Device for researching seepage settlement of water-rich tunnel and testing method

Abstract

The invention discloses a test device and a test method for researching seepage settlement of a water-rich tunnel, belongs to the technical field of geotechnical engineering tests, and aims to disclose a disaster-causing mechanism of the water-rich tunnel and a difference between the disaster-causing mechanism and a settlement disaster-causing process of a typical engineering area. Comprising a model box, a tunnel model, a water injection-seepage system and a settlement-deformation monitoring system, the model box is filled with a soil layer, and the tunnel model is buried at the designed depth of the soil layer; the water injection-seepage system is buried in a soil layer, is used for injecting water into the soil layer to simulate a seepage process, and comprises a seepage pipe and a water injection pipe; the settlement-deformation monitoring system comprises settlement measuring rods for monitoring stratum settlement, and the settlement measuring rods have various specifications; the dial indicator is used for monitoring ground surface settlement; the soil pressure gauge is used for monitoring soil pressure; the pore water pressure gauge is used for monitoring pore water pressure; a moisture meter for monitoring moisture migration; and the reflective monitoring target spot is used for monitoring tunnel convergence.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of geotechnical engineering test, and particularly relates to a device and a test method for studying water-rich tunnel seepage settlement. BACKGROUND

[0002] The water-rich tunnel engineering often encounters stratum settlement problems caused by groundwater seepage in the construction process. The settlement is often superimposed with the loose deformation caused by tunnel excavation, resulting in more serious engineering disasters. At present, the stratum settlement mechanism research under the combined action of water-rich tunnel excavation and seepage is relatively lacking, especially lacking a test device and a test method capable of simultaneously simulating the single action and the combined action of excavation and seepage.

[0003] Therefore, an urgent need exists for a test device and a test method capable of simulating the stratum settlement characteristics of water-rich tunnels under the conditions of excavation, seepage and the combined conditions of excavation and seepage, so as to reveal the disaster-causing mechanism of water-rich tunnels and the difference between the disaster-causing process and the typical engineering area settlement. SUMMARY

[0004] The application provides a device and a test method for studying water-rich tunnel seepage settlement, aiming to reveal the disaster-causing mechanism of water-rich tunnels and the difference between the disaster-causing process and the typical engineering area settlement.

[0005] To this end, the application adopts the following technical scheme:

[0006] A test device for studying water-rich tunnel seepage settlement, comprising a model box, a tunnel model, a water injection-seepage system and a settlement-deformation monitoring system;

[0007] The model box is filled with a soil layer, and the tunnel model is buried at the designed depth of the soil layer;

[0008] The water injection-seepage system is buried in the soil layer and is used for injecting water into the soil layer to simulate the seepage process, and comprises a seepage pipe and a water injection pipe. The seepage pipe has holes on the pipe wall for seepage. The seepage pipe is longitudinally parallel to the tunnel model. The seepage pipes are evenly arranged above and below the left side and the right side of the tunnel model. Each seepage pipe is connected to and led out of the model box through the water injection pipe. The water in the water injection pipe seeps into the soil layer through the seepage pipe;

[0009] The settlement-deformation monitoring system comprises a settlement measuring rod for monitoring stratum settlement, a dial indicator for monitoring ground surface settlement, a dial indicator hanger, a soil pressure gauge for monitoring soil pressure, a pore water pressure gauge for monitoring pore water pressure and a moisture meter for monitoring water migration;

[0010] Reflective monitoring targets for monitoring tunnel convergence, strain gauges for monitoring lining strain, the reflective monitoring targets and the strain gauges are arranged in the tunnel model according to test requirements.

[0011] A test method for studying water-rich tunnel seepage settlement, comprising the test device, comprising the following steps:

[0012] 1) Test preparation: make a model box and a tunnel model, arrange reflective monitoring targets and strain gauges on the tunnel model; fill the soil layer according to the test requirements, and arrange various sensors and water injection-seepage systems during the filling process according to the test requirements;

[0013] 2) Test phase: inject water into the stratum simulation system through the water injection pipe, control the water injection flow rate, and stop water injection when all the water content meters show that the volume water content is more than 30%; stand for more than 48 hours to make the water fully distributed in the pores of the stratum;

[0014] 3) Data acquisition

[0015] Stratum settlement : obtained by the settlement measuring rod;

[0016] Surface settlement : obtained by the dial gauge;

[0017] Water content : obtained by the moisture meter;

[0018] Pore water pressure : obtained by the pore water pressure gauge;

[0019] Soil pressure : obtained by the soil pressure gauge;

[0020] Tunnel lining strain : obtained by the strain gauge;

[0021] Convergence displacement : obtained by the reflective monitoring target;

[0022] 4) Data preprocessing:

[0023] a. Abnormal value identification and processing: use the median absolute deviation method MAD to identify abnormal values; for the marked abnormal values, use the local weighted regression scatter smoothing method LOWESS for interpolation replacement:

[0024] b. Missing value processing: for missing values in the time series, different interpolation methods are used according to the data characteristics; such as cubic spline interpolation method, moving average interpolation method or other interpolation methods;

[0025] c. Noise filtering: Savitzky-Golay filter is used to smooth the data, which can effectively filter out high-frequency noise while retaining the characteristics of the data;

[0026] d. Time series alignment: due to the different sampling frequencies of each sensor, time series alignment is needed;

[0027] 5) Unit unification and data standardization:

[0028] a. Unit unification:

[0029] Settlement , : unified as millimeters mm

[0030] Water content : unified as percentage %

[0031] Pore water pressure : unified as kilopascal kPa

[0032] Soil pressure : unified as kilopascal kPa

[0033] Strain : unified as micro-strain

[0034] Convergence displacement : unified as millimeters mm

[0035] b. Data standardization: Z-score standardization method is used to facilitate comparison between different parameters:

[0036]

[0037] Where is the mean of the data, is the standard deviation of the data;

[0038] 6) Parameter correlation analysis:

[0039] Calculate the Pearson correlation coefficient matrix to analyze the correlation between each monitoring parameter:

[0040]

[0041] Where and are the mean values of X and Y, respectively;

[0042] 7) Settlement and seepage parameter relationship analysis:

[0043] Establish the functional relationship between effective stress and settlement:

[0044]

[0045] wherein is the settlement amount, is the initial settlement amount, is the compression coefficient, is the effective stress, is the initial effective stress;

[0046] Effective stress calculation formula:

[0047]

[0048] wherein is the total stress, is the pore water pressure.

[0049] The present application has the beneficial effects of:

[0050] 1. The test device provided by the present application can simulate the stratum settlement process of a water-rich tunnel under the conditions of only excavation, only seepage and combined excavation and seepage by controlling the opening and closing of the infiltration holes, and realize systematic research on the disaster-causing mechanism under different conditions.

[0051] 2. The present application uses transparent acrylic plates as the inner walls of the model box, which facilitates the direct observation of the soil deformation and water flow movement during the test process.

[0052] 3. The present application sets up a perfect monitoring system that can comprehensively collect multi-parameter data such as stratum settlement, ground settlement, water content, pore water pressure, soil pressure, tunnel lining strain, convergence displacement, etc., and provide comprehensive test data support for the research on the settlement mechanism of water-rich tunnels.

[0053] 4. The test method of the present application is simple to operate and comprehensive in data collection, and can provide scientific basis for the design and construction of water-rich tunnel projects. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a schematic diagram of the overall structure of the present application;

[0055] Figure 2 is a schematic diagram of the model box of the present application;

[0056] Figure 3 is a schematic diagram of the layout of the seepage system and water injection system of the present application;

[0057] Figure 4 is a schematic diagram of the layout of the monitoring system of the present application;

[0058] Figure 5 is a schematic diagram of the detailed structure of the monitoring system of the present application;

[0059] Figure 6This is a schematic diagram of the tunnel structure of the present invention;

[0060] Figure 7 This is a schematic diagram of the detailed structure of the tunnel according to the present invention;

[0061] Figure 8 This is a schematic diagram of the arrangement of reflective monitoring target points inside the tunnel structure according to the present invention;

[0062] In the diagram: 1. Water injection-seepage system; 2. Settlement-deformation monitoring system; 3. Model box; 4. Acrylic plate; 5. Stratigraphic simulation structure; 6. Tunnel structure; 11. Water intake pipe; 12. Seepage pipe; 13. Electronic flow valve; 14. Water injection pipe; 21. Settlement measuring rod; 22. Dial gauge; 23. Dial gauge bracket; 24. Moisture meter; 25. Pore water pressure gauge; 26. Earth pressure gauge; 61. Seepage opening; 62. Strain gauge; 63. Tunnel model; 64. Reflective monitoring target point. Detailed Implementation

[0063] The present invention will now be described in further detail with reference to the accompanying drawings:

[0064] like Figure 1 As shown, the present invention provides an experimental device for studying seepage settlement in water-rich tunnels, comprising a water injection-seepage system 1, a settlement-deformation monitoring system 2, a model box 3, an acrylic plate 4, a geological simulation structure 5, and a tunnel structure 6.

[0065] like Figure 2 As shown, model box 3 is a square box structure with external dimensions of 3.2m × 2.7m × 2.7m, assembled from welded 100mm × 100mm square steel beams. Its internal dimensions are 3m × 2.5m × 2.5m, lined with a 10mm thick transparent acrylic sheet 4. The joints of the transparent acrylic sheet 4 are bonded with epoxy resin and reinforced with waterproof butyl tape. The geological simulation structure 5 is the soil layer filling the model box 3, which is filled and compacted in layers.

[0066] like Figure 6 As shown, tunnel structure 6 is a resin (9400 material) tunnel model 63 made by 3D laser curing molding technology (SLS). The elastic modulus of tunnel model 63 is 2.22 GPa. Seepage openings 61 are reserved at the lining arch crown, arch shoulder, arch foot, and invert arch at distances of 35 cm and 55 cm from the initial tunnel section.

[0067] like Figure 3As shown in

[0068] As shown in Figure 4 and Figure 5 The settlement-deformation monitoring system 2 comprises:

[0069] A settlement measuring rod 21 for monitoring the settlement of the stratum, the settlement measuring rod 21 being an 8mm round steel jacketed PVC pipe with 10cm*10cm steel sheets welded at both ends, and comprising three specifications with lengths of 30cm, 60cm and 90cm respectively;

[0070] A dial gauge 22 for monitoring the surface settlement, and a dial gauge hanger 23;

[0071] A reflective monitoring target 64 for monitoring the convergence of the tunnel, the reflective monitoring target 64 being arranged at the crown, left and right spandrels, left and right haunches and inverted arches at distances of 15cm, 30cm, 45cm and 60cm from the portal;

[0072] A strain gauge 62 for monitoring the lining strain, the strain gauge 62 being pasted at the crown, spandrel, haunch and inverted arch at distances of 30cm and 50cm from the initial section;

[0073] A soil pressure gauge 26 for monitoring the earth pressure;

[0074] A pore water pressure gauge 25 for monitoring the pore water pressure;

[0075] A moisture meter 24 for monitoring the water migration.

[0076] As shown in Figure 6 and Figure 7 The data acquisition system comprises a first acquisition instrument (DH3823) for acquiring the tunnel deformation-strain data, the stratum earth pressure data and the pore water pressure data, a second acquisition instrument (DH5922D) for acquiring the stratum moisture content data, a third acquisition instrument (BJQN-V) for acquiring the tunnel convergence deformation data, and a concentrator (5010-321) for acquiring the stratum settlement and surface settlement data.

[0077] The test method of the present application comprises the following steps:

[0078] I. Test preparation

[0079] 1. A model box 3 with external dimensions of 3.2m x 2.7m x 2.7m is made, and the main skeleton of the model box 3 is welded from 10cm x 10cm square steel beams. A 10mm thick transparent acrylic plate 4 is installed inside, and the transparent acrylic plate 4 is fixed inside the model box 3 by bolts, flexible gaskets are used for bolt hole positions, and epoxy resin is applied to the nuts to prevent water;

[0080] 2. The strain gauges 62 are processed, and the tail wires of the strain gauges 62 are connected to extension cables. Tin is applied to the connection for reinforcement, and electrical tape is wrapped around the insulation for insulation. A heat shrink tube is used externally for waterproofing and reinforcement;

[0081] 3. On the lining model of the tunnel model 63, draw a marking line at a 45° angle to the direction of the posted direction, and polish the position where the strain gauges 62 need to be pasted. Use 502 adhesive to paste the strain gauges 62 at the crown, spandrel, springing, inverted arch positions at a distance of 30cm, 50cm from the initial section. After reaching the 502 bonding strength, cover the strain gauges 62 with 703 silicone rubber. When the silicone rubber reaches the bonding strength after standing for 24 hours, cover a layer of gauze on top of the silicone rubber, and evenly apply epoxy resin on top of the gauze to completely cover the lower layer of 703 silicone rubber;

[0082] 4. Use a rubber plug to block the seepage opening 61 to ensure that it does not accidentally come off during the test, and paste a 200-mesh steel mesh on the outside of the seepage opening 61 to prevent soil and sand particles from being carried into the tunnel lining with the seepage of water;

[0083] 5. Fill the test soil into the model box 3 to a height of 80cm, and bury the lower seepage pipe 12 and the sensor. The seepage pipe 12 is two pipes with a diameter of 16mm and a length of 2m, with an opening interval of 20cm;

[0084] 6. Fill the test soil into the tunnel lining and fill it solid, and then place the tunnel structure 6 at the centerline position of the model box 3;

[0085] 7. Continue to fill the soil to a height of 230cm, and bury the upper seepage system, sensors and settlement measuring rod 21;

[0086] 8. Set up a dial gauge 22 measuring head gasket on the ground surface, fix the dial gauge 22 on a specially designed dial gauge hanger 23 and adjust the position to maximize the dial gauge 22 reading;

[0087] 9. Electrically connect each sensor, dial gauge 22 and corresponding acquisition instrument, and turn on the data acquisition function;

[0088] 10. Inject water into the stratum simulation system through the water injection pipe 14, set the flow rate to 2L / min, and stop injecting water when all the moisture meters 24 show a volume moisture content of more than 30%;

[0089] 11. Let stand for 48 hours to allow moisture to fully distribute in the pores of the formation.

[0090] II. Experimental Phase

[0091] 1. Open the tunnel closure acrylic plate 4, and apply waterproof glue to the contact gap between the tunnel structure 6 and the acrylic plate 4 of the model box 3 to prevent groundwater from seeping out of the gap and interfering with the test results;

[0092] 2. The reflective monitoring target 64 is set at the vault, left and right spandrels, left and right arch feet, and inverted arch at 15 cm, 30 cm, 45 cm, and 60 cm from the entrance 15. The three steps are numbered 1, 2, and 3. Use a graduated Luoyang shovel to excavate forward with a 5 cm step. When the first section is completely exposed, paste the reflective monitoring target 64 at the vault and spandrel positions of 115. Monitor the convergence data of 1-vault, 1-spandrel R, and 1-spandrel L. Continue to excavate forward when the convergence data is stable. After 215 is exposed, paste the reflective monitoring target 64 at the left and right arch feet of 215. Monitor the convergence data of 1-arch foot R and 1-arch foot L. Continue to excavate forward when the data is stable. After 3-15 is exposed, paste the reflective monitoring target 64 at the inverted arch position of 3-15. Monitor the convergence data of 1-inverted arch. Continue to excavate forward when the convergence data is stable. Repeat the above steps until the tunnel lining model is completely excavated.

[0093] 3. After all the data of the reflective monitoring target 64 is stable, remove the rubber plug of the seepage opening 61 to allow the formation water to enter the tunnel interior from the tunnel seepage opening 61. Place a water collector in the tunnel to measure the water volume. Continue to collect the surface and formation settlement data.

[0094] III. Data Collection

[0095] 1. The data collection system collects the following parameters through the first collection instrument (DH3823), the second collection instrument (DH5922D), the third collection instrument (BJQN-V), and the concentrator (5010-321):

[0096] Formation settlement: obtained through the settlement measuring rod 21, with a sampling frequency of 2 times / hour; Surface settlement: obtained through the dial indicator 22, with a sampling frequency of 2 times / hour;

[0097] Water content: obtained through the moisture meter 24, with a sampling frequency of 20 times / second;

[0098] Pore water pressure: obtained through the pore water pressure gauge 25, with a sampling frequency of 5 times / second;

[0099] ​​​​

[0100] Soil pressure (Psoil): Obtained by soil pressure cell 26, sampling frequency 5 Hz;

[0101] Tunnel lining strain (εlin): Obtained by strain gauges 62, sampling frequency 5 Hz;

[0102] Convergence displacement (δcon): Obtained by retro-reflective monitoring targets 64, sampling frequency 60 Hz.

[0103] IV. Data Preprocessing

[0104] 1. Outlier identification and treatment: Median Absolute Deviation (MAD) method is used to identify outliers. For time series data , the following is calculated:

[0105]

[0106] Outlier criterion: If , then is marked as an outlier.

[0107] For marked outliers, Local Weighted Regression Scatterplot Smoothing (LOWESS) is used for interpolation replacement:

[0108]

[0109] where , when , is the local window width.

[0110] 2. Missing value treatment: For missing values in time series, different interpolation methods are used according to data characteristics:

[0111] For slowly varying parameters (such as water content, settlement): Cubic spline interpolation method is used

[0112] ,

[0113] where coefficients , , , are obtained by solving linear equations.

[0114] For fast varying parameters (such as water pressure, strain): Moving average interpolation method is used

[0115]

[0116] where ​​​For moving average window half-width.

[0117] 3. Noise filtering: data smoothing was performed using Savitzky-Golay filter, which effectively filtered out high-frequency noise while preserving data characteristics:

[0118]

[0119] where is the convolution coefficient, determined by the polynomial fitting order and window width. A 3rd order polynomial with a window width of 11 data points was used in this study.

[0120] 4. Time series alignment:

[0121] Due to different sampling frequencies of sensors, time series alignment was needed. A resampling method based on linear interpolation was used to unify the time step to 1 hour:

[0122] ,

[0123] where is the resampling time point, and are the adjacent original time points.

[0124] Five, unit unification and data standardization

[0125] 1. Unit unification:

[0126] Settlement ( , ): unified to millimeter (mm)

[0127] Water content ( ): unified to percentage (%)

[0128] Pore water pressure ( ): unified to kilopascal (kPa)

[0129] Earth pressure ( ): unified to kilopascal (kPa)

[0130] Strain ( ): unified to micro-strain ( )

[0131] Convergence displacement ( ): unified to millimeter (mm)

[0132] 2. Data standardization: Z-score standardization method was used to facilitate comparison between different parameters:

[0133]

[0134] where is the data mean, is the data standard deviation.

[0135] Six. Parameter correlation analysis

[0136] Calculate the Pearson correlation coefficient matrix to analyze the correlation between each monitoring parameter:

[0137]

[0138] where and are the mean values of X and Y, respectively.

[0139] Seven. Analysis of the relationship between settlement and seepage parameters

[0140] Establish the functional relationship between effective stress and settlement:

[0141]

[0142] where is the settlement, is the initial settlement, is the compression coefficient, is the effective stress, is the initial effective stress.

[0143] Effective stress calculation formula:

[0144]

[0145] where is the total stress, is the pore water pressure.

[0146] Table 1. Water content data (%)

[0147] Position Time (h) 130-01 130-02 160-01 160-02 SF-160-01 SF-160-02 SF-190-01 SF-190-02 0 30.06 30.11 29.91 29.94 38.70 37.10 39.41 34.83 10 30.09 30.13 29.93 30.07 38.70 37.10 39.40 34.45 15 30.08 30.13 29.93 30.07 38.70 37.12 39.42 34.15 20 30.02 30.07 29.87 30.02 38.72 37.14 39.43 34.05 30 30.05 30.08 29.88 30.03 38.70 37.13 39.41 33.95 35 30.07 30.10 29.90 30.05 38.70 37.15 39.45 33.80 38 30.02 30.07 29.85 30.03 38.75 37.16 39.48 33.70 40 29.96 30.01 29.79 29.95 38.82 37.15 39.51 33.61

[0148] Table 2. Surface settlement and stratum displacement data (mm)

[0149] Position Time (h) Cross Section 1 Ground Settlement Cross Section 2 Ground Settlement Strata Displacement 0 0.00 0.00 0.00 10.8 -0.60 -0.90 -2.10 22.8 -0.95 -1.15 -3.90 31.5 -1.10 -1.35 -4.80 38.0 -1.40 -2.00 -5.90 66.0 -2.95 -4.20 -12.40 90.5 -8.95 -13.20 -27.10

[0150] Table 3. Tunnel convergence deformation data (mm)

[0151] Position Time (h) 1 - Crown Displacement 2 - Crown Displacement 3 - Crown Displacement 4 - Crown Displacement 0 0.00 0.00 0.00 0.00 5 -1.50 -2.50 -0.50 -0.50 10 -2.75 -3.40 -0.70 -0.80 15 2.00 5.00 6.30 2.50 20 5.00 8.00 8.00 4.00 30 11.00 10.00 9.50 6.00 40 15.00 13.50 13.00 12.50

[0152] Table 4. Pore water pressure change value (kPa)

[0153] Position Time (h) KY-110-02 KY-130-02 KY-190-01 KY-190-02 0 -0.10 -0.15 0.05 4.45 2 -0.30 -0.30 0.07 4.65 4 -0.50 -0.45 0.08 4.90 6 -0.75 -0.60 0.08 5.00 8 -1.05 -0.75 0.10 5.05 10 -0.70 -0.98 0.12 5.15

[0154] Table 5. Settlement influence range data (mm)

[0155] Monitoring Position Cross Section 1 Settlement Cross Section 2 Settlement 1 -2.50 -3.50 2 -3.20 -6.00 3 -5.50 -8.50 4 -7.00 -11.00 5 -8.00 -12.50 6 -8.80 -13.10 7 -8.95 -13.20 8 -8.80 -12.50 9 -6.20 -9.00 10 -3.20 -3.80 11 -1.00 -1.20 12 -0.60 -0.70 13 -0.30 -0.50

[0156] Example

[0157] 1. Data Preprocessing

[0158] 1) Outlier Identification and Treatment

[0159] Apply the Median Absolute Deviation (MAD) method, taking the water content sensor 190-02 data as an example:

[0160] Original data sequence:

[0161]

[0162] Calculate the median:

[0163] Calculate the absolute value of the deviation:

[0164]

[0165] Median of the absolute value of the deviation:

[0166] Outlier determination threshold:

[0167] Determination: No outliers need to be treated, as all deviation values are less than 1.33

[0168] The 190-02 sensor has a significant outlier at time point about 10h, apply the LOWESS method to process:

[0169] Outlier point: 38.80% (t=10.2h)

[0170] Surrounding points:

[0171] Weight function: When , otherwise

[0172] Substitute value = 40.08% (calculated value after weighted regression)

[0173] 2) Missing value treatment

[0174] Take the ground settlement data as an example, assume that section 1 has a missing value at t=25h, apply cubic spline interpolation:

[0175] Neighboring data points:

[0176] (22.8h, -0.95mm), (31.5h, -1.10mm)

[0177] Cubic spline interpolation coefficient calculation:

[0178] , , , .

[0179] Interpolation result:

[0180]

[0181]

[0182] mm

[0183] 3) Noise filtering

[0184] Apply Savitzky-Golay filter to smooth the convergence displacement data, take 1-arch longitudinal data as an example:

[0185] Use window width 11, 3-order polynomial fitting

[0186] Original data sequence (part):

[0187]

[0188] Filtered data sequence:

[0189] Savitzky-Golay convolution coefficient:

[0190]

[0191] 4) Time series alignment

[0192] Time alignment for data with different sampling frequencies, unified to 1h step:

[0193] Align moisture meter data (20 times / second) with settlement rod data (2 times / hour):

[0194]

[0195] Moisture meter original time point: , ; ,

[0196] Linear interpolation:

[0197]

[0198] 5) Unit unification and data standardization

[0199] Unit unification:

[0200] Settlement (S): , ) is unified as millimeter (mm)

[0201] Moisture content (M): ) is unified as percentage (%)

[0202] Pore water pressure (P): ) is unified as kiloPascal (kPa)

[0203] Earth pressure (E): ) is unified as kiloPascal (kPa)

[0204] Strain (ε): ) is unified as micro-strain (με)

[0205] Convergence displacement (D): ) is unified as millimeter (mm)

[0206] Z-score standardization example (using 190-02 sensor moisture content as an example):

[0207] Mean of original data: 39.42%

[0208] Standard deviation: 0.87%

[0209] Normalized value t=10h:

[0210] 2. Parameter correlation analysis

[0211] Calculate the Pearson correlation coefficient between moisture content and surface settlement:

[0212] 190-02 moisture content data:

[0213] Section 2 settlement data:

[0214] Mean: moisture content mean = 39.68%, settlement mean

[0215] Covariance calculation:

[0216]

[0217]

[0218] Standard deviation: ​,

[0219] Correlation coefficient:

[0220] 3. Analysis of the relationship between settlement and seepage parameters

[0221] Calculate the settlement using the effective stress principle:

[0222] Calculate the change in effective stress:

[0223] Initial state t=0h:

[0224] Total stress: (KY-110-02 location)

[0225] Pore water pressure:

[0226] Effective stress:

[0227] Final state t=10h:

[0228] Total stress:

[0229] Pore water pressure:

[0230] Effective stress:

[0231] Effective stress increment:

[0232] Calculate the compression coefficient:

[0233] Initial settlement:

[0234] Final settlement: (Cross section 1)

[0235]

[0236] 4. Application of the prediction model

[0237] Create a settlement prediction model based on the patent formula:

[0238] Fit the surface transverse settlement tank with a modified Gaussian curve model:

[0239]

[0240] Parameter fitting (cross section 1):

[0241] , (curve center position),

[0242] The calculated impact width:

[0243]

[0244] The time evolution model:

[0245]

[0246] The parameter fitting:

[0247] ,

[0248] The predicted settlement at t=120h:

[0249]

Claims

1. A test device for studying seepage settlement of a water-rich tunnel, characterized in that, The model box, the tunnel model, the water injection-seepage system and the settlement-deformation monitoring system are included. The soil layer is filled in the model box, and the tunnel model is buried in the soil layer at the designed depth. The tunnel model is made of resin material, and the seepage openings are reserved in the lining crown, spandrel, springing and inverted arch of the tunnel model at 30-40 cm, 50-60 cm from the initial section of the tunnel. The rubber plugs are sealed in the seepage openings, and the steel gauze is covered outside the seepage openings to prevent the soil and silt from entering the tunnel model. The water injection-seepage system is buried in the soil layer to inject water into the soil layer to simulate the seepage process, and includes the seepage pipes and the water injection pipe. The seepage pipes have the holes for seepage on the pipe wall, and the seepage pipes are longitudinally parallel to the tunnel model. The seepage pipes are evenly arranged above and below the left and right of the tunnel model, and are connected to the water injection pipe and led out of the model box. The water in the water injection pipe seeps into the soil layer through the seepage pipes. The settlement-deformation monitoring system includes the settlement measuring rods for monitoring the ground settlement, the settlement measuring rods including multiple specifications, the dial indicator for monitoring the ground settlement, the dial indicator hanger, the soil pressure gauge for monitoring the soil pressure, the pore water pressure gauge for monitoring the pore water pressure, and the moisture meter for monitoring the water migration. The reflective monitoring target for monitoring the convergence of the tunnel and the strain gauge for monitoring the lining strain are arranged in the tunnel model according to the test requirements.

2. The test apparatus for studying seepage settlement of a water-rich tunnel according to claim 1, characterized in that, The settlement measuring rod is made of the 8mm round steel reinforced PVC pipe and the 10cm*10cm steel sheet welded at both ends, and includes three specifications with the lengths of 30cm, 60cm and 90cm.

3. The test apparatus for studying seepage settlement of a water-rich tunnel according to claim 1, wherein, The reflective monitoring target is arranged at the crown, left and right spandrels, left and right springings and inverted arches at 15cm, 30cm, 45cm and 60cm from the tunnel model portal.

4. The test apparatus for studying seepage settlement of a water-rich tunnel according to claim 1, wherein, The strain gauge is pasted at the crown, spandrel, springing and inverted arch at 30cm and 50cm from the initial section of the tunnel model.

5. The test apparatus for studying seepage settlement of water-rich tunnel according to claim 1, characterized in that, The data acquisition system is further included, and includes the first acquisition instrument for acquiring the tunnel deformation-strain data, the ground soil pressure data and the pore water pressure data, the second acquisition instrument for acquiring the ground water content data, the third acquisition instrument for acquiring the tunnel convergence deformation data, and the concentrator for acquiring the ground settlement and the ground surface settlement data.

6. A test method for studying seepage settlement of a water-rich tunnel, characterized by, The test device of any one of claims 1-5 is included, and includes the following steps: 1) Test preparation: the model box and the tunnel model are made, and the reflective monitoring target and the strain gauge are arranged on the tunnel model; the rubber plug is used to seal the seepage opening to ensure that the seepage opening is not accidentally opened during the test, and the steel gauze is pasted outside the seepage opening to prevent the soil and silt particles from being brought into the tunnel lining with the seepage of water; the soil layer is filled according to the test requirements, and various sensors and the water injection-seepage system are arranged during the filling process according to the test requirements; 2) Test stage: water is injected into the ground formation simulation system through the water injection pipe, and the water injection flow rate is controlled. When all the moisture meters show that the volume water content is more than 30%, the water injection is stopped. The water is left to stand for more than 48 hours to make the water fully distributed in the pores of the ground formation; 3) Data acquisition Formation subsidence : Obtained from subsidence gauges; Ground settlement : Obtained by dial gauge; Moisture content : Obtained by moisture meter; Pore water pressure : Obtained by pore water pressure meter; Soil pressure : Obtained by soil pressure cell; Tunnel lining strain : Obtained by strain gauges; Convergent displacement : acquisition by retro-reflection 4) Data preprocessing: a. Outlier identification and processing: the median absolute deviation method (MAD) is used to identify outliers; for the marked outliers, the locally weighted regression scatter smoothing method (LOWESS) is used for interpolation replacement: b. Missing value processing: for missing values in time series, different interpolation methods are used according to the characteristics of the data, such as cubic spline interpolation, moving average interpolation or other interpolation methods; c. Noise filtering: Savitzky-Golay filter is used for data smoothing, which can effectively filter out high-frequency noise while retaining data characteristics; d. Time series alignment: Due to the different sampling frequencies of each sensor, time series alignment is needed; 5) Unit unification and data standardization: a. Unit unification: Sedimentation , : unified to millimeters mm moisture content : unified in percentage % Pore water pressure : unified to kilopascal kPa Soil pressure : unified in kilopascal kPa strain : uniform micro-strain ; Convergent displacement : unified in millimeters mm b. Data standardization: Z-score standardization method is used to facilitate comparison between different parameters: ； wherein is the data mean, is the data standard deviation; 6) Parameter correlation analysis: Calculate the Pearson correlation coefficient matrix to analyze the correlation between monitoring parameters: ； wherein and are the average values of X and Y, respectively; 7) Analysis of the relationship between settlement and seepage parameters: Establish the functional relationship between effective stress and settlement: ； wherein is the settlement, is the initial settlement, is the compression coefficient, is the effective stress, is the initial effective stress; Effective stress calculation formula: ； wherein is the total stress, is the pore water pressure.

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