium filled in the rear cavity 22 is extracted by the supporting driving unit 3, so that a negative pressure environment is formed in the cavity, so that the pair of pressure-bearing plates 254 of the rear cavity 22 are separated from the inner wall of the pipeline. Under the action of the elastic force of the walking spring 23, the rear cavity 22 will be pulled inward along the pipeline path. This is repeated to complete the alternating movement of the front cavity 21 and the rear cavity 22 of the walking unit, thereby realizing the gradual displacement of the device toward the blocked part in the pipeline until the sampling tube 1 reaches the blocked part.

[0075] During sampling, the sampling entrance of the sampling tube 1 penetrates into the blocked soil sample 42. Since the blocked soil sample 42 is mainly composed of fine particles and has a small permeability coefficient, a negative pressure environment is formed in the sampling tube 1 through the supporting driving unit 3, thereby forming a good negative pressure area on the top of the soil sample in the sampling tube 1. When the sampling device encounters resistance during the process of collecting the original soil sample, the penetration force of the sampling tube 1 can be increased by forming a negative pressure environment in the sampling tube 1. The negative pressure is continuously applied to the sampling tube 1. When the sampling tube 1 is blocked by the blocked soil, the negative pressure is increased. After the sample 42 is filled, negative pressure is continued to be applied. The soil sample in the sampling tube 1 remains stationary due to the negative pressure, the friction between the soil sample and the tube wall, the lateral friction resistance, and the weight of the soil sample itself. The disturbance of the soil sample by this sampling method of this embodiment is mainly concentrated in the sampling inlet of the sampling tube 1 and the small area of ​​the interface between the other end of the tube and the third hose 33. The large middle section of the soil sample in the tube is basically in its original state and the disturbance is limited. This is convenient and conducive to the subsequent testing and experiment of the soil properties of the original soil sample.

[0076] When displacing outward, an external pulling force is applied to pull the device outward. Referring to the method of inward displacement, the front cavity 21 and the rear cavity 22 of the walking unit are alternately moved to realize the gradual displacement of the device outward in the pipeline. For example, the matching driving unit 3 is first used to fill the medium into the front cavity 21 to form a positive pressure environment in the cavity. Under the action of positive pressure, the pressure-bearing plates 254 of the pair of pressure-bearing structures 25 are pressed against the inner wall of the pipeline, so that the front cavity 21 temporarily remains motionless. Under the action of external pulling force, , the rear cavity 22 is displaced outward along the pipeline relative to the front cavity 21, causing the walking spring 23 to deform, and then the medium filled in the front cavity 21 is extracted, forming a negative pressure environment in the cavity, so that the pair of pressure-bearing plates 254 carried by it are separated from the inner wall of the pipeline. Under the action of the elastic force of the walking spring 23, the front cavity 21 will be pulled outward along the pipeline path. This is repeated to complete the alternating movement of the front cavity 21 and the rear cavity 22 of the walking unit, and realize the gradual displacement of the device away from the blocked part in the pipeline;

[0077] The above-mentioned alternating movement of the front cavity 21 and the rear cavity 22 is also applicable in the horizontal pipe section and the curved pipe section, and can be performed slowly when encountering the horizontal pipe section and the curved pipe section.

[0078] Based on the device for sampling undisturbed soil when silting up in the hydraulic piezometer tube 41, this embodiment also provides a method for sampling undisturbed soil when silting up in the hydraulic piezometer tube 41, comprising the following steps:

[0079] Step 1: Place the device into the hydraulic pressure measuring tube 41. Under the action of gravity, the device will reach a certain position in the hydraulic pressure measuring tube 41. The supporting drive unit 3 is driven by positive pressure to form a positive pressure environment in the front cavity 21 and the rear cavity 22 of the walking unit. The device is supported horizontally in the pipe by its respective pressure-bearing plates 254 and remains stationary.

[0080] In step 2, the rear cavity 22 remains stationary, and the front cavity 21 is driven by the supporting drive unit 3 by the negative pressure, and the corresponding pressure-bearing piece 254 is separated from the inner wall of the pipeline. Under the action of gravity, the sampling tube 1 and the front cavity 21 are displaced inward along the pipeline path relative to the rear cavity 22, causing the travel spring to deform. Afterwards, the front cavity 21 is driven by the supporting drive unit 3 by the positive pressure, and is again supported in the pipeline at the current position by the pressure-bearing piece 254. The rear cavity 22 is driven by the supporting drive unit 3 by the negative pressure, so that the pressure-bearing piece 254 is separated from the inner wall of the pipeline. Under the combined action of its own gravity and the elastic force generated by the deformation of the travel spring, the rear cavity 22 is displaced inward. Afterwards, the rear cavity 22 is driven by the supporting drive unit 3 by the positive pressure, and is again supported in the pipeline at the current position by the pressure-bearing piece 254.

[0081] Step 3: Refer to step 2 and repeat the process, so that the front cavity 21 and the rear cavity 22 of the traveling unit move alternately along the pipeline path toward the blocked part until the sampling tube 1 penetrates the blocked part;

[0082] Step 4: The sampling inlet of the sampling tube 1 penetrates the blocked soil sample 42, and a negative pressure environment is formed in the sampling tube 1 through the supporting driving unit 3, so that a negative pressure area is formed at the top of the soil sample in the sampling tube 1. If resistance is encountered during the sampling process, negative pressure is continuously applied to the sampling tube 1, and the penetration force of the sampling tube 1 is increased until the sampling tube 1 is filled with the blocked soil sample 42. The negative pressure is continuously applied to the sampling tube 1, so that the soil sample in the sampling tube 1 remains stationary under the combined action of negative pressure, friction between the soil sample and the tube wall, lateral friction resistance, and gravity.

[0083] Step 5: Negative pressure is applied to the sampling tube 1 by the supporting driving unit 3. The front cavity 21 is kept stationary in the pipeline by the corresponding pressure-bearing piece 254 under the driving of the supporting driving unit 3 relying on the positive pressure. On this basis, external pulling force is applied to pull the device outward, so that the rear cavity 22 is displaced outward along the pipeline path relative to the front cavity 21, causing the travel spring to deform. Afterwards, the rear cavity 22 is kept stationary in the pipeline by the corresponding pressure-bearing piece 254 under the driving of the supporting driving unit 3 relying on the positive pressure. The cavity 21 is driven by the negative pressure of the matching drive unit 3, and the pressure-bearing piece 254 it carries is separated from the inner wall of the pipeline. Under the action of the elastic force of the travel spring, the sampling tube 1 is moved outward, and then the matching drive unit 3 is used to provide positive pressure drive to maintain the current position. The matching drive unit 3 is used to separate the pressure-bearing piece 254 of the rear cavity 22 from the inner wall of the pipeline, and the cavity 21 is continuously pulled outward by applying external pulling force, and so on, so that the front cavity 21 and the rear cavity 22 of the travel unit move forward alternately along the pipeline path away from the blocked part until they are moved out of the pipeline.

[0084] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A device for sampling undisturbed soil in a hydraulic pressure measuring tube, characterized by: The sampling cylinder comprises a sampling cylinder, a traveling unit, and a driving unit. The sampling cylinder and the traveling unit can be driven by independent driving units respectively by positive or negative pressure. The sampling cylinder is a cylindrical shell cavity structure, wherein one side of the shaft end is open as a sampling inlet, and the other side of the shaft end is used to receive the drive of the matching driving unit. The entire device can be placed in a hydraulic pressure measuring tube from the outside, and the walking unit is driven by the matching driving unit to generate deformation along the pipeline path. The elastic force of the deformation and the external pulling force are used to realize the outward displacement of the device along the pipeline path in the pipeline, and the elastic force of the deformation and the gravity of the device are used to realize the inward displacement of the device along the pipeline path in the pipeline. When the device is displaced inwardly to the blockage part, a negative pressure environment is formed in the driving cylinder of the matching driving unit, and the sampling cylinder is penetrated into the blockage part with the sampling inlet facing the blockage part. The penetration depth is increased by continuing to apply negative pressure until the sampling of the original soil sample of the blockage part is completed. The original soil sample is kept stationary in the sampling cylinder by relying on the combined action of negative pressure, friction between the original soil sample and the cylinder wall, side friction resistance and the gravity of the original soil sample, and can be displaced outward with the device to the outside of the pipeline; The device placed in the hydraulic pressure measuring tube takes the side where the sampling tube is located as the front side, and the walking unit includes a front cavity and a rear cavity with the same shape, which are arranged at the rear end of the sampling tube with a front and rear interval, and also includes a walking spring tensioned between the front cavity and the rear cavity along the pipeline path, the cavity volume of the front cavity is larger than the rear cavity, and the front cavity and the rear cavity are independently driven by the matching driving unit based on positive pressure or negative pressure, and the structural form is that it has a cavity medium flow opening for receiving the drive unit drive, and a pair of pressure-bearing structures are arranged on both sides of the cavity along the diameter direction of the pipeline, each side of the pressure-bearing structure includes a guide rod slidably inserted into the cavity along the diameter direction of the pipeline, and also includes a piston built into the cavity, a pressure-bearing spring tensioned between the inner wall of the cavity and the piston along the diameter direction of the pipeline, and a pressure-bearing plate arranged outside the cavity, the rod section of the guide rod extending into the cavity is sleeved with the pressure-bearing spring, the end is connected to the piston, and the end exposed outside the cavity is connected to the pressure-bearing plate; The driving unit is connected to the cavity medium flow openings of the front cavity and the rear cavity, and to the cylinder medium flow opening on the sampling cylinder through flexible pipes.

2. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 1 is characterized in that: The outer shape of the side of the pressure-bearing sheet that contacts the pipeline is adapted to the inner wall of the pipeline, and when pressed against the inner wall of the pipeline on the side, it is tightly attached to the inner wall of the pipeline.

3. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 1 is characterized by: The device placed in the hydraulic pressure measuring tube has the side where the sampling cylinder is located as the front side. The sampling cylinder is fixedly connected to the front end of the walking unit. The sampling cylinder has a cylinder medium flow port for receiving the drive of the matching driving unit.

4. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to any one of claims 1 to 3, characterized in that: The driving unit uses liquid or gas as a medium and relies on positive pressure or negative pressure to drive the sampling tube and the walking unit.

5. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 1 is characterized by: The driving unit is a positive and negative pressure micro air pump, and there are three sets in total, two of which are used to drive the front cavity and the rear cavity in the walking unit respectively. The driving unit matching the front cavity is fixedly connected to the cavity medium flow port on the front cavity through a first hose, and the driving unit matching the rear cavity is fixedly connected to the cavity medium flow port on the rear cavity through a second hose. The other set is used to drive the sampling cylinder, and the driving unit matching the sampling cylinder is fixedly connected to the cylinder medium flow port on the sampling cylinder through a third hose.

6. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 5 is characterized by: The front cavity, the rear cavity and the sampling cylinder are aligned along the pipeline path, and a through channel is formed in the center of the front cavity and the rear cavity for the third hose to pass through. The channel is independent of the cavities of the front cavity and the rear cavity. The cylinder medium flow port is opened in the center of the rear axial end of the sampling cylinder. The cylinder medium flow port is fixedly connected to the bottom end of the rear cavity through a hard connecting pipe, and is threadedly connected to and communicated with the end of the third hose.

7. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 5 or 6, characterized in that: The pipe sections of the first hose and the third hose between the front cavity and the rear cavity are spring hoses.

8. The undisturbed soil sampling device for silting in a hydraulic pressure measuring tube according to claim 1 is characterized by: The sampling tube is made of metal.

9. A method for sampling undisturbed soil in a hydraulic pressure measuring tube, characterized by: The method is implemented using the device for sampling undisturbed soil blocked in a hydraulic pressure measuring tube according to any one of claims 1 to 8, comprising the following steps: Step 1: Place the device into the hydraulic pressure measuring tube. Under the action of gravity, the device will fall into the hydraulic pressure measuring tube. The matching drive unit is driven by positive pressure to form a positive pressure environment in the front cavity and the rear cavity of the walking unit. The device is supported horizontally in the pipe by its own pressure-bearing plates to keep it stationary. In step 2, the rear cavity remains stationary, and the front cavity is driven by the supporting driving unit relying on the negative pressure, and the corresponding pressure-bearing piece is separated from the inner wall of the pipeline. Under the action of gravity, the sampling tube and the front cavity are displaced inward along the pipeline path relative to the rear cavity, causing the walking spring to deform. Afterwards, the front cavity is driven by the supporting driving unit relying on the positive pressure, and is again supported horizontally in the pipeline at the current position by the pressure-bearing piece. The rear cavity is driven by the supporting driving unit relying on the negative pressure, so that the pressure-bearing piece is separated from the inner wall of the pipeline. Under the combined action of its own gravity and the elastic force generated by the deformation of the walking spring, the rear cavity is displaced inward. Afterwards, the rear cavity is driven by the supporting driving unit relying on the positive pressure, and is again supported horizontally in the pipeline at the current position by the pressure-bearing piece. Step 3: Referring to step 2, the front cavity and the rear cavity of the traveling unit are alternately moved forward along the pipeline path toward the blocked portion until the sampling tube penetrates the blocked portion; Step 4: The sampling inlet of the sampling tube penetrates the blocked soil sample, and a negative pressure environment is formed in the sampling tube through the supporting driving unit, so that a negative pressure area is formed on the top of the soil sample in the sampling tube. If resistance is encountered during the sampling process, negative pressure is continued to be applied to the sampling tube, and the penetration force of the sampling tube is increased until the sampling tube is filled with the blocked soil sample. The negative pressure is continued to be applied to the sampling tube, so that the soil sample in the sampling tube remains stationary under the combined action of negative pressure, friction between the soil sample and the tube wall, lateral friction resistance, and gravity; The cam is then pulled out of the way by the spring, and the front and rear cams are moved back and forth in a continuous motion, until the cam is released and the piston is pulled back outwards, and the piston is pulled out of the way again.

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