A device and method for simulating equivalent pipe-soil interaction under high-pressure water environment

Abstract

The present invention relates to a device and method for simulating equivalent pipe-soil interaction in a high-pressure water environment. The device comprises: a pressure chamber system, an equivalent pipe-soil interaction system, a soil displacement loading system, a measurement control system, and an example test model; the soil displacement loading system comprises a lateral hydraulic loading device (9), a tail end guide flange (11), and a guide bracket (12); the lateral hydraulic loading devices (9) are two, respectively connected to the front and rear of the pressure chamber; the equivalent pipe-soil interaction system comprises a plurality of equivalent soil interaction modules (13), a rear module fixing frame (14), a front module fixing frame (15), and a matching module control system.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine engineering tests, and in particular relates to a device and method for simulating equivalent pipe-soil interaction in a high-pressure water environment. Background Art

[0002] To effectively withstand external hydrostatic high pressure, tubular structures are one of the most commonly used structural forms in marine engineering equipment, such as submarine pipelines and submarine tunnels. Pipe-soil interaction has a significant impact on the in-situ stability, global buckling, and local buckling behavior of the structure, and is a key factor that must be considered during the design and operation of tubular structures such as submarine pipelines and submarine tunnels. Invention patent CN111537434B proposes a test device for buried pipelines across seismic faults, which mainly includes a vertically movable soil box, a fixed soil box, a horizontally movable soil box, and a test pipe arranged along the length of the boxes and running through the three boxes. Invention patent CN112651151A proposes a test device and determination method for simulating pipelines crossing strike-slip faults. The pressure-bearing structure included in the device can adjust its structural parameters so that the stress-strain relationship of the structure when subjected to pressure is similar to that of the soil. Invention patent CN108007792B proposes a combined earthquake-high-pressure load test method for in-service deep-sea submarine buried pipelines, involving devices such as a pressure chamber, high-temperature oil, a pipe-soil actuator, and a shock actuator rod.

[0003] The main deficiencies in the simulation of pipe-soil interaction in high-pressure water environments at home and abroad are:

[0004] 1. Existing pipe-soil interaction simulations are mainly implemented using soil boxes and centrifuges. Due to factors such as soil conditions, soil preparation, test costs, and loading control, it is difficult to meet the test similarity requirements.

[0005] 2. The use of a pressure-bearing structure to simulate soil forces is different from the arrangement of soil springs in discrete finite elements and can only simulate pipe-soil interaction in one direction;

[0006] 3. When using a soil box in a pressure chamber, the high-pressure water environment will change the properties of the originally prepared soil, and the soil will easily contaminate the water in the chamber, causing problems such as corrosion of the chamber and blockage of the drainage holes. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a device and method for simulating equivalent pipe-soil interaction in a high-pressure water environment. The device, which is an external water pressure-equivalent pipe-soil interaction device, can achieve combined loading of external water pressure and pipe-soil interaction forces on a tubular test model. The present invention adopts the following technical solutions:

[0008] A device for simulating equivalent pipe-soil interaction in a high-pressure water environment includes: a pressure chamber system, an equivalent pipe-soil interaction system, a soil displacement loading system, a measurement and control system, and an example test model, wherein:

[0009] The pressure cabin system includes a pressure cabin body 1, a side loading mounting hole 4, a forward hatch 7, a rear hatch 8 and a matching water tank and pump station;

[0010] The soil displacement loading system includes a lateral hydraulic loading device 9, a tail end guide flange 11 and a guide bracket 12;

[0011] There are two lateral hydraulic loading devices 9, which are connected to the front and rear of the pressure cabin body respectively; the components of the lateral hydraulic loading device 9 include a lateral hydraulic shell 90, a lateral hydraulic rod 91, a lateral front hydraulic cabin 93, a lateral rear hydraulic cabin 94, a lateral hydraulic sealing ring 97, a lateral water pressure cabin 98, a lateral hydraulic movable sealing ring 99 and a matching hydraulic pump station; one end of the lateral hydraulic rod 91 is located in the lateral water pressure cabin 98, and the other end is in contact with the rear module fixing frame 14 or the front module fixing frame 15, and a water pressure balance channel 92 is opened in the lateral hydraulic rod 91 to connect to the pressure cabin body 1 and lateral water pressure chamber 98; the lateral hydraulic rod 91 is provided with an expanded diameter section, a hydraulic chamber is provided around the expanded diameter section, and a lateral hydraulic movable seal ring 99 is coated on the outside of the expanded diameter section. The lateral hydraulic movable seal ring 99 isolates the hydraulic chamber into two parts with variable volume: a lateral front hydraulic chamber 93 and a lateral rear hydraulic chamber 94; the front hydraulic chamber 93 and the lateral rear hydraulic chamber 94 are respectively connected to the hydraulic pump station via hydraulic pipelines for the flow of hydraulic oil; the hydraulic pressure difference in the front hydraulic chamber 93 and the lateral rear hydraulic chamber 94 acts on the lateral hydraulic movable seal ring 99, thereby driving the lateral hydraulic rod 91 to move;

[0012] The lateral hydraulic loading device 9 is provided with a differential pressure sensor and a displacement sensor. The differential pressure sensor is used to measure the water pressure difference between the lateral front hydraulic compartment 93 and the lateral rear hydraulic compartment 94. The displacement sensor is used to measure the displacement of the lateral hydraulic rod 91.

[0013] One end of the tail guide flange 11 is a flange plate, which is fixedly connected to the flange of the test piece; the other end is a guide rail, which is matched with the guide groove 123 of the guide bracket 12;

[0014] The guide bracket 12 includes a bracket base plate 120, a bracket hydraulic rod 121, a bracket fixing rod 122, a guide groove 123, and a hydraulic rod connecting hole 124. The bracket base plate 120 is connected to the tail hatch 8. The guide groove 123 is connected to the bracket hydraulic rod 121 through the hydraulic rod connecting hole 124. The guide groove 123 and the bracket fixing rod 122 are rotatably connected to facilitate adjusting the length of the bracket hydraulic rod 121 to change the inclination angle of the guide groove 123.

[0015] The equivalent pipe-soil action system includes a plurality of equivalent soil action modules 13, a rear module fixing frame 14, a front module fixing frame 15, and a matching module control system; the equivalent soil action modules 13 are arranged on the rear module fixing frame 14 and the front module fixing frame 15; the rear module fixing frame 14 is fixedly connected to the rear end of the test piece 16, and the front module fixing frame 15 is fixedly connected to the front end of the test piece 16;

[0016] The hydraulic rod of the lateral hydraulic loading device 9 arranged at the front of the pressure cabin body is fixedly connected to the front module fixing frame 15; during unidirectional displacement loading, the hydraulic rod contact head of the lateral hydraulic loading device 9 arranged at the rear of the pressure cabin body is a spherical joint, and the hydraulic rod contact head always maintains contact with the rear module fixing frame 14 during the loading process. The actual displacement of the rear module fixing frame 14 and the unidirectional displacement of the hydraulic rod satisfy the trigonometric cosine relationship with respect to the guide groove inclination angle; during reciprocal displacement loading, the guide groove inclination angle is maintained at 0° by adjusting the length of the bracket hydraulic rod 121. The hydraulic rod of the lateral hydraulic loading device 9 arranged at the rear of the pressure cabin body is fixedly connected to the rear module fixing frame 14, and the actual displacement of the rear module fixing frame 14 is equal to the displacement of this hydraulic rod;

[0017] Each equivalent soil action module 13 includes a module frame 17 and a plurality of zero-stiffness hydraulic components 18 arranged between the module frame 17 and the test piece 16. Each module frame 17 is fixedly connected to the rear module fixing frame 14 or the front module fixing frame 15.

[0018] The zero-rigidity hydraulic component 18 includes a pressure-limiting valve 19, a contact plate 20, a hydraulic component push rod 180, a hydraulic component housing 181, a hydraulic component cylinder 182, a hydraulic component front hydraulic compartment 183, a hydraulic component rear hydraulic compartment 184, a hydraulic component moving seal ring 185, a hydraulic component seal ring 186, a micro hydraulic pump 187, a micro displacement sensor 188 and a micro differential pressure sensor 189; the contact plate 20 is fixed to the end of the hydraulic component push rod 180 and contacts the test piece 16; the hydraulic component push rod 180 is provided with an expanded diameter section, and the expanded diameter section is wrapped with a hydraulic component moving seal ring 185 for isolating the hydraulic component front hydraulic compartment 183 and the hydraulic component rear hydraulic compartment 184; the hydraulic pressure difference in the hydraulic component front hydraulic compartment 183 and the hydraulic component rear hydraulic compartment 184 acts on the hydraulic component moving seal ring 185, thereby pushing the hydraulic component push rod 180 to move left and right; the hydraulic component front hydraulic compartment The cabin 183 and the rear hydraulic cabin 184 of the hydraulic component are respectively connected to the hydraulic component cylinder 182 through hydraulic pipelines, and a micro hydraulic pump 187 for controlling the inflow and outflow of hydraulic oil is connected to the hydraulic pipeline. In addition, the rear hydraulic cabin 184 of the hydraulic component is also connected to the hydraulic component cylinder 182 through another hydraulic pipeline via a pressure-limiting valve 19. When the hydraulic pressure difference between the rear hydraulic cabin 184 of the hydraulic component and the front hydraulic cabin 183 of the hydraulic component exceeds the set pressure, the pressure-limiting valve 19 will start to guide the hydraulic oil in the rear hydraulic cabin 184 of the hydraulic component back to the hydraulic component cylinder 182, thereby ensuring that the hydraulic pressure difference between the rear hydraulic cabin 184 of the hydraulic component and the front hydraulic cabin 183 of the hydraulic component does not exceed the set pressure. The micro displacement sensor 188 is used to measure the displacement of the contact plate 20, and the micro differential pressure sensor 189 is used to measure the hydraulic pressure difference between the front hydraulic cabin 183 of the hydraulic component and the rear hydraulic cabin 184 of the hydraulic component.

[0019] There are multiple zero-stiffness hydraulic components 18 distributed in the same equivalent soil action module 13, and there is no physical interference between the contact plates 20. The resultant frictional resistance between the contact plates 20 and the test piece 16 corresponds to the axial soil spring force.

[0020] The exemplary test model includes a test piece 16 and flanges at both ends thereof. The two ends of the test piece 16 are fixedly connected to the front end and the rear end of the pressure chamber body through the flanges.

[0021] Furthermore, the pressure chamber body is provided with an exhaust hole 2 and a water supply hole 3. The exhaust hole 2 is opened when water is injected to discharge the gas in the pressure chamber body 1; it remains closed when pressurizing; and is opened when draining water after depressurization to form a free liquid surface in the chamber to ensure smooth drainage; the water supply hole 3 is used for water injection and drainage and is connected to the pump station and water tank through a pressure pipe.

[0022] Furthermore, the guide rail is detachable, which facilitates selection of a suitable guide rail for connection with the flange according to the inclination angle of the guide groove 123;

[0023] Furthermore, the hydraulic component push rod 180 has the same cross-section at both ends and passes through the hydraulic component housing 181. When immersed in a high-pressure water environment, it can automatically achieve axial balance.

[0024] Furthermore, the module frame 17 is a rounded rectangle. Four zero-stiffness hydraulic components 18 are distributed in the same equivalent soil action module 13 and are perpendicular to the four sides of the rounded rectangle. The length of the contact plate 20 is smaller than the diameter of the test specimen 16 to avoid physical interference between the four zero-stiffness hydraulic components 18. The combined frictional resistance of the four contact plates 20 and the test specimen 16 corresponds to the axial soil spring force.

[0025] Furthermore, both ends of the test piece 16 are fixedly connected to the head end mounting plate 10 and the tail end guide flange 11 fixed to the head end of the pressure chamber body through flanges, which penetrate the equivalent soil action module 13;

[0026] Furthermore, the measurement and control system includes an external water pressure measurement and control subsystem, a soil displacement loading measurement and control subsystem, an equivalent pipe-soil action module measurement and control subsystem and a test model measurement subsystem; the external water pressure measurement and control subsystem is matched with the pressure chamber system, and is used to control the water injection, pressurization and drainage operations of the pump station, and measure the water pressure inside the pressure chamber; the soil displacement loading measurement and control subsystem is matched with the soil displacement loading system, and is used to control the displacement excitation of the lateral hydraulic loading device, and collect the hydraulic and displacement data of the lateral hydraulic loading device; the equivalent pipe-soil action module measurement and control subsystem is matched with the equivalent pipe-soil action system, and is used to set the structural parameters of the zero-stiffness hydraulic parts and control the opening and closing of the pressure limiting valve, and collect the hydraulic and displacement data of the zero-stiffness hydraulic parts; the test model measurement subsystem is a matching system for arranging mechanical and deformation sensors on the test pieces, and is used to record the structural response of the example test model.

[0027] The present invention also provides a method for simulating equivalent pipe-soil interaction in a high-pressure water environment using the above-mentioned device, comprising the following steps:

[0028] Step 1: Develop a test plan

[0029] S1-1 Determine the test object parameters, including outer diameter, wall thickness, length, and material properties;

[0030] S1-2 Determine the load parameters, including external water pressure amplitude, soil conditions, soil displacement type and time history;

[0031] S1-3 calculates the nonlinear soil spring parameters per unit length, including vertical upward, vertical downward, horizontal rightward, horizontal leftward, and axial directions;

[0032] S1-4 determines the similarity ratio and produces the test piece 16;

[0033] Step 2: Determine the module layout plan

[0034] S2-1 Establish a discrete finite element model of the buried tubular structure;

[0035] S2-2 sets the spacing of soil springs and calculates the yield force P0 of each nonlinear soil spring;

[0036] S2-3 calculates the strain distribution of the tubular structure under the soil conditions and soil displacement;

[0037] S2-4 The spacing of soil springs increases from small to large, repeating S2-2 and S2-3;

[0038] S2-5 Determine the spacing of the nonlinear soil springs that meets the calculation accuracy requirements based on the convergence of the strain distribution;

[0039] Step 3: Equipment installation and debugging

[0040] Flanges are installed at both ends of the S3-1 test piece 16, and strain gauge sensors and acceleration sensors are arranged;

[0041] S3-2 assembles the equivalent soil action module 13 by means of the module frame 17 and the zero-stiffness hydraulic components 18;

[0042] S3-3 Install the equivalent soil action module 13 on the rear module fixing frame 14 and the front module fixing frame 15 according to the nonlinear soil spring arrangement spacing determined in step 2;

[0043] The S3-4 test piece 16 passes through the equivalent soil action module 13, and the flanges at both ends are fixedly connected to the rear module fixing frame 14 and the front module fixing frame 15;

[0044] S3-5 Adjust the hydraulic rod of the zero-rigidity hydraulic component 18 so that the contact plate 20 is in pressure-free contact with the test piece 16;

[0045] S3-6 installs tail hatch 8;

[0046] S3-7 fixes the guide bracket 12 according to the soil displacement type;

[0047] S3-8: Adjust the length of the hydraulic rod 121 of the guide bracket 12 to change the inclination angle of the guide groove 123 according to the type of soil displacement;

[0048] S3-9 Install the tail end guide flange 11 on the guide groove 123 of the guide bracket 12;

[0049] S3-10 connects the flange of the test piece 16 and the tail end guide flange 11;

[0050] S3-11 connects the flange of the test piece 16 and the head end mounting plate 10;

[0051] S3-12 The head end mounting plate 10 is fixed by the mounting ears on the inner wall of the pressure chamber body 1;

[0052] S3-13 The hydraulic rod of the lateral hydraulic loading device 9 provided at the front of the pressure cabin body is fixedly connected to the front module fixing frame 15;

[0053] S3-14 Determine the connection method between the hydraulic rod of the lateral hydraulic loading device 9 located at the rear of the pressure chamber and the rear module mounting bracket 14 according to the test plan. If unidirectional displacement loading is used, install the lateral hydraulic loading device 9 and adjust its hydraulic rod to ensure pressure-free contact with the rear module mounting bracket 14. If reciprocating displacement loading is used, securely connect the hydraulic rod of the lateral hydraulic loading device 9 to the rear module mounting bracket 14, and maintain the guide slot 123 tilt angle at 0°.

[0054] S3-15 connects the strain gauge sensor, acceleration sensor, differential pressure sensor, each miniature differential pressure sensor and each displacement sensor wire, installs the data connector at the data connector mounting hole 5, and connects to the external data acquisition instrument;

[0055] S3-16 installs the first hatch cover 7;

[0056] S3-17 debug all sensors and hydraulic devices;

[0057] Step 4: Water injection, pressurization and measurement

[0058] S4-1 Open the exhaust hole 2 and the water delivery hole 3;

[0059] S4-2 starts the pump station and fills the pressure chamber with water until a steady, bubble-free flow appears at the exhaust port 2;

[0060] S4-3 Close the exhaust hole 2 and continue to inject water until the water pressure in the pressure chamber 1 reaches the target value;

[0061] The S4-4 pump station and water delivery hole 3 are always kept open to maintain pressure;

[0062] S4-5 records the structural response of the test piece 16 during the pressurization process;

[0063] Step 5: Displacement loading and measurement

[0064] S5-1 starts one or two lateral hydraulic loading devices;

[0065] S5-2 performs displacement loading according to the test plan;

[0066] S5-3 records the pressure and displacement of the zero-stiffness hydraulic component 18 and the structural response of the test piece 16 during the displacement loading process.

[0067] The present invention has the following advantages due to the adoption of the above technical solution:

[0068] 1. The equivalent soil action module used simulates soil displacement loads without the need for a soil box or centrifuge. It is not restricted by factors such as soil conditions, soil preparation, test cost, and loading control, and is easy to meet test similarity.

[0069] 2. The zero-stiffness hydraulic components used simulate nonlinear soil springs, which directly correspond to the discrete finite element model. Their displacement-load curves meet the requirements of the specification and are easy to adjust according to test requirements.

[0070] 3. The soil displacement loading system used is capable of carrying out various types of soil displacement loads, including unidirectional displacement loading at different angles and horizontal reciprocating displacement excitation;

[0071] 4. The soil displacement loading system used can work in a high-pressure water environment and its parameters remain unchanged after being set, which facilitates the quantitative study of the pipe-soil interaction in a high-pressure water environment with high accuracy;

[0072] 5. The test equipment has a simple mechanical structure, is economical and convenient to manufacture, is easy to install and install, can be reused, and is suitable for experimental research and teaching. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 Front view of the test device

[0074] Figure 2 Top view of the test device

[0075] Figure 3 Side view of the test device

[0076] Figure 4 Top view of the internal components of the pressure chamber

[0077] Figure 5 Schematic diagram of lateral hydraulic loading device

[0078] Figure 6 Front view of guide bracket

[0079] Figure 7 Top view of guide bracket

[0080] Figure 8 Front view of the equivalent soil action module

[0081] Figure 9 Front view mid-section of zero-rigidity hydraulic components

[0082] Figure 10 Zero-stiffness hydraulic control principle diagram

[0083] Figure 11 Schematic diagram of load-displacement curve of zero-stiffness hydraulic components

[0084] Explanation of the numbers in the figure: 1-pressure chamber body; 2-exhaust hole; 3-water delivery hole; 4-lateral loading installation hole; 5-data connector installation hole; 6-base; 7-fore hatch; 8-stern hatch; 9-lateral hydraulic loading device; 10-fore end mounting plate; 11-stern end guide flange; 12-guide bracket; 13-equivalent soil action module; 14-rear module fixing frame; 15-front module fixing frame; 16-test piece; 17-module frame; 18-zero stiffness hydraulic component; 19-pressure limiting valve; 20-contact plate; 90-lateral hydraulic housing; 91-lateral hydraulic rod; 92-water pressure balance channel; 93-lateral front hydraulic chamber; 94-side Rear hydraulic compartment; 95-lateral front hydraulic hole; 96-lateral rear hydraulic hole; 97-lateral hydraulic sealing ring; 98-lateral water pressure compartment; 99-lateral hydraulic moving sealing ring; 120-bracket base plate; 121-bracket hydraulic rod; 122-bracket fixing rod; 123-guide groove; 124-hydraulic rod connecting hole; 180-hydraulic component push rod; 181-hydraulic component housing; 182-hydraulic component cylinder; 183-hydraulic component front hydraulic compartment; 184-hydraulic component rear hydraulic compartment; 185-hydraulic component moving sealing ring; 186-hydraulic component sealing ring; 187-micro hydraulic pump; 188-micro displacement sensor; 189-micro differential pressure sensor DETAILED DESCRIPTION

[0085] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0086] It should be noted that the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to these processes, methods, products or equipment.

[0087] The device for simulating equivalent pipe-soil interaction in a high-pressure water environment of the present invention comprises: a pressure chamber system, an equivalent pipe-soil interaction system, a soil displacement loading system, a measurement and control system, and an example test model.

[0088] The pressure chamber system includes a pressure chamber body 1, an exhaust hole 2, a water supply hole 3, a side loading mounting hole 4, a data connector mounting hole 5, a base 6, a bow hatch 7, a stern hatch 8 and a matching water tank and pump station. The exhaust hole 2 is opened when water is injected to discharge the gas in the pressure chamber body 1; it remains closed when pressurized; it is opened when draining after depressurization to form a free liquid surface in the chamber to ensure smooth drainage. The water supply hole 3 is used for water injection and drainage, and is connected to the pump station and water tank through a pressure pipe. A circumferential array of threaded holes is provided on the end face of the stern hatch 8 facing the interior of the pressure chamber body 1. Preferably, the pressure chamber system adopts the submarine pipeline complex load combined loading buckling test device of invention patents CN105424484B and CN105466791B.

[0089] The soil displacement loading system includes a lateral hydraulic loading device 9 , a head end mounting plate 10 , a tail end guide flange 11 and a guide bracket 12 .

[0090] The lateral hydraulic loading device 9 is equipped with a differential pressure sensor and a displacement sensor and is connected to the pressure chamber body 1 through the lateral loading mounting hole 4. The components of the lateral hydraulic loading device 9 include a lateral hydraulic housing 90, a lateral hydraulic rod 91, a lateral front hydraulic chamber 93, a lateral rear hydraulic chamber 94, a lateral hydraulic seal 97, a lateral water ballast chamber 98, a lateral hydraulic movable seal 99, and a supporting high-power hydraulic pump station. Preferably, the cross-sections of the lateral hydraulic rod 91 are identical at both ends, and a water pressure balance channel 92 is provided in the lateral hydraulic rod 91 to connect the pressure chamber body 1 and the lateral water ballast chamber 98. Regardless of the water pressure within the pressure chamber body 1, the water pressure balance channel 92 can effectively offset the thrust of the water pressure within the pressure chamber body 1 on the lateral hydraulic rod 91, thereby avoiding the pre-set hydraulic pressure difference between the lateral front hydraulic chamber 93 and the lateral rear hydraulic chamber 94. A lateral hydraulic movement seal 99 wraps around the expanded diameter section of the lateral hydraulic rod 91, isolating it from the front hydraulic compartment 93 and the rear hydraulic compartment 94. The front hydraulic compartment 93 and the rear hydraulic compartment 94, respectively, feature a front hydraulic port 95 and a rear hydraulic port 96. These ports are connected to a high-power hydraulic pump station via hydraulic pipelines for the flow of hydraulic oil. The differential pressure within the front and rear hydraulic compartments 93 and 94 acts on the lateral hydraulic movement seal 99, thereby driving the lateral hydraulic rod 91 in left and right motion.

[0091] The head-end mounting plate 10 is secured via mounting ears on the inner wall of the pressure chamber hull 1. The tail-end guide flange 11 has a flange at one end that is fixedly connected to the flange of the test piece; the other end is a guide rail that mates with the guide slot 123 of the guide bracket 12. Preferably, the guide rail is removable, allowing for easy selection of the appropriate guide rail for connection to the flange, depending on the inclination angle of the guide slot 123.

[0092] The guide bracket 12 comprises a bracket base plate 120, a bracket hydraulic rod 121, a bracket fixing rod 122, a guide slot 123, and a hydraulic rod connection hole 124. The bracket base plate 120 is connected to the tail hatch 8 via three threaded holes. The circumferential array of threaded holes on the end surface of the tail hatch 8 can be selected as mounting holes based on the desired guide rail layout. The guide slot 123 is connected to the bracket hydraulic rod 121 via the hydraulic rod connection hole 124. The guide slot 123 and bracket fixing rod 122 are pivotally connected, allowing for adjustment of the length of the bracket hydraulic rod 121 and the inclination angle of the guide slot 123.

[0093] The equivalent soil-pipe action system includes an equivalent soil action module 13, a rear module mounting frame 14, a front module mounting frame 15, and a supporting module control system. The equivalent soil action module 13 consists of a module frame 17 and a zero-stiffness hydraulic component 18. The equivalent soil action modules 13 are equidistantly spaced on the rear module mounting frame 14 and the rear module mounting frame 15 via threaded connections. One end of the rear module mounting frame 14 is fixedly connected to the left flange of the test specimen 16, while one end of the front module mounting frame 15 is fixedly connected to the right flange of the test specimen 16. During unidirectional displacement loading, the hydraulic rod contact head of the lateral hydraulic loading device 9 on the guide bracket 12 side is a spherical joint and maintains contact with the rear module mounting frame 14 throughout the loading process. The actual displacement of the rear module mounting frame 14 and the unidirectional displacement of the hydraulic rod satisfy a trigonometric cosine relationship with respect to the guide groove inclination angle. During reciprocating displacement loading, the hydraulic rod of the lateral hydraulic loading device 9 on the guide bracket 12 side is fixedly connected to the rear module mounting frame 14, maintaining the guide groove inclination angle at 0°. The actual displacement of the rear module fixing frame 14 is equal to the displacement of the hydraulic rod. The hydraulic rod of the lateral hydraulic loading device 9 on one side of the head end mounting plate 10 is fixedly connected to the front module fixing frame 15.

[0094] The zero-stiffness hydraulic component 18 consists of a pressure-limiting valve 19, a contact plate 20, a hydraulic push rod 180, a hydraulic housing 181, a hydraulic cylinder 182, a front hydraulic compartment 183, a rear hydraulic compartment 184, a hydraulic moving seal 185, a hydraulic seal 186, a micro hydraulic pump 187, a micro displacement sensor 188, and a micro differential pressure sensor 189. The contact plate 20 is mounted at the end of the hydraulic push rod 180, contacting the test specimen 16. Its length should be slightly smaller than the diameter of the test specimen 16 to prevent physical interference between the four zero-stiffness hydraulic components 18. The four contact plates 20 are made of the same material, and the combined frictional resistance with the test specimen 16 corresponds to the axial soil spring force. An expanded section is located in the middle of the hydraulic push rod 180, encased in a hydraulic moving seal 185 to isolate the front hydraulic compartment 183 from the rear hydraulic compartment 184. Preferably, the hydraulic push rod 180 has the same cross-section at both ends, passes through the hydraulic housing 181, and can automatically achieve axial balance when immersed in a high-pressure water environment. The hydraulic pressure difference within the hydraulic component front hydraulic chamber 183 and the hydraulic component rear hydraulic chamber 184 acts on the hydraulic component moving seal 185, thereby pushing the hydraulic component push rod 180 to move left and right. The hydraulic component front hydraulic chamber 183, the hydraulic component rear hydraulic chamber 184 and the hydraulic component cylinder 182 are connected by hydraulic pipelines, and the hydraulic pipelines pass through micro hydraulic pumps 187 to control the inflow and outflow of hydraulic oil. In addition, the hydraulic component rear hydraulic chamber 184 is also connected to the hydraulic component cylinder 182 via another hydraulic pipeline via the pressure-limiting valve 19. When the hydraulic pressure difference between the rear hydraulic compartment 184 of the hydraulic component and the front hydraulic compartment 183 of the hydraulic component exceeds the set pressure, the pressure limiting valve 19 will start to guide the hydraulic oil in the rear hydraulic compartment 184 of the hydraulic component back to the hydraulic component cylinder 182, thereby ensuring that the hydraulic pressure difference between the rear hydraulic compartment 184 of the hydraulic component and the front hydraulic compartment 183 of the hydraulic component does not exceed the set pressure.

[0095] According to the nonlinear soil spring model, each equivalent soil action module 13 has four zero-stiffness hydraulic components 18, one vertically downward, one vertically upward, one horizontally to the left, and one horizontally to the right. When the zero-stiffness hydraulic component 18 and the test piece 16 squeeze each other, their displacement (Δ)-load (P) curve satisfies the mechanical characteristics of a nonlinear soil spring. Preferably, the yield displacement Δ0 and yield force P0 of the soil spring are calculated based on soil conditions and the ALA-2001 design specification "Guidelines for the design of buried steelpipe." When Δ<Δ0, Δ and P exhibit a linear relationship; when Δ≥Δ0, P no longer increases with the increase of Δ, exhibiting a zero-stiffness characteristic. The implementation method is as follows: the micro displacement sensor 188 measures the displacement of the contact plate 20 in real time, and the micro differential pressure sensor 189 measures the differential pressure between the front hydraulic compartment 183 of the hydraulic component and the rear hydraulic compartment 184 of the hydraulic component in real time, and controls the oil volume of the front hydraulic compartment 183 of the hydraulic component and the rear hydraulic compartment 184 of the hydraulic component through the micro hydraulic pump 187 to satisfy the preset linear relationship; when the differential pressure between the front hydraulic compartment 183 of the hydraulic component and the rear hydraulic compartment 184 of the hydraulic component reaches the preset value, the pressure limiting valve is started to assist the micro hydraulic pump 187 to guide the hydraulic oil of the rear hydraulic compartment 184 of the hydraulic component back to the hydraulic cylinder 182, thereby ensuring that the differential pressure between the front hydraulic compartment 183 of the hydraulic component and the rear hydraulic compartment 184 of the hydraulic component remains unchanged under large displacement conditions.

[0096] The exemplary test model includes a test piece 16 and flanges at both ends. The test piece 16 is welded to the flanges. The test piece 16 is fixedly connected to the head mounting plate 10 and the tail guide flange 11 via the flanges, and extends through the equivalent soil action module 13.

[0097] The measurement and control system includes an external water pressure measurement and control subsystem, a soil displacement loading measurement and control subsystem, an equivalent pipe-soil action module measurement and control subsystem, and a test model measurement subsystem. The external water pressure measurement and control subsystem is matched with the pressure chamber system, and is used to control the water injection, pressurization and drainage operations of the pump station, and to measure the water pressure inside the pressure chamber. The soil displacement loading measurement and control subsystem is matched with the soil displacement loading system, and is used to control the displacement excitation of the lateral hydraulic loading device 9, and to measure the hydraulic pressure and displacement of the lateral hydraulic loading device 9. The equivalent pipe-soil action module measurement and control subsystem is matched with the equivalent pipe-soil action system, and is used to set the structural parameters of the zero-stiffness hydraulic component 18 and control the opening and closing of the pressure-limiting valve 19, and to measure the hydraulic pressure and displacement of the zero-stiffness hydraulic component 18. The test model measurement subsystem is a matching system for arranging mechanical and deformation sensors on the test piece 16, and is used to record the structural response of the test model.

[0098] A method for simulating equivalent pipe-soil interaction in a high-pressure water environment comprises the following steps:

[0099] Step 1: Develop a test plan

[0100] S1-1 Determine the test object parameters, including outer diameter, wall thickness, length, and material properties;

[0101] S1-2 Determine the load parameters, including external water pressure amplitude, soil conditions, soil displacement type and time history;

[0102] S1-3 calculates the nonlinear soil spring parameters per unit length, including vertical upward, vertical downward, horizontal rightward, horizontal leftward, and axial directions;

[0103] S1-4 determines the similarity ratio and produces the test piece 16.

[0104] Step 2: Determine the module layout plan

[0105] S2-1 Establish a discrete finite element model of the buried tubular structure;

[0106] S2-2 sets the spacing of soil springs and calculates the yield force P0 of each nonlinear soil spring;

[0107] S2-3 calculates the strain distribution of the tubular structure under the soil conditions and soil displacement;

[0108] S2-4 The spacing of soil springs increases from small to large, repeating S22 and S23;

[0109] S2-5 determines the maximum nonlinear soil spring spacing that meets the calculation accuracy requirements based on the convergence of the strain distribution;

[0110] Step 3: Equipment installation and debugging

[0111] Flanges are installed at both ends of the S3-1 test piece 16, and strain gauge sensors and acceleration sensors are arranged;

[0112] S3-2 assembles the equivalent soil action module 13 by means of the module frame 17 and the zero-stiffness hydraulic components 18;

[0113] S3-3 Install the equivalent soil action module 13 on the rear module fixing frame 14 and the front module fixing frame 15 according to the nonlinear soil spring arrangement spacing determined in step 2;

[0114] The S3-4 test piece 16 passes through the equivalent soil action module 13, and the flanges at both ends are fixedly connected to the rear module fixing frame 14 and the front module fixing frame 15;

[0115] S3-5 Adjust the hydraulic rod of the zero-rigidity hydraulic component 18 so that the contact plate 20 is in pressure-free contact with the test piece 16;

[0116] S3-6 installs tail hatch 8;

[0117] S3-7 selects a mounting hole from the threaded holes in the circumferential array on the end surface of the tail hatch cover 8 according to the soil displacement type, and fixes the guide bracket 12;

[0118] S3-8 adjusts the length of the hydraulic rod 121 of the guide bracket 12 according to the soil displacement type and changes the inclination angle of the guide groove 123;

[0119] S3-9 Install the tail end guide flange 11 on the guide groove 123 of the guide bracket 12;

[0120] S3-10 connects the flange of the test piece 16 and the tail end guide flange 11;

[0121] S3-11 connects the flange of the test piece 16 and the head end mounting plate 10;

[0122] S3-12 The head end mounting plate 10 is fixed by the mounting ears on the inner wall of the pressure chamber body 1;

[0123] S3-13 The hydraulic rod of the lateral hydraulic loading device 9 on one side of the head end mounting plate 10 is fixedly connected to the front module fixing frame 15.

[0124] S3-14: Determine the connection method between the hydraulic rod of the lateral hydraulic loading device 9 on the side of the guide bracket 12 and the rear module mounting frame 14 according to the test plan. If unidirectional displacement loading is required, install the lateral hydraulic loading device 9 and adjust its hydraulic rod to ensure pressure-free contact with the rear module mounting frame 14. If reciprocating displacement loading is required, securely connect the hydraulic rod of the lateral hydraulic loading device 9 on the side of the guide bracket 12 to the rear module mounting frame 14, and maintain the guide slot 123 at a 0° inclination angle.

[0125] S3-15 connects the strain gauge sensor, acceleration sensor, water pressure sensor, differential pressure sensor, and displacement sensor wires, installs a data connector at data connector mounting hole 5, and connects to an external data acquisition instrument;

[0126] S3-16 installs the first hatch cover 7;

[0127] S3-17 Debug all sensors and hydraulic devices.

[0128] Step 4: Water injection, pressurization and measurement

[0129] S4-1 Open the exhaust hole 2 and the water delivery hole 3;

[0130] S4-2 starts the pump station and fills the pressure chamber with water until a steady, bubble-free flow appears at the exhaust port 2;

[0131] S4-3 Close the exhaust hole 2 and continue to inject water until the water pressure in the pressure chamber 1 reaches the target value;

[0132] The S4-4 pump station and water delivery hole 3 are always kept open to maintain pressure;

[0133] S4-5 records the structural response of the test piece 16 during the pressurization process.

[0134] Step 5: Displacement loading and measurement

[0135] S5-1 starts the lateral hydraulic loading device;

[0136] S5-2 performs displacement loading according to the test plan;

[0137] S5-3 records the pressure and displacement of the zero-stiffness hydraulic component 18 and the structural response of the test piece 16 during the displacement loading process.

[0138] Step 6: Data storage and analysis

[0139] S6-1 save recorded data;

[0140] S6-2 Analyze the recorded data. If there is any abnormality, repeat steps 4 and 5.

[0141] Step 7: Pressure relief and drainage

[0142] The S7-1 pump station is working to relieve pressure;

[0143] S7-2 When the cabin pressure drops to zero, open the exhaust hole 2;

[0144] S7-3 Pump out the water in the cabin.

[0145] Step 8: Equipment disassembly and placement

[0146] S8-1 Turn off all power supplies;

[0147] S8-2 disassemble the equipment in the reverse order of step 3;

[0148] S8-2 placement device.

[0149] Example 1: Cross-fault submarine buried pipeline test

[0150] Long-distance submarine buried pipelines inevitably cross seismic fault zones, posing a significant risk of damage. Cross-fault submarine buried pipeline testing is used to study the buckling behavior of submarine buried pipelines under the combined effects of external water pressure and fault displacement. The implementation steps are as follows:

[0151] Step 1: Develop a test plan

[0152] S1-1 Determine the parameters of submarine pipelines, including outer diameter, wall thickness, length and material properties;

[0153] S1-2 Determine the load parameters, including external water pressure amplitude, soil conditions, fault crossing angle, fault dip, and fault displacement;

[0154] S1-3 calculates the nonlinear soil spring parameters per unit pipe length, including five directions: vertical upward, vertical downward, horizontal rightward, horizontal leftward, and axial;

[0155] S1-4 determines the similarity ratio and produces the test piece 16.

[0156] Step 2: Determine the module layout plan

[0157] S2-1 Establish a discrete finite element model of the submarine buried pipeline. The pipeline can use beam elements or pipe elements;

[0158] S2-2 arranges nonlinear soil springs on unit nodes. The spacing between soil springs is equal to the length of each pipe unit. Calculate the yield force P0 of each nonlinear soil spring.

[0159] S2-3 calculates the strain distribution of the tubular structure under the soil conditions and soil displacement;

[0160] S2-4 pipeline units change from small to large, repeating S22 and S23;

[0161] S2-5 determines the larger pipe unit that meets the calculation accuracy requirements based on the convergence of the strain distribution, that is, selects a larger nonlinear soil spring arrangement spacing.

[0162] Step 3: Equipment installation and debugging

[0163] Flanges are installed at both ends of the S3-1 test specimen 16, and strain gauge sensors are installed. For submarine pipelines buried across faults, strain gauge sensors should be placed in the middle section of the pipeline between every two equivalent soil action modules 13. Preferably, strain gauge sensors are attached along the length of the pipeline, with at least one sensor placed at each of the two intersections of the fault direction and the middle section to measure top and bottom bending strains.

[0164] S3-2 assembles the equivalent soil action module 13 by means of the module frame 17 and the zero-stiffness hydraulic components 18;

[0165] S3-3 Install the equivalent soil action module 13 on the rear module fixing frame 14 and the front module fixing frame 15 according to the nonlinear soil spring arrangement spacing determined in step 2;

[0166] The S3-4 test piece 16 passes through the equivalent soil action module 13, and the flanges at both ends are fixedly connected to the rear module fixing frame 14;

[0167] S3-5 Adjust the hydraulic rod of the zero-rigidity hydraulic component 18 so that the contact plate 20 is in pressure-free contact with the test piece 16;

[0168] S3-6 installs tail hatch 8;

[0169] S3-7 selects a mounting hole from the threaded holes in the circumferential array on the end surface of the tail hatch 8 according to the fault crossing angle, and fixes the guide bracket 12;

[0170] S3-8 adjusts the length of the hydraulic rod 121 of the guide support 12 according to the fault dip angle to change the inclination angle of the guide groove 123;

[0171] S3-9 Install the tail end guide flange 11 on the guide groove 123 of the guide bracket 12;

[0172] S3-10 connects the flange of the test piece 16 and the tail end guide flange 11;

[0173] S3-11 connects the flange of the test piece 16 and the head end mounting plate 10;

[0174] S3-12 The head end mounting plate 10 is fixed by the mounting ears on the inner wall of the pressure chamber body 1;

[0175] S3-13 The hydraulic rod of the lateral hydraulic loading device 9 on one side of the head end mounting plate 10 is fixedly connected to the front module fixing frame 15;

[0176] S3-14 Install the lateral hydraulic loading device 9 on one side of the guide bracket 12 and adjust its hydraulic rod to contact the rear module fixing bracket 14 without pressure;

[0177] S3-15 connects the strain gauge sensor, water pressure sensor, hydraulic pressure sensor and displacement sensor wires, installs the data connector at the data connector installation hole 5, and connects to the external data acquisition instrument;

[0178] S3-16 installs the first hatch cover 7;

[0179] S3-17 Debug all sensors and hydraulic devices.

[0180] Step 4: Water injection, pressurization and measurement

[0181] S4-1 Open the exhaust hole 2 and the water delivery hole 3;

[0182] S4-2 starts the pump station and fills the pressure chamber with water until a steady, bubble-free flow appears at the exhaust port 2;

[0183] S4-3 Close the exhaust hole 2 and continue to inject water until the water pressure in the pressure chamber 1 reaches the target value;

[0184] The S4-4 pump station and water delivery hole 3 are always kept open to maintain pressure;

[0185] S4-5 records the structural response of the test piece 16 during the pressurization process.

[0186] Step 5: Displacement loading and measurement

[0187] S5-1 starts the lateral hydraulic loading device;

[0188] S5-2 performs displacement loading. For fault displacement loading, the displacement amplitude of the startup loading should be the horizontal component of the fault displacement.

[0189] S5-3 records the pressure and displacement of the zero-stiffness hydraulic component 18 and the strain of the test piece 16 during the displacement loading process.

[0190] Step 6: Data storage and analysis

[0191] S6-1 save recorded data;

[0192] S6-2 Analyze the recorded data. If there is any abnormality, repeat steps 4 and 5.

[0193] Step 7: Pressure relief and drainage

[0194] The S7-1 pump station is working to relieve pressure;

[0195] S7-2 When the cabin pressure drops to zero, open the exhaust hole 2;

[0196] S7-3 Pump out the water in the cabin.

[0197] Step 8: Equipment disassembly and placement

[0198] S8-1 Turn off all power supplies;

[0199] S8-2 Disassemble the equipment in the reverse order of step 3;

[0200] S8-2 placement device.

[0201] Example 2: Dynamic response test of buried submarine pipeline under non-uniform excitation

[0202] Submarine pipelines are long-span, extended structures, and the soil conditions along their path vary significantly. The dynamic response test of submarine pipelines under non-uniform uniform excitation is used to study the effects of non-uniform soil displacement excitation along the pipeline path on its dynamic response. The implementation steps are as follows:

[0203] Step 1: Develop a test plan

[0204] S1-1 Determine the parameters of submarine pipelines, including outer diameter, wall thickness, length and material properties;

[0205] S1-2 Determine the load parameters, including the external water pressure amplitude, soil conditions along the pipeline, and the uniform displacement excitation time history;

[0206] S1-3 calculates the nonlinear soil spring parameters per unit length of the pipeline at different positions along the pipeline length, including vertical upward, vertical downward, horizontal rightward, horizontal leftward, and axial directions;

[0207] S1-4 determines the similarity ratio and produces the test piece 16.

[0208] Step 2: Determine the module layout plan

[0209] S2-1 Establish a discrete finite element model of the submarine buried pipeline. The pipeline can use beam elements or pipe elements;

[0210] S2-2 arranges the corresponding nonlinear soil springs according to the position of the unit nodes along the length of the pipeline. The spacing between the soil springs is the length of each pipeline unit. Calculate the yield force P0 of each nonlinear soil spring.

[0211] S2-3 calculates the strain distribution of the tubular structure under the soil conditions and soil displacement;

[0212] S2-4 pipeline units change from small to large, repeating S22 and S23;

[0213] S2-5 determines the larger pipe unit that meets the calculation accuracy requirements based on the convergence of the strain distribution, that is, selects a larger nonlinear soil spring arrangement spacing.

[0214] Step 3: Equipment installation and debugging

[0215] Flanges are installed at both ends of the S3-1 test specimen 16, where strain gauges and accelerometers are installed. For submarine buried pipelines with non-uniform excitation, strain gauges and accelerometers should be placed in the middle section of the pipeline between every two equivalent soil action modules 13. Preferably, strain gauges are attached along the length of the pipeline, with at least one placed at each of the two intersections of the fault direction and the middle section to measure the top and bottom bending strains. A single accelerometer is sufficient for each section.

[0216] S3-2 assembles the equivalent soil action module 13 by means of the module frame 16 and the zero-stiffness hydraulic components 18;

[0217] S3-3 Install the equivalent soil action module 13 on the rear module fixing frame 14 and the front module fixing frame 15 according to the nonlinear soil spring arrangement spacing determined in step 2;

[0218] The S3-4 test piece 16 passes through the equivalent soil action module 13, and the flanges at both ends are fixedly connected to the module fixing frame 14;

[0219] S3-5 Adjust the hydraulic rod of the zero-rigidity hydraulic component 17 so that the contact plate 19 is in pressure-free contact with the test piece 16;

[0220] S3-6 installs tail hatch 8;

[0221] S3-7 Select a horizontal mounting hole from the circumferential array of threaded holes on the end surface of the tail hatch 8 to fix the guide bracket 12;

[0222] S3-8: Adjust the length of the hydraulic rod of the guide bracket 12 so that the inclination angle of the guide groove 123 is zero;

[0223] S3-9 Install the tail end guide flange 11 on the guide groove 123 of the guide bracket 12;

[0224] S3-10 connects the flange of the test piece 16 and the tail end guide flange 11;

[0225] S3-11 connects the flange of the test piece 16 and the head end mounting plate 10;

[0226] S3-12 The head end mounting plate 10 is fixed by the mounting ears on the inner wall of the pressure chamber body 1;

[0227] S3-13 The hydraulic rod of the lateral hydraulic loading device 9 on one side of the head end mounting plate 10 is fixedly connected to the front module fixing frame 15;

[0228] S3-14 The hydraulic rod of the lateral hydraulic loading device 9 on one side of the guide bracket 12 is fixedly connected to the rear module fixing bracket 14;

[0229] S3-15 connects the strain gauge sensor, water pressure sensor, hydraulic pressure sensor and displacement sensor wires, installs the data connector at the data connector installation hole 5, and connects to the external data acquisition instrument;

[0230] S3-16 installs the first hatch cover 7;

[0231] S3-17 Debug all sensors and hydraulic devices.

[0232] Step 4: Water injection, pressurization and measurement

[0233] S4-1 Open the exhaust hole 2 and the water delivery hole 3;

[0234] S4-2 starts the pump station and fills the pressure chamber with water until a steady, bubble-free flow appears at the exhaust port 2;

[0235] S4-3 Close the exhaust hole 2 and continue to inject water until the water pressure in the pressure chamber 1 reaches the target value;

[0236] The S4-4 pump station and water delivery hole 3 are always kept open to maintain pressure;

[0237] S4-5 records the structural response of the test piece 16 during the pressurization process.

[0238] Step 5: Displacement loading and measurement

[0239] S5-1 starts the lateral hydraulic loading device;

[0240] S5-2 performs displacement loading. It should be noted that the uniform displacement excitation only acts on the pipe section close to the guide frame 12.

[0241] S5-3 records the pressure and displacement of the zero-stiffness hydraulic component 18 and the strain and acceleration of the test piece 16 during the displacement loading process.

[0242] Step 6: Data storage and analysis

[0243] S6-1 save recorded data;

[0244] S6-2 Analyze the recorded data. If there is any abnormality, repeat steps 4 and 5.

[0245] Step 7: Pressure relief and drainage

[0246] The S7-1 pump station is working to relieve pressure;

[0247] S7-2 When the cabin pressure drops to zero, open the exhaust hole 2;

[0248] S7-3 Pump out the water in the cabin.

[0249] Step 8: Equipment disassembly and placement

[0250] S8-1 Turn off all power supplies;

[0251] S8-2 Disassemble the equipment in the reverse order of step 3;

[0252] S8-2 placement device.

[0253] The above describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A device for simulating equivalent pipe-soil interaction in a high-pressure water environment, comprising: Pressure chamber system, equivalent pipe-soil interaction system, soil displacement loading system, measurement and control system, and sample test model, including: The pressure cabin system comprises a pressure cabin body (1), a side loading mounting hole (4), a forward cabin cover (7), a rear cabin cover (8), and a matching water tank and a pump station; The soil displacement loading system comprises a lateral hydraulic loading device (9), a tail end guide flange (11) and a guide bracket (12); There are two lateral hydraulic loading devices (9), which are respectively connected to the front and rear of the pressure cabin body; the components of the lateral hydraulic loading device (9) include a lateral hydraulic shell (90), a lateral hydraulic rod (91), a lateral front hydraulic cabin (93), a lateral rear hydraulic cabin (94), a lateral hydraulic sealing ring (97), a lateral water pressure cabin (98), a lateral hydraulic movable sealing ring (99) and a matching hydraulic pump station; one end of the lateral hydraulic rod (91) is located in the lateral water pressure cabin (98), and the other end is in contact with the rear module fixing frame (14) or the front module fixing frame (15), and a water pressure balance channel (92) is opened on the lateral hydraulic rod (91) to connect to the pressure cabin body (1) and lateral water pressure chamber (98); the lateral hydraulic rod (91) is provided with an expanded diameter section, a hydraulic chamber is provided around the expanded diameter section, and a lateral hydraulic movable sealing ring (99) is coated on the outside of the expanded diameter section, and the hydraulic chamber is separated into two parts of a lateral front hydraulic chamber (93) and a lateral rear hydraulic chamber (94) with variable volume by the lateral hydraulic movable sealing ring (99); the front hydraulic chamber (93) and the lateral rear hydraulic chamber (94) are respectively connected to the hydraulic pump station through hydraulic pipelines for the inflow and outflow of hydraulic oil; the hydraulic pressure difference in the front hydraulic chamber (93) and the lateral rear hydraulic chamber (94) acts on the lateral hydraulic movable sealing ring (99), thereby pushing the lateral hydraulic rod (91) to move; The lateral hydraulic loading device (9) is provided with a differential pressure sensor and a displacement sensor, the differential pressure sensor is used to measure the water pressure difference between the lateral front hydraulic compartment (93) and the lateral rear hydraulic compartment (94), and the displacement sensor is used to measure the displacement of the lateral hydraulic rod (91); One end of the tail end guide flange (11) is a flange plate fixedly connected to the flange of the test piece; the other end is a guide rail, which is matched and connected to the guide groove (123) of the guide bracket (12); The guide bracket (12) comprises a bracket base plate (120), a bracket hydraulic rod (121), a bracket fixing rod (122), a guide groove (123) and a hydraulic rod connecting hole (124); the bracket base plate (120) is connected to the tail hatch (8); the guide groove (123) is connected to the bracket hydraulic rod (121) via the hydraulic rod connecting hole (124); the guide groove (123) and the bracket fixing rod (122) are rotatably connected, so that the length of the bracket hydraulic rod (121) can be adjusted to change the inclination angle of the guide groove (123); The equivalent soil-pipe action system comprises a plurality of equivalent soil action modules (13), a rear module fixing frame (14), a front module fixing frame (15) and a matching module control system; the equivalent soil action modules (13) are arranged on the rear module fixing frame (14) and the front module fixing frame (15); the rear module fixing frame (14) is fixedly connected to the rear end of the test piece (16), and the front module fixing frame (15) is fixedly connected to the front end of the test piece (16); The hydraulic rod of the lateral hydraulic loading device (9) arranged at the front of the pressure cabin body is fixedly connected to the front module fixing frame (15); during unidirectional displacement loading, the hydraulic rod contact head of the lateral hydraulic loading device (9) arranged at the rear of the pressure cabin body is a spherical joint, and the hydraulic rod contact head always keeps in contact with the rear module fixing frame (14) during the loading process, and the actual displacement of the rear module fixing frame (14) and the unidirectional displacement of the hydraulic rod satisfy a trigonometric cosine relationship with respect to the guide groove inclination angle; during reciprocal displacement loading, the guide groove inclination angle is kept at zero degrees by adjusting the length of the bracket hydraulic rod (121), and the hydraulic rod of the lateral hydraulic loading device (9) arranged at the rear of the pressure cabin body is fixedly connected to the rear module fixing frame (14), and the actual displacement of the rear module fixing frame (14) is equal to the displacement of the hydraulic rod; Each equivalent soil action module (13) includes a module frame (17) and a plurality of zero-rigidity hydraulic components (18) arranged between the module frame (17) and the test piece (16), and each module frame (17) is fixedly connected to the rear module fixing frame (14) or the front module fixing frame (15); The zero-rigidity hydraulic component (18) comprises a pressure limiting valve (19), a contact plate (20), a hydraulic component push rod (180), a hydraulic component housing (181), a hydraulic component oil cylinder (182), a hydraulic component front hydraulic compartment (183), a hydraulic component rear hydraulic compartment (184), a hydraulic component moving seal ring (185), a hydraulic component seal ring (186), a micro hydraulic pump (187), a micro displacement sensor (188) and a micro differential pressure sensor (189); the contact plate (20) is fixed The hydraulic component push rod (180) is fixed at the end thereof and contacts the test piece (16); the hydraulic component push rod (180) is provided with an expanded diameter section, and the expanded diameter section is wrapped with a hydraulic component moving sealing ring (185) for isolating the hydraulic component front hydraulic compartment (183) and the hydraulic component rear hydraulic compartment (184); the hydraulic pressure difference in the hydraulic component front hydraulic compartment (183) and the hydraulic component rear hydraulic compartment (184) acts on the hydraulic component moving sealing ring (185), thereby pushing the hydraulic component push rod (180) to move left and right; The front hydraulic compartment (183) of the hydraulic component and the rear hydraulic compartment (184) of the hydraulic component are respectively connected to the hydraulic component cylinder (182) through hydraulic pipelines, and a micro hydraulic pump (187) for controlling the inflow and outflow of hydraulic oil is connected to the hydraulic pipelines; in addition, the rear hydraulic compartment (184) of the hydraulic component is also connected to the hydraulic component cylinder (182) through another hydraulic pipeline via a pressure limiting valve (19); when the hydraulic pressure difference between the rear hydraulic compartment (184) of the hydraulic component and the front hydraulic compartment (183) of the hydraulic component exceeds the set pressure, the hydraulic pressure is increased. When the pressure is applied, the pressure limiting valve (19) is activated to guide the hydraulic oil in the hydraulic compartment (184) of the hydraulic component back to the hydraulic cylinder (182), thereby ensuring that the hydraulic pressure difference between the hydraulic compartment (184) of the hydraulic component and the hydraulic compartment (183) of the hydraulic component does not exceed the set pressure; the micro displacement sensor (188) is used to measure the displacement of the contact plate (20), and the micro differential pressure sensor (189) is used to measure the hydraulic pressure difference between the hydraulic compartment (183) of the hydraulic component and the hydraulic compartment (184) of the hydraulic component; There are multiple zero-stiffness hydraulic components (18) distributed in the same equivalent soil action module (13), and no physical interference occurs between the contact plates (20). The resultant frictional resistance between the contact plates (20) and the test piece (16) corresponds to the axial soil spring action force. The exemplary test model includes a test piece (16) and flanges at both ends thereof, and the two ends of the test piece (16) are fixedly connected to the front end and the rear end of the pressure chamber body through the flanges.

2. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The pressure chamber body is provided with an exhaust hole (2) and a water delivery hole (3). The exhaust hole (2) is opened when water is injected to discharge the gas in the pressure chamber body (1); it is kept closed when pressurizing; it is opened when draining water after depressurization to form a free liquid surface in the chamber to ensure smooth drainage; the water delivery hole (3) is used for water injection and drainage, and is connected to the pump station and the water tank through a pressure pipe.

3. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The guide rail is detachable, and it is convenient to select a suitable guide rail for connection with the flange according to the inclination angle of the guide groove (123).

4. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The hydraulic component push rod (180) has the same cross-section at both ends and passes through the hydraulic component housing (181). It can automatically achieve axial balance when immersed in a high-pressure water environment.

5. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The module frame (17) is a rounded rectangle. There are four zero-rigidity hydraulic components (18) distributed in the same equivalent soil action module (13), which are perpendicular to the four sides of the rounded rectangle. The length of the contact plate (20) is smaller than the diameter of the test piece (16) to avoid physical interference between the four zero-rigidity hydraulic components (18). The friction resistance of the four contact plates (20) and the test piece (16) corresponds to the axial soil spring force.

6. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The two ends of the test piece (16) are fixedly connected to the head end mounting plate (10) and the tail end guide flange (11) fixed to the head end of the pressure chamber body through flanges, and the test piece (16) passes through the equivalent soil action module (13).

7. The device for simulating equivalent pipe-soil interaction under high-pressure water environment according to claim 1 is characterized in that: The measurement and control system includes an external water pressure measurement and control subsystem, a soil displacement loading measurement and control subsystem, an equivalent pipe-soil action module measurement and control subsystem, and a test model measurement subsystem; the external water pressure measurement and control subsystem is matched with the pressure chamber system, and is used to control the water injection, pressurization and drainage operations of the pump station, and measure the water pressure inside the pressure chamber; the soil displacement loading measurement and control subsystem is matched with the soil displacement loading system, and is used to control the displacement excitation of the lateral hydraulic loading device, and collect the hydraulic and displacement data of the lateral hydraulic loading device; the equivalent pipe-soil action module measurement and control subsystem is matched with the equivalent pipe-soil action system, and is used to set the structural parameters of the zero-stiffness hydraulic parts and control the opening and closing of the pressure-limiting valve, and collect the hydraulic and displacement data of the zero-stiffness hydraulic parts; the test model measurement subsystem is a matching system for arranging mechanical and deformation sensors on the test pieces, and is used to record the structural response of the example test model.

8. A method for simulating equivalent pipe-soil interaction in a high-pressure water environment using the apparatus of any one of claims 1 to 7, comprising the following steps: Step 1: Develop a test plan S1-1 Determine the test object parameters, including outer diameter, wall thickness, length, and material properties; S1-2 Determine the load parameters, including external water pressure amplitude, soil conditions, soil displacement type and time history; S1-3 calculates the nonlinear soil spring parameters per unit length, including vertical upward, vertical downward, horizontal rightward, horizontal leftward, and axial directions; S1-4 determines the similarity ratio and makes a test piece (16); Step 2: Determine the module layout plan S2-1 Establish a discrete finite element model of the buried tubular structure; S2-2 sets the spacing of soil springs and calculates the yield force P0 of each nonlinear soil spring; S2-3 calculates the strain distribution of the tubular structure under the soil conditions and soil displacement; S2-4 The spacing of soil springs increases from small to large, repeating S2-2) and S2-3); S2-5 Determine the spacing of the nonlinear soil springs that meets the calculation accuracy requirements based on the convergence of the strain distribution; Step 3: Equipment installation and debugging Flanges are installed at both ends of the S3-1 test piece (16) and strain gauge sensors and acceleration sensors are arranged; S3-2 assembles an equivalent soil action module (13) by means of a module frame (17) and a zero-rigidity hydraulic component (18); S3-3 installing the equivalent soil action module (13) on the rear module fixing frame (14) and the front module fixing frame (15) according to the nonlinear soil spring arrangement spacing determined in step 2; The S3-4 test piece (16) passes through the equivalent soil action module (13), and the flanges at both ends are fixedly connected to the rear module fixing frame (14) and the front module fixing frame (15); S3-5 adjusting the hydraulic rod of the zero-rigidity hydraulic component (18) so that the contact plate (20) and the test piece (16) are in pressure-free contact; S3-6 Install the tail hatch (8); S3-7 fixes the guide bracket (12) according to the soil displacement type; S3-8: adjusting the length of the support hydraulic rod (121) of the guide support (12) to change the inclination angle of the guide groove (123) according to the type of soil displacement; S3-9 Install the tail end guide flange (11) on the guide groove (123) of the guide bracket (12); S3-10 connects the flange of the test piece (16) and the tail end guide flange (11); S3-11 connects the flange of the test piece (16) and the head end mounting plate (10); S3-12 The head end mounting plate (10) is fixed via mounting ears on the inner wall of the pressure chamber body (1); S3-13 The hydraulic rod of the lateral hydraulic loading device (9) provided at the front of the pressure cabin body is fixedly connected to the front module fixing frame (15); S3-14 Determine the connection mode of the hydraulic rod of the lateral hydraulic loading device (9) provided at the rear of the pressure cabin body and the rear module fixing frame (14) according to the test plan; if it is unidirectional displacement loading, install the lateral hydraulic loading device (9) and adjust its hydraulic rod to have no pressure contact with the rear module fixing frame (14); if it is reciprocating displacement loading, the hydraulic rod of the lateral hydraulic loading device (9) is fixedly connected to the rear module fixing frame (14), and the inclination angle of the guide groove (123) is kept at zero degrees; S3-15 connects the strain gauge sensor, the acceleration sensor, the differential pressure sensor, each miniature differential pressure sensor and each displacement sensor wire, installs a data connector at the data connector mounting hole (5), and connects to an external data acquisition instrument; S3-16 Install the front hatch cover (7); S3-17 debug all sensors and hydraulic devices; Step 4: Water injection, pressurization and measurement S4-1 opens the exhaust hole (2) and the water delivery hole (3); S4-2 starts the pump station and fills the pressure chamber with water until a steady, bubble-free flow of water is observed from the exhaust port (2); S4-3 close the exhaust hole (2) and continue to inject water until the water pressure in the pressure chamber (1) reaches the target value; The S4-4 pump station and the water delivery hole (3) are always kept open to maintain pressure; S4-5 records the structural response of the test piece (16) during the pressurization process; Step 5: Displacement loading and measurement S5-1 starts one or two lateral hydraulic loading devices; S5-2 performs displacement loading according to the test plan; S5-3 records the pressure and displacement of the zero-stiffness hydraulic component (18) and the structural response of the test piece (16) during displacement loading.

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