A kind of earth-rockfill dam type seepage prevention method for coping with uneven settlement

Abstract

The present application relates to the technical field of building construction methods, and particularly relates to a soil-rock mixed dam type anti-seepage method for coping with uneven settlement, which comprises the following steps: S1: potential deformation area identification and pre-crack setting; S2: microbial repair system and monitoring sensor pre-burying; S3: dam body filling construction and system protection; S4: running period deformation monitoring and threshold early warning; and S5: electric power driven targeted repair. In the present application, through geological survey and numerical simulation analysis before construction, the potential deformation area in which cracks may be generated due to uneven settlement in the dam body is accurately identified, and a pre-crack is actively set in the area to guide stress release, so that the uncontrollable random cracks are changed into controllable induced cracks, and the change from passive coping to active guidance is realized, and the risk of concentrated seepage channel formation is reduced from the source.

Description

Technical Field

[0001] This invention relates to the field of building construction methods, and in particular to a seepage prevention method for earth-rock mixed dams to cope with uneven settlement. Background Technology

[0002] In the field of water conservancy engineering, earth-rock dams are widely used due to their advantages such as the availability of local materials and strong adaptability. However, due to the differences in the properties of the dam filling materials and the unevenness of the foundation conditions, earth-rock dams are prone to uneven settlement during construction and operation. This uneven settlement often leads to localized areas of tensile stress concentration within the dam body. When the tensile stress exceeds the tensile strength of the soil, cracks will be triggered. Once these cracks form, they become weak points within the dam body and are easily developed into concentrated seepage channels under the pressure of reservoir water. This not only affects the normal water storage benefits of the reservoir but may also cause soil loss within the dam body, i.e., piping, and in severe cases, even endanger the overall structural stability and safety of the dam.

[0003] Traditional countermeasures primarily rely on passive engineering methods, such as grouting repairs after cracks appear or stress relief through settlement joints during the design phase. However, these methods often struggle to accurately predict the exact location and timing of crack formation, representing a reactive approach with sometimes unsatisfactory results. Furthermore, while conventional deformation monitoring technologies can detect anomalies, the time lag between detection and intervention allows minor initial damage to develop into severe seepage channels. Therefore, transforming passive repair into proactive prevention and control, endowing the dam body with self-sensing and self-repairing capabilities, and achieving full-process deformation control from construction to operation is a crucial problem urgently needing to be solved in the field of earth-rock dam engineering. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a seepage prevention method for earth-rock hybrid dams to cope with uneven settlement, thereby solving the technical problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A seepage prevention method for earth-rock hybrid dams to cope with uneven settlement includes the following steps:

[0007] S1: Identification of potential deformation zones and setting of pre-cracks. Potential deformation zones within the dam body are identified through geological surveys and numerical simulations. During the filling process in these areas, high-pressure water jets are used to cut trenches to form pre-cracks for guiding stress release.

[0008] S2: Microbial remediation system and monitoring sensor pre-embedded, a microbial remediation system including a bacterial solution fixation layer and an electrode array is pre-embedded within the potential deformation zone, and a multi-point displacement meter and fiber optic strain sensor for real-time monitoring of soil deformation are also pre-embedded.

[0009] S3: Dam body filling construction and system protection, continue to fill the dam body in layers, take protective measures for the pre-embedded electrodes, sensors and their leads during the filling process, and connect all lines to the dam top control center;

[0010] S4: Deformation monitoring and threshold early warning during operation. During the operation of the dam, strain and displacement data are collected in real time by monitoring sensors, and judgment and processing are performed according to preset multi-level thresholds.

[0011] S5: Electrodynamic targeted repair. When the monitoring data triggers a level 3 warning, it automatically applies a DC voltage to the electrode array in the corresponding area to form an electric field. At the same time, it injects calcium source solution through the pre-embedded injection branch pipe at the anode to induce microorganisms to generate calcium carbonate precipitate to fill the crack.

[0012] Preferably, in step S1, the identification of potential deformation zones within the dam body through geological survey and numerical simulation specifically includes: establishing a three-dimensional geological model containing dam foundation and dam body material zones based on borehole sampling, indoor geotechnical tests, and field test data from the geological survey; calculating the stress-strain field of each unit within the dam body using finite element numerical simulation software according to the actual construction sequence and changes in operating water level; comparing the calculated maximum principal tensile stress with the tensile strength of the soil, and defining the area where the maximum principal tensile stress reaches more than 0.8 times the tensile strength of the soil as a potential deformation zone.

[0013] Preferably, in step S1, the setting of the pre-cracks specifically includes: when filling to the elevation of the potential deformation zone, after the filling material of this layer is compacted and before the upper layer is filled, using a high-pressure water jet cutting device to cut according to the design grid; the cutting direction of the trench is determined according to the direction of the maximum principal tensile stress obtained by numerical simulation, and is set to be perpendicular to the direction of the principal tensile stress; after the cutting is completed, the trench is not filled with material temporarily, so that it will naturally close under the subsequent filling load to form a weak surface.

[0014] Preferably, in step S2, the pre-embedded microbial remediation system includes a bacterial solution fixation layer and an electrode array; the bacterial solution fixation layer is made by uniformly mixing bacterial-loaded ceramic particles, slow-release urea particles and medium-coarse sand and laying it on both sides of the pre-cracks in the potential deformation zone, and the surface is covered with permeable geotextile after laying; the electrode array is arranged in a square grid within the potential deformation zone.

[0015] Preferably, the electrodes in the electrode array are made of conductive material with annular grooves on the surface, and the anodes and cathodes are arranged alternately in a checkerboard pattern, that is, the adjacent nodes of each anode are cathodes, and the adjacent nodes of each cathode are anodes; the electrode array is divided into multiple independently controllable blocks along the dam axis, and each electrode is connected to the DC power supply cabinet through an insulated wire.

[0016] Preferably, in step S2, an injection branch pipe is simultaneously buried at the anode location. One end of the injection branch pipe extends into the soil surrounding the anode, and an outlet hole is opened in the pipe wall and wrapped with permeable geotextile. The other end is connected to the calcium source delivery pipeline on the top of the dam through a solenoid valve.

[0017] Preferably, in step S4, the preset multi-level thresholds include: a first-level warning threshold, used to trigger data recording and technician notification; a second-level warning threshold, used to trigger automatic inspection of the status of electrodes, injection pipelines and bacterial fixation layers in the corresponding area; and a third-level warning threshold, used to automatically trigger the electrodynamic repair procedure for that area.

[0018] Preferably, in step S5, the electrodynamic targeted repair specifically includes: using the cathode as the target reinforcement area and the anode as the calcium source injection area, applying a DC voltage to form an electric field; estimating the injection volume based on the pore volume of the anode area, and opening the injection solenoid valve corresponding to the anode to inject calcium chloride solution; calcium ions migrate to the cathode under the action of the electric field, and combine with carbonate ions generated by the hydrolysis of urea by microbial urease in the cathode area to form calcium carbonate precipitate.

[0019] Preferably, in step S5, strain and current changes are continuously monitored during the repair process. When the strain value drops below the set value and shows no increasing trend, or when the current value drops by more than a set proportion from the initial time, the electric field application and calcium source injection are automatically stopped.

[0020] Beneficial effects compared to existing technologies:

[0021] 1. In this plan, through geological survey and numerical simulation analysis before construction, potential deformation zones that may be caused by uneven settlement inside the dam body are accurately identified, and pre-cracks are proactively set in these areas to guide stress release, transforming uncontrollable random cracks into controllable induced cracks. This achieves a shift from passive response to proactive guidance, reducing the risk of concentrated seepage channels from the source.

[0022] 2. In this scheme, by pre-embedding a microbial liquid fixation layer and an electrode array in the potential deformation zone and constructing an electric field-driven calcium source directional migration, the repair material can accurately reach the deformation area and work together with the calcium carbonate precipitate induced by microorganisms to achieve instant targeted filling of microcracks. This electrodynamic and biomineralization coupled repair mechanism significantly improves the targeting and effectiveness of the repair.

[0023] 3. In this solution, by linking the real-time deformation monitoring system with the electrodynamic repair system and setting multi-level early warning thresholds, once the monitoring data reaches the preset triggering conditions, the repair program can be automatically started without manual intervention. This realizes the transformation of the dam from simple deformation monitoring to intelligent protection of the entire process of self-sensing, self-diagnosis, and self-repair, which greatly improves the timeliness of dealing with uneven settlement. Attached Figure Description

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the overall structure of the earth-rock hybrid dam of the present invention;

[0026] Figure 2 This is a schematic diagram of the electrode array layout structure of the present invention;

[0027] Figure 3 This is a schematic diagram of the steps of the seepage prevention method of the present invention.

[0028] Legend: 100, Main body of earth-rock dam; 200, Monitoring hole; 300, Dam axis of earth-rock dam. Detailed Implementation

[0029] Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can also be implemented in various different forms, and therefore the present invention is not limited to the embodiments described below. In addition, for the purpose of more clearly describing the present invention, parts not connected to the invention will be omitted from the drawings.

[0030] The technical solutions in this application are designed to address the problems described in the background, and are generally as follows:

[0031] Example:

[0032] This embodiment introduces a seepage prevention method for earth-rock hybrid dams to address uneven settlement. More specifically, it provides an active seepage prevention method that combines potential deformation zone identification and pre-crack guidance, pre-embedding of a microbial remediation system, deformation monitoring, and electrodynamic targeted repair to address cracks that may arise within the dam body due to uneven settlement. This method actively intervenes in the settlement process from the construction phase through full-process control and endows the dam body with self-sensing and self-repairing capabilities during operation, thereby effectively preventing the formation of seepage channels caused by uneven settlement.

[0033] The monitoring system used in this embodiment includes a multi-point displacement gauge, a fiber optic strain sensor, a data acquisition module, and a dam crest control center. The multi-point displacement gauge measures the relative displacement of the soil at different depths, with a range of ±50 mm, an accuracy of 0.1 mm, and an output signal of a 4 mA-20 mA current loop. The fiber optic strain sensor, using a Bragg grating, measures micro-strain changes in the soil, with a resolution of 1×10⁻⁶. −6 The wavelength range is 1510 nm-1590 nm. All sensor signals are collected at the dam crest control center via a distributed fieldbus, with a sampling frequency of 1 Hz. The control center has an embedded data processing algorithm that can calculate the strain at each measuring point in real time. and displacement It will automatically trigger subsequent repair procedures based on preset thresholds.

[0034] S1: Identification of Potential Deformation Zones and Pre-crack Setting in the Dam Body

[0035] Before commencing dam construction, a detailed geological survey of the dam site area must be conducted. For example... Figure 1 As shown, the main body of the earth-rock dam, 100mm, is arranged along the dam axis, 300mm, which serves as the baseline for the dam design. The exploration work includes drilling exploratory boreholes along the dam axis. In this embodiment, the borehole spacing along the main exploration line is set to no more than 50m, with 3-5 boreholes arranged on each exploration line. The borehole depth should penetrate 5-10m below the relatively impermeable layer of the dam foundation; the specific depth can be adjusted according to the bedrock depth. Soil samples taken from the boreholes are subjected to indoor geotechnical tests to determine their physical and mechanical properties, including density, water content, liquid and plastic limits, compressibility coefficient, consolidation coefficient, shear strength, and tensile strength. Tensile strength... For cohesive soils, the results were determined by uniaxial tensile testing or Brazilian splitting test. The value range is generally 20 kPa-50 kPa; for sand and gravel, The range of values ​​is generally 5 kPa to 15 kPa, with the specific value determined based on actual soil property test results. Field tests include standard penetration tests and static cone penetration tests to obtain in-situ mechanical parameters of the soil. Geophysical exploration uses ground-penetrating radar and high-density electrical resistivity tomography to continuously detect stratigraphic interfaces and potential weak zones, supplementing the information obtained from boreholes.

[0036] Based on survey and experimental data, a three-dimensional geological model of the dam site area was established. The modeling process included: digitizing the borehole columnar sections and extracting the elevations of each soil layer interface; using Kriging interpolation, a geostatistical method, to spatially interpolate the discrete borehole data and generate continuous stratigraphic layers; constructing a three-dimensional solid model using tetrahedral or hexahedral elements based on the stratigraphic layers, with element sizes controlled between 1 m and 5 m, adjusted according to the model scale and computational accuracy requirements; assigning corresponding material parameters to each solid element, including density, elastic modulus, Poisson's ratio, cohesion, internal friction angle, and tensile strength. The model should include the soil and rock layers of the dam foundation, the zoning of the proposed dam body's fill materials, and topographic features. The model boundary should extend beyond the dam foundation's influence zone, with the bottom boundary extending below the relatively impermeable layer and the lateral boundaries extending beyond twice the dam height from the dam toe.

[0037] Based on a three-dimensional geological model, finite element numerical simulation software was used to calculate the stress-strain field of the dam body under water load during the phased filling process and operation period. The calculation needs to consider the layered nonlinear constitutive relationship of the filling material, for example, using a Duncan-Chang hyperbolic model. The model parameters, including the failure ratio, were determined through indoor triaxial compression tests. Elastic modulus Elastic modulus index Cohesion internal friction angle The simulation process should follow the actual construction sequence, activating the filling units step by step. The filling thickness for each step can be 1 m-2 m, and a corresponding self-weight load should be applied. Simultaneously, reservoir water pressure should be considered, and the upstream water level should be raised step by step, by 5 m-10 m each step, until the normal storage level is reached. The calculation uses an incremental iterative method, iterating under each load level until convergence. The convergence criterion can be set as a displacement increment of less than 0.1 mm.

[0038] Numerical simulation was used to extract the maximum principal tensile stress of each element inside the dam body at each calculation step. and the tensile strength of the soil Compare. Will satisfy ≥0.8 The area was designated as a potential deformation zone. Furthermore, the spatial distribution, depth, and orientation of these areas are analyzed. These areas are typically located directly above abrupt changes in the thickness of the dam foundation overburden, at the contact zone between the dam body and the bank slope, at the boundary between different material zones, and in the tensile stress concentration zone in the middle of the dam body. For each potential deformation zone, its tensile stress safety factor can also be calculated. ,when When the value is less than 1.2, it is considered a high-risk area and requires special attention.

[0039] Within the potential deformation zone, proactive intervention measures are taken to pre-create controllable microcracks, guiding the release of stress generated by future uneven settlement in these areas. Specifically, when filling to the elevation of the potential deformation zone, after compaction of this layer of fill material and before the next layer is filled, a high-pressure water jet cutting device is used to cut longitudinal trenches on the surface of the potential deformation zone according to the design grid. In this embodiment, the trench depth is... A width of 0.3 m to 0.5 m is acceptable. A groove spacing of 5 mm to 10 mm is acceptable. The trench width can be 2-3 m, with the specific value adjusted according to the dam size and stress distribution. The trench direction should be perpendicular to the expected direction of the maximum principal tensile stress, which can be determined through numerical simulation results. It is typically the direction of the dam axis or parallel to the bank slope. During cutting, the water jet pressure can be controlled at 30 MPa-50 MPa, and the nozzle moving speed at 0.2 m / min-0.5 m / min to ensure regular trench formation and smooth trench walls. After cutting, the trench is not filled with any material immediately, allowing it to close naturally. However, under subsequent filling loads, these weak surfaces will become priority locations for stress release, thus transforming random cracks into controllable induced cracks.

[0040] S2: Microbial remediation system and pre-embedded monitoring sensors

[0041] A microbial remediation system and associated monitoring sensors are pre-installed in the potential deformation zone and around pre-cracks. The system mainly consists of a bacterial suspension layer and an electrode array, while the monitoring sensors include multi-point displacement gauges and fiber optic strain sensors.

[0042] The preparation method of the bacterial suspension is as follows: *Bacillus pasteurellii* was selected as the mineralizing strain, as this strain has high urease activity and is tolerant to alkaline environments. It was cultured in a fermenter until the logarithmic growth phase, at a temperature of 30℃, a pH of approximately 9.0, an aeration rate of 1 vvm, and for about 24 hours, until the bacterial suspension concentration reached 1×10⁻⁶. 9 Cells / mL. The bacterial cells were then collected by centrifugation at 5000 rpm for 10 min. The bacterial cells were resuspended in a protective solution containing 5% glycerol to prepare a concentrated bacterial suspension, with the concentration adjusted to 5 × 10⁻⁶ cells / mL. 9 Cells / mL. Porous ceramic particles were used as the bacterial carrier, with a particle size of 5 mm to 10 mm, a porosity greater than 40%, and a bulk density of approximately 800 kg / m³. 3Ceramsite was immersed in a concentrated bacterial suspension and vacuum-treated for 30 min at a vacuum degree of −0.08 MPa, allowing the bacteria to adsorb into the pores of the ceramsite. The ceramsite was then removed, drained, and freeze-dried for 24 h at a freezing temperature of −40℃ and a vacuum degree of 10 Pa to obtain bacteria-loaded ceramsite. This ceramsite can be stored for a long time under dry conditions, and the bacteria recover upon contact with water. Simultaneously, slow-release urea granules were prepared: urea and gypsum were mixed at a mass ratio of 3:1, and an appropriate amount of starch was added as a binder. The mixture was then pressed into spherical granules with a diameter of 10 mm using a granulator at a pressing pressure of 10 MPa. The slow-release urea granules dissolve slowly upon contact with water, with a dissolution rate controllable between 0.5 g / d and 1.0 g / d, providing a continuous nutrient source for the bacteria.

[0043] On-site, bacterial-loaded ceramsite, slow-release urea granules, and medium-coarse sand were mixed evenly at a volume ratio of 1:1:2 to form a bacterial solution fixation layer material. In each layer of fill within the potential deformation zone, a 0.2m thick bacterial solution fixation layer was laid within a 0.5m radius on both sides of the pre-cracks. During laying, the mixture was first spread evenly, then lightly compacted using a plate vibrator to achieve a compaction degree of over 85%, ensuring close contact with the surrounding soil. The surface of the fixation layer was covered with a layer of permeable geotextile with a unit area mass of 200 g / m². 2 This is to prevent the upper layer of fill material from mixing in.

[0044] Electrode array layout: Within the potential deformation zone, electrodes are arranged in a square grid. For example... Figure 2 As shown, the electrode array is symmetrically arranged with the dam axis 300 as the reference, and the grid spacing is... In this embodiment, the grid depth is set to 1.5 m, with anodes (+) and cathodes (-) alternating, meaning that adjacent electrodes at each grid node have opposite polarities. Specifically, the entire potential deformation zone is divided into several blocks, and electrodes within each block are arranged in a checkerboard pattern. If the coordinates of a node are... ,when When the number is even, the anode is arranged. When the number of electrodes is odd, cathodes are deployed. This ensures that each anode is surrounded by four adjacent nodes that are cathodes, and each cathode is surrounded by four adjacent nodes that are anodes, forming a uniform alternating electric field. Along the dam axis, each 10-20 m section is designated as an independent electrode block, with electrical isolation between blocks. Each block can be controlled independently. The block division should be coordinated with the distribution of potential deformation zones to ensure that the number of electrodes in each block does not exceed the number of control channels in the power supply cabinet.

[0045] The electrodes are made of titanium alloy plated with ruthenium, with a diameter of In this embodiment, the length is set to 20 mm. The depth of the electrode is determined based on the thickness of the potential deformation zone, typically 2-3 m, to ensure the electrode penetrates the entire potential deformation layer. Annular grooves, 1 mm deep and spaced 10 mm apart, are engraved on the electrode surface to increase the contact area with the surrounding soil. The electrodes are installed using a drilling method with a 50 mm diameter hole, the drilling depth slightly greater than the electrode length. The electrode is inserted vertically into the hole, with the bottom 50 mm from the bottom of the hole. Then, medium-coarse sand with good conductivity is backfilled, compacted in layers of 100 mm each, and tamped with a thin steel rod. An insulated wire, 2.5 mm diameter, is welded to the top of each electrode. 2 Copper core wires, insulated with polyvinyl chloride (PVC), are laid along pre-buried trenches on the dam slope to a junction box on the dam crest. Wires within the trenches are grouped and numbered for easy maintenance. The wires connect to a DC power supply cabinet, which should be capable of independently controlling each electrode pair, outputting an adjustable DC voltage of 0V-220V, and a current output capacity of no less than 10A. Simultaneously, an injection branch pipe is installed at the anode location for later injection of calcium source solution. This injection branch pipe is a 20mm diameter HDPE flexible tube with a 2mm wall thickness. One end extends 0.5m into the soil surrounding the anode, is sealed, and outlet holes with a diameter of 2mm and a spacing of 100mm are formed in the pipe wall. The holes are wrapped with permeable geotextile to prevent blockage. The other end connects to the main calcium source delivery pipeline on the dam crest via a solenoid valve.

[0046] S3: Dam body filling construction and system protection

[0047] After completing the pre-embedding work for S1 and S2, the dam body layer filling construction continues. During the filling process, strict adherence to design requirements and construction specifications is essential, with particular attention paid to protecting the pre-embedded system. When spreading each layer of fill material, avoid direct compaction of the electrode tops and sensor lead wire positions by heavy machinery; temporarily cover these areas with steel plates or set up warning signs. Within 0.5 m of the pre-embedded parts, use a small rammer or manual compaction to ensure the pre-embedded parts are not damaged. Heavy vibratory rollers can only be used for normal operation after filling to 1 m above the electrode tops. As the filling elevation increases, the electrode wires and sensor signal lines should be lengthened segment by segment, and waterproof sealing treatment should be performed. After all filling is completed, connect all lines to the junction box on the dam crest and the control center for system commissioning.

[0048] S4: Operational Deformation Monitoring and Threshold Early Warning

[0049] After the dam was put into operation, the monitoring system continued to work. The control center collected strain data at each measuring point in real time. and displacement Data was collected, and three trigger thresholds were set based on previous numerical simulation results and field tests:

[0050] Level 1 warning threshold: When the strain at a certain measuring point... >150×10 −6 And it continues to grow, or the displacement rate If the displacement rate is greater than 0.3 mm / d, the system will automatically record the data and alert the control center, notifying technicians to pay attention. The displacement rate is obtained through linear regression of displacement observation data over 7 consecutive days, requiring a high regression correlation coefficient. >0.8.

[0051] Level 2 warning threshold: when strain >250×10 −6 or displacement rate When the flow rate is greater than 0.6 mm / d, the system automatically checks the status of the electrodes, injection pipelines, and bacterial fixation layer in the corresponding area, including electrode conductivity, injection solenoid valve operation, and bacterial fixation layer moisture content, to ensure the equipment is in good condition and prepare to initiate the repair procedure.

[0052] Level 3 warning threshold: When the emergency response... >350×10 −6 If a displacement abrupt change occurs (the difference between two adjacent readings exceeds 2 mm), the system will immediately and automatically initiate the corresponding electrodynamic repair procedure for that area without manual intervention. A displacement abrupt change is defined as a difference of more than 2 mm between two adjacent measurements (1 hour apart), and the displacement value does not recover after the abrupt change.

[0053] S5: Electrodynamic Targeted Repair

[0054] When a Level 3 alert is triggered in a certain area, the control center automatically executes the following repair steps:

[0055] First, a DC voltage is applied to the electrode array within this area via a DC power supply cabinet. The cathode (-) is designated as the target hardening region, and the anode (+) as the calcium source injection region. Voltage gradient. It can be set from 0.5V / cm to 1.0V / cm, with the specific value depending on the distance between the anode and cathode. The calculation is performed using the following formula:

[0056]

[0057] in To apply voltage. Current density. Controlled at 0.1 mA / cm 2 -0.5 mA / cm 2 The electrode surface area is used in the calculation. ,but The specific values ​​are dynamically adjusted based on the soil resistivity and the target calcium ion migration rate. It can be calculated in real time through the voltage and current relationship between the electrodes.

[0058] While applying an electric field, the injection solenoid valve corresponding to the anode is opened, and calcium chloride solution is injected into the soil surrounding the anode through the injection branch pipe. In this embodiment, it is set to 0.5 mol / L. Injection rate Based on the estimated pore volume of the anode region, the injection rate can be controlled between 0.1 L / min and 0.5 L / min to ensure the anode region remains saturated but not over-saturated. The injection rate is achieved by adjusting the solenoid valve opening and the booster pump speed, with real-time feedback from the flow meter. Total injection volume... Calculate using the following formula:

[0059]

[0060] in The volume of soil within the anode treatment area is determined based on the electrode spacing and treatment depth. A 1.5 m × 1.5 m area centered on the anode is selected, and the depth is defined as the electrode burial depth range. The soil porosity was determined through preliminary tests. The injection coefficient can be set to 0.3-0.5 to avoid excessive injection that could lead to calcium ion waste or soil splitting. During injection, the soil moisture content in the anode zone should be continuously monitored. If the moisture content exceeds 110% of the saturation moisture content, injection should be immediately suspended.

[0061] Under the influence of an electric field, positively charged calcium ions... They migrate from anode to anode, then directionally reach the cathode region. The migration rate is related to the electric field strength and ion mobility; the migration time can be estimated. ,in The electromobility of calcium ions in soil can be taken as 5 × 10⁻⁶. −8 m 2 / (V⋅s)-1×10 −7 m 2 / (V⋅s). Simultaneously, water electrolysis occurs at the cathode:

[0062]

[0063] The generated The pH value in the cathode area is raised to above 9, which can be monitored in real time using a pre-embedded pH electrode. In the bacterial suspension layer surrounding the cathode, the bacteria-carrying ceramic particles revive upon contact with water. Urea, slowly released from the slow-release urea particles, is then hydrolyzed by urease to produce… , and those who migrated They combine to form calcium carbonate precipitate.

[0064] Precipitation preferentially forms in cracks and pores, gradually filling voids, increasing soil density and strength, and blocking potential seepage channels. The precipitation rate is indirectly assessed by monitoring changes in resistivity in the cathodic region; an increase in resistivity indicates pore filling.

[0065] During the repair process, the control center continuously monitors strain and current changes. Strain is acquired in real time using a fiber optic strain sensor at a measurement frequency of 1 Hz; the data is smoothed and filtered before use for analysis. Current is read from an ammeter built into the power cabinet, with an accuracy of 0.01 A. The electric field and liquid injection are stopped when any of the following conditions are met:

[0066] The strain value drops below 100×10−6 and shows no increasing trend over 24 hours. The strain value is measured directly by a sensor. No increasing trend means that the strain change per hour is less than 1×10−6. The linear regression test requires that the absolute value of the regression slope over 24 hours be less than 0.5×10−6 / h.

[0067] The current value has decreased by more than 50% compared to the initial time. (Initial time) This refers to the current value immediately after the electric field is applied and before significant precipitation has occurred. This value was recorded 5 minutes after startup. Thereafter, the current was recorded every 10 minutes. ,when <0.5 The condition is considered met if the current continues for more than 1 hour. A decrease in current indicates that the pores are blocked by precipitation, and ion migration is hindered.

[0068] Preset maximum processing time In this embodiment, the time is set to 72 hours, controlled by a timer in the control center, with the timing starting from the application of the electric field.

[0069] After the repair is completed, the system returns to standby mode and continues monitoring the area. If the anomaly recurs, the above procedure can be repeated. After each repair, the processing record is stored in the database, including the trigger time, location, processing parameters, and monitoring data, for subsequent analysis and optimization. Through multiple repairs, it can be ensured that the dam body maintains good seepage prevention performance throughout its entire operation period.

[0070] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A seepage prevention method for earth-rock hybrid dams to cope with uneven settlement, characterized in that, Includes the following steps: S1: Identification of potential deformation zones and setting of pre-cracks. Potential deformation zones within the dam body are identified through geological surveys and numerical simulations. During the filling process in these areas, high-pressure water jets are used to cut trenches to form pre-cracks for guiding stress release. S2: Microbial remediation system and monitoring sensor pre-embedded, a microbial remediation system including a bacterial solution fixation layer and an electrode array is pre-embedded within the potential deformation zone, and a multi-point displacement meter and fiber optic strain sensor for real-time monitoring of soil deformation are also pre-embedded. S3: Dam body filling construction and system protection, continue to fill the dam body in layers, take protective measures for the pre-embedded electrodes, sensors and their leads during the filling process, and connect all lines to the dam top control center; S4: Deformation monitoring and threshold early warning during operation. During the operation of the dam, strain and displacement data are collected in real time by monitoring sensors, and judgment and processing are performed according to preset multi-level thresholds. S5: Electrodynamic targeted repair. When the monitoring data triggers a level 3 warning, it automatically applies a DC voltage to the electrode array in the corresponding area to form an electric field. At the same time, it injects calcium source solution through the pre-embedded injection branch pipe at the anode to induce microorganisms to generate calcium carbonate precipitate to fill the crack.

2. The seepage prevention method for a mixed earth-rock dam type to cope with uneven settlement as described in claim 1, characterized in that, In step S1, the identification of potential deformation zones within the dam body through geological survey and numerical simulation specifically includes: establishing a three-dimensional geological model containing material partitions of the dam foundation and dam body based on borehole sampling, indoor geotechnical tests, and field test data from the geological survey; calculating the stress-strain field of each unit within the dam body using finite element numerical simulation software according to the actual construction sequence and changes in operating water level; comparing the calculated maximum principal tensile stress with the tensile strength of the soil, and defining the area where the maximum principal tensile stress reaches more than 0.8 times the tensile strength of the soil as a potential deformation zone.

3. The seepage prevention method for a mixed earth-rock dam type to cope with uneven settlement as described in claim 1, characterized in that, In step S1, the setting of the pre-cracks specifically includes: when filling to the elevation of the potential deformation zone, after the filling material of this layer is compacted and before the upper layer is filled, using a high-pressure water jet cutting device to cut according to the design grid; the cutting direction of the trench is determined according to the direction of the maximum principal tensile stress obtained by numerical simulation, and is set to be perpendicular to the direction of the principal tensile stress; after the cutting is completed, the trench is not filled with material temporarily, so that it will naturally close under the action of subsequent filling load to form a weak surface.

4. The seepage prevention method for a mixed earth-rock dam type to cope with uneven settlement as described in claim 1, characterized in that, In step S2, the pre-embedded microbial remediation system includes a bacterial solution fixation layer and an electrode array; the bacterial solution fixation layer is made by uniformly mixing bacterial-loaded ceramic particles, slow-release urea particles and medium-coarse sand and laying it on both sides of the pre-cracks in the potential deformation zone, and the surface is covered with permeable geotextile after laying; the electrode array is arranged in a square grid within the potential deformation zone.

5. A seepage prevention method for a soil-rock hybrid dam type to cope with uneven settlement as described in claim 4, characterized in that, The electrodes in the electrode array are made of conductive material with annular grooves on the surface. The anodes and cathodes are arranged alternately in a checkerboard pattern, that is, the adjacent nodes of each anode are cathodes and the adjacent nodes of each cathode are anodes. The electrode array is divided into multiple independently controllable blocks along the dam axis, and each electrode is connected to the DC power supply cabinet through an insulated wire.

6. A seepage prevention method for a soil-rock hybrid dam type to cope with uneven settlement as described in claim 4, characterized in that, In step S2, an injection branch pipe is simultaneously installed at the anode location. One end of the injection branch pipe extends into the soil surrounding the anode, and an outlet hole is opened in the pipe wall and wrapped with permeable geotextile. The other end is connected to the calcium source delivery pipeline on the top of the dam via a solenoid valve.

7. A seepage prevention method for a soil-rock hybrid dam type to cope with uneven settlement as described in claim 1, characterized in that, In step S4, the preset multi-level thresholds include: a first-level warning threshold, used to trigger data recording and technician notification; a second-level warning threshold, used to trigger automatic inspection of the status of electrodes, injection pipelines and bacterial fixation layers in the corresponding area; and a third-level warning threshold, used to automatically trigger the electrodynamic repair procedure for that area.

8. A seepage prevention method for a soil-rock hybrid dam type to cope with uneven settlement as described in claim 1, characterized in that, In step S5, the electrodynamic targeted repair specifically includes: using the cathode as the target reinforcement area and the anode as the calcium source injection area, applying a DC voltage to form an electric field; estimating the injection volume based on the pore volume of the anode area, and opening the injection solenoid valve corresponding to the anode to inject calcium chloride solution; calcium ions migrate to the cathode under the action of the electric field, and combine with carbonate ions generated by the hydrolysis of urea by microbial urease in the cathode area to form calcium carbonate precipitate.

9. A seepage prevention method for a soil-rock hybrid dam type to cope with uneven settlement as described in claim 8, characterized in that, In step S5, strain and current changes are continuously monitored during the repair process. When the strain value drops below the set value and shows no increasing trend, or when the current value drops by more than a set proportion from the initial time, the electric field application and calcium source injection are automatically stopped.

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