Testing device for evaluating influence of slurry on pile foundation settlement after shield direct pile cutting

Abstract

The invention relates to the technical field of shield tunnels and grouting materials, in particular to a test device for evaluating the influence of grout on pile foundation settlement after shield direct pile cutting. The device comprises a model box, a model duct piece, a model shield, a pushing device, a model pile foundation, a synchronous grouting system and a data acquisition and analysis system, the model box is provided with a protection base, a semicircular hole and a semicircular hole; the model duct piece penetrates through the semicircular hole and is fixed on the protection base; the model shield penetrates through the semicircular hole to be nested on the outer wall of the model duct piece, and is connected with the protection base through a pushing device; the model pile foundation is arranged above the front end of the model shield; the model pile foundation is provided with a sensor, and the data acquisition and analysis system is connected with the sensor; the model shield is provided with a grouting pipe hole, and the synchronous grouting system is communicated with the grouting pipe hole. According to the method, an innovative semicircular structure is adopted in combination with the equivalent principle, materials and space are saved, stress and settlement behaviors of a model pile foundation are analyzed, and slurry optimization and pile foundation settlement amount minimization can be better achieved.

Description

Technical Field

[0001] The invention relates to the technical field of shield tunnels and grouting materials, and in particular to a test device for evaluating the influence of slurry on pile foundation settlement after direct pile cutting by a shield machine. Background Art

[0002] Shield tunneling, as one of the modern tunnel construction methods, is widely used in subway, railway, and highway tunnel projects due to its high efficiency and safety. During shield tunneling, existing pile foundation obstacles are unavoidable. The fastest and most cost-effective method is direct cutting. However, as a critical supporting component, the settlement of pile foundations after cutting is directly related to the stability and safety of the superstructure. Currently, research on direct shield cutting of pile foundations mainly focuses on the cutting process and the optimization of shield equipment performance, while relatively few systematic studies have been conducted on the settlement of pile foundations after cutting. On the other hand, although shield synchronous grouting technology is widely used to fill shield tail gaps and reinforce soil, and can reduce the settlement of pile foundations after cutting to a certain extent, there is still a lack of research that can evaluate the impact of grouting on the settlement of pile foundations after direct shield cutting.

[0003] Therefore, how to evaluate the impact of slurry on pile foundation settlement after direct shield cutting, so as to continuously optimize the slurry components and ratios, maximize the reduction of pile foundation settlement after direct shield cutting, and protect the stability and safety of the superstructure is an urgent problem that technical personnel in this field need to solve. Summary of the Invention

[0004] The invention provides a test device for evaluating the influence of slurry on pile foundation settlement after direct pile cutting by a shield machine, aiming to solve the deficiencies in the prior art.

[0005] The present invention provides a test device for evaluating the influence of slurry on pile foundation settlement after direct pile cutting by a shield machine, comprising: Model box, model segments, model shield, driving device, model pile foundation, synchronous grouting system, data acquisition and analysis system; The top of the model box is provided with an opening, and a protective base is provided around and at the bottom; the front side plate of the model box and the corresponding positions of the protective base are provided with semicircular holes, and the rear side plate of the model box and the corresponding positions of the protective base are provided with semicircular holes; The front end of the model tube segment passes through the semicircular holes of the protective base and the rear side plate of the model box, and the rear end cover of the model tube segment is fixed to the protective base; The front end of the model shield passes through the semicircular holes of the protective base and the front side plate of the model box and is nested in the outer wall of the model segment. The rear end cover of the model shield is connected to the protective base through a pushing device. The model pile foundation is arranged above the front end of the model shield; the model pile foundation is provided with a plurality of sensors, and the data acquisition and analysis system establishes a data transmission connection with the sensors; The model shield is provided with grouting pipe holes, and the synchronous grouting system is connected to the grouting pipe holes.

[0006] As a further improvement of the present invention, the model box is formed by integrally connecting side panels and a bottom panel on all four sides. The side panels and the bottom panel of the model box are both made of transparent materials. The model box is used to be filled with model soil.

[0007] As a further improvement of the present invention, the model shield is a semi-circular barrel structure matching the semi-circular hole, the model pipe segment is a semi-cylindrical barrel structure matching the semi-circular hole, a groove is provided on the outer wall of the model pipe segment, a sliding guide rail is connected in the groove, a slider is connected at the sleeve joint of the model shield, a sealing strip is provided on the side of the slider, the slider is cooperatively connected to the sliding guide rail, and the sealing strip is in close contact with the sliding guide rail.

[0008] As a further improvement of the present invention, the sensors provided on the model pile foundation include fiber grating strain sensors, soil pressure sensors, and load sensors. Several fiber grating strain sensors are evenly buried axially in the body of the model pile foundation, several soil pressure sensors are evenly installed along the outer side of the body of the model pile foundation, and a load sensor is installed in the center of the top of the model pile foundation.

[0009] As a further improvement of the present invention, the data acquisition and analysis system includes a data acquisition instrument for collecting the settlement, soil pressure value and upper additional load value of the model pile foundation collected by the fiber grating strain sensor, soil pressure sensor and load sensor; computer software, connected to the data acquisition instrument, for setting data acquisition parameters and performing real-time display, storage and subsequent analysis and drawing processing of the collected data; and a signal conditioner for amplifying and filtering the sensor signals.

[0010] As a further improvement of the present invention, the test device for evaluating the influence of slurry on pile foundation settlement after direct shield pile cutting also includes a cover plate and weights. The cover plate is arranged on the top of the model pile foundation, and a number of weights are evenly placed on the cover plate.

[0011] As a further improvement of the present invention, the pushing device includes an electric telescopic push rod, and both ends of the electric telescopic push rod are respectively installed on the protective base and the rear end cover of the model shield.

[0012] As a further improvement of the present invention, the synchronous grouting system includes a grouting pump and a composite grouting pipe. The output end of the grouting pump is connected to the grouting pipe hole of the model shield through the composite grouting pipe, and the grouting pump is fed with colored grouting liquid.

[0013] As a further improvement of the present invention, the synchronous grouting system also includes a cart, and the grouting pump is installed on the cart; the composite grouting pipe includes a PVC pipe and a rubber pipe, the front end of the PVC pipe passes through the grouting pipe hole of the model shield, the rear end of the PVC pipe is exposed and tightly connected to one end of the rubber pipe, and the other end of the rubber pipe is connected to the grouting pump.

[0014] As a further improvement of the present invention, a test device for evaluating the effect of slurry on pile foundation settlement after direct shield pile cutting comprises the following steps when performing a test operation: S1. Insert the front end of the model segment through the semicircular holes in the model box and the protective base, and secure the rear end of the model segment to the protective base. Insert the front end of the model shield through the semicircular holes in the model box and the protective base. Nest the model shield and the model segment together and install them in the model box using the slider and the sliding guide rail. Attach one end of the pusher to the protective base, and connect the other end to the rear cover of the model shield. S2. Install a PVC pipe into the grouting hole of the model shield and secure it tightly. Connect the exposed end of the PVC pipe to one end of the rubber tube. Connect the other end of the rubber tube to the grouting pump on the cart to form a synchronized grouting system. S3. Pour the pre-prepared model soil into the model box until it just covers the model segments. Fix the model pile foundation, which has several sensors installed on its surface and inside, above the front end of the model shield. Continue pouring the model soil until it just covers the model pile foundation. Then, cover it with a cover plate and place several weights. S4. Simultaneously start the pushing device and the synchronous grouting system, the data acquisition and analysis system's data acquisition instrument and computer software collect and analyze data from several sensors of the model pile foundation to obtain the model pile foundation settlement, the earth pressure value and the upper additional load value; S5. After one test is completed, part of the model soil is taken out and relevant tests are carried out to observe the diffusion and filling of the grouting liquid, and the test is repeated after adjusting the grouting liquid.

[0015] The beneficial effects of the present invention are as follows: the device combines the equivalent principle with an innovative semicircular structure, saving materials and space, and focusing on analyzing the stress and settlement behavior of the model pile foundation, providing relatively accurate test data support, and can better achieve slurry optimization and minimization of pile foundation settlement, thereby protecting the safety of the superstructure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an overall structural diagram of a test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by a shield machine according to the present invention; Figure 2 This is a detailed structural diagram of the front side plate of the model box and the corresponding protective base in the present invention; Figure 3This is a detailed structural diagram of the rear side panels of the model box and the corresponding protective base in the present invention; Figure 4 It is a structural cross-sectional view of the model segment in the present invention; Figure 5 It is a structural cross-sectional view of the model shield in the present invention; Figure 6 It is a structural diagram of the model segment in the present invention; Figure 7 It is a structural diagram of the model shield in the present invention; Figure 8 It is a structural diagram of the model pile foundation in the present invention.

[0017] The figure shows the names of the components and their corresponding marks: model box 1, protective base 2, semicircular hole 3, semicircular hole 4, model shield 5, rear end cover plate of model shield 6, pushing device 7, model segment 8, rear end cover plate of model segment 9, model pile foundation 10, fiber Bragg grating strain sensor 11, soil pressure sensor 12, load sensor 13, cover plate 14, weight 15, grouting pump 16, cart 17, PVC pipe 18, rubber pipe 19, data acquisition and analysis system 20, computer software 21, signal conditioner 22, grouting pipe hole 23, sliding guide rail 24, slider 25. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0019] like Figures 1 to 3 As shown, a test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by a shield machine according to the present invention comprises: Model box 1, model segments 8, model shield 5, pushing device 7, model pile foundation 10, synchronous grouting system, data acquisition and analysis system; The model box 1 has an opening at the top and a protective base 2 around and at the bottom; a semicircular hole 3 is provided at the corresponding positions of the front side plate of the model box 1 and the protective base 2, and a semicircular hole 4 is provided at the corresponding positions of the rear side plate of the model box 1 and the protective base 2; the semicircular hole 3 and the semicircular hole 4 are of equal size, that is, the inner radius of the semicircular hole 3 is equal to the radius of the semicircular hole 4; The front end of the model tube segment 8 passes through the semicircular hole 4 of the protective base 2 and the rear side plate of the model box 1, and the rear end cover plate 9 of the model tube segment 8 is fixed to the protective base 2 by bolts; The front end of the model shield 5 passes through the semicircular hole 3 of the protective base 2 and the front side plate of the model box 1, and is embedded in the outer wall of the model segment 8. The rear end cover plate 6 of the model shield 5 is connected to the protective base 2 through the pushing device 7; The model pile foundation 10 is arranged above the front end of the model shield 5; the model pile foundation 10 is provided with a number of sensors, and the data acquisition and analysis system establishes a data transmission connection with the sensors; the data acquisition and analysis system collects relevant variables of the model pile foundation 10 after synchronous grouting in real time, and can analyze different data results after multiple tests; The model shield 5 is provided with a grouting pipe hole 23 , and the synchronous grouting system is connected to the grouting pipe hole 23 .

[0020] The model box 1 is composed of four integrally connected side panels and a bottom panel. Both panels are made of transparent material and are used to fill the model box 1 with model soil. The bottom panel and side panels of the model box 1 are made of acrylic glass and can be filled with pre-prepared model soil. The holes on the bottom of the front and rear side panels and the corresponding protective base 2 are sized to match the model shield 5 and model segments 8, respectively. The protective base 2 is made of aluminum alloy, which facilitates the reinforcement and transportation of the model box 1.

[0021] like Figures 4 to 7 As shown, the model shield 5 is a semicircular sleeve barrel structure that matches the semicircular hole 3, and the model pipe segment 8 is a semi-cylindrical barrel structure that matches the semicircular hole 4. A groove is provided on the outer wall of the model pipe segment 8, and a sliding guide rail 24 is connected in the groove. A slider 25 is connected at the sleeve joint of the model shield 5, and a sealing strip is provided on the side of the slider 25. The slider 25 is matched with the sliding guide rail 24, and the sealing strip is in close contact with the sliding guide rail 24.

[0022] According to the equivalent principle, the model shield 5 and the model segment 8 respectively adopt a semi-circular sleeve barrel structure and a semi-cylindrical barrel structure made of stainless steel, and are both welded with a rear end cover plate 6 / 9 made of stainless steel; the model shield 5 is provided with three cylindrical through-hole grouting pipe holes 23 for synchronous grouting; three grooves are provided on the outer wall of the model segment 8 for welding three parallel sliding guide rails 24 along the axial direction, and six sliders 25 are correspondingly welded at the joint of the model shield 5. The shape and size of the slider 25 match the sliding guide rail 24 to ensure that the model segment 8 and the model shield 5 can move smoothly without deviation or detachment. At the same time, a rubber sealing strip is provided on the side of the slider 25. When the slider 25 slides on the sliding guide rail 24, the sealing strip is in close contact with the sliding guide rail 24 to prevent slurry or debris from entering the interior of the model segment 8 and the model shield 5 (the influence of the groove on synchronous grouting is negligible).

[0023] like Figure 8As shown, the sensors installed on the model pile foundation 10 include fiber Bragg grating strain sensors 11, soil pressure sensors 12, and load sensors 13. Several fiber Bragg grating strain sensors 11 are evenly embedded along the axial direction within the model pile foundation 10, several soil pressure sensors 12 are evenly installed along the outer side of the model pile foundation 10, and a load sensor 13 is installed at the center of the top of the model pile foundation 10. The fiber Bragg grating strain sensors 11 are used to obtain settlement data of the model pile foundation 10, the soil pressure sensors 12 are used to obtain soil pressure data on the model pile foundation 10, and the load sensor 13 is used to obtain load data applied to the top of the model pile foundation 10.

[0024] The data acquisition and analysis system includes a data acquisition instrument 20 for collecting the settlement, soil pressure and upper additional load values ​​of the model pile foundation 10 collected by the fiber Bragg grating strain sensor 11, the soil pressure sensor 12 and the load sensor 13; computer software 21, connected to the data acquisition instrument 20, for setting data acquisition parameters and performing real-time display, storage and subsequent analysis and drawing processing of the collected data; and a signal conditioner 22 for amplifying, filtering and other processing of the sensor signals to improve the signal quality.

[0025] The test apparatus for evaluating the effect of slurry on pile foundation settlement after shield direct pile cutting also includes a cover plate 14 and weights 15. The cover plate 14 is placed on top of the model pile foundation 10, and a number of weights 15 are evenly placed on the cover plate 14. The cover plate 14 and the evenly placed weights 15 above the model pile foundation 10 simulate the top load of the model pile foundation 10.

[0026] The propulsion mechanism 7 includes electrically retractable push rods, each mounted on the protective base 2 and the rear end cover 6 of the model shield 5. This mechanism drives the model shield 5 axially, thereby simulating the shield tunneling process that creates a gap at the shield tail. Specifically, the propulsion mechanism 7 comprises four electrically retractable push rods, each symmetrically mounted on the protective base 2 and the rear end cover 6 of the model shield 5. These push rods are made of rigid material and resist deformation, ensuring that they can retract and extend to drive the model shield 5 axially.

[0027] The synchronous grouting system includes a grouting pump 16 and a composite grouting pipe. The output end of the grouting pump 16 is connected to the grouting pipe hole 23 of the model shield 5 through the composite grouting pipe. The grouting pump 16 is fed with colored grouting liquid. Figure 5 As shown, the model shield 5 is evenly distributed with three grouting holes 23. Three composite grouting pipes are also provided, each connected to a grouting hole 23. All three composite grouting pipes are connected to the output of a grouting pump 16. Food coloring is added to the grouting liquid to give it a distinct color, facilitating soil sampling and observation. After the propulsion device 7 is activated, the grouting pump 16 inputs the grouting liquid into the composite grouting pipes, which are then synchronously output through the grouting holes 23 at the front end of the model shield 5.

[0028] The synchronous grouting system also includes a trolley 17, and the grouting pump 16 is installed on the trolley 17. The grouting pump 16 can be moved by pushing the trolley 17, which is convenient for adjusting the position of the grouting pump 16 during the test; the composite grouting pipe includes a PVC pipe 18 and a rubber pipe 19. The front end of the PVC pipe passes through the grouting pipe hole 23 of the model shield 5, and the rear end of the PVC pipe is exposed and tightly connected to one end of the rubber pipe 19. The other end of the rubber pipe 19 is connected to the grouting pump 16.

[0029] The composite grouting pipe adopts a detachable structure. The composite grouting pipe consists of a PVC pipe 18 and a rubber pipe. The front end of the PVC pipe 18 (slurry output end) can just pass through the cylindrical through-hole grouting pipe hole 23 of the model shield 5. The rear end is exposed and tightly connected to one end of the rubber pipe 19 through a connecting ring. The other end of the rubber pipe 19 is connected to the grouting pump 16. The PVC pipe 18 is sealed and fixed by setting a detachable sealing ring and a fixing ring.

[0030] The test device for evaluating the effect of slurry on pile foundation settlement after shield direct pile cutting includes the following steps when performing the test operation: S1. Insert the front end of the model segment 8 through the semicircular hole 4 in the model box 1 and the protective base 2, and bolt the rear end of the model segment 8 to the protective base 2. Insert the front end of the model shield 5 through the semicircular hole 3 in the model box 1 and the protective base 2. Using the slider 25 and the sliding guide rail 24, nest the model shield 5 and the model segment 8 together and install them in the model box 1. Install one end of the pusher 7 symmetrically on the protective base 2, and connect the other end to the rear end cover 6 of the model shield 5. S2. Install the PVC tube 18 into the grouting hole 23 of the shield model 5, and seal and fix the PVC tube 18 through a removable sealing ring and a fixing ring. Connect the exposed end of the PVC tube 18 to one end of the rubber tube 19, and the other end of the rubber tube 19 to the grouting pump 16 on the cart 17 to form a synchronous grouting system. S3. Pour the pre-prepared model soil into the model box 1 until it just covers the model segments 8. Then, secure the model pile foundation 10, equipped with several sensors (fiber Bragg grating strain sensor 11, soil pressure sensor 12, load sensor 13) mounted on its surface and interior, above the front end of the model shield 5. Continue pouring model soil until it just covers the model pile foundation 10. Then, close the cover plate 14 and place several weights 15. S4. Simultaneously start the pushing device 7 and the synchronous grouting system, the pushing device 7 pushes the shield model 5 to move, while the grouting pump 16 outputs the grouting liquid, the data acquisition and analysis system data acquisition instrument and computer software collect and analyze data from several sensors of the model pile foundation 10, and obtain the model pile foundation settlement, the earth pressure value and the upper additional load value; S5. After one test is completed, part of the model soil is taken out and relevant tests are carried out to observe the diffusion and filling of the grouting liquid. The composition and proportion of the grouting liquid are adjusted and the test is repeated.

[0031] This invention installs several types of sensors on a model pile foundation 10 and simulates the synchronous grouting process during shield tunneling to monitor and analyze relevant variable data of the model pile foundation 10, thereby evaluating the effect of slurry on pile foundation settlement. Incorporating the equivalent principle and employing an innovative semicircular structure, this method saves material and space, while focusing on analyzing the stress and settlement behavior of the model pile foundation 10. This provides relatively accurate test data support, enabling slurry optimization and minimization of pile foundation settlement, thereby protecting the superstructure.

[0032] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling, characterized in that: include: Model box (1), model segment (8), model shield (5), pushing device (7), model pile foundation (10), synchronous grouting system, data acquisition and analysis system; The model box (1) has an opening at the top, and a protective base (2) is provided around and at the bottom; a semicircular hole (3) is provided at the corresponding positions of the front side plate of the model box (1) and the protective base (2); and a semicircular hole (4) is provided at the corresponding positions of the rear side plate of the model box (1) and the protective base (2); The front end of the model tube segment (8) passes through the semicircular hole (4) of the protective base (2) and the rear side plate of the model box (1), and the rear end cover plate (9) of the model tube segment (8) is fixed to the protective base (2); The front end of the model shield (5) passes through the semicircular hole (3) of the protection base (2) and the front side plate of the model box (1), and is nested in the outer wall of the model segment (8); the rear end cover (6) of the model shield (5) is connected to the protection base (2) via a pushing device (7); The model pile foundation (10) is arranged above the front end of the model shield (5); the model pile foundation (10) is provided with a plurality of sensors, and the data acquisition and analysis system establishes a data transmission connection with the sensors; The model shield (5) is provided with a grouting pipe hole (23), and the synchronous grouting system is connected to the grouting pipe hole (23).

2. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: The model box (1) is formed by integrally connecting side panels and a bottom panel on all four sides; the side panels and the bottom panel of the model box (1) are both made of transparent materials; and the model box (1) is used to be filled with model soil.

3. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: The model shield (5) is a semicircular sleeve barrel structure matching the semicircular hole (3); the model pipe segment (8) is a semi-cylindrical barrel structure matching the semicircular hole (4); a groove is provided on the outer wall of the model pipe segment (8); a sliding guide rail (24) is connected in the groove; a slider (25) is connected at the sleeve joint of the model shield (5); a sealing strip is provided on the side of the slider (25); the slider (25) is matched and connected to the sliding guide rail (24), and the sealing strip is in close contact with the sliding guide rail (24).

4. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: The sensors provided on the model pile foundation (10) include a fiber Bragg grating strain sensor (11), a soil pressure sensor (12), and a load sensor (13). A plurality of fiber Bragg grating strain sensors (11) are evenly buried along the axial direction in the pile body of the model pile foundation (10), a plurality of soil pressure sensors (12) are evenly installed along the outer side of the pile body of the model pile foundation (10), and a load sensor (13) is installed at the center of the pile top of the model pile foundation (10).

5. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 4, characterized in that: The data acquisition and analysis system includes a data acquisition instrument (20) for collecting the settlement, soil pressure value and upper additional load value of the model pile foundation (10) collected by the fiber optic Bragg grating strain sensor (11), the soil pressure sensor (12) and the load sensor (13); Computer software (21) is connected to the data acquisition instrument (20) and is used to set data acquisition parameters and perform real-time display, storage, and subsequent analysis and drawing processing on the collected data; a signal conditioner (22) is used to amplify and filter the sensor signal.

6. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: It also includes a cover plate (14) and weights (15). The cover plate (14) is arranged on the top of the model pile foundation (10), and a plurality of weights (15) are evenly placed on the cover plate (14).

7. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: The pushing device (7) comprises an electric telescopic push rod, and the two ends of the electric telescopic push rod are respectively mounted on the protective base (2) and the rear end cover plate (6) of the model shield (5).

8. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 1, characterized in that: The synchronous grouting system comprises a grouting pump (16) and a composite grouting pipe. The output end of the grouting pump (16) is connected to the grouting pipe hole (23) of the model shield (5) through the composite grouting pipe. The grouting pump (16) is fed with colored grouting liquid.

9. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to claim 8, characterized in that: The synchronous grouting system also includes a trolley (17), and the grouting pump (16) is installed on the trolley (17); the composite grouting pipe includes a PVC pipe (18) and a rubber pipe (19), the front end of the PVC pipe passes through the grouting pipe hole (23) of the model shield (5), the rear end of the PVC pipe is exposed and tightly connected to one end of the rubber pipe (19), and the other end of the rubber pipe (19) is connected to the grouting pump (16).

10. The test device for evaluating the effect of slurry on pile foundation settlement after direct pile cutting by shield tunneling according to any one of claims 1 to 9, characterized in that: When performing the test operation, the following steps are included: S1. The front end of the model segment (8) is passed through the semicircular hole (4) of the model box (1) and the protective base (2), and the rear end of the model segment (8) is fixed to the protective base (2). The front end of the model shield (5) is passed through the semicircular hole (3) of the model box (1) and the protective base (2). The model shield (5) and the model segment (8) are nested together and installed in the model box (1) through the cooperation of the slider (25) and the sliding guide rail (24). One end of the pushing device (7) is installed on the protective base (2), and the other end is connected to the rear end cover (6) of the model shield (5); S2. Install a PVC tube (18) into the grouting hole (23) of the shield model (5) and seal it securely. Connect the exposed end of the PVC tube (18) to one end of the rubber tube (19). The other end of the rubber tube (19) is connected to the grouting pump (16) on the cart (17) to form a synchronous grouting system. S3. Pour the pre-prepared model soil into the model box (1) until it just covers the model segments (8), fix the model pile foundation (10) with several sensors installed on the surface and inside at the top of the front end of the model shield (5), continue to pour the model soil until it just covers the model pile foundation (10), cover it with a cover plate (14) and place several weights (15); S4. Simultaneously start the pushing device (7) and the synchronous grouting system, the data acquisition and analysis system data acquisition instrument and computer software to collect and analyze the data of several sensors of the model pile foundation (10), and obtain the model pile foundation settlement, the soil pressure value and the upper additional load value; S5. After one test is completed, part of the model soil is taken out and relevant tests are carried out to observe the diffusion and filling of the grouting liquid, and the test is repeated after adjusting the grouting liquid.

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