A grouting pressure and soil layer action influence under fluid loss rate experimental device and method

Abstract

This invention discloses an experimental method and apparatus for measuring water loss rate under the influence of grouting pressure and soil layer action. The method includes the following steps: Step S1: Insert the experimental soil layer into the bottom of the pressure tank; Step S2: Adjust the height of the filter screen so that the bottom surface of the filter screen just contacts the experimental soil layer; Step S3: Pour freshly mixed grout onto the filter screen and measure the mass of the grout at this time, recording it as m0; Step S4: Use an air compressor to simulate the actual grouting pressure, applying a constant pressure to the grout to stabilize the pressure value; Step S5: When the pressure reaches X MPa, the pressure relief valve begins to release pressure, and free water flows into the water receiving container from the outlet; Step S6: Continue to maintain constant pressure loading and record the change in water volume in the water receiving container after Y minutes of pressurization. This invention achieves the regulation of the input air pressure of the experimental tank through a stable pressure input and an air intake pressure regulating device and corresponding pressure gauge readings on the experimental tank, thereby simulating the grouting pressure in actual shield tunnel construction.

Description

Technical Field

[0001] This invention relates to the field of experimental measurement devices and methods for synchronous grouting water loss rate, and in particular to an experimental device and method for measuring the water loss rate of synchronous grouting slurry during shield tunneling under the influence of grouting pressure and soil layer action. Background Technology

[0002] With the continuous development of urban transportation in my country, the demand for urban tunnel construction continues to increase. Shield tunneling, with its advantages of minimal disturbance, high safety, and rapid construction, has been increasingly widely applied in urban tunnel construction. Although shield tunneling greatly reduces the disturbance to the surrounding surface, the dimensional differences between the shield cutting blades and the shield body inevitably create gaps between the excavated strata and the shield body. Currently, synchronous grouting behind the tunnel wall is commonly used to fill these gaps. Specifically, during the tunneling process, after the tunnel segments are assembled, a grouting system injects a properly proportioned, high-performance grout with a certain early strength into the gap between the tunnel segments and the soil. After the grout hardens, it forms a cohesive system with the tunnel segments and the soil, effectively filling the gaps between the strata and the shield tail, and reducing ground deformation caused by tunnel construction.

[0003] However, during actual shield tunnel construction, the presence of the overlying soil inevitably causes the grout to flow into the soil, especially when the soil has a high permeability coefficient and the grout is thin. The grout loss is even more likely in such cases. The grouting pressure further exerts a pushing effect on the grout, exacerbating the loss. Excessive grout loss will affect the filling effect of the shield tail gap, and the resulting voids will still cause ground disturbance and deformation. Generally, grout loss depends primarily on the grout's water loss rate; therefore, the laboratory typically uses the grout bleeding rate index to characterize the static water loss of the grout.

[0004] The problem with traditional techniques is that they neglect the influence of grouting pressure and soil layer action on grout water loss during dynamic construction, leading to discrepancies between experimental results and engineering applications. Therefore, it is necessary to innovate and improve the design of an experimental device and method for testing the water loss rate of synchronous grouting grout during shield tunneling under the influence of grouting pressure and soil layer action, based on actual construction conditions. Summary of the Invention

[0005] This invention provides an experimental device and method for measuring the water loss rate of grouting slurry during shield tunneling under the influence of grouting pressure and soil layer action. The aim is to simulate the actual grouting environment and measure the water loss rate of synchronous grouting under the coupled influence of grouting pressure and soil layer action by adjusting different parameters.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] An experimental method for measuring water loss rate under the influence of grouting pressure and soil layer action includes the following steps:

[0008] Step S1: Fill the bottom of the pressure tank with the experimental soil layer (saturated sand or mudstone);

[0009] Step S2: Adjust the height of the filter screen so that the bottom surface of the filter screen just touches the experimental soil layer;

[0010] Step S3: Pour the freshly mixed slurry onto the filter screen and measure the mass of the slurry at this time, which is recorded as m0;

[0011] Step S4: Using an air compressor, simulate the actual grouting pressure and apply constant pressure to the grout to stabilize the pressure value;

[0012] Step S5: When the pressure reaches X MPa, where X is a positive real number not exceeding 2, the pressure relief valve starts to release pressure, and free water flows from the outlet into the water receiving container;

[0013] Step S6: Continue to maintain constant pressure loading and record the change in water volume in the water receiving container at time Ymin after pressurization. Y is a positive real number not exceeding 120, denoted as my, where y is a positive real number not exceeding 2.

[0014] As a preferred approach, X can be 0.1, 0.15, or 0.2.

[0015] As a preferred option, Y can be 5, 10, 15, or 20.

[0016] As a preferred method, an airtightness check is performed before the experiment begins: connect the apparatus in the order of the experiment, turn on the air compressor, open the outlet valve, observe the changes in the pressure gauge readings of the outlet pressure gauge and the pressure gauge of the air inlet regulating device of the experimental barrel, and check whether there is any leakage at each joint in turn.

[0017] Adjust the intake pressure regulating device and observe whether the readings of the two pressure gauges are stable. After they are stable, close the air compressor outlet valve, open the exhaust valve of the test barrel, and exhaust the air to bring the pressure gauge readings back to zero. If the readings are unstable, check and adjust them in time.

[0018] The second aspect of the present invention provides an experimental device for water loss rate under the influence of grouting pressure and soil layer action, including a pressure input device and a sealing experimental device. The pressure input device includes an air compressor, an outlet pressure regulating device, an outlet pressure gauge, and an air pressure pipe. The sealing experimental device includes a top cover and an experimental barrel.

[0019] The air compressor body is equipped with an outlet pressure regulating device, an outlet valve, and an outlet pressure gauge. The air pressure pipe is connected to the outlet valve. The top cover is equipped with three connection holes, namely the first connection hole, the second connection hole, and the third connection hole. The first connection hole is used to connect the inlet pressure regulating device, the second connection hole is used to connect the safety valve, and the third connection hole is used to connect the exhaust device.

[0020] The intake pressure regulating device has an upper threaded hole and a lower threaded hole in the vertical direction. The upper threaded hole is connected to the connector of the air pressure pipe, and the lower threaded hole is connected to the top cover through a connector. The intake pressure regulating device is equipped with an intake pressure gauge.

[0021] The experimental barrel is equipped with an adjustable height filter device, which includes a filter and a lifting device. The lifting device is connected to the filter to control the height of the filter. The experimental barrel is filled with slurry and soil, which are respectively a slurry layer and a soil layer.

[0022] As a preferred method, the outlet pressure regulating device is a pressure regulating ball valve, and an outlet valve is also installed on the outlet pipe. The outlet pipe and the pressure pipe are connected by a flange.

[0023] As a preferred embodiment, the top cover has a connecting slot on its edge, and the experimental barrel has a connecting seat on its body. The connecting seat is connected to the vertical bolt rod, and the vertical bolt rod is engaged with a nut to connect the top cover to the experimental barrel.

[0024] As a preferred embodiment, the experimental barrel is equipped with a water outlet at the bottom, and a pressure relief valve is installed at the water outlet. As a preferred embodiment, the air compressor is a small air pump type with a range of 0-1.2 MPa and an accuracy of 0.05 MPa, and the air compressor is equipped with casters at the bottom for easy movement.

[0025] As a preferred method, a filter screen is placed between the slurry layer and the soil layer, and the filter screen contacts the experimental soil layer placed below the slurry layer, forming a barrier between the slurry layer and the soil layer.

[0026] The present invention has at least the following beneficial effects:

[0027] 1. The pressure input is stabilized by adjusting the air compressor's outlet valve. The air pressure input to the test chamber is further controlled by the air inlet pressure regulating device and the corresponding pressure gauge reading on the test chamber, thereby simulating the grouting pressure in actual shield tunnel construction.

[0028] 2. Using the experimental bucket device and pressure relief valve, different grouting slurries and different soil layers can be loaded according to actual conditions, while also considering the water pressure in the soil layer. Under pressure-bearing conditions, the effect of different stratum parameters on the grouting water loss rate is measured. The adjustable height filter device inside the experimental bucket can meet the requirements for determining the grout water loss rate under working conditions of soil layers (gravel layers) of different thicknesses.

[0029] 3. By installing safety valves and venting devices, the safety of the entire device is ensured.

[0030] 4. The air pressure pipe connection and the air pressure regulating device, safety valve, exhaust device and pressure relief valve on the experimental barrel are easy to disassemble, reducing the footprint and enabling recycling.

[0031] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0032] The invention will now be described in more detail using exemplary embodiments with reference to the accompanying drawings, in which different features of the exemplary embodiments may be combined with each other as needed, based on the above description. In particular, if the effect of an individual feature is necessary for a particular application, these features may be added to existing embodiments based on the above description. Conversely, if the technical effect of an individual feature is not important for a particular application, these features may be omitted from existing embodiments. Similar, identical, and functionally identical elements in the drawings are given the same reference numerals within the appropriate scope.

[0033] Figure 1 A schematic diagram of the overall structure of the experimental device for measuring water loss rate under the coupled influence of grouting pressure and soil layer action during synchronous grouting.

[0034] Figure 2 This is a partial enlarged view of the air compressor's outlet device;

[0035] Figure 3 This is an enlarged view of the top cover of the experimental barrel and its connecting parts;

[0036] Figure 4 This is a schematic diagram of the front structure of the pressure relief valve;

[0037] Figure 5 This is a schematic diagram of the side structure of the pressure relief valve;

[0038] Figure 6 This is one of the schematic diagrams of the interior of the sealed experimental barrel;

[0039] Figure 7 This is the second schematic diagram of the interior of the sealed experimental barrel;

[0040] Figure 8 This is a schematic diagram of the angle adjustment device.

[0041] Figure 9 A schematic diagram of the bucket restraint frame and its connection relationship;

[0042] Figure 10 This is a schematic diagram of the rotating connection of the bolt adjustment component;

[0043] In the diagram, 1-Air compressor, 2-Automatic air pressure switch, 3-Pressure regulating ball valve, 4-Outlet pressure gauge, 5-Outlet valve, 6-Flange, 7-Air pressure pipe, 8-Top cover, 9-Experimental barrel, 10-Fastening bolt, 11-Inlet pressure regulating device, 12-Safety valve, 13-Exhaust device, 14-Barrel outlet, 15-Pressure relief valve, 16-Adjustable height filter device, 17-Slurry layer, 18-Soil layer, 19-Vertical support, 20-First hinge seat, 21-Support plate, 22-Telescopic device, 23-Second hinge seat, 24-Barrel restraint frame, 25-Wing nut, 26- 27-Supporting ring, 28-Connecting rod, 29-Horizontal support, 30-Annular groove, 31-Heater, 32-Refrigerator, 33-First temperature sensor, 34-Second temperature sensor, 35-Third temperature sensor, 36-Baffle, 37-Bolt adjusting component, 1001-Vertical bolt rod, 1002-Lifting eye nut, 1101-Inlet pressure regulating knob, 1102-Inlet, 1103-Inlet pressure gauge, 1301-Silencer plug, 1302-Pressure relief butterfly valve, 1501-Outlet valve, 1502-Outlet, 1503-Pressure regulating knob. Detailed Implementation

[0044] In the following description, different embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that the present disclosure is not intended to be limited to the specific forms disclosed herein, but rather should be interpreted as covering various changes, equivalents, and / or substitutions of the embodiments of the present disclosure. In describing the drawings, similar reference numerals may be used to indicate similar constituent elements.

[0045] In this disclosure, the expression “A or B”, “at least one of A and / or B”, or “one or more of A and / or B” may include all possible combinations of the listed items. For example, the expression “A or B”, “at least one of A and B”, or “at least one of A or B” refers to all of the following: (1) including at least one A, (2) including at least one B, or (3) including both at least one A and at least one B.

[0046] The expressions used in the different embodiments of this disclosure, such as "first," "second," "the first," or "the second," may modify different elements regardless of their order and / or importance, and do not limit the corresponding elements. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of this disclosure.

[0047] It will be understood that when an element (e.g., the first element) is referred to as being (operationally or communicatively) "connected to" or "coupled to" another element (e.g., the second element), that element may be directly connected to or coupled to the other element, or any other element (e.g., the third element) may be inserted between them. Conversely, when an element (e.g., the first element) is referred to as being "directly connected" or "directly coupled" to another element (the second element), no element (e.g., the third element) is inserted between them.

[0048] In this disclosure, terminology is used to describe particular embodiments and is not intended to limit the disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be understood in the specification that the terms “comprising” or “having” indicate the presence of a feature, number, step, operation, structural element, component, or combination thereof, without precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, structural elements, components, or combinations thereof.

[0049] It should be understood that specific details are provided in the following description to facilitate a complete understanding of the exemplary embodiments. However, those skilled in the art will understand that the exemplary embodiments can be implemented without these specific details. For example, the system may be shown in block diagrams to avoid obscuring the example with unnecessary details. In other instances, well-known processes, structures, and techniques may be omitted with non-essential details to avoid obscuring the example.

[0050] Example 1

[0051] An experimental method for measuring water loss rate under the influence of grouting pressure and soil layer action includes the following steps:

[0052] Step S1: According to the designed volume ratio, fill the bottom of the pressure tank with experimental soil layer 18 (including saturated sand or mudstone).

[0053] Step S2: Adjust the height of the filter screen so that the bottom surface of the filter screen just contacts the experimental soil layer 18 to prevent a large amount of slurry from entering the soil layer 18;

[0054] Step S3: Pour the freshly mixed slurry onto the filter screen and measure the mass of the slurry at this time, which is recorded as m0;

[0055] Step S4: Press the air inlet switch, use the air compressor 1 to simulate the actual grouting pressure, apply constant pressure to the grout, and stabilize the pressure value through the pressure regulating knob 1503 of the air inlet pressure regulating device 11 on the experimental barrel 9.

[0056] Step S5: When the pressure reaches XMPa, where XMPa is the experimental set pressure and X is a positive real number not exceeding 2, the pressure relief valve 15 starts to release pressure, and free water flows into the water receiving container from the outlet 1502.

[0057] Step S6: Continue to maintain constant pressure loading and record the change in water volume in the water receiving container at time Ymin after pressurization. Y is a positive real number not exceeding 120 (generally, Y is 5, 10, 15 or 20), denoted as my, where y is a positive real number not exceeding 2.

[0058] The formula for calculating the water loss rate is: Water loss rate = (initial weight - final weight) / initial weight × 100%, which means that the water loss rate under the influence of grouting pressure and soil layer 18 can be calculated by R = (m0 - my) / m0 × 100%.

[0059] It can measure the changes in water loss at different times under different formations and pressures of 0.1MPa, 0.15MPa and 0.2MPa (X is 0.1, 0.15 or 0.2).

[0060] In a preferred embodiment, before the experiment begins, an air tightness check is performed: connect the devices in the order of the experiment, turn on the air compressor 1 (lift the air compressor 1 air inlet button (i.e., automatic air pressure switch 2)), turn on the air outlet valve 5, observe the changes in the pressure gauge readings of the air outlet pressure gauge 4 and the air inlet pressure regulating device 11 of the experimental barrel 9, and check whether there is any leakage at each joint in turn.

[0061] An automatic air pressure switch 2 is installed on the air compressor 1. The automatic air pressure switch 2 can be pressed or lifted. Pressing the automatic air pressure switch 2 will allow air intake to increase pressure, and lifting the automatic air pressure switch 2 will stop air intake and stabilize the pressure.

[0062] Press the air intake button (i.e., automatic air pressure switch 2) and adjust the air intake pressure regulating device 11. Observe whether the readings of the two pressure gauges are stable. After they are stable, close the air outlet valve 5 of the air compressor 1 and open the exhaust valve (i.e. exhaust device 13) of the experimental barrel 9 to exhaust the air and bring the pressure gauge readings to zero. If the readings are unstable, check and adjust them in time.

[0063] After the experiment is completed, the apparatus and instruments should be put away properly: each part can be disassembled and put away. Components such as the experimental barrel 9, pressure gauge, and pressure relief valve 15, which are prone to rust and precision instruments, should be placed in boxes to facilitate the protection of the instruments (components or parts of the apparatus) and subsequent use.

[0064] Corresponding to the experimental method, the present invention also provides an experimental device for measuring water loss rate under the influence of grouting pressure and soil layer action, such as... Figures 1-7As shown, it includes a pressure input device and a sealing test device. The pressure input device includes an air compressor 1, an outlet pressure regulating device, an outlet pressure gauge 4, and an air pressure pipe 7. The sealing test device includes a top cover 8 and a test barrel 9, with the test barrel 9 and the top cover 8 being sealed together.

[0065] The air compressor 1 is equipped with an outlet pressure regulating device, an outlet valve 5 and an outlet pressure gauge 4. The air pressure pipe 7 is connected to the outlet valve 5. The top cover 8 is equipped with three connection holes, namely the first connection hole, the second connection hole and the third connection hole. The first connection hole is used to connect the inlet pressure regulating device 11, the second connection hole is used to connect the safety valve 12, and the third connection hole is used to connect the exhaust device 13.

[0066] The intake pressure regulating device 11 is provided with an upper threaded hole and a lower threaded hole in the vertical direction. The upper threaded hole is connected to the connector of the air pressure pipe 7, and the lower threaded hole is connected to the top cover 8 through a connector. The intake pressure regulating device 11 is provided with an intake pressure gauge 1103.

[0067] The experimental barrel 9 is equipped with an adjustable height filter device, which includes a filter and a lifting device. The lifting device is connected to the filter to control the height of the filter. The experimental barrel 9 is filled with slurry and soil, which are respectively a slurry layer 17 and a soil layer 18.

[0068] In a preferred embodiment, the pressure gauge 4 at the outlet of the air compressor 1 has a range of 0-1.2 MPa and an accuracy of 0.05 MPa, allowing for real-time monitoring of pressure changes.

[0069] In a preferred embodiment, the outlet pressure regulating device is a pressure regulating ball valve 3, and an outlet valve 5 is also provided on the outlet pipe. The outlet pipe and the pressure pipe 7 are connected by a self-locking flange 6. The outlet valve 5 of the air compressor 1 is a ball valve, and the pressure and flow rate can be adjusted by changing the opening and closing angle of the ball valve. The pressure pipe 7 is a PU pipe with an inner diameter of 8mm. One end of the PU pipe is sealed to the outlet valve 5 of the air compressor 1 through the self-locking flange 6, and the other end is connected to the inlet pressure regulating device 11 of the experimental barrel 9.

[0070] In a preferred embodiment, the intake pressure regulating device 11 includes an intake pressure gauge 1103, an intake pressure regulating knob 1101, a pressure regulating valve, and an intake port 1102. The intake pressure regulating knob 1101 and the pressure regulating valve are a set for adjusting the pressure of the pressure regulating valve. The pressure regulating valve has an upper threaded hole and a lower threaded hole in the vertical direction. The upper threaded hole is connected to the connector of the air pressure pipe 7, and the lower threaded hole is connected to the top cover 8 through a connector. The connector is a two-way connector, with one end connected to the lower threaded hole and the other end threadedly connected to the top cover 8. The pressure regulating valve has a threaded hole in the horizontal direction, which is threadedly connected to the intake pressure gauge 1103. The range of the intake pressure gauge 1103 can be 0-1 MPa or 0-2 MPa. The intake pressure regulating device 11 integrates the pressure gauge and the intake valve (pressure regulating valve) and is connected to the air compressor 1 through the air pressure pipe 7.

[0071] In a preferred embodiment, the exhaust device 13 includes a silencer 1301 (or silencer) and a pressure relief butterfly valve 1302. The silencer 1301 and the pressure relief butterfly valve 1302 are connected by threads to achieve exhaust and silence.

[0072] In a preferred embodiment, the safety valve 12 is a spring-loaded safety valve 12, which can ensure experimental safety.

[0073] In a preferred embodiment, the top cover 8 has a connecting slot on its edge, and the experimental barrel 9 has a connecting seat on its body. The connecting seat is connected to the vertical bolt rod 1001, and the vertical bolt rod 1001 cooperates with a nut to connect the top cover 8 and the experimental barrel 9. The connecting seat can be a hinged seat, which is hinged to the vertical bolt rod 1001.

[0074] In a preferred embodiment, the top cover 8 and the experimental barrel 9 are made of stainless steel, with a volume of 5L and a maximum pressure resistance of 0.8MPa. The top cover 8 has three identical 2-point through-threaded holes in its center, which are respectively connected to the air intake pressure regulating device 11, the safety valve 12, and the exhaust device 13. The edge of the top cover 8 has an elliptical opening (connecting bayonet), the size of which matches the vertical bolt rod 1001. A sealing ring, the size of which matches the barrel body, is provided on the inner surface of the top cover 8. The top cover 8 and the barrel body of the experimental barrel 9 are connected by a sealing groove with a sealing ring. Bolts are welded to the center of the barrel body of the experimental barrel 9 to fix the vertical bolt rod 1001, and are connected to the top cover 8 via a lifting eye nut 1002 (the vertical bolt rod 1001 and the lifting eye nut 1002 constitute a fastening bolt 10). A 4-point internal threaded water outlet 1502 is provided on the bottom side of the barrel body of the experimental barrel 9, which is connected to a pressure relief valve 15 via a thread. In this embodiment, the top cover 8 and the experimental barrel 9 are sealed and fixed by a pull-ring nut 1002 (i.e., a pull-ring type nut) connected to a screw welded to the upper part of the barrel body. All bolt joints in the device are sealed to ensure the airtightness of the experimental barrel 9 during the experiment, avoiding distortion of experimental measurement data due to improper sealing.

[0075] In a preferred embodiment, the experimental barrel 9 has a barrel body outlet 14 at its lower part, and a pressure relief valve 15 is installed at the barrel body outlet 14. Figure 4 and Figure 5 As shown, the pressure relief valve 15 is a 1-bar pressure relief valve 15, with an opening on the side forming a water outlet 1502. When the pressure inside the tank reaches X MPa (e.g., 1 MPa), the valve head automatically loosens, allowing fluid to flow out from the opening. The pressure relief valve 15 is also equipped with a pressure regulating knob 1503 to adjust the pressure of the pressure relief valve 15.

[0076] In a preferred embodiment, the air compressor 1 is a small air pump type air compressor 1 with a range of 0-1.2MPa and an accuracy of 0.05MPa. The air compressor 1 is equipped with rollers at the bottom for easy movement.

[0077] In a preferred embodiment, a filter screen is provided between the slurry layer 17 and the soil layer 18. The filter screen contacts the experimental soil layer 18 located below the slurry layer 17, forming a barrier between the slurry layer 17 and the soil layer 18, preventing a large amount of slurry from entering the soil layer 18.

[0078] In a preferred embodiment, the lifting device consists of three telescopic rods, each connected to the bottom of the filter screen. The length of the three telescopic rods can be adjusted to accommodate the thickness requirements of different soil layers 18.

[0079] This experimental apparatus and method features adjustable pressure, high safety, and easy disassembly. Different grouting pressures, different types of grout, and different soil layers 18 can be set according to the actual engineering conditions to measure the water loss rate of the grout under the coupled influence of different grouting pressures and different soil layers 18.

[0080] Considering the varying slopes and temperature conditions present during actual construction, these factors significantly impact the water loss rate. A steeper slope, such as 30°, accelerates water flow, causing soil erosion and increasing the water loss rate. Higher temperatures also increase the diffusion rate of water molecules during infiltration. Therefore, experiments are needed to accurately simulate the construction environment, minimizing ground disturbance and improving construction safety.

[0081] In one embodiment, the experimental apparatus further includes an angle adjustment device for simulating the slope of the soil layer 18 at the construction site.

[0082] like Figure 8 As shown, the angle adjustment device includes:

[0083] Experimental support: used to support the experimental barrel 9, including vertical support 19 and horizontal support 29. The vertical support 19 and horizontal support 29 are connected to form a frame structure. An arc-shaped groove is provided on the top horizontal support 29 of the frame structure to serve as the support part of the barrel restraint frame 24.

[0084] like Figure 9 As shown, the barrel restraint frame 24 is equipped with a connecting rod 28, which is used to cooperate with the arc-shaped groove to form a fulcrum structure or hinge structure for adjusting the tilt angle of the experimental barrel 9. After the barrel restraint frame 24 is installed on the experimental support, the bottom of the barrel restraint frame 24 is suspended to ensure that the barrel restraint frame 24 can rotate around the fulcrum structure or hinge structure. The experimental barrel 9 is installed on the barrel restraint frame 24.

[0085] Telescopic structure: includes a first hinge seat 20, a second hinge seat 23, and a telescopic device 22 disposed between the first hinge seat 20 and the second hinge seat 23. One end of the telescopic device 22 is hinged to the first hinge seat 20, and the other end of the telescopic device 22 is hinged to the second hinge seat 23.

[0086] In this embodiment, the experimental support frame serves as the overall support, and the bucket restraint frame 24 serves as the adjustment device. The bucket restraint frame 24 is driven to swing through the telescopic structure, thereby adjusting the tilt angle of the experimental bucket 9 to simulate the slope of the soil layer 18.

[0087] Furthermore, the first hinge seat 20 includes a first support plate and a second support plate. The telescopic device 22 can be a telescopic cylinder or a telescopic hydraulic cylinder. One end of the telescopic device 22 is disposed between the first support plate and the second support plate, and can rotate around the first hinge seat 20. The second hinge seat 23 includes a third support plate and a fourth support plate. The third support plate and the fourth support plate are disposed on the barrel restraint frame 24. The other end of the telescopic device 22 is disposed between the third support plate and the fourth support plate, and can rotate around the second hinge seat 23.

[0088] To mount the experimental barrel 9 onto the barrel restraint frame 24, an annular groove 30 is provided at the top of the barrel restraint frame 24, and a support ring 27 is provided on the top cover 8 of the experimental barrel 9. The support ring 27 cooperates with the annular groove 30 to hold the experimental barrel 9. Furthermore, to fix the sealing experimental device to the barrel restraint frame 24, a through hole is provided on the support ring 27, and a threaded hole is provided at the bottom of the annular groove 30. The support ring 27 is fixed to the barrel restraint frame 24 by bolts.

[0089] In one embodiment, the experimental apparatus further includes a temperature control device, which comprises:

[0090] Heater 31: Used to heat the experimental barrel 9;

[0091] Cooler 32: Used to cool down experimental barrel 9;

[0092] Functional plate 26: used to install the heater 31 and the cooler 32; the functional plate 26 is fixed inside the bucket restraint frame 24.

[0093] In this embodiment, the temperature of the experimental barrel 9 can be adjusted by the heater 31 and the cooler 32, thereby simulating the temperature of the soil layer 18 at the construction site.

[0094] Furthermore, to better install the experimental barrel 9 and observe its external condition, the barrel restraint frame 24 is designed with a hollow structure. Threaded holes and matching bolt adjustment pieces 37 are provided on the side wall of the barrel restraint frame 24. The bolt adjustment pieces 37 pass through the threaded holes and are rotatably connected to the action plate 26 located inside the barrel restraint frame 24. For example, as... Figure 10 As shown, a baffle 36 can be provided on the back of the action plate 26, and a cylindrical protrusion is provided at the end of the bolt adjusting member 37. The cylindrical protrusion cooperates with the baffle 36 to achieve a rotatable connection between the bolt adjusting member 37 and the baffle 36 or the action plate 26. Preferably, the baffle 36 has two parts. The first part of the baffle 36 includes a semi-circular ring and an arc-shaped plate one, and the second part of the baffle 36 includes a semi-circular ring and an arc-shaped plate two. The arc-shaped plate one and the arc-shaped plate two are used to connect the semi-circular ring and the action plate 26. The arc-shaped plate one and the arc-shaped plate two are welded to the action plate 26 or connected by screws. A circular hole is formed in the middle of the two semi-circular rings, through which the bolt adjusting member 37 can pass. Preferably, a wing nut 25 is provided at the end of the bolt adjusting member 37 to allow rotation of the bolt adjusting member 37.

[0095] Furthermore, such as Figure 9As shown, the heater 31, when mounted on the action plate 26, forms a cylindrical heating matrix; the cooler 32, when mounted on the action plate 26, forms a cylindrical cooling matrix. The heating and cooling matrices are staggered, forming a dual-matrix structure. During use, the dual-matrix structure needs to contact or abut against the outside of the experimental barrel 9. Only one matrix of the heating and cooling matrices is active at a time to heat or cool the experimental barrel 9. Preferably, the heater 31 can be a ceramic heating element, and the cooler 32 can be a semiconductor cooling element. Since ceramic heating elements and semiconductor cooling elements are generally flat, they can be embedded into the action plate 26 during installation. In addition, for better cooperation with the experimental barrel 9, an arc-shaped intermediate conductive plate can be provided in front of the heater 31 and the cooler 32. The intermediate conductive plate includes a flat surface and an arc surface. The flat surface contacts the heater 31 or the cooler 32 (and can be fixedly connected), and the arc surface mates with the outer surface of the experimental barrel 9. Alternatively, mounting grooves (with a flat bottom) can be made on the outer wall of the experimental barrel 9 to mate with the heater 31 and the cooler 32. During use, the heater 31 and the cooler 32 can be directly embedded into these mounting grooves. Since the thermoelectric cooler not only has cooling but also heating functions, the heating part (one side) of the thermoelectric cooler can be used as the heater 31, and the cooling part (the other side) as the cooler 32.

[0096] To form a heating matrix and a cooling matrix, the present invention provides the following embodiments.

[0097] Several action plates 26 are arranged inside the barrel restraint frame 24. The action plates 26 are vertically arranged and their forward and backward movement is controlled by bolt adjustment components 37. Each action plate 26 is provided with a heater 31 and a cooler 32 from bottom to bottom. Preferably, the heaters 31 and coolers 32 are arranged alternately, so that when all action plates 26 are in place, the heaters 31 and coolers 32 can form a heating matrix and a cooling matrix.

[0098] In order to monitor the temperature environment inside the experimental barrel 9, in addition to adopting the above-mentioned open-loop control structure, this embodiment also installs a temperature sensing device inside the experimental barrel 9 so that the entire temperature system becomes a closed-loop control system.

[0099] Furthermore, the temperature sensing device includes:

[0100] First temperature sensor 33: installed at the lower part of slurry layer 17 to monitor the temperature at the lower part of slurry layer 17;

[0101] Second temperature sensor 34: installed on the upper part of slurry layer 17 to monitor the temperature of the upper part of slurry layer 17;

[0102] Third temperature sensor 35: installed in soil layer 18, used to measure the temperature of soil layer 18;

[0103] The control method in this embodiment is:

[0104] Option 1: When the temperature detected by the third temperature sensor 35 in soil layer 18 is no more than 2℃ different from the temperature of soil layer 18 at the construction site, for example, when the actual site temperature is 10℃, and the temperature detected by the third temperature sensor 35 is in the range of 8℃-12℃, the air compressor 1 can be started to pressurize and simulate the water loss rate of soil layer 18 at the construction site.

[0105] Option 2: The first temperature sensor 33 and the second temperature sensor 34 serve as auxiliary temperature sensors. The air compressor 1 can be started to pressurize the soil when the temperature detected by the first temperature sensor 33 and the second temperature sensor 34 is no more than 5°C different from the temperature of the soil layer 18 at the construction site, and the temperature detected by the third temperature sensor 35 in the soil layer 18 is no more than 2°C different from the temperature of the soil layer 18 at the construction site.

[0106] Option 1 is suitable for situations where the shield tunneling platform is 20-30m above the ground, a relatively short distance, and grouting is relatively safe. Option 2 is suitable for situations where the shield tunneling platform is more than 30m above the ground. In this case, the impact of grout temperature on shield tunnel construction needs to be considered; that is, the grout temperature cannot differ too much from the soil layer 18 temperature, otherwise it may easily damage the support facilities and walls inside the shield tunnel. Furthermore, there will be a significant error between the measured water loss rate and the actual water loss rate of the soil layer 18 during construction.

[0107] In summary, this invention discloses an experimental apparatus and method for water loss rate under the influence of multiple factors, which has the following advantages.

[0108] 1. The pressure input is stabilized by adjusting the air inlet button and air outlet valve 5 of the air compressor 1. The air pressure input of the experimental barrel 9 is further controlled by the air inlet pressure regulating device 11 and the corresponding pressure gauge reading on the experimental barrel 9, so as to accurately simulate the grouting pressure in the actual shield tunnel construction.

[0109] 2. Using the experimental bucket 9 and pressure relief valve 15, different synchronous grouting slurries and different soil layers 18 can be loaded according to actual conditions. The water pressure in the soil layer 18 is also taken into account. Under pressure-bearing conditions, the effect of different formation parameters on the synchronous grouting water loss rate is measured. The adjustable height filter device inside the experimental bucket 9 can meet the requirements for determining the slurry water loss rate under different thicknesses of soil layers 18 (gravel layers).

[0110] 3. The safety of the entire device is ensured by setting up safety valve 12, exhaust device 13, etc.

[0111] 4. The air pressure pipe 7 connection and the air pressure regulating device 11, safety valve 12, exhaust device 13 and pressure relief valve 15 on the experimental barrel 9 are easy to disassemble, reducing the footprint and enabling recycling.

[0112] 5. The angle adjustment device can simulate the slope of the soil layer 18 at the construction site (understood as the tilt angle in this invention). The entire angle adjustment device includes the telescopic device 22, the bucket restraint frame 24, the support structure, etc. It is reasonably designed and easy to implement.

[0113] 6. This invention also includes a temperature regulation device, which can regulate the temperature of the experimental tank 9 through a heating matrix or a cooling matrix. Compared with single-point temperature regulation, matrix regulation provides more reasonable and uniform temperature control. Furthermore, a temperature sensing device is included to make the temperature system a closed-loop control system. Combined with actual construction conditions, water loss rate simulation measurement can only be performed after certain temperature conditions are met, thus improving the accuracy of water loss rate measurement.

[0114] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention. The above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A method for testing the filtration rate under the influence of grouting pressure and soil layer action, characterized in that, The method comprises the following steps: Step S1: loading the experimental soil layer in the pressure barrel bottom; Step S2: adjusting the filter screen height so that the lower bottom surface of the filter screen just contacts the experimental soil layer; Step S3: pouring the freshly mixed slurry above the filter screen, and measuring the mass of the slurry at this time, denoted as m0; Step S4: using the air compressor, simulating the actual grouting pressure, and loading the slurry with constant pressure, and stabilizing the pressure value; Step S5: when the pressure reaches X MPa, wherein X is a positive real number not more than 2, the pressure relief valve starts to release pressure, and the free water flows into the water receiving container from the water outlet; Step S6: continue to maintain constant pressure loading, and record the change of the water amount in the water receiving container at Ymin after pressurization, Y is a positive real number not more than 120, denoted as my, wherein y is a positive real number not more than 2.

2. The method of claim 1, wherein the method is characterized by, X is 0.1, 0.15 or 0.

2.

3. The method of claim 1, wherein the method is characterized by, Y is 5, 10, 15 or 20.

4. The method of claim 1, wherein the method is characterized by, Before the experiment, the air tightness is checked: according to the experiment, the device is connected in turn, the air compressor is turned on, the air outlet valve is opened, the change of the pressure indication of the air outlet pressure gauge and the pressure indication of the experimental barrel air inlet pressure regulating device is observed, and whether the air leakage of each joint is checked in turn; Adjust the air inlet pressure regulating device, observe whether the two pressure indications are stable, close the air outlet valve of the air compressor after the pressure indications are stable, open the exhaust valve of the experimental barrel, and exhaust to make the pressure indications zero, if the indications are unstable, adjust in time. The device comprises a pressure input device and a sealed experimental device, the pressure input device comprises an air compressor, an air outlet pressure regulating device, an air outlet pressure gauge and an air pressure pipe, and the sealed experimental device comprises a top cover and an experimental barrel.

5. A device for testing the filtration rate under the influence of grouting pressure and soil layer action, characterized in that, The air compressor is provided with an air outlet pressure regulating device, an air outlet valve and an air outlet pressure gauge on the machine body, and the air pressure pipe is connected with the air outlet valve; the top cover is provided with three connecting holes, which are a first connecting hole, a second connecting hole and a third connecting hole; the first connecting hole is used for connecting an air inlet pressure regulating device, the second connecting hole is used for connecting a safety valve, and the third connecting hole is used for connecting an exhaust device. The air inlet pressure regulating device is provided with an upper threaded hole and a lower threaded hole in the vertical direction, the upper threaded hole is connected with the joint of the air pressure pipe, and the lower threaded hole is connected with the top cover through a connecting piece; the air inlet pressure regulating device is provided with an air inlet pressure gauge. The experimental barrel is provided with an adjustable height filter screen device, the adjustable height filter screen device comprises a filter screen and a lifting device, the lifting device is connected with the filter screen and used for controlling the height of the filter screen; the experimental barrel is filled with slurry and soil, which are a slurry layer and a soil layer respectively. The air outlet pressure regulating device is a pressure regulating ball valve, and the air outlet pipe is further provided with an air outlet valve and connected with the air pressure pipe through a flange.

6. The experimental device for testing the filtration rate under the influence of grouting pressure and soil action according to claim 5, characterized in that, The top cover is provided with a connecting bayonet at the edge, and the barrel body of the experimental barrel is provided with a connecting seat, the connecting seat is connected with a vertical bolt rod, and the vertical bolt rod is matched with a nut to connect the top cover with the experimental barrel.

7. The experimental device for testing the filtration rate under the influence of grouting pressure and soil action according to claim 5, characterized in that, The lower part of the experimental barrel is provided with a barrel body water outlet, and the barrel body water outlet is provided with a pressure relief valve.

8. The experimental device for testing the filtration rate under the influence of grouting pressure and soil action according to claim 5 or 7, characterized in that, The air compressor adopts a small air pump type air compressor with a range of 0-1.2 MPa and an accuracy of 0.05 MPa, and a roller is attached to the lower part of the air compressor for convenient movement.

9. The experimental device for testing the filtration rate under the influence of grouting pressure and soil action according to claim 5, characterized in that, The filter screen is arranged between the slurry layer and the soil layer, contacts the experimental soil layer arranged below the slurry layer, and forms an obstacle between the slurry layer and the soil layer.

10. The experimental device for measuring the filtration rate under the influence of grouting pressure and soil action according to claim 5, characterized in that, ​

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