Device and method for testing pushing frictional resistance of jacking pipe

Abstract

The invention discloses a jacking pipe pushing frictional resistance testing device and a testing method.The jacking pipe pushing frictional resistance testing device comprises a confining pressure loading assembly, a horizontal pushing mechanism, a pressurizing mechanism, a filling mechanism and a signal processing unit, a tested jacking pipe and the confining pressure loading assembly are arranged in a matched mode, and the filling mechanism is used for filling liquid into the confining pressure loading assembly; the pressurizing mechanism is used for applying circumferential pressure to a tested jacking pipe through the confining pressure loading assembly, and the horizontal pushing mechanism is used for providing horizontal load for the tested jacking pipe to push the tested jacking pipe. And the signal processing unit is used for acquiring displacement data and horizontal load data of the tested jacking pipe in the jacking process of the tested jacking pipe, and calculating the frictional resistance of the tested jacking pipe under the corresponding pressure according to the displacement data and the horizontal load data. The device can improve the accuracy of the pushing frictional resistance test of the jacking pipe, and is simple in structure and easy to realize.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering, and in particular to a pipe jacking friction resistance testing device and a testing method. Background Art

[0002] Pipe jacking technology is a trenchless underground pipeline construction process that uses hydraulic cylinders to push the pipe jacking machine and the pipe sections to be laid underground section by section until the pipe jacking receiving well without excavating the surface. It has the following advantages: high construction accuracy, wide applicable soil, wide applicable pipe diameter range, low construction cost, and less impact on the surrounding environment. With the acceleration of my country's urbanization process, it has been widely used in urban underground space development, underground railway rail transit construction, and municipal tunnel engineering in recent years. At present, most of the determination of friction resistance in pipe jacking construction is based on theoretical calculation methods or some empirical data. The existing test devices and methods for testing the friction resistance of pipe jacking cannot simulate the actual construction conditions, and only test the friction resistance between the slurry and the pipe wall of the pipe jacking. In fact, the friction resistance of the pipe jacking structure in pipe jacking construction is related to many factors such as the roughness of the contact interface, the properties of the soil, and the properties of the slurry, especially the effect of the interaction between the slurry and the soil on the friction resistance, so the influence of the soil is ignored. Therefore, the determination of friction resistance plays a vital role in determining the parameters of pipe jacking construction.

[0003] Patent document CN101271056B discloses a friction coefficient test device between underground pipelines and soil in the field of construction engineering technology, including: a test box, a vertical loading system, and a horizontal loading system, wherein: the top of the test box is open and is provided with a vertical loading system, two opposite sides of the test box are provided with oblong holes, one of which is provided with a horizontal loading system, the test box is filled with soil samples, and the pipeline to be tested passes through the test box through the oblong holes on both sides of the test box. This technology can be used to test the friction coefficient and friction resistance between the pipeline and the soil, but it cannot be used to test the friction coefficient and friction resistance between the pipeline and the soil in the actual pipe jacking project. In the actual pipe jacking project, mud is wrapped around the pipeline, not the soil.

[0004] Patent document CN110146209A discloses a friction test device and method for rectangular pipe jacking, including a horizontally laid simulated soil body for simulating the soil layer on site; a rectangular pipe set on the simulated soil body for simulating the rectangular pipe jacking; a traction device for providing horizontal traction for the rectangular pipe jacking; and a dynamometer set between the traction device and the rectangular pipe for detecting the magnitude of the traction. This solution does not consider the influence of formation pressure on friction, is applicable to specific environments, and has limitations in application when the pipe jacking tunnel is buried deep.

[0005] Patent document CN102636430A discloses an indoor simulation experimental system for pipe jacking grouting resistance reduction. The test system can simulate the process of pipe jacking in the soil layer. During the jacking process, the prepared slurry is injected into the soil around the pipe to test the friction resistance and friction coefficient during the process of pipe jacking under different slurry ratios and different grouting pressures, so as to comprehensively and accurately give the grouting pressure and grouting ratio suitable for pipe jacking in the soil layer. This device is relatively complex, and it is difficult to load the soil layer vertically and horizontally simultaneously. Summary of the invention

[0006] The invention provides a pipe jacking friction resistance test device and a test method, which can improve the accuracy of the pipe jacking friction resistance test and has a simple structure and is easy to implement.

[0007] A pipe jacking friction resistance test device comprises a confining pressure loading assembly, a horizontal propulsion mechanism, a pressurizing mechanism, a perfusion mechanism and a signal processing unit;

[0008] The jacking pipe to be tested is arranged in cooperation with the confining pressure loading assembly, the filling mechanism is used to fill liquid into the confining pressure loading assembly, the pressurizing mechanism is used to apply circumferential pressure to the jacking pipe to be tested through the confining pressure loading assembly, and the horizontal propulsion mechanism is used to provide a horizontal load to the jacking pipe to be tested and push the jacking pipe to be tested;

[0009] During the jacking process of the jacking pipe under test, the signal processing unit is used to collect displacement data and horizontal load data of the jacking pipe under test, and calculate the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and horizontal load data.

[0010] Furthermore, the device also includes a jacking pipe support frame and a confining pressure support frame, which are respectively used to install the jacking pipe to be tested and the confining pressure loading assembly. The jacking pipe support frame is also provided with a guide rail for limiting the position of the jacking pipe to be tested during the jacking process.

[0011] Furthermore, the confining pressure loading assembly includes a flexible sleeve, a flexible inflatable part and a rigid reaction force fixing part, the measured jacking pipe is arranged in the flexible sleeve, the flexible inflatable part is arranged outside the flexible sleeve, the rigid reaction force fixing part is arranged outside the flexible inflatable part, an inflatable space is formed in the flexible inflatable part, a grouting groove is formed between the flexible sleeve and the measured jacking pipe, the pouring mechanism is used to pour liquid into the grouting groove, and the pressurizing mechanism is used to fill the air space with high-pressure gas.

[0012] Furthermore, both ends of the flexible sleeve are respectively provided with an inflatable sealing structure, and a moisture content sensor is also provided in the flexible sleeve, and the moisture content sensor is connected to the signal processing unit and is used to detect the moisture content of the slurry;

[0013] A pressure sensor is arranged in the flexible inflatable member, and the pressure sensor is connected to the signal processing unit and is used to collect the pressure value in the flexible inflatable member.

[0014] Furthermore, the horizontal propulsion mechanism includes a load loading plate, a horizontal jacking force mechanism, a dynamometer and a displacement sensor. The load loading plate is connected to the jacking pipe to be measured, the horizontal jacking force mechanism is connected to the load loading plate, the dynamometer is installed between the load loading plate and the horizontal jacking force mechanism, and the displacement sensor is arranged on the top of the load loading plate.

[0015] Furthermore, the filling mechanism includes a water storage container, a slurry storage container, a connecting pipeline, a pump body, a first control valve and a second control valve. The first flexible sleeve is provided with a filling hole. The water storage container and the slurry storage container are connected to the filling hole through the connecting pipeline. The pump body is arranged on the connecting pipeline. The first control valve is cooperatively connected to the slurry storage container, and the second control valve is cooperatively connected to the water storage container.

[0016] A method for testing the friction resistance of a pipe jacking push using the above-mentioned pipe jacking push friction resistance testing device comprises:

[0017] Installing the jacking pipe to be measured in the confining pressure loading assembly;

[0018] Filling soil into the confining pressure loading assembly;

[0019] Controlling the pouring mechanism to pour water into the confining pressure loading assembly until the moisture content of the soil meets the preset requirement;

[0020] Controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met;

[0021] The horizontal propulsion mechanism is controlled to provide a horizontal load to the jacking pipe under test to push the jacking pipe under test. During the pushing process of the jacking pipe under test, the signal processing unit collects displacement data and horizontal load data of the jacking pipe under test, and calculates the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and horizontal load data.

[0022] Further, controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met, further comprising:

[0023] The injection mechanism is controlled to inject the drag reducing agent into the confining pressure loading assembly.

[0024] Further, the frictional resistance of the tested jacking pipe under the corresponding pressure is calculated according to the displacement data and the horizontal load data, including:

[0025] According to the displacement data, the jacking distance of the jacking pipe under test is obtained;

[0026] According to the horizontal load data, the horizontal jacking force of the jacking pipe under test is obtained;

[0027] Calculate the circumference of the circular section of the top pipe being measured;

[0028] The frictional resistance of the jacking pipe under the corresponding pressure is calculated according to the horizontal jacking force, the circumference of the circular cross section of the jacking pipe under test and the jacking distance of the jacking pipe under test.

[0029] Furthermore, the frictional resistance is calculated by the following formula:

[0030]

[0031] Among them, f k is the friction resistance, P is the horizontal jacking force, D 0 is the diameter of the jacking pipe under test, L is the jacking distance of the jacking pipe under test, and π is the pi.

[0032] Further, the confining pressure loading assembly includes a flexible sleeve, a flexible inflatable member and a rigid reaction force fixing member, the jacking pipe to be measured is arranged in the flexible sleeve, the flexible inflatable member is arranged outside the flexible sleeve, the rigid reaction force fixing member is arranged outside the flexible inflatable member, an inflatable space is formed in the flexible inflatable member, and a grouting groove is formed between the flexible sleeve and the jacking pipe to be measured; a water content sensor is also arranged in the flexible sleeve;

[0033] The pouring mechanism comprises a water storage container, a slurry storage container, a connecting pipeline, a pump body, a first control valve and a second control valve; the flexible sleeve is provided with a pouring hole, the water storage container and the slurry storage container are connected to the pouring hole through the connecting pipeline, the pump body is arranged on the connecting pipeline, the first control valve is connected to the slurry storage container, and the second control valve is connected to the water storage container;

[0034] The soil is filled into the grouting groove;

[0035] Controlling the injection mechanism to inject water into the confining pressure loading assembly until preset requirements are met, including:

[0036] Controlling the opening of the second control valve, pouring water into the grouting groove through the water storage container, detecting the moisture content of the soil through the moisture content sensor, and controlling the closing of the second control valve when the moisture content of the soil reaches a preset value;

[0037] The slurry storage container stores a drag reducer;

[0038] Controlling the injection mechanism to inject the drag reducing agent into the confining pressure loading assembly comprises:

[0039] Controlling to open the first control valve, and injecting the drag reducing agent into the grouting groove through the grout storage container;

[0040] A pressure sensor is provided in the flexible inflatable member;

[0041] Controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met, including:

[0042] The pressurizing mechanism is controlled to fill the inflation space with high-pressure gas, and the pressure value in the inflation space is collected by the pressure sensor until the pressure value reaches a preset pressure value.

[0043] The pipe jacking friction resistance testing device and testing method provided by the present invention have at least the following beneficial effects:

[0044] (1) Through the coordinated action of the pouring mechanism, the confining pressure loading assembly and the pressurizing mechanism, the pressure and mud state that the jacking pipe is subjected to in the most realistic construction environment can be simulated, thereby improving the accuracy of subsequent friction resistance tests;

[0045] (2) It can simulate the mud environment of different properties in the actual pipe jacking project, and can also add drag reducers to test the friction resistance under the action of drag reducers. It has wide applicability and can provide a basis for the study of the friction resistance of muds of different properties and the performance of different drag reducers;

[0046] (3) By cooperating with the pressurizing mechanism and the confining pressure loading assembly, the magnitude of the applied confining pressure is controlled to simulate the confining pressure effect of different formations, thereby meeting the test requirements of the friction resistance of the top pipe in different formations;

[0047] (4) The application of pressure and the simulation of slurry are achieved by using different structures. Compared with the scheme of completely using mud to simulate pressure, the volume of the entire device can be reduced, and different confining pressures can be simulated. The application of pressure will not affect the properties of the mud, thus ensuring the accuracy of the friction resistance test. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The present invention is a schematic structural diagram of an embodiment of a pipe jacking friction resistance testing device provided by the present invention.

[0049] Figure 2 A schematic structural diagram of another embodiment of a pipe jacking friction resistance testing device provided by the present invention.

[0050] Figure 3 A schematic structural diagram of an embodiment of a confining pressure loading assembly in a pipe jacking friction resistance testing device provided by the present invention.

[0051] Figure 4 The present invention is a schematic structural diagram of an embodiment of signal processing in a pipe jacking friction resistance testing device provided by the present invention.

[0052] Figure 5 A stereoscopic diagram of an embodiment of a confining pressure loading assembly in a pipe jacking friction resistance testing device provided by the present invention.

[0053] Figure 6 The present invention is a schematic structural diagram of an embodiment of a flexible sleeve in a pipe jacking friction resistance testing device provided by the present invention.

[0054] Figure 7 The present invention provides a flow chart of an embodiment of a method for testing the friction resistance of a pipe jacking provided by the present invention.

[0055] Reference numerals:

[0056] 1-confining pressure loading assembly, 2-horizontal propulsion mechanism, 3-pressurization mechanism, 4-injection mechanism, 5-signal processing unit, 6-tested jacking pipe, 7-jacking pipe support frame, 8-confining pressure support frame, 9-guide rail, 11-flexible sleeve, 12-flexible inflatable member, 13-rigid reaction force fixing member, 111-water content sensor, 112-injection hole, 113-flexible inflatable sealing ring, 121-pressure sensor, 21-load loading plate, 22-horizontal jacking force mechanism, 23-dynamometer, 24-displacement sensor, 41-water storage container, 42-slurry storage container, 43-connecting pipeline, 44-pump body, 45-first control valve, 46-second control valve. DETAILED DESCRIPTION

[0057] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0058] refer to Figure 1 In some embodiments, a pipe jacking friction resistance test device is provided, comprising a confining pressure loading assembly 1, a horizontal propulsion mechanism 2, a pressurizing mechanism 3, a perfusion mechanism 4, and a signal processing unit 5;

[0059] The jacking pipe 6 to be tested is arranged in cooperation with the confining pressure loading assembly 1, the filling mechanism 4 is used to fill the liquid into the confining pressure loading assembly 1, the pressurizing mechanism 2 is used to apply circumferential pressure to the jacking pipe to be tested through the confining pressure loading assembly 1, and the horizontal pushing mechanism 2 is used to provide a horizontal load to the jacking pipe 6 to push the jacking pipe 6 to be tested;

[0060] During the jacking process of the jacking pipe 6 under test, the signal processing unit 5 is used to collect displacement data and horizontal load data of the jacking pipe under test, and calculate the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and horizontal load data.

[0061] Specifically, the jacking pipe 6 to be tested is installed in the confining pressure loading assembly 1, and the injection mechanism 4 is used to inject liquid into the confining pressure loading assembly 1, which can simulate the mud environment in the actual jacking project. A drag reducer can also be added to test the friction resistance under the action of the drag reducer. The pressurizing mechanism 2 applies circumferential pressure to the jacking pipe to be tested through the confining pressure loading assembly 1. Through the synergistic effect of the injection mechanism 4, the confining pressure loading assembly 1 and the pressurizing mechanism 2, the pressure and mud state that the jacking pipe is subjected to in the most real construction environment can be simulated, thereby improving the accuracy of subsequent friction resistance tests.

[0062] Further, refer to Figure 2 The device also includes a jacking pipe support frame 7 and a confining pressure support frame 8, which are respectively used to install the jacking pipe 6 to be tested and the confining pressure loading assembly 1. The jacking pipe support frame 7 is also provided with a guide rail 9 for limiting the position of the jacking pipe to be tested during the jacking process.

[0063] Further, refer to Figure 2 and Figure 3 The confining pressure loading assembly 1 includes a flexible sleeve 11, a flexible inflatable member 12 and a rigid reaction force fixing member 13. The measured jacking pipe 6 is arranged in the flexible sleeve 11, the flexible inflatable member 12 is arranged outside the flexible sleeve 11, and the rigid reaction force fixing member 13 is arranged outside the flexible inflatable member 12. An inflation space is formed in the flexible inflatable member 12, and a grouting groove is formed between the flexible sleeve 11 and the measured jacking pipe 6. The grouting mechanism 4 is used for grouting into the grouting groove, and the pressurizing mechanism 3 is used for filling the inflation space with high-pressure gas.

[0064] Specifically, the grouting groove formed between the flexible sleeve 11 and the jacking pipe 6 to be tested can be filled with soil first, and then water is poured into the grouting groove through the pouring mechanism 4, so that the water and soil are mixed to form mud. The moisture content of the mud can be controlled by the amount of water injected, so the required mud can be prepared according to actual needs. In addition, the drag reducer can be poured into the grouting groove through the pouring mechanism 4, so that the friction resistance test can be realized in the absence of the drag reducer, and the drag reducer can be conveniently added to realize the friction resistance test of the jacking pipe under the action of the drag reducer and analyze the performance of the drag reducer.

[0065] refer to Figure 4 In some embodiments, a water content sensor 111 is further provided in the flexible sleeve 11, and the water content sensor 111 is connected to the signal processing unit 5 for detecting the water content of the slurry. During the water injection process, the water content of the slurry can be detected in real time by the water content sensor 111, and the water injection is stopped when the required water content is reached.

[0066] Furthermore, when the slurry in the grouting tank meets the test requirements, the pressurizing mechanism 3 is used to fill the inflation space in the flexible inflatable member 12 with high-pressure gas, and the pressure is transmitted to the slurry through the flexible inflatable member 12 and the flexible sleeve 11, and applied to the jacking pipe under test.

[0067] In some implementations, the rigid reaction force fixing part 13 can be a cylindrical structure, which is used to fill the inflation space in the flexible inflatable part 12 with high-pressure gas through the pressurizing mechanism 3. The pressure is transmitted to the slurry through the flexible inflatable part 12 and the flexible sleeve 11, and applied to the jacking pipe under test. The rigid reaction force fixing part 13 with a cylindrical structure limits the outward transmission of pressure, and the cylindrical sleeve can form a confining pressure on the jacking pipe under test, so as to better simulate the real scene.

[0068] In some embodiments, the flexible inflatable member 12 may be an integrally formed bladder-like structure.

[0069] refer to Figure 5 In some embodiments, the rigid reaction force fixing member 13 can also be a plurality of rigid circular rings, which are sleeved outside the flexible inflatable member 12, thereby reducing the production cost while ensuring the stability of the flexible inflatable member 12.

[0070] Further, refer to Figure 4 A pressure sensor 121 is provided in the flexible inflatable member 12, and the pressure sensor 121 is connected to the signal processing unit 5, and is used to collect the pressure value in the flexible inflatable member 12. In the process of the pressurizing mechanism 3 filling the inflation space of the flexible inflatable member 12 with high-pressure gas, the applied pressure value can be detected in real time, and the pressure is stopped when the pressure value reaches the preset pressure value, so the magnitude of the applied confining pressure can be controlled to simulate the confining pressure effect of different formations. For example, when simulating a shallow buried depth of the top pipe, the applied pressure can be reduced, and when simulating a deep buried depth of the top pipe, the applied pressure can be increased, so that the test requirements of the top pipe pushing friction resistance under different formations can be met.

[0071] In some embodiments, the material of the flexible sleeve 11 and / or the flexible inflatable member 12 may be neoprene.

[0072] Therefore, in the device provided by the above embodiment, the grouting groove formed between the flexible sleeve 11 and the top pipe 6 to be tested can be filled with soil and water to form slurry, and the slurry is in direct contact with the top pipe 6 to be tested. The slurry with the required moisture content can be obtained by controlling the moisture content, which better simulates the mud of different concentrations, moisture contents and viscosities in the real application scene, making the device more applicable. The confining pressure applied to the top pipe to be tested is filled with high-pressure gas into the inflation space of the flexible inflatable member 12 through the pressurizing mechanism 3. The pressure is transmitted to the slurry through the flexible inflatable member 12 and the flexible sleeve 11, and applied to the top pipe to be tested, while the rigid reaction force fixing member 13 limits the pressure from being transmitted outward. The circular sleeve can form confining pressure on the top pipe to be tested, which better simulates the real scene. The application of pressure and the simulation of slurry are realized by different structures. Compared with the solution of completely adopting mud simulation pressure, the volume of the entire device can be reduced, and different confining pressures can be simulated. The application of pressure will not affect the properties of the mud, ensuring the accuracy of the friction resistance test.

[0073] Further, refer to Figure 2 The injection mechanism 4 includes a water storage container 41, a slurry storage container 42, a connecting pipeline 43, a pump body 44, a first control valve 45 and a second control valve 46. The flexible sleeve 11 is provided with an injection hole 112. The water storage container 41 and the slurry storage container 42 are connected to the injection hole 112 through the connecting pipeline 43. The pump body 44 is arranged on the connecting pipeline 43. The first control valve 45 is connected to the slurry storage container 42, and the second control valve 46 is connected to the water storage container 41. The slurry storage container 42 is used to store the drag reducer.

[0074] Specifically, after the soil is filled into the grouting slot, the second control valve 46 is controlled to be opened, so that the water in the water storage container 41 enters the grouting slot and mixes with the soil in the grouting slot to form mud. The water content of the mud is detected in real time by the water content sensor 111, and the water injection is stopped when the required water content is reached. If it is necessary to add drag reducer, the first control valve is controlled to be opened, so that the drag reducer in the slurry storage container 42 enters the grouting slot, and the amount of drag reducer injected can be controlled by the pump body 44.

[0075] Furthermore, both ends of the flexible sleeve 11 are respectively provided with an inflatable sealing structure. After the sealing structure is inflated, the grouting groove can be sealed. When filling the soil into the grouting groove, the inflatable sealing structure at one end can be inflated first, and the inflatable sealing structure at the other end is not inflated. The soil is filled into the grouting groove through the uninflated end. After the filling is completed, it is inflated to achieve sealing at both ends.

[0076] refer to Figure 6In some embodiments, the inflatable sealing structure at both ends of the flexible sleeve 11 can be a flexible inflatable sealing ring 113. After the flexible inflatable sealing ring 113 is inflated, its inner diameter is slightly smaller than the diameter of the top pipe 6 to be tested, thereby achieving sealing of the grouting groove and preventing large leakage of mud in the grouting groove during the advancement of the top pipe to be tested. The flexible material can also reduce the friction with the rigidity of the top pipe 6 to ensure the reliability of the test.

[0077] The grouting slot is sealed by an inflatable sealing structure, which can meet the sealing requirements and make it more convenient to fill the soil.

[0078] Further, refer to Figure 2 The horizontal propulsion mechanism 2 includes a load loading plate 21, a horizontal jacking force mechanism 22, a dynamometer 23 and a displacement sensor 24. The load loading plate 21 is connected to the jacking pipe 6 to be measured, the horizontal jacking force mechanism 22 is connected to the load loading plate 21, the dynamometer 23 is installed between the load loading plate 21 and the horizontal jacking force mechanism 22, and the displacement sensor 24 is arranged on the top of the load loading plate 21.

[0079] Specifically, the horizontal jacking driving force mechanism 22 is a power source for providing a horizontal load, and the horizontal load is applied to the jacking pipe 6 under test through the load loading plate 21. During the advancement of the jacking pipe 6 under test, the size of the applied horizontal load is detected by the dynamometer 23, so the size of the horizontal load can be adjusted as needed to meet the test requirements. During the advancement process, the displacement data of the movement of the jacking pipe 6 under test is collected by the displacement sensor 24, and the frictional resistance of the jacking pipe 6 under test under the corresponding pressure is calculated based on the displacement data and the horizontal load data.

[0080] refer to Figure 7 In some embodiments, a method for testing the friction resistance of a pipe jacking push using the above-mentioned pipe jacking push friction resistance testing device is provided, comprising:

[0081] S1. Installing the jacking pipe to be measured in the confining pressure loading assembly;

[0082] S2, filling soil into the confining pressure loading assembly;

[0083] S3, controlling the pouring mechanism to pour water into the confining pressure loading assembly until the moisture content of the soil meets the preset requirement;

[0084] S4, controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met;

[0085] S5, controlling the horizontal propulsion mechanism to provide a horizontal load to the jacking pipe under test to push the jacking pipe under test, wherein the signal processing unit collects displacement data and horizontal load data of the jacking pipe under test during the jacking process of the jacking pipe under test, and calculates the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and the horizontal load data.

[0086] Further, refer to Figure 2 The confining pressure loading assembly 1 includes a flexible sleeve 11, a flexible inflatable member 12 and a rigid reaction force fixing member 13. The top pipe 6 to be tested is arranged inside the flexible sleeve 11, the flexible inflatable member 12 is arranged outside the flexible sleeve 11, the rigid reaction force fixing member 13 is arranged outside the flexible inflatable member 12, an inflatable space is formed inside the flexible inflatable member 12, and a grouting groove is formed between the flexible sleeve 11 and the top pipe 6 to be tested; a water content sensor is also arranged inside the flexible sleeve 11;

[0087] The injection mechanism 4 includes a water storage container 41, a slurry storage container 42, a connecting pipeline 43, a pump body 44, a first control valve 45 and a second control valve 46. The first flexible sleeve 11 is provided with an injection hole. The water storage container 41 and the slurry storage container 42 are connected to the injection hole through the connecting pipeline 43. The pump body 44 is arranged on the connecting pipeline 43. The first control valve 45 is connected to the slurry storage container 42, and the second control valve 46 is connected to the water storage container 41. The slurry storage container 42 is used to store the drag reducer.

[0088] Specifically, in step S1 , the jacking pipe to be measured is installed in the confining pressure loading assembly, specifically, the jacking pipe to be measured is arranged in the flexible sleeve 11 .

[0089] Furthermore, in step S2, soil is filled into the confining pressure loading assembly 1, and specifically, the soil is filled into the grouting groove.

[0090] Furthermore, an inflatable sealing structure is respectively provided at both ends of the flexible sleeve 11, and the inflatable sealing structure can be a flexible inflatable sealing ring. After the sealing structure is inflated, the grouting groove can be sealed. When filling the soil into the grouting groove, the inflatable sealing structure at one end can be inflated first, and the inflatable sealing structure at the other end is not inflated. The soil is filled into the grouting groove through the non-inflated end. After the filling is completed, the inflatable sealing structure at the non-inflated end is inflated to achieve sealing at both ends.

[0091] In step S3, the pouring mechanism is controlled to pour water into the confining pressure loading assembly until the preset requirements are met, including:

[0092] The second control valve 46 is controlled to be opened, water is poured into the grouting groove through the water storage container 41, the moisture content of the soil is detected by the moisture sensor, and when the moisture content of the soil reaches a preset value, the second control valve 46 is controlled to be closed.

[0093] Furthermore, a pressure sensor is provided in the flexible inflatable member;

[0094] In step S4, the pressurizing mechanism is controlled to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met, including:

[0095] The pressurizing mechanism is controlled to fill the inflation space with high-pressure gas, and the pressure value in the inflation space is collected by the pressure sensor until the pressure value reaches a preset pressure value.

[0096] Furthermore, a drag reducer is stored in the slurry storage container.

[0097] In some embodiments, after step S4, the method further includes:

[0098] The injection mechanism is controlled to inject the drag reducing agent into the confining pressure loading assembly.

[0099] In some embodiments, the components of the drag reducer in mass proportions may be: 35-40 parts of polyurethane, 168-173 parts of epoxy resin, 5-12 parts of inorganic material, 10-13 parts of graphite, 10-13 parts of soda ash, and 2-5 parts of polyacrylamide.

[0100] Specifically, the first control valve is controlled to be opened, and the drag reducing agent is poured into the grouting groove through the slurry storage container.

[0101] Further, in step S5, the frictional resistance of the tested jacking pipe under the corresponding pressure is calculated according to the displacement data and the horizontal load data, including:

[0102] S51, obtaining the jacking distance of the jacking pipe under test according to the displacement data;

[0103] S52, obtaining the horizontal jacking force of the jacking pipe under test according to the horizontal load data;

[0104] S53, calculating the circumference of the circular cross section of the top pipe to be measured;

[0105] S54, calculating and obtaining the frictional resistance of the jacking pipe under the corresponding pressure according to the horizontal jacking force, the circumference of the circular cross section of the jacking pipe under test, and the jacking distance of the jacking pipe under test.

[0106] Further, in step S54, the frictional resistance is calculated by the following formula:

[0107]

[0108] Among them, f k is the friction resistance, P is the horizontal jacking force, D 0 is the diameter of the jacking pipe under test, L is the jacking distance of the jacking pipe under test, and π is the pi.

[0109] The pipe jacking friction resistance testing device and testing method provided in the above embodiments have at least the following beneficial effects:

[0110] (1) Through the coordinated action of the pouring mechanism, the confining pressure loading assembly and the pressurizing mechanism, the pressure and mud state that the jacking pipe is subjected to in the most realistic construction environment can be simulated, thereby improving the accuracy of subsequent friction resistance tests;

[0111] (2) It can simulate the mud environment of different properties in the actual pipe jacking project, and can also add drag reducers to test the friction resistance under the action of drag reducers. It has wide applicability and can provide a basis for the study of the friction resistance of muds of different properties and the performance of different drag reducers;

[0112] (3) By cooperating with the pressurizing mechanism and the confining pressure loading assembly, the magnitude of the applied confining pressure is controlled to simulate the confining pressure effect of different formations, thereby meeting the test requirements of the friction resistance of the top pipe in different formations;

[0113] (4) The application of pressure and the simulation of slurry are achieved by using different structures. Compared with the scheme of completely using mud to simulate pressure, the volume of the entire device can be reduced, and different confining pressures can be simulated. The application of pressure will not affect the properties of the mud, thus ensuring the accuracy of the friction resistance test.

[0114] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A pipe jacking friction resistance test device, characterized in that: It includes a confining pressure loading component, a horizontal propulsion mechanism, a pressurizing mechanism, a perfusion mechanism and a signal processing unit; The jacking pipe to be tested is arranged in cooperation with the confining pressure loading assembly, the filling mechanism is used to fill liquid into the confining pressure loading assembly, the pressurizing mechanism is used to apply circumferential pressure to the jacking pipe to be tested through the confining pressure loading assembly, and the horizontal propulsion mechanism is used to provide a horizontal load to the jacking pipe to be tested and push the jacking pipe to be tested; During the jacking process of the jacking pipe under test, the signal processing unit is used to collect displacement data and horizontal load data of the jacking pipe under test, and calculate the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and horizontal load data.

2. The device according to claim 1, characterized in that The device also includes a jacking pipe support frame and a confining pressure support frame, which are respectively used to install the jacking pipe to be tested and the confining pressure loading assembly. The jacking pipe support frame is also provided with a guide rail for limiting the position of the jacking pipe to be tested during the jacking process.

3. The device according to claim 1, characterized in that The confining pressure loading assembly includes a flexible sleeve, a flexible inflatable part and a rigid reaction force fixing part. The measured jacking pipe is arranged in the flexible sleeve, the flexible inflatable part is arranged outside the flexible sleeve, and the rigid reaction force fixing part is arranged outside the flexible inflatable part. An inflation space is formed in the flexible inflatable part. A grouting groove is formed between the flexible sleeve and the measured jacking pipe. The pouring mechanism is used to pour liquid into the grouting groove, and the pressurizing mechanism is used to fill the inflation space with high-pressure gas.

4. The device according to claim 3, characterized in that Both ends of the flexible sleeve are respectively provided with an inflatable sealing structure, and a moisture content sensor is also provided in the flexible sleeve, and the moisture content sensor is connected to the signal processing unit and is used to detect the moisture content of the slurry; A pressure sensor is arranged in the flexible inflatable member, and the pressure sensor is connected to the signal processing unit and is used to collect the pressure value in the flexible inflatable member.

5. The device according to claim 1, characterized in that The horizontal propulsion mechanism includes a load loading plate, a horizontal jacking force mechanism, a dynamometer and a displacement sensor. The load loading plate is connected to the jacking pipe to be measured, the horizontal jacking force mechanism is connected to the load loading plate, the dynamometer is installed between the load loading plate and the horizontal jacking force mechanism, and the displacement sensor is arranged on the top of the load loading plate.

6. The device according to claim 3, characterized in that The filling mechanism includes a water storage container, a slurry storage container, a connecting pipeline, a pump body, a first control valve and a second control valve. The flexible sleeve is provided with a filling hole. The water storage container and the slurry storage container are connected to the filling hole through the connecting pipeline. The pump body is arranged on the connecting pipeline. The first control valve is connected to the slurry storage container, and the second control valve is connected to the water storage container.

7. A method for testing the friction resistance of a pipe jacking using the pipe jacking friction resistance testing device as claimed in any one of claims 1 to 6, characterized in that: include: Installing the jacking pipe to be measured in the confining pressure loading assembly; Filling soil into the confining pressure loading assembly; Controlling the pouring mechanism to pour water into the confining pressure loading assembly until the moisture content of the soil meets the preset requirement; Controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met; The horizontal propulsion mechanism is controlled to provide a horizontal load to the jacking pipe under test to push the jacking pipe under test. During the pushing process of the jacking pipe under test, the signal processing unit collects displacement data and horizontal load data of the jacking pipe under test, and calculates the frictional resistance of the jacking pipe under test under corresponding pressure according to the displacement data and horizontal load data.

8. The method according to claim 7, characterized in that Controlling the pressurizing mechanism to apply circumferential pressure to the tested jacking pipe through the confining pressure loading assembly until the test pressure requirement is met, further comprising: The injection mechanism is controlled to inject the drag reducing agent into the confining pressure loading assembly.

9. The method according to claim 7, characterized in that: Calculating the frictional resistance of the tested jacking pipe under the corresponding pressure according to the displacement data and the horizontal load data, including: According to the displacement data, the jacking distance of the jacking pipe under test is obtained; According to the horizontal load data, the horizontal jacking force of the jacking pipe under test is obtained; Calculate the circumference of the circular section of the top pipe being measured; The frictional resistance of the jacking pipe under the corresponding pressure is calculated according to the horizontal jacking force, the circumference of the circular cross section of the jacking pipe under test and the jacking distance of the jacking pipe under test.

10. The method according to claim 9, characterized in that The frictional resistance is calculated by the following formula: Among them, f k is the friction resistance, P is the horizontal jacking force, D0 is the diameter of the jacking pipe under test, L is the jacking distance of the jacking pipe under test, and π is the pi.

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