Underground structure waterproof layer failure self-early warning self-repairing active material and preparation method

Abstract

The application discloses a kind of underground structure waterproof layer failure self-warning self-repairing active material and preparation method, belong to underground engineering technical field.The application solves the problem that current underground engineering leakage concealment is strong, waterproof failure is not easy to find, and waterproof failure repair difficulty is big.The waterproof material production method of self-warning and self-repairing function is that self-warning active material and self-repairing active material are mixed uniformly according to 1:1 volume ratio, and self-warning active material and self-repairing active material mixture are uniformly applied on one side of base material with waterproof non-woven fabric as base material.The underground structure waterproof layer failure self-warning self-repairing active material and preparation method provided by the application can carry out early warning, positioning, self-repairing, effect test and secondary waterproof repair to the water seepage area caused by implicit underground structure waterproof layer failure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underground engineering, and particularly relates to a self-early-warning and self-repairing technology for a waterproof layer of an underground structure. BACKGROUND

[0002] With the improvement of engineering construction technology in China, urban underground engineering construction has developed rapidly, and underground engineering is deeper, larger in space and more widely used. Underground structures, including tunnels, subway stations, underground garages, high-rise and super high-rise building basements, large commercial centers and urban comprehensive pipe galleries, are often located in strata affected by underground water. A waterproof layer is arranged outside the structure to achieve the effect of isolating the influence of underground water on the main structure. The leakage problem of underground engineering is still one of the common engineering quality problems, and has become one of the problems that hinder the sustainable and green development of underground engineering, which has a huge impact on society and economy. Due to its strong concealment, the failure of the waterproof layer is not easy to detect, and the waterproof repair of the failure position is not timely. This leads to corrosion of the main steel reinforcement of the underground engineering structure, internal stress and cracking of the concrete structure, and therefore, it is necessary to propose a self-early-warning and self-repairing technology for a waterproof layer of an underground structure. SUMMARY

[0003] The application provides a self-early-warning and self-repairing active material for a waterproof layer of an underground structure and a preparation method thereof, and solves the problems of strong concealment of underground engineering leakage, difficulty in finding waterproof failure and difficulty in waterproof failure repair.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0005] A preparation method of a self-early-warning active material, the method being:

[0006] (1) potassium nitrate is placed in a sealed container and heated to above 334 DEG C to melt, vacuum is extracted, and then carbon dioxide gas is injected by using a high-pressure pump, so that the pressure in the sealed container is at least 4.1369 MPa;

[0007] (2) the pressure in step (1) is maintained, and the potassium nitrate is cooled to form a glassy solid;

[0008] (3) the pressure inside the sealed container is released, the carbon dioxide gas inside the sealed container escapes, and at the same time, the potassium nitrate inside the sealed container disintegrates to form active particles, and a self-early-warning active material is obtained.

[0009] A self-early-warning active material, which is prepared by the above-mentioned method.

[0010] A waterproof structure with self-warning function, the waterproof structure comprises a waterproof layer, the waterproof structure further comprises a self-warning active material layer, the self-warning active material is laid below the waterproof layer, the thickness of the self-warning active material ranges from 1 to 5 mm.

[0011] A self-repairing active material, the self-repairing active material is granular, the particle size ranges from 10 to 50 μm, the coating of the particle is water-soluble chitosan carboxymethyl chitosan and gum arabic, and the core of the particle is a non-emulsified self-repairing solid adhesive.

[0012] A preparation method of a self-repairing active material, the method comprises the following steps:

[0013] (1) 0.3 g of water-soluble chitosan carboxymethyl chitosan is added into 10 ml of 0.2 mol / L acetic acid solution, heated at 50 ℃ for 20 min to dissolve, stirred to obtain solution A, and placed for 8 h for standby;

[0014] (2) 0.3 g of gum arabic is added into 10 ml of 0.2 mol / L acetic acid solution in sequence, dissolved, and stirred to obtain solution B, and placed for 8 h for standby;

[0015] (3) 2.5 g of paraffin is added into 100 ml of water to melt at 70 ℃, then 1.5 g of Tween 80 is added, heated in a water bath at 75 ℃, the rotating speed of a magnetic stirrer is set to 1400 r / min, and the paraffin is stirred for 20 min to be uniform to obtain solution C;

[0016] (4) solution B is added into solution C to obtain solution D;

[0017] (5) solution A is slowly added into solution D under the condition of stirring at 1000 r / min, and the temperature is kept at 70 ℃ to obtain solution E;

[0018] (6) the pH value of solution E is adjusted, a glutaraldehyde solution is added into solution E to obtain solution F;

[0019] (7) solution F is separated by a centrifuge, the upper layer material is extracted, and then dried and ground into powder to obtain the self-repairing active material.

[0020] A waterproof structure with self-repairing function, the waterproof structure comprises a waterproof layer, the waterproof structure further comprises a self-repairing active material layer, and the self-repairing active material layer is laid below the waterproof layer.

[0021] A waterproof material manufacturing method with self-warning and self-repairing functions, the method comprises the following steps: the self-warning active material and the self-repairing active material are uniformly mixed according to a volume ratio of 1:1, a waterproof non-woven fabric is used as a base material, and the mixed material of the self-warning active material and the self-repairing active material is uniformly coated on one side of the base material.

[0022] A waterproof system with self-warning and self-repairing functions, comprising a waterproof layer, a functional layer, a plurality of acoustic emission sensors, a preamplifier and a data processor, the functional layer is made of waterproof material with self-warning and self-repairing functions, the functional layer is located below the waterproof layer, the plurality of acoustic emission sensors are distributed and fixed below the functional layer, the preamplifier is used for amplifying the signal generated by each acoustic emission sensor respectively, and sending the amplified signal to the data processor, and the data processor processes the received signal to obtain the water seepage position.

[0023] The working principle of the waterproof system is as follows: the self-warning active material generates continuous acoustic emission after encountering water, a plurality of acoustic emission sensors are arranged in the underground structure to monitor the change of acoustic emission of the self-warning active material when encountering water, the sensors are connected to the acoustic emission system, the preamplifier is set to 60 dB, and the threshold is set to 25 dB to eliminate environmental noise; the self-defined code is written by using IDL to obtain the position of the acoustic emission event; the acoustic emission signal area is continuously monitored, if the signal amplitude decays to below 5%-10%, it indicates that the self-repairing active material can repair the waterproof of the underground structure; if the signal continues to be emitted, secondary repair of the waterproof of the underground structure is needed.

[0024] The steps of writing the self-defined code by using IDL are as follows: (1) sorting the signals according to events, wherein an event is defined as acoustic emission recorded by 3 or more acoustic emission sensors; (2) performing Hilbert transform on each signal to determine the acoustic wave arrival time according to the first peak value of the Hilbert transform; (3) using a nonlinear Broyden solver to obtain the acoustic emission event position according to the difference of the acoustic wave arrival time.

[0025] A secondary grouting repair method, which adopts double-liquid chemical grouting plugging technology, and uses PO.32.5 Portland cement and water glass double-liquid slurry as grouting materials, the water glass concentration is 35Be', the water-cement ratio of the cement slurry is 1:1, and the volume ratio of the cement slurry to the water glass is 1:0.5, the two kinds of slurry are mixed to generate a polymerization reaction, and the proportion of the two kinds of slurry is adjusted according to the site condition to perform secondary grouting repair.

[0026] The beneficial technical effects of the present application

[0027] The underground structure waterproof layer failure self-warning and self-repairing active material and the preparation method provided by the present application can perform warning, positioning, self-repairing, effect testing and secondary waterproof repair on the water seepage area caused by the failure of the implicit underground structure waterproof layer. The corrosion of the main reinforcement of the underground engineering structure is reduced to the greatest extent, internal stress and concrete structure cracking are prevented, maintenance is reduced, cost is saved, and the service life of the underground engineering structure is improved. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0029] A self-warning and self-repairing technology for waterproof layer of underground structure mainly includes preparation and use of self-warning active material and self-repairing active material, triangular positioning method for waterproof failure area, secondary repair of waterproof layer, etc.

[0030] The preparation method of the self-warning active material is as follows: potassium nitrate is dissolved in a small amount of water, and the solution is placed in a sealed container and heated to 334℃; vacuum is first extracted to reduce the moisture content, and then high-pressure pump is used to inject carbon dioxide so that the pressure in the sealed container is at least 4.1369 MPa; the high-pressure condition is maintained while cooling to let the potassium nitrate cool into a large glass-like solid; the pressure is released by opening the container to let most of the carbon dioxide escape, and at the same time, the solidified potassium nitrate block is disintegrated to form active particles. These active particles contain many fine carbon dioxide bubbles, and when the active particles come into contact with water, as the surface of the active particles gradually dissolves, the small bubbles inside also break one by one, which can emit sound. The sound emission signal intensity of the active material is basically not attenuated, which is mainly related to the volume of the material.

[0031] The waterproof structure with self-warning function includes a waterproof layer, and further includes a self-warning active material layer, which is laid under the waterproof layer, and the thickness of the self-warning active material ranges from 5mm.

[0032] The self-repairing active material is in the form of particles with a particle size of 10-50μm. Water-soluble chitosan carboxymethyl chitosan and gum arabic are used as the coating, and non-emulsified self-repairing solid adhesive is used as the core. After coming into contact with water, the coating of the self-repairing active material dissolves in water, releasing the non-emulsified self-repairing solid adhesive core. The non-emulsified self-repairing solid adhesive becomes sticky when it comes into contact with water, and has a solidified tensile strength of more than 44MPa, a normal use temperature of-30℃ to 65℃, and a fast curing speed. It can effectively reinforce for a long time in a humid / strong seepage environment.

[0033] The preparation of the self-repairing active material includes the steps of preliminary film formation, emulsification and dispersion, cross-linking and curing, separation and drying, and grinding into powder. The preparation method is as follows:

[0034] (1) 0.3g water-soluble chitosan carboxymethyl chitosan is added to 10ml 0.2mol / L acetic acid solution, heated at 50℃ for 20min to dissolve, stirred to obtain solution A, and placed for 8h for standby;

[0035] (2) 0.3g arabic gum is added into 10ml 0.2mol / L acetic acid solution in turn, dissolved, stirred evenly to obtain solution B, placed for 8h for standby;

[0036] (3) 2.5g paraffin is added into 100ml water, melted at 70℃, then 1.5g Tween 80 is added, heated in 75℃ water bath, the speed of magnetic stirrer is set to 1400r / min, stirred for 20min to make paraffin uniform, to obtain solution C;

[0037] (4) solution B is added to solution C to obtain solution D;

[0038] (5) solution A is slowly added into solution D under 1000r / min stirring, keeping the temperature at 70℃, to obtain solution E;

[0039] (6) the pH value of solution E is adjusted, glutaraldehyde solution is added into solution E to obtain solution F;

[0040] (7) solution F is separated by centrifuge, the upper layer material is extracted, then dried and ground into powder to obtain self-repairing active material.

[0041] A waterproof material with self-warning and self-repairing functions is prepared by the following method: self-warning active material and self-repairing active material are mixed uniformly at a volume ratio of 1:1, a waterproof non-woven fabric is used as a base material, a layer of mixture of self-warning active material and self-repairing active material is evenly coated on one side of the base material to form a waterproof material with active material, and the material layer is adhered to the inner side of the waterproof layer of an underground structure for warning and repairing of the failure of the waterproof layer.

[0042] A waterproof system with self-warning and self-repairing functions comprises a waterproof layer, a functional layer, a plurality of acoustic emission sensors, a preamplifier and a data processor, the functional layer is made of waterproof material with self-warning and self-repairing functions, the functional layer is located below the waterproof layer, the plurality of acoustic emission sensors are distributed and fixed below the functional layer, the preamplifier is used for amplifying the signals generated by each acoustic emission sensor and sending the amplified signals to the data processor, and the data processor processes the received signals to obtain the water seepage position.

[0043] The working principle of the waterproof system is as follows: the self-warning active material generates continuous acoustic emission after meeting water, a plurality of acoustic emission sensors are arranged in the underground structure to monitor the change of acoustic emission of the self-warning active material when meeting water, the sensors are connected to an acoustic emission system, a preamplifier is set to 60dB, and a threshold is set to 25dB to eliminate environmental noise; a self-defined code is written by using IDL to obtain the position of acoustic emission event; the acoustic emission signal area is continuously monitored, if the signal amplitude attenuates to below 5%-10%, it indicates that the self-repairing active material can repair the waterproof of the underground structure; if the signal continues to be emitted, secondary repair of the waterproof of the underground structure is needed.

[0044] The self-defined code is written by using IDL: (1) the signals are sorted by events, wherein one event is defined as acoustic emission recorded by three or more acoustic emission sensors (the initial position of the recording sensor); (2) Hilbert transform is performed on each signal, and the acoustic wave arrival time is determined according to the first peak value of the Hilbert transform; (3) the acoustic emission event position is calculated according to the difference of the acoustic wave arrival time by using a nonlinear Broyden solver.

[0045] The secondary repair adopts a new chemical grouting plugging technology based on micro-swelling polymer plugging material, double-liquid grouting is adopted, the grouting material adopts PO.32.5 Portland cement and water glass double-liquid slurry, the water glass concentration is 35Be', the water-cement ratio of the cement slurry is about 1:1, and the volume ratio of the cement slurry to the water glass is about 1:0.5; when the two liquids are mixed, a polymerization reaction occurs, the initial setting is 30 seconds, and the final setting is 2-3 minutes to form a gel. The grouting is injected into the structure layer in a water-soluble form, the slurry has low viscosity and good permeability, and can be injected into cracks below 0.1mm; the slurry can condense in the conditions of moisture, high water speed and large water volume; the gel also has the characteristics of good impermeability, water swelling and corrosion resistance, and the gel has a compressive strength of 0.01-0.06MPa and a tensile strength of 0.02-0.04MPa.

[0046] A hole is drilled near the failure area of the waterproof layer in the underground structure, and 1-2 grouting pipes are pre-buried for diversion; then the sealing material is used for sealing, and after the sealing material waterproof mortar reaches a certain strength, the slurry is injected from the grouting pipe; the grouting effect is judged according to the slurry flowing out of the corresponding grouting pipe, and the slurry is filled in the gap and distributed uniformly; the grouting pressure is controlled, which is generally determined through on-site test; after the grouting is completed, the grouting pipe opening is tied firmly with iron wire to prevent the slurry from flowing out; after the slurry is condensed, the grouting pipe is cut off. After the waterproof mortar reaches a certain strength, the wet repair area is sprayed, and 1:2 ordinary mortar is brushed for leveling, with a thickness of 0.5-0.8cm.

[0047] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a self-warning active material, characterized by, The method is: (1) Put the potassium nitrate in a closed container and heat it to above 334℃ to melt, then vacuumize, and then inject carbon dioxide gas by using a high-pressure pump to make the pressure in the closed container at least 4.1369MPa; (2) Maintain the pressure in step (1) and cool the potassium nitrate to form a glassy solid; (3) Release the pressure inside the closed container to make the carbon dioxide gas inside escape, and at the same time, the potassium nitrate inside the closed container disintegrates to form active particles, thus obtaining the self-warning active material.

2. A self-warning active material, characterized by, The self-warning active material is prepared by the method of claim 1.

3. A waterproof structure with a self-warning function, the waterproof structure comprising a waterproof layer, characterized by, The waterproof structure further comprises a self-warning active material layer, which is prepared by the method of claim 1, and is laid under the waterproof layer, with a thickness ranging from 1mm to 5mm. The waterproof structure further comprises a self-warning active material layer, which is prepared by the method of claim 1, and is laid under the waterproof layer, with a thickness ranging from 1mm to 5mm.