CN-121976536-A - Seepage-proofing construction method for diversion tunnel of high-altitude hydropower station

CN121976536ACN 121976536 ACN121976536 ACN 121976536ACN-121976536-A

Abstract

The invention relates to the technical field of hydropower engineering construction, in particular to an anti-seepage construction method for a diversion tunnel of a high-altitude hydropower station; the method introduces a temperature compensation mechanism in a high altitude environment, a material solidification regulation and control technology under low air pressure and an environment parameter dynamic monitoring system, adopts a multi-component composite anti-seepage material system, combines the technologies of surface pretreatment, deep grouting, interface reinforcing agent coating and the like, combines a plurality of monitoring devices such as a distributed displacement sensor, a pore water pressure gauge, an ultrasonic compactness detector and the like, constructs a real-time data acquisition and intelligent construction control platform, enables the anti-seepage construction technology to be stably adapted to complex conditions such as high altitude, low air temperature, low air pressure and the like, greatly improves the overall construction quality and reliability, and realizes the long-term anti-seepage effects of high strength, high toughness, freeze thawing resistance, water pressure impact resistance and the like.

Inventors

ZENG JIA
SONG WENSHUO
ZHANG BINGYU
WANG ZILIANG
TUO XIAOJUN
WANG GUOYANG
ZHENG YU
LIAO YOULIN
ZHANG JIANPENG
GAO YIFENG
WU MENGKUN
LIANG HONGRU

Assignees

华电金沙江上游水电开发有限公司波罗分公司

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (7)

1. The seepage-proofing construction method for the diversion tunnel of the high-altitude hydropower station is characterized by comprising the following steps of: (1) Cleaning and flattening the inner wall surface of the diversion tunnel to remove all loose objects and sharp protrusions; (2) Uniformly spraying a layer of solidified polymer waterproof paint on the surface of the inner wall of the cleaned tunnel to form a continuous waterproof film; (3) After the first layer of waterproof membrane is solidified, paving a layer of composite impermeable felt on the surface of the waterproof membrane; (4) Coating a layer of self-healing grouting material on the outer part of the impermeable felt layer; (5) Carrying out heating treatment on the construction area by adopting infrared heating equipment, wherein the heating temperature is 50-70 ℃, and the heating time is not less than 2 hours; (6) And (3) performing air tightness test on the diversion tunnel after the heating treatment, injecting compressed air into the tunnel and maintaining the preset pressure, and verifying the seepage prevention effect by observing pressure change and whether seepage signs exist on the surface of the manual inspection.
2. The method for constructing the diversion tunnel in the high-altitude hydropower station according to claim 1, wherein in the step (1), a quantitative inspection step is added in the process of cleaning and flattening treatment, and the quantitative inspection process is as follows: (1.1) obtaining the height field of the inner wall surface of the diversion tunnel by adopting laser scanning, and measuring the arithmetic average roughness by using a surface roughness meter Obtaining the density of loose particles per unit area on the inner wall surface of the diversion tunnel by adopting a vacuum sampling counting method The water content of the inner wall surface of the diversion tunnel is measured by adopting a capacitance type moisture meter Defining surface preparation quality index The calculation formula is as follows: ; in the above-mentioned description of the invention, Indicating an acceptable maximum particle count criterion, Indicating the maximum height of the residual protrusion, Representing a predetermined reference value of the cancellation height, The water content of the surface is represented by the water content, Indicating the maximum water content allowed to be present, Representing target roughness, weighting coefficient set for subsequent coating bond optimization ; (1.2) When If the surface is judged to be qualified, otherwise, reinforcing is carried out according to a self-adaptive grinding round number model based on the deficiency rate, and the required grinding round number is defined as follows: ; in the above-mentioned description of the invention, Is a target qualification value of 0.95, For the current calculated value of the current value, For the length of the tunnel to be treated, The throughput coefficient is averaged over a unit length to map the deficiency rate to the workload, The symbols are rounded up for the effective processing capacity of the single grinding or cleaning device; (1.3) carrying out a drawing bonding test on preset key positions to ensure the drawing strength of the substrate Greater than the thickness of the subsequent waterproof coating And curing temperature Determined minimum bond value 。
3. The method for constructing a diversion tunnel in a high-altitude hydropower station according to claim 2, wherein in the step (2), the surface preparation quality index obtained in the step (1) is used before the spraying step is started And substrate pull strength Is standard only when And is also provided with The spraying operation is started only when the spraying operation is started; the sprayed material is a double-component polymer optimized by a low-temperature curing formula, and the proportion of the main agent and the curing agent is regulated in real time according to the site temperature and the altitude so as to maintain constant viscosity And constant curing Activity ; Introducing a curing time correction model, and defining the on-site surface dry curing time as follows: ; Wherein, the For the number of seconds of tack-free cure time, Is a material constant which is a function of the material, As the altitude impact coefficient, For the actual number of meters of altitude, For the reference altitude calibration value, As a function of the temperature-sensitive coefficient, For the in-situ ambient absolute temperature kelvin value, Is the reference temperature kelvin value; the spray thickness is controlled according to the target thickness Between 2.0mm and 3.0 mm, adopting a multi-pass thin layer accumulation spraying strategy, and enabling a spraying machine to deposit thickness according to nominal each pass of equipment calibration Executing and combining overlapping coefficients Calculating the required number of passes, and defining the number of passes as follows: ; in the above-mentioned description of the invention, In order to round up the number of spray passes, The spray delivery efficiency represents the effective deposition ratio of the spray gun to the substrate, For a single pass nominal deposition thickness, Is the adjacent track overlapping ratio; in the spraying operation, the curing time is monitored in parallel To adjust the dead time between each pass; after the specified times are completed and the on-line thickness and bonding spot inspection reach the standards, performing primary curing inspection and entering the subsequent process of paving the flexible composite impermeable felt, and ensuring that the surface of the coating reaches the physical and chemical conditions required by the mechanical fixation of the composite felt.
4. The method for constructing a diversion tunnel in a high-altitude hydropower station according to claim 3, wherein in the step (3), the flexible composite impermeable felt is laid immediately after the first waterproof film is cured and the thickness and bonding spot inspection are performed, and the bonding strength of the substrate is retested at a plurality of mark points by adopting a nondestructive bonding force detector before the laying Quality index of surface preparation The composite felt is unfolded in the roll direction and laid at a certain angle with the axial direction of the tunnel, and a zonal tension controller is adopted to apply constant pretension to the felt body during laying The primary fixation displacement constraint is carried out by a mechanical fixing system mainly comprising a joint belt and a stainless steel stab pin, the minimum distance of mechanical fixing is calculated according to load balance design, and the local expansion unit area is defined And taking the effective width of felt Bearing shear with a single anchor The most allowable large anchoring distance The expression is: ; As measured by actual construction The anchoring density must be increased until After mechanical fixing is completed, a peeling bonding test and an anchoring drawing test are carried out on a plurality of representative units to verify that the single-point bonding force and the anchoring shearing resistance meet the design value and the quality index of the step (1) Strength of drawing Keeping consistent, and after all the sampling inspection is qualified, performing seaming treatment on the felt sheet according to the formulated overlapping rule and according to the fiber modulus And interfacial shear strength Calculating minimum overlap length of joint So as to ensure that the stress at the joint can be transmitted together with the joint strip through interface bonding in long-term freeze thawing cycle, and the expression of the joint overlap length is as follows: ; Wherein, the Parameters for the target thickness of the coating controlled in the step (2) and directly responding to interface constraint at the joint To design the safety factor and set in the construction file with the value not less than 1.3, the parameter The interface shear transfer efficiency is that; and (3) finishing laying and fixing, and entering an injection procedure of the external self-healing grouting material after the joints and anchors meet the design requirements through spot check.
5. The method for constructing a diversion tunnel in a high-altitude hydropower station according to claim 4, wherein in step (4), the laying of the impermeable felt and the joint fixing are completed and the overlapping length of the joint is confirmed After meeting the design requirements, starting to inject the self-healing grouting material; The grouting system adopts a constant-pressure constant-current composite control method and is implemented according to grouting section partition, and key quantities of on-site real-time monitoring include injection pressure Flow rate of grouting Dynamic viscosity of grouting material Effective permeability of composite Defining a penetration time formula for calculating the required grouting duration: ; Wherein, the For the duration of the grouting in seconds, For the effective porosity of the composite layer, Is the ideal average implantation depth; a healing coverage rate model is introduced to evaluate microcapsule repair efficacy and provide decision support for grouting proportions: ; Wherein, the Indicating the desired coverage of healing over a unit depth, Indicating the effective volume fraction of microcapsules in the grouting material, Actual plugging efficiency coefficient after the microcapsule is broken and the repairing agent is released; in the grouting process, a mode of low-pressure pre-pumping and uniform-speed boosting to set working pressure is adopted, and a reflux ratio and the earth surface grouting recovery rate are recorded at the same time in each grouting section; after grouting is completed and pressed Requiring the pressure-stopping curing to wait for the microcapsules to enter a standby state, reserving a plurality of sampling ports and averaging in a grouting section And after reaching a preset value, starting to perform a pressure reduction test and pore back pressure detection, and uniformly heating the construction area by adopting an infrared heating mode after all the materials are confirmed to be qualified.
6. The method for constructing a diversion tunnel in a high-altitude hydropower station according to claim 5, wherein in the step (5), the surface dry curing time in the step (2) is set before the infrared heating is started And the coating target thickness of the step (3) Commonly input into a heating energy scheduling model to quantify the required heating energy and guide the heater layout, and define the necessary heat per unit area The expression is that the sum of the heat capacity and steady-state loss of the material is: ; in the above-mentioned description of the invention, Is the equivalent density of the composite layer, For the equivalent specific heat capacity, Is equivalent to the heat capacity thickness and is controlled by the previous step Is obtained by linear superposition with the effective thickness of the composite impermeable felt, In this step, the temperature is calculated by absolute temperature measurement at 50-70 ℃ in order to heat the target temperature, To the initial surface temperature at the start of the construction, In order to be at the temperature of the environment, Is the heat loss coefficient per unit area per unit time, For the duration of heating; Defining temperature uniformity index The expression is as follows, which is the ratio of the standard deviation of the regional temperature to the temperature scale: ; And is used in combination A heating gradient is indicated and is indicated, Is the standard deviation of the temperature of a number of hot spots within the construction area.
7. The method for constructing a diversion tunnel in a high-altitude hydroelectric power station according to claim 6, wherein in step (6), heating and curing are completed and interlayer adhesion is determined Coverage rate of healing Then starting the air tightness test, and raising the pressure to the initial test pressure by using adjustable compressed air according to the working section partition And time-recording duration after voltage stabilization Corresponding to pressure intensity Substituting the recorded value into a pressure decay index for quantitative evaluation, wherein the pressure decay index is defined as follows: ; Introducing an upper allowable attenuation limit As a qualification threshold, the expression is: ; Wherein, the And (3) with For the calibration constant based on the material and the site calibration, the construction judgment rule is that if the measurement is carried out And manual inspection and infrared scanning have no active seepage record, then the air tightness is qualified, all time sequence data pressure curves and sampling detection results are recorded, if any one of the time sequence data pressure curves and sampling detection results is not qualified, the specified section is subjected to grouting spot welding reinforcement or local reheating treatment according to the positioning result, and the air tightness test is repeated until the air tightness test is met 。

Description

Seepage-proofing construction method for diversion tunnel of high-altitude hydropower station Technical Field The invention relates to the technical field of hydropower engineering construction, in particular to an anti-seepage construction method for a diversion tunnel of a high-altitude hydropower station. Background In the existing technical field of hydropower engineering construction, mechanical grouting, drilling grouting, local seepage treatment and other modes are adopted to perform seepage prevention reinforcement on tunnels. For example, through searching, application number CN201711336192.3 provides a seepage-proofing device and a seepage treatment method for a tunnel, the device is composed of a power driving device, a slurry spraying device and a portable operation gun, and local drilling, slurry spraying and slurry injection treatment on the seepage position of the tunnel are realized through matching of a dual-driving drilling machine and a slurry spraying drilling machine. The method has the characteristics of independent structure, convenience in operation, no damage to the rock mass structure, high seepage prevention efficiency and the like, can be used for rapidly processing seepage points, and has a certain application value in general tunnel engineering. However, the above-mentioned conventional technology is mainly aimed at the local seepage treatment under the conventional working condition, and its seepage-proofing effect depends on local grouting or intubation grouting, and lacks the adaptability control of high-altitude complex environmental factors, and it is difficult to ensure slurry diffusivity, solidification strength and interface bonding performance under the low-temperature and low-pressure conditions. Meanwhile, the technology generally lacks systematic seepage prevention design on the integral structure of the tunnel, uniform forming and long-term stable maintenance of a large-scale seepage prevention layer cannot be realized, and long-term safety requirements of the diversion tunnel of the high-altitude hydropower station under high water pressure and high deformation environments are difficult to meet. Therefore, a construction method which can adapt to the characteristics of high-altitude environments, has dynamic regulation and control capability and can realize the overall high-density seepage prevention of tunnels is urgently needed, so as to overcome the defects of the traditional technology. Disclosure of Invention Aiming at the problems existing in the prior art, the invention aims to provide the seepage prevention construction method for the diversion tunnel of the high-altitude hydropower station, which not only can adapt to the characteristics of the high-altitude environment, but also has the dynamic regulation and control capability and can realize the overall high-density seepage prevention of the tunnel. In order to solve the problems, the technical scheme adopted by the invention is as follows: The seepage-proofing construction method for the diversion tunnel of the high-altitude hydropower station comprises the following steps of: (1) Cleaning and flattening the inner wall surface of the diversion tunnel to remove all loose objects and sharp protrusions; (2) Uniformly spraying a layer of solidified polymer waterproof paint on the surface of the inner wall of the cleaned tunnel to form a continuous waterproof film; (3) After the first layer of waterproof membrane is solidified, paving a layer of composite impermeable felt on the surface of the waterproof membrane; (4) Coating a layer of self-healing grouting material on the outer part of the impermeable felt layer; (5) Carrying out heating treatment on the construction area by adopting infrared heating equipment, wherein the heating temperature is 50-70 ℃, and the heating time is not less than 2 hours; (6) And (3) performing air tightness test on the diversion tunnel after the heating treatment, injecting compressed air into the tunnel and maintaining the preset pressure, and verifying the seepage prevention effect by observing pressure change and whether seepage signs exist on the surface of the manual inspection. Further, in the step (1), a quantitative inspection step is added in the process of cleaning and flattening treatment, and the quantitative inspection process is as follows: (1.1) obtaining a surface height field by laser scanning and measuring an arithmetic average roughness by a surface roughness meter Vacuum sampling counting method is adopted to obtain the density of loose particles in unit areaAnd the surface moisture content is measured by adopting a capacitance moisture meterDefining surface preparation quality indexThe calculation formula is as follows: ; in the above-mentioned description of the invention, Indicating an acceptable maximum particle count criterion,Indicating the maximum height of the residual protrusion,Representing a predetermined reference value of the cancellation he