Method and device for measuring frictional resistance of shield penetrating under existing subway tunnel

Abstract

The invention relates to a method and a device for measuring the frictional resistance of a shield under an existing subway tunnel, and the method comprises the steps: 1, judging the types of the existing subway tunnel and the shield tunnel according to the vertical pressure of the tunnel and the weight of a soil body, and calculating the thickness of the soil body on the tunnel according to the type of a shallow-buried or deep-buried tunnel; 2, the soil body pressure of the bottom of the existing subway tunnel is measured based on the thickness of the overlying soil body; 3, according to the soil pressure of the bottom of the existing subway tunnel and the thickness of the overlying soil body, the friction resistance of the shield tunnel is obtained. According to the method, the influence of vibration of the existing subway tunnel and the subway on the frictional resistance of the newly-built shield tunnel is considered, the accuracy of calculation of the frictional resistance of the shield penetrating through the existing subway tunnel is ensured, various tunneling parameters of the shield are effectively controlled, the tunneling speed of the shield penetrating through the subway tunnel is ensured, and the construction efficiency is improved. And meanwhile, the safety of shield tunneling is guaranteed, and rapid tunneling of the shield tunnel can be achieved under the condition that normal existing line operation is not affected.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling surveying, specifically to a method and apparatus for measuring the frictional resistance of a shield tunnel passing under an existing subway tunnel. Background Technology

[0002] Shield tunneling involves a tunnel boring machine (TBM) using a cutterhead to cut through the soil ahead while simultaneously using the shield and tunnel segments to support the surrounding rock. Jacks apply pressure from behind as the excavation proceeds, and tunnel segments are installed to complete the underground tunnel. Shield tunneling offers advantages such as safety, speed, minimal construction impact, and high mechanization, making it a primary method for constructing underground tunnels. However, the construction of TBMs under existing subway tunnels presents significant risks, requiring strict control of tunneling parameters to keep settlement within a controlled range. The frictional resistance experienced by the TBM during excavation is related to factors such as the geological conditions of the tunnel, the depth of overburden, the tunnel's burial depth, the TBM's weight, and the distance from the existing railway line. Calculating this frictional resistance allows for better control of other TBM parameters, including tunneling speed and pressure. This not only affects the TBM's excavation speed and construction safety but also significantly impacts the operational safety of the existing subway system.

[0003] On the one hand, traditional methods for calculating the frictional resistance of tunnel boring machines (TBMs) passing under existing subway lines do not consider the impact of the existing subway on the earth pressure of the TBM, or downplay the influence of the existing tunnel on the frictional force calculation. On the other hand, the core design technology of TBMs has long been monopolized by foreign countries, and the domestic TBM manufacturing industry lacks theoretical calculation formulas as guidance.

[0004] In summary, current research still lacks a method for calculating the frictional resistance of tunnel boring machines (TBMs) when rapidly tunneling under existing subway lines. Composite earth pressure balance TBMs require the design of thrust and other parameters based on varying frictional resistance levels during tunneling to ensure both high efficiency and safety. Therefore, studying the frictional resistance of TBMs when rapidly tunneling under existing tunnels is crucial, and a new calculation method is needed to address this issue. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a method and apparatus for measuring the frictional resistance of a shield tunneling machine passing under an existing subway tunnel, enabling accurate calculation of the shield frictional resistance and ensuring safe construction and tunneling speed.

[0006] The technical solution of this invention is as follows:

[0007] A method for measuring the frictional resistance of a shield tunneling machine passing under an existing subway tunnel includes:

[0008] Step 1: Determine the type of existing subway tunnel and shield tunnel based on the vertical pressure of the tunnel and the weight of the soil, and calculate the thickness of the overburden soil based on the type of shallow or deep tunnel.

[0009] Step 2: Measure the soil pressure at the bottom of the existing subway tunnel based on the thickness of the overlying soil;

[0010] Step 3: Calculate the frictional resistance of the shield tunnel based on the earth pressure at the bottom of the existing subway tunnel and the thickness of the overlying soil.

[0011] As a preferred approach, step 1 determines the type of existing subway tunnels and shield tunnels based on tunnel vertical pressure and soil weight, including: type discrimination formula:

[0012] H p =(2~2.5)h q

[0013] h q =

[0014] In the formula, H p h is the dividing depth between shallow and deep tunnels. q Where is the equivalent height of the load, q is the vertical pressure of the tunnel, and γ is the weight of the soil.

[0015] The judgment includes: when the tunnel burial depth H ≥ H p At that time, it was designated as a deep-buried tunnel, and when H <H p At that time, it was designated as a shallow-buried tunnel.

[0016] As a preferred option, step 1, determining the thickness of the overlying soil, includes:

[0017] When the existing subway tunnel is a shallow-buried tunnel, H1 is the thickness of the overlying soil, that is, the actual thickness of the soil layer from the top of the existing subway tunnel to the ground surface.

[0018] When it is a deeply buried tunnel, then H1 = In the formula, To balance the arch span of the tunnel; The friction angle within the soil.

[0019] As a preferred embodiment, the measurement formula in step 2 includes: based on the overlying soil thickness H1,

[0020] F1=K v (γ1H1+γ1'D1)+T

[0021] In the formula: F1 is the earth pressure at the bottom of the existing subway tunnel; K vγ1 is the vertical static earth pressure coefficient; γ1 is the weight of the soil overlying the existing subway tunnel; γ1' is the equivalent weight of the existing subway tunnel; H1 is the soil layer thickness; D1 is the diameter of the existing subway tunnel; T is the soil pressure at the bottom of the existing subway tunnel caused by the subway's self-weight and vibration, i.e., T=w(1+μ), where w is the vertical static live load of the subway and μ is the dynamic coefficient of the subway.

[0022] As a preferred embodiment, step 3 includes: measuring the surrounding earth pressure of the shield tunnel based on the earth pressure F1 at the bottom of the existing subway tunnel and the thickness H1 of the overlying soil.

[0023] F2=F1+σ nr

[0024] In the formula: F2 is the normal static earth pressure acting on the surface of the shield; F1 is the earth pressure at the bottom of the existing subway tunnel; σ nr This refers to the soil reaction force caused by the soil between the tunnel boring machine (TBM) and the existing subway tunnel, as well as the TBM itself.

[0025] As a preferred option, step 3 also includes the earth pressure coefficient K in any direction. θ , used to calculate σ nr ,

[0026] K θ = , where K h K is the coefficient of horizontal earth pressure at rest. v θ is the vertical at-rest earth pressure coefficient, and θ is the angle between the normal line at a point on the shield and the horizontal line.

[0027] As a preferred option,

[0028] Step 3 also includes the soil thickness H2 between the top of the shield and the bottom of the existing subway tunnel, used to calculate σ. nr :

[0029] When the shield tunnel is a shallow-buried tunnel, H2 is the distance between the top of the shield and the bottom of the existing subway tunnel.

[0030] When it is a deeply buried tunnel, let H2 = In the formula To balance the arch span of the shield tunnel, The friction angle within the soil.

[0031] As a preferred option, σ nr The measurement formula is:

[0032] σ nr =K θ [γ2 [(1-sinθ)+γ2H2],θϵ[0, ]

[0033] σ nr =K θ [γ2( +H2)-γ e ' sinθ],θϵ[- ,0)

[0034] In the formula, γ2 is the weight of the soil between the shield and the existing subway tunnel; D2 is the diameter of the shield; γ e The equivalent density of the tunnel boring machine (TBM) should be used for the corresponding TBM area, using the formula:

[0035] γ e '=

[0036] Where w' is the weight of the tunnel boring machine and its equipment, and L is the length of the tunnel boring machine.

[0037] As a preferred option, in step 3, the frictional resistance F of the shield tunnel is:

[0038] F=2L

[0039] In the formula: F is the frictional resistance of the tunnel boring machine; The friction coefficient between the soil and the shield shell. The calculation formula is =tanα, where α is the friction angle between the soil and the shield.

[0040] The present invention also includes a measuring device for the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel, comprising the aforementioned method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel, the device comprising:

[0041] Judgment module: used to obtain the vertical pressure of the tunnel and the weight of the soil, calculate the boundary depth between shallow and deep tunnels through a preset discrimination formula, determine the burial depth type of existing subway tunnels and shield tunnels by comparing the actual burial depth of the tunnel, and output the corresponding overlying soil thickness data.

[0042] First measuring device: connected to the judgment module, receives the overlying soil thickness data, and calculates and outputs the soil pressure data at the bottom of the existing subway tunnel by combining the structural parameters and operating load parameters of the existing subway tunnel through a preset soil pressure formula.

[0043] The second measuring device is connected to both the judgment module and the first pressure measuring module. It receives the overlying soil thickness data and the soil pressure data at the bottom of the existing subway tunnel. It combines the shield tunnel structural parameters, the soil parameters between the shield and the existing subway tunnel, and the shield machine's own parameters. It calculates the surrounding soil pressure of the shield tunnel using a preset circumferential soil pressure formula, and then derives and outputs the friction resistance of the shield tunnel based on a preset friction resistance formula.

[0044] The data storage module is used to store the input parameters, calculation process data, and output results of the determination module, the first pressure measurement module, and the second pressure measurement module.

[0045] According to the above-mentioned solution, the beneficial effects of this invention are as follows: In this invention, considering the influence of existing subway tunnels and subway vibrations on the frictional resistance of newly built shield tunnels, the accuracy of the shield frictional resistance calculation for tunneling under existing subway tunnels is ensured, thereby effectively controlling various tunneling parameters of the shield, ensuring the tunneling rate of the shield when tunneling under subway tunnels, and ensuring the safety of shield tunneling, enabling rapid tunneling of shield tunnels without affecting the normal operation of existing lines. Attached Figure Description

[0046] Figure 1 This is a location diagram of the shield tunnel passing under an existing subway tunnel according to the present invention;

[0047] Figure 2 This is a schematic diagram illustrating the change in earth pressure around the shield according to the present invention. Detailed Implementation

[0048] To better understand the purpose, technical solution, and technical effects of this invention, the invention will be further explained and described below in conjunction with the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also stated that the embodiments described below are only for explaining this invention and are not intended to limit this invention.

[0049] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intermediate component.

[0050] The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed when in use, or the orientation or positional relationship in which a person skilled in the art would normally understand it, or the orientation or positional relationship in which the product is usually placed when in use. It is only for the purpose of facilitating the description of this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0051] The following detailed description, in conjunction with the accompanying drawings and specific embodiments one through three, illustrates a method and apparatus for measuring the frictional resistance of a shield tunnel boring machine (SMT) passing under an existing subway tunnel, making the technical solution of this invention easier to understand and master. The experimental measurement parameters used in each embodiment are only for demonstrating the specific implementation process of the technical solution and do not constitute any limitation or reduction of the scope of protection of the claims of this invention.

[0052] Example 1: Selection and Implementation of Shallow Burial Scheme

[0053] This embodiment corresponds to a shallow-buried scenario, specifically a frictional resistance measurement scheme when both existing subway tunnels and shield tunnels are determined to be shallow-buried tunnels. The specific implementation is as follows:

[0054] refer to Figure 1 This embodiment applies to a shallow-buried construction scenario where a second-phase subway tunnel in a certain city passes under an existing first-phase subway tunnel. The existing first-phase subway tunnel is a reinforced concrete shield tunnel with an operational life of 10 years and a relatively shallow actual burial depth. The new second-phase subway tunnel will be excavated using a composite earth pressure balance shield machine. The shield excavation direction will perpendicularly intersect the axis of the existing first-phase subway tunnel. The vertical distance between the bottom of the existing subway tunnel and the top of the shield tunnel at the intersection needs to be accurately measured. During the construction, the settlement of the existing subway tunnel during the shield tunneling process must be controlled within 5mm, and the shield excavation speed must not be less than 25mm / min. The measurement method of this invention is needed to accurately obtain the shield friction resistance to provide a basis for adjusting parameters such as shield thrust and excavation speed.

[0055] Step 1: Tunnel type determination and overlying soil thickness calculation

[0056] The core of this step is to determine the burial depth type of existing subway tunnels and shield tunnels by using the vertical pressure of the tunnel and the weight of the soil, and to calculate the corresponding overburden thickness. The specific implementation is as follows:

[0057] Parameter acquisition: Soil parameters were obtained through on-site geotechnical tests: vertical pressure of the tunnel q = 220 kN / m², soil weight γ = 19 kN / m³; the actual tunnel depth H was obtained from existing subway phase I design data. 10 =12m, actual burial depth H of the newly built shield tunnel 20 =18m; the internal friction angle of the soil was obtained from the geological survey report. =28°.

[0058] Calculation of equivalent load height and boundary depth: Based on the aforementioned discrimination formula, first calculate the equivalent load height h. q :

[0059] h q =q / γ=220 / 19≈11.58m

[0060] Next, calculate the boundary depth Hp between shallow and deep buried tunnels:

[0061] H p =(2~2.5)h q In this embodiment, the coefficient is taken as 2.2, resulting in H. p =2.2×11.58≈25.48m.

[0062] Tunnel type determination:

[0063] Existing subway tunnel burial depth H 10 =12m<Hp=25.48m, which is determined to be a shallow tunnel; the thickness of the overlying soil H1 is the actual thickness of the soil layer from the top of the existing subway tunnel to the ground surface, which is 12m according to on-site measurement;

[0064] Shield tunnel burial depth H 20 =18m < Hp=25.48m, which is determined to be a shallow tunnel; the thickness of the overlying soil H2 is the distance between the top of the shield and the bottom of the existing subway tunnel, which is 6m as determined by three-dimensional ground-penetrating radar.

[0065] Step 2: Earth pressure measurement at the bottom of existing subway tunnels

[0066] This step, based on the overlying soil thickness H1 calculated in step 1, calculates the earth pressure F1 at the bottom of the existing subway tunnel. The specific implementation is as follows:

[0067] Parameter acquisition: Parameters were obtained through existing subway design data and on-site testing: vertical static earth pressure coefficient Kv=0.55; unit weight of overlying soil in existing subway tunnels γ1=19kN / m³; equivalent unit weight of existing subway tunnels γ1'=26kN / m³; diameter of existing subway tunnels D1=6m; vertical static live load of subway w=600kN; dynamic coefficient of subway μ=0.35, determined according to the type of train in operation.

[0068] Calculation of soil pressure caused by the subway's self-weight and vibration:

[0069] T = w(1 + μ) = 600 × ( =810kN

[0070] Calculation of earth pressure at the bottom of existing subway tunnels: F1 = Kv(γ1H1 + γ1'D1) + T

[0071] Substituting the parameters, we get: F1 = 0.55 × (19 × 12 + 26 × 6) + 810 = 0.55 × (228 + 156) + 810 = 0.55 × 384 + 810 = 211.2 +

[0072] 810 = 1021.2 kN;

[0073] Step 3: Calculation of frictional resistance in shield tunnels

[0074] Based on the calculation results of steps 1 and 2, the earth pressure and frictional resistance around the shield tunnel are calculated sequentially, as follows:

[0075] Earth pressure coefficient K in any direction θ calculate

[0076] Horizontal Earth Pressure Coefficient at Rest K h =0.45; Vertical earth pressure at rest coefficient K v =0.55, which is consistent with step 2; take the angle θ = 30° between the normal of a point on the shield and the horizontal line, θ∈[0,π / 2].

[0077] K θ = ≈0.477

[0078] Calculation of equivalent density γe' of tunnel boring machine

[0079] Parameters obtained: gravity of the tunnel boring machine and its equipment w' = 12000kN; length of the tunnel boring machine L = 12m; diameter of the tunnel boring machine D2 = 6.4m.

[0080] γe'= =4w' / (πD2²L)=4×12000 / (π×6.4²×12)=48000 / (π×40.96×12)=48000 / (1547.34)≈31.02kN / m³

[0081] Soil reaction force σ nr calculate

[0082] Parameter acquisition: Soil weight γ2 between the shield and the existing subway tunnel is 19kN / m³; shield diameter D2 is 6.4m; according to step 1, soil layer thickness H2 between the top of the shield and the bottom of the existing subway tunnel is 6m.

[0083] σ nr =K θ Substituting the values ​​into [γ²×(D² / 2)×(1-sinθ)+γ²H²]: D² / 2=3.2m, sin30°=0.5

[0084] σ nr=0.477×[19×3.2×(1-0.5)+19×6]=0.477×[19×3.2×0.5+114]=0.477×[30.4+114]=0.477×144.4≈68.98kN

[0085] If θ = -30° (θ ∈ [-π / 2, 0) scenario), then:

[0086] σ nr =K θ Substituting [γ2×(D2 / 2+H2)-γe'×(D2 / 2)×sinθ], sin(-30°)=-0.5, we get:

[0087] σ nr =0.477×[19×(3.2+6)-31.02×3.2×(-0.5)]=0.477×[19×9.2+49.63]=0.477×[174.8+49.63]=0.477×224.43≈106.05kN

[0088] refer to Figure 2 Press the shield around the perimeter at an angle Divided into different regions, the text clearly displays the earth pressure calculation expressions for each region, such as the one at the top. The side area is F1+ The lower area is F1+ Corresponding to scenarios 1 and 2 in this embodiment: The calculation logic is consistent, intuitively reflecting the earth pressure around the shield as... The distribution pattern of the changes is as follows:

[0089] Calculation of normal at-rest earth pressure F2 on the shield surface:

[0090] For the scenario θ∈[0, π / 2], the calculated σnr is F2=F1+σ nr =1021.2 + 68.98 = 1090.18 kN

[0091] Calculation of shield friction resistance F

[0092] Parameter acquisition: The friction angle between the soil and the shield shell is α=22°, so the friction coefficient μ=tanα=tan22°≈0.404; the length of the tunnel boring machine is L=12m; the diameter of the shield is D2=6.4m.

[0093] Complete formula for frictional resistance: Based on , :

[0094]

[0095] because exist and If the intervals have different values, the integral is split into two intervals for summation:

[0096]

[0097] Extract constant parameters for each interval ( All with (Irrelevant)

[0098]

[0099] Substitute the above parameters into the calculation:

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] This embodiment applies the aforementioned measurement method and device in a subway underpass construction project, measuring the shield tunnel friction resistance. Based on this, the shield tunneling thrust was set at 9800kN and the tunneling speed at 28mm / min. During construction, the maximum settlement of the existing subway tunnel was measured to be 3.2mm using a settlement monitoring device, which met the settlement requirements. Construction requirements.

[0106] Example 2:

[0107] Unlike Example 1, this example corresponds to a deeply buried scenario, specifically a frictional resistance measurement scheme when a shield tunnel is determined to be a deeply buried tunnel, as detailed below:

[0108] This embodiment applies to a deep-buried construction scenario where a Phase IV shield tunnel of a city's subway system passes under an existing Phase III subway line. The existing Phase III subway tunnel is a shallow-buried tunnel with stable operation. Due to the planned construction route, the new Phase IV shield tunnel needs to be excavated in deeper strata. The tunneling direction of the shield tunnel intersects perpendicularly with the axis of the existing Phase III subway tunnel. The geological conditions at the intersection are complex, requiring precise calculation of frictional resistance to ensure construction safety and the stable operation of the existing subway system. The construction requirement is to control the settlement of the existing subway tunnel to within 5mm.

[0109] Specific implementation steps

[0110] 1. Tunnel type identification and overlying soil thickness calculation

[0111] Parameter acquisition: Soil parameters were obtained through on-site geotechnical tests, including tunnel vertical pressure. Soil weight The actual burial depth of the tunnel was determined by referring to the existing design data for the third phase of the subway. Actual burial depth of newly built shield tunnel The internal friction angle of the soil is obtained through geological survey reports. Shield tunnel balance arch span The determination is based on the tunnel diameter and geological conditions.

[0112] Calculation of equivalent load height and boundary depth: Calculate the equivalent load height according to the discrimination formula described in claim 2. and boundary depth : Taking a coefficient of 2.3, we get: ,

[0113] Tunnel type determination:

[0114] Existing subway tunnel burial depth It was determined to be a shallow-buried tunnel;

[0115] Shield tunnel burial depth The tunnel was determined to be a deep-buried tunnel, so the deep-buried measurement scheme was selected.

[0116] Calculation of overburden thickness:

[0117] Existing subway tunnels (shallow burial): thickness of overlying soil These are actual measured values, obtained through on-site measurements. ;

[0118] Shield tunnel (deep burial): thickness of overlying soil According to the balanced arch theory, the formula is: Substituting the parameters, we get:

[0119] Measurement of earth pressure at the bottom of existing subway tunnels: Vertical at-rest earth pressure coefficient The existing subway tunnel overburden is heavy. Equivalent severity of existing subway tunnels Existing subway tunnel diameter Metro vertical static and live load Metro dynamic coefficient

[0120] Calculation of soil pressure caused by the subway's self-weight and vibration:

[0121] Calculation of earth pressure at the bottom of existing subway tunnels:

[0122] Substituting the parameters, we get:

[0123] Calculation of frictional resistance in shield tunnels:

[0124] Earth pressure coefficient in any direction Calculation: Coefficient of horizontal earth pressure at rest ;Pick ( Scene).

[0125]

[0126] equivalent weight of tunnel boring machine Calculate: the gravity of the tunnel boring machine and its equipment ; Shield machine length Shield diameter .

[0127]

[0128] Soil reaction force calculate

[0129] Scene 1 :

[0130] Weight of soil between the tunnel boring machine and the existing subway tunnel

[0131]

[0132] Substitute the values:

[0133]

[0134] Scene 2 :

[0135]

[0136] Substituting, we get:

[0137]

[0138] Normal earth pressure on the shield surface calculate:

[0139]

[0140]

[0141] Shield friction resistance Calculate the friction angle between the shield and the shield. coefficient of friction .

[0142] Substitute into the integral formula to calculate:

[0143]

[0144]

[0145]

[0146] After the deep burial scheme in this embodiment was applied to actual construction, the calculated frictional resistance was used... The shield tunneling thrust was set at 11800 kN, and the tunneling speed was 26 mm / min. During construction, the maximum settlement of the existing subway tunnel was 3.5 mm, which met the settlement control requirements. The shield tunneling was smooth and there were no safety hazards, verifying the accuracy and applicability of the deep burial scheme.

[0147] Example 3

[0148] Based on the method described in Embodiment 1 or Embodiment 2, Embodiment 3 further includes a measuring device for the frictional resistance of a shield tunneling beneath an existing subway tunnel, comprising:

[0149] Judgment Module: Utilizing an STM32F407 microcontroller as the core processor, coupled with a CYB-10 earth pressure sensor, this module measures vertical pressure in tunnels. JTM-1 type soil unit weight sensor, used to measure soil weight. The sensor communicates with the processor via an RS485 bus, and the data sampling frequency is 10Hz.

[0150] The microcontroller processor has a built-in preset discrimination formula algorithm and receives data from the sensor. and Data, real-time calculation and At the same time, the actual burial depth of the tunnel is obtained through a GPS positioning module or a Beidou navigation module. It automatically determines the tunnel burial depth type and then calculates the overburden thickness based on the type. and The calculation results are transmitted to the first and second measuring devices via the CAN bus and simultaneously stored in the data storage module.

[0151] The first measuring device uses an STM32F103 processor with an ARM Cortex-M4 core, integrates a 12-bit ADC acquisition module, and receives the output of the judgment module via a CAN bus. Data, and simultaneously receives manual input through a preset interface. , , , , , Based on parameters such as those described in Example 1, a calculation program was written to calculate the earth pressure at the bottom of existing subway tunnels in real time. The calculation results are synchronized to the second measuring device and data storage module via a full-duplex communication link, and the calculation error is controlled within [a certain range]. Within.

[0152] The second measuring device consists of an earth pressure calculation unit and a friction resistance derivation unit. It adopts an FPGA + microcontroller architecture, with the FPGA (EP4CE6F17C8) responsible for rapid calculation of complex formulas, and the microcontroller handling data interaction and logic control.

[0153] Earth pressure calculation unit: receiving judgment module Data and the first measuring device Data collection Parameters, calculated using the relevant formulas described in Example 1 And thus obtain

[0154] ;

[0155] Friction resistance derivation unit: receiving earth pressure calculation unit Data collection Parameter calculation The frictional resistance of the tunnel boring machine is calculated according to the integral formula described in Example 1. The calculation results are output to the shield tunneling control system via the RS232 interface to adjust tunneling parameters (such as thrust and tunneling speed).

[0156] Data storage module: Employs a dual backup mode of SD card storage + cloud storage. The SD card has a capacity of 64GB and supports local data caching. Cloud storage is connected to the IoT platform via a 4G module. Input parameters for the storage determination module, the first measuring device, and the second measuring device (such as...) (etc.); calculation process data such as The output results are as follows: The storage format can be CSV, and it supports adding timestamps to the output data, as well as local reading and remote access.

[0157] The workflow of the implementation device includes:

[0158] After the device is started, the sensors in the determination module begin to collect the vertical pressure of the tunnel. Soil weight Basic parameters, and simultaneously acquire actual tunnel burial depth data;

[0159] The determination module completes the determination of burial depth type and , The calculation is performed, and the results are sent to the first and second measurement modules.

[0160] The first measurement module combines the received data and input parameters to calculate... And send it to the second measurement module;

[0161] The second measurement module calculates sequentially. , , , Finally, the frictional resistance is obtained. And output to the shield tunneling control system;

[0162] The data storage module stores the input, process, and output data of each module in real time, completing the entire process data recording.

[0163] The device described in this embodiment has a simple structure and high integration, and can be adapted to both shallow and deep burial construction scenarios. It has high measurement accuracy and fast response speed, and can provide reliable parameter support for shield tunneling under existing subway tunnels.

[0164] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel, characterized in that, include: Step 1: Determine the type of existing subway tunnel and shield tunnel based on the vertical pressure of the tunnel and the weight of the soil, and calculate the thickness of the overburden soil based on the type of shallow or deep tunnel. Step 2: Measure the soil pressure at the bottom of the existing subway tunnel based on the thickness of the overlying soil; Step 3: Based on the earth pressure at the bottom of the existing subway tunnel and the thickness of the overlying soil, the frictional resistance of the shield tunnel is determined.

2. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 1, characterized in that, Step 1 determines the type of existing subway tunnels and shield tunnels based on tunnel vertical pressure and soil weight, including: Discrimination formula: H p =(2~2.5)h q h q = In the formula, H p h is the dividing depth between shallow and deep tunnels. q Where is the equivalent height of the load, q is the vertical pressure of the tunnel, and γ is the weight of the soil. The judgment includes: when the tunnel burial depth H ≥ H p At that time, it was designated as a deep-buried tunnel, and when H <H p At that time, it was designated as a shallow-buried tunnel.

3. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 2, characterized in that, Step 1, determining the thickness of the overlying soil, includes: When the existing subway tunnel is a shallow-buried tunnel, H1 is the thickness of the overlying soil, that is, the actual thickness of the soil layer from the top of the existing subway tunnel to the ground surface. When it is a deeply buried tunnel, then H1 = In the formula, To balance the arch span of the tunnel; The friction angle within the soil.

4. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 3, characterized in that, The measurement formula in step 2 includes: based on the overlying soil thickness H1, F1=K v (γ1H1+γ1’D1)+T In the formula: F1 is the earth pressure at the bottom of the existing subway tunnel; K v γ1 is the vertical static earth pressure coefficient; γ1 is the weight of the soil overlying the existing subway tunnel; γ1' is the equivalent weight of the existing subway tunnel; H1 is the soil layer thickness; D1 is the diameter of the existing subway tunnel; T is the soil pressure at the bottom of the existing subway tunnel caused by the subway's self-weight and vibration, i.e., T=w(1+μ), where w is the vertical static live load of the subway and μ is the dynamic coefficient of the subway.

5. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 4, characterized in that, Step 3 includes: Measuring the surrounding earth pressure of the shield tunnel based on the earth pressure F1 at the bottom of the existing subway tunnel and the thickness H1 of the overlying soil. F2=F1+σ nr In the formula: F2 is the normal static earth pressure acting on the surface of the shield; F1 is the earth pressure at the bottom of the existing subway tunnel; σ nr This refers to the soil reaction force caused by the soil between the tunnel boring machine (TBM) and the existing subway tunnel, as well as the TBM itself.

6. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 5, characterized in that, Step 3 also includes the earth pressure coefficient K in any direction. θ , used to calculate σ nr , K θ = , where K h K is the coefficient of horizontal earth pressure at rest. v θ is the vertical at-rest earth pressure coefficient, and θ is the angle between the normal line at a point on the shield and the horizontal line.

7. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 6, characterized in that, Step 3 also includes the soil thickness H2 between the top of the shield and the bottom of the existing subway tunnel, used to calculate σ. nr : When the shield tunnel is a shallow-buried tunnel, H2 is the distance between the top of the shield and the bottom of the existing subway tunnel. When it is a deeply buried tunnel, let H2 = In the formula To balance the arch span of the shield tunnel, The friction angle within the soil.

8. The method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 7, characterized in that, In step 3, σ nr The measurement formula is: s nr =K θ [c2 (1-sinθ)+γ2H2],θϵ[0, ] s nr =K θ [γ2( +H2)-g e ' sinθ],θϵ[- ,0) In the formula, γ2 is the weight of the soil between the shield and the existing subway tunnel; D2 is the diameter of the shield; γ e The equivalent density of the tunnel boring machine (TBM) should be used for the corresponding TBM area, using the formula: c e '= Where w' is the weight of the tunnel boring machine and its equipment, and L is the length of the tunnel boring machine.

9. A method for measuring the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel according to claim 8, characterized in that, In step 3, the frictional resistance F of the shield tunnel is: F=2L In the formula: F is the frictional resistance of the tunnel boring machine; The friction coefficient between the soil and the shield shell. The calculation formula is =tanα, where α is the friction angle between the soil and the shield.

10. A measuring device for the frictional resistance of a shield tunnel boring machine passing under an existing subway tunnel, characterized in that, The method for measuring the frictional resistance of a shield tunnel boring machine (TBM) passing under an existing subway tunnel, as described in any one of claims 1-9, includes the following apparatus: Judgment module: used to obtain the vertical pressure of the tunnel and the weight of the soil, calculate the boundary depth between shallow and deep tunnels through a preset discrimination formula, determine the burial depth type of existing subway tunnels and shield tunnels by comparing the actual burial depth of the tunnel, and output the corresponding overlying soil thickness data. First measuring device: connected to the judgment module, receives the overlying soil thickness data, and calculates and outputs the soil pressure data at the bottom of the existing subway tunnel by combining the structural parameters and operating load parameters of the existing subway tunnel through a preset soil pressure formula. The second measuring device is connected to both the judgment module and the first pressure measuring module. It receives the overlying soil thickness data and the soil pressure data at the bottom of the existing subway tunnel. It combines the shield tunnel structural parameters, the soil parameters between the shield and the existing subway tunnel, and the shield machine's own parameters. It calculates the surrounding soil pressure of the shield tunnel using a preset circumferential soil pressure formula, and then derives and outputs the friction resistance of the shield tunnel based on a preset friction resistance formula. The data storage module is used to store the input parameters, calculation process data, and output results of the determination module, the first pressure measurement module, and the second pressure measurement module.

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