A dynamic adjustment test device for simulating multi-point random leakage of a shield tunnel

Abstract

A kind of dynamic adjustment test device of simulating shield tunnel multi-point random leakage, including model bucket system, tunnel model system and CT measurement system.The positive effect of the present application is that: a kind of dynamic adjustment test device of simulating shield tunnel multi-point random leakage described in the present application, including model bucket system, tunnel model system, CT measurement system, array cube partition room is equipped in the inner wall of cylinder, each partition room is connected with water inlet and outlet passage, barrel cover and cylinder bottom are equipped with round plate lining, the tunnel model system includes sleeve, tunnel model and end fastener, CT measurement system includes X-ray emission system, X-ray receiving system and image reconstruction system, wherein round plate lining can drive tunnel model relative cylinder rotation, end fastener can be transverse adjustment relative round plate lining, to realize the free adjustment of two end constraint boundary of tunnel model.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel engineering technology, specifically a dynamic adjustment test device for simulating multi-point random leakage in shield tunnels. Background Technology

[0002] In recent years, with the increasing number of shield tunnels put into operation, the problems of leakage and damage in operating tunnels have become increasingly prominent, with "nine out of ten tunnels leaking." To address this issue, many scholars have used simulation devices to study it. However, the simulation devices currently developed all have certain shortcomings. For example, existing tunnel models cannot adjust the constraint boundaries at both ends, cannot adjust the size of leakage gaps, do not correlate segment joint deformation with leakage water, cannot simulate the directional flow of groundwater around the tunnel, and cannot simulate the entire process of groundwater seeping from the strata into the tunnel. Summary of the Invention

[0003] The purpose of this invention is to provide a dynamic adjustment test device for simulating multi-point random leakage in shield tunnels. The constraint boundaries at both ends of the tunnel model can be freely adjusted, which can simulate the groundwater seepage field around the tunnel under different strata and water pressures, thus solving the problems in the prior art.

[0004] The technical solution adopted by this invention to solve its technical problem is: a dynamic adjustment test device for simulating multi-point random leakage in shield tunnels, comprising a model barrel system, a tunnel model system, and a CT measurement system. The model barrel system includes a matching barrel lid and a cylindrical body. An adjustable upper circular plate liner is installed at the bottom of the barrel lid, and an adjustable lower circular plate liner is installed at the bottom of the cylindrical body. An array of compartments is provided on the inner circumferential wall of the cylindrical body, and each compartment is equipped with an inlet / outlet water channel. The inlet / outlet water channel can simulate the leakage according to the test requirements. The system features multi-point random seepage within a model barrel system. A tunnel model system is installed between the upper and lower circular plate linings. This tunnel model system includes a model sleeve and a tunnel model. An upper end fastener is installed at the top of the tunnel model, and a lower end fastener is installed at the bottom. The upper end fastener can be adjusted laterally relative to the upper circular plate lining, and the lower end fastener can also be adjusted laterally relative to the lower circular plate lining. The tunnel model can adjust the size of its own seepage gaps. A CT measurement system can monitor the soil displacement in real time when multi-point seepage occurs within the model barrel system. Cylindrical permeable stones are installed on the inner circumference of the cylinder. An array of acrylic plates is arranged between the permeable stones and the inner wall of the cylinder, dividing the space between the permeable stones and the cylinder into arrayed compartments. The water inlet and outlet channels include an inlet channel and an outlet channel connected to the compartments, with a water pressure gauge installed on the inlet channel. The inner circumference of the lid is provided with an internal thread, and the outer circumference of the upper part of the cylinder is provided with an external thread that mates with the internal thread. A first circular groove is formed at the center of the lid, and a first raised groove that mates with the first circular groove is formed at the center of the top surface of the upper circular plate liner. A first pulley assembly is installed between the first circular groove and the first raised groove. A first annular groove and a second annular groove are also formed concentrically arranged inside the lid. The top surface of the upper circular plate liner is provided with a third annular groove that mates with the first annular groove and a fourth annular groove that mates with the second annular groove. The upper circular plate liner can be relatively The lid rotates; a second circular groove is formed at the center of the bottom surface of the cylinder, and a second raised groove is formed at the center of the lower circular plate liner that mates with the second circular groove. A second pulley assembly is installed between the second circular groove and the second raised groove. A fifth and a sixth circular groove are also formed concentrically on the bottom surface of the cylinder. A seventh and an eighth circular groove, mates with the fifth and sixth circular grooves, are formed on the lower circular plate liner. The lower circular plate liner can rotate relative to the cylinder. Steel balls are installed between the mating circular grooves. The lid has several first holes arranged circumferentially, the upper circular plate liner has second holes that mate with the first holes, the bottom surface of the cylinder has several third holes arranged circumferentially, and the lower circular plate liner has a fourth hole that mates with the third holes. Each hole is threaded, and locking bolts are installed between the mating holes.The bottom surface of the upper circular plate liner is provided with a first strip groove, and the top surface of the upper end fastener is provided with a third protruding groove that matches the first strip groove. A third pulley group is installed in the third protruding groove. The top surface of the lower circular plate liner is provided with a second strip groove, and the bottom surface of the lower end fastener is provided with a fourth protruding groove that matches the second strip groove. A fourth pulley group is installed in the fourth protruding groove. The upper and lower ends of the tunnel model can move laterally relative to the upper and lower circular plate liners, respectively. The top surface of the lower circular plate liner has a positioning groove that matches the model sleeve. The tunnel model is located inside the model sleeve. The tunnel model is assembled from ordinary pipe segments and permeable pipe segments by bolts. Sealing gaskets are attached between the pipe segments. The ordinary pipe segments can prevent mud and water from entering the tunnel model. The permeable pipe segments can adjust the size of the permeable gaps in the tunnel model. The ordinary pipe segments are solid and homogeneous structures. The permeable pipe segments include a cubic platform container. The cubic platform container has an outer baffle and an inner baffle. Gaps are left between the outer baffle and the cubic platform container, and between the inner baffle and the cubic platform container. A movable permeable stone is also installed in the space between the outer baffle and the inner baffle. The movable permeable stone can change the size of the gap between the movable permeable stone and the cubic platform container. A guide tube is installed in the cubic platform container at the end away from the outer baffle. Holes that match the guide tube are opened on the upper end fastener, the upper circular plate liner, and the bucket lid. The guide tube extends upward through the holes into the model bucket system. The CT measurement system includes a soil displacement visualization sphere group, an X-ray emission system, an X-ray receiving system, and an image reconstruction and processing system. The soil displacement visualization sphere group is located inside the model barrel system. During multi-point leakage tests, the soil displacement visualization sphere group can move in the same direction as the soil. The signal emitted by the X-ray emission system can pass through the model barrel system and be received by the X-ray receiving system. The image reconstruction and processing system can display the position of the soil displacement visualization sphere group within the model barrel system in real time, thereby realizing the monitoring of soil displacement.The dynamic adjustment test device for simulating multi-point random seepage in shield tunnels has the following test steps: ① Determine the size of the partition chamber according to the required accuracy of the seepage field, and fix the acrylic plate to the inner wall of the cylinder to build the partition chamber. Place the cylindrical permeable stone into the cylinder, ensuring a tight connection between the cylindrical permeable stone and the acrylic plate; ② After the partition chamber in step ① is built, connect the water pipes to the inlet and outlet channels respectively, and install a water pressure gauge on the inlet channel; ③ After the inlet and outlet channels in step ② are installed, install the lower circular plate lining at the bottom of the cylinder, positioning the second pulley group between the second circular groove and the second strip groove; ④ After the lower circular plate lining in step ③ is installed, install the model sleeve with the positioning groove into the cylinder, and fill and compact the soil in the space enclosed by the model sleeve and the cylinder. During the filling process, embed special steel balls as soil displacement manifestation spheres; ⑤ After the soil in step ④ is compacted... After filling, determine the location of tunnel leakage according to experimental needs, and assemble ordinary segments and leakage segments to form a tunnel model. Install the third and fourth pulley groups in the raised grooves of the upper and lower fasteners respectively, and install them at both ends of the tunnel model to form a tunnel model system; ⑥ After the tunnel model system in step ⑤ is assembled, put the tunnel model system into the model sleeve, then pull the model sleeve upward, and then install the upper circular plate lining on the upper part of the tunnel model system and cover it with the bucket lid; ⑦ After the tunnel model system in step ⑥ is installed in the model bucket system, open the water inlet and outlet channels at each location according to experimental needs, and adjust the water inlet pressure according to the water pressure gauge: S1: Monitor the engineering geological and hydrological conditions around the actual engineering tunnel to obtain the soil layer type i and the pore water pressure head h0 around the tunnel in the actual working conditions. Take the undisturbed soil for geotechnical testing to obtain the soil compaction degree λ. i Permeability coefficient k i , where λ i k represents the compaction degree of soil type i. i Let be the permeability coefficient of soil type i;

[0005] S2: To achieve the predetermined compaction degree λ of the soil. i Open the switches for each water inlet and outlet channel, adjust the pressure head at one side of the water inlet to h0, and adjust the pressure head at the corresponding side of the water outlet to h0. Once the seepage stabilizes, the flow rate q of each outlet channel will be recorded. j ;

[0006] S3: Calculate the following physical quantities: Define the seepage cross-sectional area A as the area of ​​a rectangle with the side length a of the permeable stone inscribed in the model barrel as its width and the height h of the soil inside the model barrel as its length; Calculate the seepage cross-sectional area A of the model according to the following formula: A=a×h; Calculate the side length a of the square according to the following formula: Where R is the radius of curvature of the permeable stone inside the model bucket; calculate the cross-sectional seepage flow rate Q. Where qj Let J be the seepage flow rate of the j-th injection pipe corresponding to the seepage cross-section; calculate the average seepage velocity of the cross-section. Where Q is the cross-sectional seepage flow rate, and A is the seepage cross-sectional area; the equivalent permeability coefficient k is used to calculate the vertical seepage case. a , Where a = 1, 2, 3…m, H i H represents the thickness of each layer, and H represents the total thickness of all soil layers. Calculate the equivalent permeability coefficient k. Where H a For vertical seepage, the equivalent permeability coefficient k a Corresponding soil layer thickness; calculate hydraulic gradient i. Where v is the average seepage velocity of the cross section, and k is the equivalent permeability coefficient; calculate the head loss Δh = i × L, where i is the hydraulic gradient, L is the seepage path length, i.e., L = Rr, where R is the radius of curvature of the permeable stone inside the model barrel, and r is the radius of the outer surface of the tunnel model; calculate the pressure P of each inlet and outlet channel. n =ρgh1, where ρ is the density of water, g is the acceleration due to gravity, and h1 is the pressure head at that point, where h1 = h0 + Δh, n = 1, 2, 3…m; S4: Adjust the pressure of each inlet and outlet channel to the pressure P calculated in step S3 for each inlet and outlet channel. n Size; S5: Repeat steps S3-S4 until... ⑧ After the water inlet pressure in step ⑦ is adjusted, turn on the CT measurement system to record the displacement of the special steel balls in the soil around the tunnel in real time.

[0007] The positive effects of this invention are as follows: The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels, as described in this invention, includes a model barrel system, a tunnel model system, and a CT measurement system. An array of cubic compartments is provided on the inner wall of the barrel, and each compartment is connected to an inlet and outlet water channel. The barrel lid and the bottom of the barrel are provided with circular plate liners. The tunnel model system includes a sleeve, a tunnel model, and end fasteners. The CT measurement system includes an X-ray emission system, an X-ray receiving system, and an image reconstruction system. The circular plate liner can drive the tunnel model to rotate relative to the barrel, and the end fasteners can be adjusted laterally relative to the circular plate liner, thereby realizing the free adjustment of the constraint boundaries at both ends of the tunnel model.

[0008] Furthermore, the device of this invention has undergone significant optimization in structure and function, enabling it to simulate the groundwater seepage field around tunnels under different strata and water pressures. It allows for free adjustment of the number and location of different seepage points, seepage pressure, and seepage volume, and can simulate the entire process of joint or segment leakage, as well as the entire process of segment joint deformation. The tunnel model is prefabricated and assembled, with a modular and multifunctional design, making the patented device more convenient to operate, wider in application, and more accurate in analyzing seepage problems induced by large deformations at joints in operating shield tunnels. This provides a scientific basis for waterproofing design and operation and maintenance of tunnel engineering. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the present invention;

[0010] Figure 2 This is a structural diagram of the model barrel system;

[0011] Figure 3 This is a structural diagram of the bucket lid;

[0012] Figure 4 This is a schematic diagram of the cylinder structure;

[0013] Figure 5 This is a top view of the cylinder;

[0014] Figure 6 This is a top view of the inner lining of the upper circular plate;

[0015] Figure 7 This is a bottom view of the inner lining of the upper circular plate;

[0016] Figure 8 This is a schematic diagram of the first pulley block installed in the inner lining of the upper circular plate;

[0017] Figure 9 This is a schematic diagram of the first clip installed in the inner lining of the upper circular plate;

[0018] Figure 10 This is a bottom view of the inner lining of the lower circular plate;

[0019] Figure 11 This is a top view of the inner lining of the lower circular plate;

[0020] Figure 12 This is a schematic diagram of the second pulley block installed in the inner lining of the lower circular plate;

[0021] Figure 13 This is a schematic diagram of the second clip installed in the inner lining of the lower circular plate;

[0022] Figure 14 This is a schematic diagram of the structure with inlet and outlet water pipes installed on the cylinder;

[0023] Figure 15 This is a schematic diagram of the structure of a cylindrical permeable stone;

[0024] Figure 16 This is a schematic diagram of the tunnel model system.

[0025] Figure 17 This is a schematic diagram of the model sleeve structure;

[0026] Figure 18 This is a structural diagram of the upper end fastener;

[0027] Figure 19 This is a structural diagram of the lower end fastener;

[0028] Figure 20 This is a schematic diagram of the leakage pipe segment;

[0029] Figure 21 This is an internal cross-sectional view of the leaking segment;

[0030] Figure 22 This is a schematic diagram of the third pulley block installed inside the upper fastener;

[0031] Figure 23 This is a schematic diagram of the fourth pulley block installed inside the lower end fastener;

[0032] Figure 24 This is a schematic diagram of the CT measurement system;

[0033] Figure 25 This is an exploded assembly diagram of the present invention;

[0034] Figure 26 yes Figure 25 The main view in the middle;

[0035] Figure 27 yes Figure 26 A magnified view of part of I;

[0036] Figure 28 yes Figure 26 A magnified view of part II. Detailed Implementation

[0037] The present invention describes a dynamic adjustment test device for simulating multi-point random leakage in shield tunnels, such as... Figure 1-28 As shown, the system includes a model barrel system 1, a tunnel model system 2, and a CT measurement system 3. The model barrel system 1 includes a matching barrel cover 101 and a cylindrical body 102. The bottom of the barrel cover 101 is equipped with an adjustable upper circular plate liner 103, and the bottom of the cylindrical body 102 is equipped with an adjustable lower circular plate liner 104. The constraint direction of the tunnel model system 2 can be controlled by rotating the upper circular plate liner 103 and the lower circular plate liner 104.

[0038] An array of compartments 1023 are provided on the inner circumferential wall of the cylinder 102. Each compartment 1023 is equipped with a water inlet / outlet channel 105. The water inlet / outlet channel 105 can simulate multiple random leaks in the model barrel system 1 according to the test requirements.

[0039] A tunnel model system 2 is installed between the upper circular plate liner 103 and the lower circular plate liner 104. The tunnel model system 2 includes a model sleeve 201 and a tunnel model 202. The model sleeve 201 provides guidance and support for the installation of the tunnel model 202. An upper end fastener 203 is installed at the upper end of the tunnel model 202, and a lower end fastener 204 is installed at the lower end of the tunnel model 202. The upper end fastener 203 can be adjusted laterally relative to the upper circular plate liner 103, and the lower end fastener 204 can be adjusted laterally relative to the lower circular plate liner 104. The tunnel model 202 can adjust the size of its own leakage gaps. The free adjustment of the constraint boundaries at both ends of the tunnel model 202 is achieved by moving the end fasteners and the circular plate liner relative to the model barrel system 1. After the tunnel model system 2 is placed into the model barrel system 1, it is filled with soil. The CT measurement system 3 can monitor the soil displacement in real time when multiple leakage points occur in the model barrel system 1.

[0040] A cylindrical permeable stone 106 is installed on the inner circumference of the cylinder 102. An array of acrylic plates 1022 are arranged between the cylindrical permeable stone 106 and the inner wall of the cylinder 102. The acrylic plates 1022 divide the space between the cylindrical permeable stone 106 and the cylinder 102 into an array of partitions 1023. The partitions 1023, together with the cylindrical permeable stone 106, form a water storage tank.

[0041] The water inlet and outlet channels 105 include an inlet channel 1052 and an outlet channel 1053 connected to the partition 1023, wherein a water pressure gauge 1051 is installed on the inlet channel 1052. The inlet channel 1052 and the outlet channel 1053 are respectively connected to pipelines, which can simulate multi-point random leakage by pumping water, and the water pressure gauge 1051 is set to facilitate the observation of real-time water pressure during the test.

[0042] Each compartment 1023 is connected to an inlet channel 1052 and an outlet channel 1053, allowing water to be added and released simultaneously, and the water pressure in the reservoir to be monitored in real time. Inside the cylinder 102, a cylindrical permeable stone 106 is installed close to the compartment 1023. The cylindrical permeable stone 106 and the acrylic plate 1022 are coated with waterproof sealant, thus creating a reservoir with water seepage on one side.

[0043] To facilitate a reliable and detachable connection between the lid 101 and the cylinder 102, the inner circumference of the lid 101 is provided with an internal thread 1011, and the outer circumference of the upper part of the cylinder 102 is provided with an external thread 1021 that mates with the internal thread 1011.

[0044] In order to achieve relative rotation between the upper circular plate liner 103 and the barrel lid 101, a first circular groove 1012 is provided at the center position inside the barrel lid 101, and a first protruding groove 1031 that cooperates with the first circular groove 1012 is provided at the center position of the top surface of the upper circular plate liner 103. The first circular groove 1012 can be engaged with the first protruding groove 1031, and a first pulley group 1036 is installed between the first circular groove 1012 and the first protruding groove 1031.

[0045] In order to achieve relative rotation between the lower circular plate liner 104 and the cylinder 102, a second circular groove 1024 is provided at the center of the bottom surface of the cylinder 102. A second protruding groove 1041 is provided at the center of the bottom of the lower circular plate liner 104 to cooperate with the second circular groove 1024. The second circular groove 1024 can be engaged with the second protruding groove 1041. A second pulley group 1047 is installed between the second circular groove 1024 and the second protruding groove 1041.

[0046] To reduce the relative rotational friction between the upper circular plate liner 103 and the barrel lid 101, a first annular groove 1013 and a second annular groove 1014 are concentrically arranged inside the barrel lid 101. The top surface of the upper circular plate liner 103 has a third annular groove 1032 that mates with the first annular groove 1013 and a fourth annular groove 1033 that mates with the second annular groove 1014. To reduce the relative rotational friction between the lower circular plate liner 104 and the cylinder 102, a fifth annular groove 1025 and a sixth annular groove 1026 are concentrically arranged on the bottom surface of the cylinder 102. The bottom surface of the lower circular plate liner 104 has a seventh annular groove 1042 that mates with the fifth annular groove 1025 and an eighth annular groove 1043 that mates with the sixth annular groove 1026. Steel balls are installed between the aforementioned mating annular grooves and lubricated with oil to reduce rotational friction.

[0047] The aforementioned raised grooves can be used to install pulley sets first, and then they can be installed and fastened to the lid 101 or the cylinder 102.

[0048] To achieve relative rotational adjustment and positioning between the upper circular plate liner 103 and the barrel lid 101, and between the lower circular plate liner 104 and the cylinder 102, the barrel lid 101 has several circumferentially arranged first holes 1015, the upper circular plate liner 103 has second holes 1034 that mate with the first holes 1015, the bottom surface of the cylinder 102 has several circumferentially arranged third holes 1027, and the lower circular plate liner 104 has a fourth hole 1044 that mates with the third holes 1027. Each of the above holes is threaded, and locking bolts are installed between the mating holes to achieve rotational locking.

[0049] To reduce friction when the end fasteners move laterally relative to the inner lining of the circular plate, a first strip groove 1035 is provided on the bottom surface of the upper circular plate lining 103, and a third raised groove 2031 that mates with the first strip groove 1035 is provided on the top surface of the upper end fastener 203. A third pulley group 207 is installed in the third raised groove 2031. A second strip groove 1045 is provided on the top surface of the lower circular plate lining 104, and a fourth raised groove 2041 that mates with the second strip groove 1045 is provided on the bottom surface of the lower end fastener 204. A fourth pulley group 208 is installed in the fourth raised groove 2041. The upper and lower ends of the tunnel model 202 can move laterally relative to the upper circular plate lining 103 and the lower circular plate lining 104, respectively.

[0050] The aforementioned third protruding groove 2031 and fourth protruding groove 2041 can be respectively locked in the first strip groove 1035 and the second strip groove 1045. At the same time, the first buckle 1037 and the second buckle 1048 can be used to fix the two ends of the tunnel model 202 to the upper circular plate lining 103 and the lower circular plate lining 104 in a certain constrained form.

[0051] Furthermore, a positioning groove 1046 is provided on the top surface of the lower circular plate liner 104 to cooperate with the model sleeve 201. The positioning groove 1046 is used to fix the lower end of the model sleeve 201. During installation, the tunnel model 202 is located inside the model sleeve 201 to avoid the influence of the filling soil on the tunnel model 202. The model sleeve 201 has an umbrella-shaped hollow structure, which provides operating space for adding soil. The outer ring is a downwardly bent folding component, so that the model sleeve 201 can be fastened to the outer edge of the model cylinder 102 for easy assembly and placement.

[0052] The tunnel model 202 is assembled by bolts from ordinary pipe segments 205 and leakage pipe segments 206. Sealing gaskets are attached between the pipe segments. Ordinary pipe segments 205 can prevent mud and water from entering the tunnel model 202, while leakage pipe segments 206 can adjust the size of the leakage gaps in the tunnel model 202, thereby simulating different degrees of leakage in the tunnel.

[0053] The ordinary segment 205 is a solid homogeneous structure, and the leakage segment 206 includes a cubic platform container 2061. The cubic platform container 2061 is provided with an outer baffle 2062 and an inner baffle 2063. Gaps are left between the outer baffle 2062 and the cubic platform container 2061, and between the inner baffle 2063 and the cubic platform container 2061, to simulate the leakage of the tunnel.

[0054] A movable permeable stone 2064 is installed in the space between the outer baffle 2062 and the inner baffle 2063. The movable permeable stone 2064 can change the size of the gap between the movable permeable stone 2064 and the cubic platform container 2061. A guide tube 2065 is installed in the cubic platform container 2061 at the end away from the outer baffle 2062. Holes that mate with the guide tube 2065 are opened on the upper end fastener 203, the upper circular plate liner 103, and the bucket lid 101. The guide tube 2065 extends upward through the holes into the model bucket system 1. In addition, holes reserved for the guide tube 2065 to pass through are also opened on the first circular groove 1012, the first raised groove 1031, the first pulley group 1036, the third pulley group 207, and the first strip groove 1035.

[0055] The conduit 2065 can drain cement and other contaminants that have entered the seepage segment 206 from the tunnel model 202. The movable permeable stone 2064 can be driven by existing power devices such as motors, or the size of the seepage gap can be changed as needed before the test by replacing different types of movable permeable stones 2064.

[0056] Furthermore, the CT measurement system 3 includes a soil displacement visualization sphere group, an X-ray emission system 301, an X-ray receiving system 302, and an image reconstruction and processing system 303. The soil displacement visualization sphere group is located inside the model barrel system 1. During multi-point leakage tests, the soil displacement visualization sphere group can change position with the soil. The signal emitted by the X-ray emission system 301 can pass through the model barrel system 1 and be received by the X-ray receiving system 302. The image reconstruction and processing system 303 can display the position of the soil displacement visualization sphere group inside the model barrel system 1 in real time, thereby realizing the monitoring of soil displacement.

[0057] The soil displacement visualization spheres are iron spheres placed inside the model barrel according to a certain spatial distribution pattern, which can be identified by CT scanning. The X-ray emitting system 301 and the X-ray receiving system 302 work together. The X-rays emitted by the X-ray emitting system 301 pass through the model barrel system 1 and the tunnel model system 2 and are received by the X-ray receiving system 302. The received X-rays are then sent to the image reconstruction and processing system 303. In this way, the displacement field changes inside the soil within the model barrel 202 and the deformation of the tunnel model 202 can be analyzed by observing the displacement changes of the iron spheres.

[0058] The method for conducting tests using the dynamic adjustment test device for simulating multi-point random leakage in shield tunnels includes the following steps:

[0059] ① Determine the size of the partition 1023 according to the accuracy of the seepage field to be controlled in the experiment, and fix the acrylic plate 1022 to the inner wall of the cylinder 102 to build the partition 1023. Then put the cylindrical permeable stone 106 into the cylinder 102 so that the cylindrical permeable stone 106 is tightly connected to the acrylic plate 1022.

[0060] ②After the partition 1023 in step ① is built, connect the water pipes to the water inlet channel 1052 and the water outlet channel 1053 respectively, and install the water pressure gauge 1051 on the water inlet channel 1052;

[0061] ③ After the water inlet and outlet channels 105 in step ② are installed, the lower circular plate liner 104 is installed at the bottom of the cylinder 102, so that the second pulley group 1047 is located between the second circular groove 1024 and the second strip groove 1045.

[0062] ④ After the lower circular plate liner 104 in step ③ is installed, the model sleeve 201 is installed in the cylinder 102 in conjunction with the positioning groove 1046, and the space surrounded by the model sleeve 201 and the cylinder 102 is filled with soil and compacted. During the filling process, special steel balls are buried as a group of balls to manifest soil displacement.

[0063] ⑤ After the soil filling in step ④ is completed, determine the location of tunnel leakage according to the experimental needs, and assemble the ordinary pipe segment 205 and the leakage pipe segment 206 to form tunnel model 202. Install the third pulley group 207 and the fourth pulley group 208 in the protruding grooves of the upper end fastener 203 and the lower end fastener 204 respectively, and install them at both ends of tunnel model 202 to form tunnel model system 2.

[0064] ⑥ After the tunnel model system 2 in step ⑤ is assembled, put the tunnel model system 2 into the model sleeve 201, then pull the model sleeve 201 upward, and then install the upper circular plate liner 103 on the upper part of the tunnel model system 2, and cover it with the bucket lid 101.

[0065] ⑦ After the tunnel model system 2 from step ⑥ is installed into the model barrel system 1, open the water inlet channel 1052 and water outlet channel 1053 at each location according to the test requirements, and adjust the water inlet pressure according to the water pressure gauge 1051:

[0066] S1: Monitor the engineering geological and hydrological conditions around the actual tunnel to obtain the soil layer type i and the pore water pressure head h0 around the tunnel under actual working conditions. Take undisturbed soil samples for geotechnical testing to obtain the soil compaction degree λ. i Permeability coefficient k i , where λ i k represents the compaction degree of soil type i. i Let be the permeability coefficient of soil type i;

[0067] S2: To achieve the predetermined compaction degree λ of the soil. i Open the switches for each water inlet and outlet channel, adjust the pressure head at one side of the water inlet to h0, and adjust the pressure head at the corresponding side of the water outlet to h0. Once the seepage stabilizes, the flow rate q of each outlet channel will be recorded. j ;

[0068] S3: Calculate the following physical quantities

[0069] Define the seepage cross-sectional area A as the area of ​​a rectangle with the side length a of the permeable stone inscribed in the model barrel and the height h of the soil inside the model barrel; calculate the seepage cross-sectional area A of the model according to the following formula: A=a×h;

[0070] Calculate the side length a of the square using the following formula: Where R is the radius of curvature of the permeable stone inside the model bucket;

[0071] Calculate the cross-sectional seepage flow rate Q. Where q j Let J be the seepage flow rate of the j-th injection pipe corresponding to the seepage section;

[0072] Calculate the average seepage velocity of the cross section Where Q is the cross-sectional seepage flow rate and A is the cross-sectional area of ​​the seepage flow;

[0073] Calculating the equivalent permeability coefficient k in vertical seepage cases a , Where a = 1, 2, 3…m, H i H represents the thickness of each layer, and H represents the total thickness of all soil layers.

[0074] Calculate the equivalent permeability coefficient k. Where H a For vertical seepage, the equivalent permeability coefficient k a The corresponding soil layer thickness;

[0075] Calculate the hydraulic gradient i. Where v is the average cross-sectional permeability velocity and k is the equivalent permeability coefficient;

[0076] Calculate the head loss Δh = i × L, where i is the hydraulic gradient, L is the seepage path length, i.e., L = Rr, where R is the radius of curvature of the permeable stone inside the model barrel, and r is the radius of the outer surface of the tunnel model.

[0077] Calculate the pressure P of each inlet and outlet water channel. n =ρgh1, where ρ is the density of water, g is the acceleration due to gravity, h1 is the pressure head at that point, and h1 = h0 + Δh, n = 1, 2, 3…m;

[0078] S4: Adjust the pressure of each inlet and outlet water channel to the pressure P calculated in step S3. n size;

[0079] S5: Repeat steps S3-S4 until...

[0080] ⑧ After the water inlet pressure in step ⑦ is adjusted, turn on the CT measurement system 3 to record the displacement of the special steel ball in the soil around the tunnel in real time.

[0081] The actual operation process of the above steps can be described as follows:

[0082] Place the cylindrical permeable stone 106 into the cylinder 102, and then apply waterproof adhesive to the contact area between the acrylic plate 1022 and the cylindrical permeable stone 106. Place the second pulley group 1047 in the second circular groove 1024 on the bottom surface of the cylinder 102, place several steel balls in the fifth annular groove 1025 and the sixth annular groove 1026, and apply lubricating oil. Then place the lower circular plate liner 104 at the bottom of the cylinder 102, and rotate the lower circular plate liner 104 according to the test requirements. Then, determine whether it is necessary to use bolts to fix the lower circular plate liner 104 to the bottom of the cylinder 102 according to the test requirements, and determine whether it is necessary to place the second buckle 1048 according to the test requirements.

[0083] The outer ring of the model sleeve 201 is placed on the upper edge of the cylinder 102. The lower end of the model sleeve 201 is inserted into the positioning groove 1046 on the upper surface of the bottom circular plate lining 104. Then, test soil is added to the cylinder, with iron balls evenly distributed in layers until the cylinder 102 is filled. The ordinary pipe segment 205 and the leakage pipe segment 206 are assembled into the tunnel model 202, and the strain gauges are attached to the inner arc surface of the tunnel model 202. The upper end fastener 203 and the lower end fastener 204 of the tunnel model 202 are fastened tightly to the tunnel model 202, and waterproof adhesive is applied to the contact points. At the same time, the conduit 2065 of the leakage pipe segment 206 is led out from the reserved channel of the upper end fastener 203. Then, the entire tunnel model system 2 is placed into the model sleeve 201, and then the model sleeve 201 is removed.

[0084] Next, invert the lid 101, place the first pulley assembly 1036 in the first circular groove 1012, and place several steel balls in the first annular groove 1013 and the second annular groove 1014, applying lubricant. Then, fasten the upper circular plate liner 103 into the top cover 101, rotating the upper circular plate liner 103 according to the test requirements. Determine whether bolts are needed to fix the upper circular plate liner 103 to the lid 101, and whether the first clip 1037 needs to be placed, based on the test requirements. Simultaneously, lead the conduit 2065 of the leakage pipe segment 206 out from the pre-reserved channel in the upper circular plate liner 103 and the top cover 101. Finally, place the lid 101 and the upper circular plate liner 103 on top of the cylinder 102. Rotate the lid 101 to achieve a tight seal on the test model.

[0085] Next, a water pressure gauge 1051 is installed on the water inlet channel 1052, and then each water inlet channel 1052 and water outlet channel 1053 are connected. Then, according to the test requirements, the on / off status of each water inlet and outlet channel is controlled, and the water pressure in each cubic compartment 1023 is monitored using the water pressure gauge 1051. The permeable stone 2064 inside the leaking segment 206 is replaced, thereby dynamically controlling the tunnel segment opening amount.

[0086] Finally, the CT measurement system 3 is placed in a suitable position. The CT scan time interval is set, and the CT machine performs a CT scan on the model barrel system 1. The X-ray images from the CT scan are processed to ultimately analyze the changes in the displacement field inside the soil and the displacement changes of the tunnel model 202.

[0087] In this embodiment, the tunnel model undergoes dynamic seepage failure within an artificially designed seepage field. Under the coupled effect of surrounding pore water seepage and tunnel leakage, the tunnel model experiences changes in its displacement field, and its internal forces also continuously change. A pre-set CT measurement system can scan the model, thereby analyzing the changes in the displacement field within the entire soil mass and the deformation of the tunnel model. Strain gauges attached to the surface of the tunnel model can be used to analyze the changes in the internal forces within the tunnel model.

[0088] The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels in this invention can perform the following tests: In a set seepage field, it explores the changes in tunnel displacement field and internal force under different constraint conditions of the tunnel under the coupling effect of seepage from surrounding pore water and tunnel leakage.

[0089] In use, the model is assembled first, and the water pressure gauge is observed while the inlet and outlet channels are controlled. This artificially sets up a seepage field, controls the position of the permeable stones in the seepage segments, and realizes dynamic seepage of the tunnel model. Using a CT measurement system and strain gauges attached to the surface of the tunnel model, the deformation and convergence deformation of the tunnel model under coupling action, as well as the pressure of the surrounding soil on the tunnel model, can be measured.

[0090] The model tank is pre-divided into multiple water storage tanks, each with two channels connecting it to the outside. Water pressure gauges are added to the pumping pipes, allowing for simultaneous water filling and pumping, and precise water pressure control. This simulates a seepage field similar to actual working conditions, more accurately mimicking the tunnel displacement field changes under the coupled effects of pore water seepage around the tunnel and tunnel leakage.

[0091] The inner lining plates on both sides can rotate freely without bolts, or they can be fixed to the top cover and base of the model barrel with bolts. The constraint type at both ends of the tunnel model can be adjusted according to the inner lining plate structure at both ends, and can simulate various constraint types such as fixed constraints at both ends, fixed constraints in one section, and directional displacement constraints.

[0092] The tunnel model allows for the alteration of the position of the permeable segments to simulate leakage at different locations. Furthermore, the outer and inner baffles can be replaced to simulate varying degrees of seepage. By pushing and pulling the internal permeable stones, different tunnel segment opening angles can be continuously simulated, thus achieving the function of simulating dynamic tunnel leakage.

[0093] In practical operation, this patent allows for manual control of the seepage field distribution within the model barrel and dynamic control of the tunnel segment opening, thus maximizing the simulation of tunnel conditions in real engineering hydrogeology. This invention simulates and analyzes the tunnel leakage process by artificially setting the seepage field and directly observes the soil displacement field, providing a scientific means to study the internal force changes and displacement deformation patterns of tunnels under seepage conditions of mud and water.

[0094] The technical solutions of this invention are not limited to the embodiments described herein. All technical contents not described in detail herein are well-known technologies.

Claims

1. A dynamic adjustment test device for simulating multi-point random leakage in shield tunnels, characterized in that: The system includes a model barrel system (1), a tunnel model system (2), and a CT measurement system (3). The model barrel system (1) includes a matching barrel lid (101) and a cylindrical body (102). The bottom of the barrel lid (101) is fitted with an adjustable upper circular plate liner (103). The bottom of the cylindrical body (102) is fitted with an adjustable lower circular plate liner (104). An array of compartments (1023) is provided on the inner circumferential wall of the cylindrical body (102). Each compartment (1023) is equipped with a water inlet / outlet channel (105). The water inlet / outlet channel (105) can simulate multiple random leaks within the model barrel system (1) according to experimental requirements. The upper circular plate liner (103) A tunnel model system (2) is installed between the tunnel model and the lower circular plate lining (104). The tunnel model system (2) includes a model sleeve (201) and a tunnel model (202). An upper end fastener (203) is installed on the upper end of the tunnel model (202), and a lower end fastener (204) is installed on the lower end of the tunnel model (202). The upper end fastener (203) can be adjusted laterally relative to the upper circular plate lining (103), and the lower end fastener (204) can be adjusted laterally relative to the lower circular plate lining (104). The tunnel model (202) can adjust the size of its own leakage gaps. The CT measurement system (3) can monitor the soil displacement when multiple leakage points occur in the model bucket system (1) in real time.

2. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 1, characterized in that: The inner circumference of the cylinder (102) is equipped with a cylindrical permeable stone (106), and an array of acrylic plates (1022) are arranged between the cylindrical permeable stone (106) and the inner wall of the cylinder (102). The acrylic plates (1022) divide the space between the cylindrical permeable stone (106) and the cylinder (102) into arrayed partitions (1023).

3. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 2, characterized in that: The water inlet and outlet channels (105) include a water inlet channel (1052) and a water outlet channel (1053) connected to the partition (1023), wherein a water pressure gauge (1051) is installed on the water inlet channel (1052).

4. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 3, characterized in that: The inner circumference of the lid (101) is provided with an internal thread (1011), and the outer circumference of the upper part of the cylinder (102) is provided with an external thread (1021) that mates with the internal thread (1011). A first circular groove (1012) is opened at the center position inside the lid (101), and a first raised groove (1031) that mates with the first circular groove (1012) is provided at the center position of the top surface of the upper circular plate liner (103). 12) A first pulley assembly (1036) is installed between the first protruding groove (1031) and the first pulley assembly (1036). A first annular groove (1013) and a second annular groove (1014) are concentrically arranged inside the lid (101). The top surface of the upper circular plate liner (103) is provided with a third annular groove (1032) that mates with the first annular groove (1013) and a fourth annular groove (1033) that mates with the second annular groove (1014). The upper circular plate... The liner (103) can rotate relative to the lid (101); a second circular groove (1024) is opened at the center of the bottom surface of the cylinder (102), and a second raised groove (1041) that matches the second circular groove (1024) is provided at the center of the bottom of the lower circular plate liner (104). A second pulley group (1047) is installed between the second circular groove (1024) and the second raised groove (1041). 2) A fifth annular groove (1025) and a sixth annular groove (1026) arranged concentrically are also provided on the bottom surface. The bottom surface of the lower circular plate liner (104) is provided with a seventh annular groove (1042) that cooperates with the fifth annular groove (1025) and an eighth annular groove (1043) that cooperates with the sixth annular groove (1026). The lower circular plate liner (104) can rotate relative to the cylinder (102). Steel balls are installed between the above-mentioned cooperating annular grooves.

5. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 4, characterized in that: The barrel lid (101) has several first holes (1015) arranged in a circle, the upper circular plate liner (103) has a second hole (1034) that matches the first holes (1015), the bottom surface of the cylinder (102) has several third holes (1027) arranged in a circle, and the lower circular plate liner (104) has a fourth hole (1044) that matches the third holes (1027). Each of the above holes is threaded, and locking bolts are installed between the matching holes.

6. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 5, characterized in that: The bottom surface of the upper circular plate liner (103) is provided with a first strip groove (1035), and the top surface of the upper end fastener (203) is provided with a third protruding groove (2031) that cooperates with the first strip groove (1035). A third pulley group (207) is installed in the third protruding groove (2031). The top surface of the lower circular plate liner (104) is provided with a second strip groove (1045), and the bottom surface of the lower end fastener (204) is provided with a fourth protruding groove (2041) that cooperates with the second strip groove (1045). A fourth pulley group (208) is installed in the fourth protruding groove (2041). The upper and lower ends of the tunnel model (202) can move laterally relative to the upper circular plate liner (103) and the lower circular plate liner (104), respectively.

7. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 6, characterized in that: The top surface of the lower circular plate liner (104) is provided with a positioning groove (1046) that matches the model sleeve (201). The tunnel model (202) is located inside the model sleeve (201). The tunnel model (202) is assembled by bolts from ordinary pipe segments (205) and leakage pipe segments (206). Sealing gaskets are attached between the pipe segments. Ordinary pipe segments (205) can prevent mud and water from entering the interior of the tunnel model (202). Leakage pipe segments (206) can adjust the size of the leakage gaps in the tunnel model (202). Ordinary pipe segments (205) are solid homogeneous structures. Leakage pipe segments (206) include a cubic platform container (2061). The cubic platform container (2061) is provided with an outer baffle (2062) and an inner baffle (2063). Gaps are left between the plate (2062) and the cubic platform container (2061), and between the inner baffle (2063) and the cubic platform container (2061). A movable permeable stone (2064) is also installed in the space between the outer baffle (2062) and the inner baffle (2063). The movable permeable stone (2064) can change the size of the gap between the movable permeable stone (2064) and the cubic platform container (2061). A guide tube (2065) is installed in the cubic platform container (2061) at the end away from the outer baffle (2062). Holes that match the guide tube (2065) are opened on the upper end fastener (203), the inner lining of the upper circular plate (103), and the bucket lid (101). The guide tube (2065) extends upward through the hole to the model bucket system (1).

8. The dynamic adjustment test device for simulating multi-point random leakage in shield tunnels according to claim 1, characterized in that: The CT measurement system (3) includes a soil displacement visualization sphere, an X-ray emission system (301), an X-ray receiving system (302), and an image reconstruction and processing system (303). The soil displacement visualization sphere is located inside the model barrel system (1). During the multi-point leakage test, the soil displacement visualization sphere can move with the soil. The signal emitted by the X-ray emission system (301) can pass through the model barrel system (1) and be received by the X-ray receiving system (302). The image reconstruction and processing system (303) can display the position of the soil displacement visualization sphere in the model barrel system (1) in real time, thereby realizing the monitoring of soil displacement.

9. A method for conducting tests using the dynamic adjustment test apparatus for simulating multi-point random leakage in shield tunnels as described in any one of claims 1-8, characterized in that: Includes the following steps: ① Determine the size of the partition (1023) according to the accuracy of the seepage field to be controlled in the experiment, and fix the acrylic plate (1022) to the inner wall of the cylinder (102) to build the partition (1023), and put the cylindrical permeable stone (106) into the cylinder (102) so that the cylindrical permeable stone (106) is tightly connected to the acrylic plate (1022); ②After the partition room (1023) in step ① is built, connect the water pipes to the water inlet channel (1052) and the water outlet channel (1053) respectively, and install a water pressure gauge (1051) on the water inlet channel (1052). ③ After the water inlet and outlet channels (105) in step ② are installed, the lower circular plate liner (104) is installed at the bottom of the cylinder (102), so that the second pulley group (1047) is between the second circular groove (1024) and the second protruding groove (1041); ④ After the lower circular plate liner (104) in step ③ is installed, the model sleeve (201) is installed in the cylinder (102) with the positioning groove (1046), and the space surrounded by the model sleeve (201) and the cylinder (102) is filled with soil and compacted. During the filling process, special steel balls are buried as a group of balls to manifest soil displacement. ⑤ After the soil filling in step ④ is completed, the location of tunnel leakage is determined according to the experimental needs. Ordinary pipe segments (205) and leakage pipe segments (206) are spliced ​​and assembled to form a tunnel model (202). The third pulley group (207) and the fourth pulley group (208) are installed in the raised grooves of the upper end fastener (203) and the lower end fastener (204) respectively. They are installed at both ends of the tunnel model (202) to form a tunnel model system (2). ⑥ After the tunnel model system (2) in step ⑤ is assembled, put the tunnel model system (2) into the model sleeve (201), then pull the model sleeve (201) upward, and then install the upper circular plate liner (103) on the upper part of the tunnel model system (2) and cover it with the bucket lid (101). ⑦ After the tunnel model system (2) from step ⑥ is installed into the model barrel system (1), open the water inlet channel (1052) and water outlet channel (1053) at each location according to the test requirements, and adjust the water inlet pressure according to the water pressure gauge (1051): S1: Monitor the engineering geological and hydrological conditions around the actual tunnel to obtain the soil layer types in the actual working conditions. and the pore water pressure head around the tunnel The soil was taken as is and subjected to geotechnical tests to obtain the soil compaction degree. Permeability coefficient ,in Soil types The degree of compaction, Soil types The permeability coefficient; S2: To achieve the predetermined compaction degree of the soil. Open all inlet and outlet water valves, and adjust the pressure head at one side of the water injection point to... The pressure head at the outlet on the corresponding side is... Once the seepage stabilizes, the flow rate of each outlet channel will be recorded. S3: Calculate the following physical quantities Define the seepage cross-sectional area A as: the area of ​​a rectangle with the side length a of the permeable stone inscribed in the model barrel as the width and the height h of the soil in the model barrel as the length; calculate the seepage cross-sectional area A of the model according to the following formula: A = a × h; Calculate the side length of the square using the following formula: , where R is the radius of curvature of the permeable stone inside the model bucket; Calculate the cross-sectional seepage flow ,in The first corresponding to the permeable section The leakage flow rate of each water injection pipe; Calculate the average seepage velocity of the cross section in Let A be the cross-sectional seepage flow rate, and A be the cross-sectional area of ​​the seepage flow. Equivalent permeability coefficient for vertical seepage ,in , For the thickness of each soil layer, The total thickness of each soil layer, i.e. ; Calculate the equivalent permeability coefficient ,in Equivalent permeability coefficient in vertical seepage cases The corresponding soil layer thickness; Calculate hydraulic gradient in The average seepage velocity across the cross section. It is the equivalent permeability coefficient; Calculate head loss in For hydraulic gradient, The seepage path length, i.e. In the formula The radius of curvature of the permeable stone inside the model barrel. The radius of the outer surface of the tunnel model; Calculate the pressure of each inlet and outlet water channel. ,in The density of water, It is the acceleration due to gravity. The pressure head at that location is given by the formula. ; S4: Adjust the pressure of each inlet and outlet water channel to the pressure calculated in step S3. size; S5: Repeat steps S3-S4 until... ; ⑧ After the water pressure in step ⑦ is adjusted, turn on the CT measurement system (3) to record the displacement of the special steel ball in the soil around the tunnel in real time.

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