A wall protection slurry for cast-in-place piles and a preparation method thereof

Abstract

The application relates to the field of wall protection mortar, and particularly discloses a wall protection mortar for bored piles and a preparation method, the wall protection mortar comprises the following raw materials in parts by weight: mixing water 900 parts; bentonite 54-60 parts; soda ash 1.7-2.7 parts; mineral aggregate 7-8.2 parts; weighting agent 14-24.6 parts; adhesive 0.13-0.4 parts; anti-permeation auxiliary material 2-23 parts; the raw materials of the anti-permeation auxiliary material comprise porous loading agent, nitro humic acid potassium and coating agent, and the weight ratio of the porous loading agent, the nitro humic acid potassium and the coating agent is (10-16):(4-5):5. The preparation process is as follows: S1, preparing the adhesive; S2, preparing the anti-permeation auxiliary material, and uniformly mixing the anti-permeation auxiliary material with the adhesive to obtain a filler; S4, uniformly stirring bentonite, mixing water, soda ash, mineral aggregate, weighting agent and the filler to obtain the wall protection mortar. The application has the effect of blocking the penetration of surrounding soil into the bored piles.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wall protection slurry, in particular to a wall protection slurry for bored piles and a preparation method. BACKGROUND

[0002] With the acceleration of urbanization process and the increasing shortage of land resources, the foundation engineering of soft soil layer is more and more common. As a common foundation reinforcement method, bored piles are widely used in soft soil layer foundation engineering due to their strong bearing capacity, strong adaptability, convenient construction, energy saving and environmental protection and other characteristics.

[0003] Bored piles are usually divided into mud protection bored piles, dry operation bored piles, manual hole digging bored piles, casing hole bored piles and blast expansion hole concrete hollow pipe piles. Among them, the mud protection bored pile is formed by the method of using underwater concrete pouring to replace the mud after the slow drilling of the pile machine under the condition of mud protection, and the drilling slag is taken out by the mud, and the mud skin is formed to protect the hole wall from collapsing. The mud protection bored pile construction is simple, fast and mature, and is suitable for complex geological strata and is widely used in soft soil layer foundation engineering.

[0004] In areas with heavy rainfall, under the double action of rainfall and vehicle load, the silt soft soil in the soft soil layer penetrates into the bored pile, the water in the bored pile erodes the reinforcement cage, the bearing capacity of the bored pile is reduced, and the service life of the bored pile is shortened. SUMMARY

[0005] In order to block the penetration of the surrounding soil into the bored pile and prolong the service life of the bored pile, the present application provides a wall protection slurry for bored piles and a preparation method.

[0006] In the first aspect, the wall protection slurry for bored piles provided by the present application adopts the following technical scheme:

[0007] A wall protection slurry for bored piles comprises the following raw materials by weight: 900 parts of mixing water; 54-60 parts of bentonite; 1.7-2.7 parts of soda ash; 7-8.2 parts of mineral aggregate; 14-24.6 parts of weighting agent; 0.13-0.4 parts of adhesive; 2-23 parts of anti-permeation auxiliary material; the preparation raw materials of the anti-permeation auxiliary material include porous loading agent, nitro humic acid potassium and coating agent, and the weight ratio of the porous loading agent, nitro humic acid potassium and coating agent is (10-16):(4-5):5.

[0008] By adopting the technical scheme, the porous loading agent loads the nitro humic acid potassium, and then is coated by the coating agent to form the anti-permeation auxiliary material; in the mud preparation process, the nitro humic acid potassium is wrapped, reducing the probability of the nitro humic acid potassium participating in the reaction and being consumed; the mud forms a mud skin on the hole wall of the borehole under the action of the cementing agent and the weighting agent, at this time, the anti-permeation filler is fixed in the mud skin; after the cast-in-place pile is formed, the coating film formed by the coating agent cracks under the double action of the rainfall and the vehicle load, free potassium ions, carboxyl groups and hydroxyl groups in the nitro humic acid potassium form negative charged hydration groups, after absorbing part of the infiltrated water molecules, a ductile bonding structure is formed, which bonds the clay particles in the mud skin together, increases the compactness of the mud skin, blocks the surrounding soil from permeating into the cast-in-place pile, and at the same time, improves the impact resistance of the cast-in-place pile, thereby prolonging the service life of the cast-in-place pile; the existence of the potassium ions compresses the double electric layer of the clay particles, reduces the hydration swelling capacity of the clay particles, and improves the stability of the mud skin.

[0009] Optionally, the porous loading agent is selected from vaterite.

[0010] By adopting the technical scheme, the vaterite is used in cooperation with the nitro humic acid potassium, in the mud preparation link, the vaterite loads the nitro humic acid potassium; after the coating film formed by the coating agent cracks, the nitro humic acid potassium acts on the clay particles, and at the same time, the vaterite is converted into calcite in a low-temperature and humid environment; in the process of the vaterite being converted into calcite, potassium ions are embedded between adjacent crystal layers of the vaterite and form a bonding effect with the vaterite, which limits the expansion and separation of adjacent crystal layers, improves the formed particle size and formed strength of the calcite, thereby improving the compressive strength of the cast-in-place pile and prolonging the service life of the cast-in-place pile.

[0011] Optionally, the coating agent is selected from calcium tung oil rosin.

[0012] By adopting the technical scheme, under the joint action of the conjugated double bond, carboxyl group, triphenyl ring structure and turpentine oil in the calcium tung oil rosin, the calcium tung oil rosin has certain viscosity and water resistance, and at the same time, the calcium tung oil rosin is rigid and brittle, and is easy to crack under the action of impact pressure. The calcium tung oil rosin, the vaterite and the nitro humic acid potassium are used in cooperation to form the anti-permeation auxiliary material, and when the anti-permeation auxiliary material is prepared, due to the uneven surface of the vaterite, pores exist between the calcium tung oil rosin and the surface of the vaterite, which facilitates the cracking of the calcium tung oil rosin when it is subjected to extrusion pressure, thereby facilitating the exposure of the vaterite and the nitro humic acid potassium in the mud skin.

[0013] Optionally, tung oil and rosin are mixed, heated to 220-230℃, and stirred at constant temperature for 5-10min; calcium hydroxide is added, heated to 240-250℃, and stirred at constant temperature for 20-40min to obtain the calcium tung oil rosin.

[0014] By adopting the technical scheme, the tung oil and the rosin are mixed to improve the water resistance of the coating agent, and the effect of the alkali solution on the nitro humic acid potassium is reduced; the calcium hydroxide is added to improve the drying speed and the water resistance of the coating agent, facilitate the coating of the icicle spar, and improve the slow-release effect of the nitro humic acid potassium.

[0015] Optionally, the preparation of the anti-infiltration adjuvant comprises the following steps: placing the porous carrier and the nitro humic acid potassium in water, stirring and ultrasonic treatment for 10-20 min; after dehydration, the anti-infiltration particles are obtained after dispersion; the coating agent is sprayed on the surface of the anti-infiltration particles, and the anti-infiltration adjuvant is obtained after oscillation.

[0016] By adopting the technical scheme, the nitro humic acid potassium is loaded in the porous carrier through the water medium and the ultrasonic treatment; the coating agent is wrapped on the surface of the anti-infiltration particles through the spraying process, and the wrapping efficiency and the wrapping uniformity of the coating agent are improved, so that the coating agent can slow release the nitro humic acid potassium.

[0017] Optionally, the adhesive comprises hydroxyethyl carboxymethyl cellulose and polyacrylamide, and the weight ratio of the hydroxyethyl carboxymethyl cellulose and the polyacrylamide is (5-48):8.

[0018] By adopting the technical scheme, the hydroxyethyl carboxymethyl cellulose and the polyacrylamide are combined to form a three-dimensional network adhesive structure with thixotropy, so that the bentonite particles, the mineral aggregate particles and the weighting agent can be adhered to the hole wall of the drill hole to improve the stability of the mud skin; the amide groups in the polyacrylamide are combined with the oxygen atoms on the surfaces of the bentonite particles, the hydroxyethyl carboxymethyl cellulose, the icicle spar and the nitro humic acid potassium, the hydroxyethyl carboxymethyl cellulose is crosslinked with metal ions such as calcium ions and potassium ions, the adhesion of the adhesive is increased, the bentonite particles are not easily separated from the clay particles in the process of the icicle spar being converted into calcite, and in addition, the potassium ions are fixed in the mud skin to play the anti-infiltration role, block the infiltration of the surrounding soil into the cast-in-place pile, and prolong the service life of the cast-in-place pile.

[0019] Optionally, the weighting agent is barite, and the mineral aggregate is tailings sand.

[0020] By adopting the technical scheme, the metal ions in the tailings sand are adsorbed by the hydroxyethyl carboxymethyl cellulose to improve the bonding strength of the tailings sand as the framework material and the adhesive, facilitate the tailings sand to play a role in the mud skin, and facilitate the recycling of the mud slurry.

[0021] In a second aspect, the application provides a preparation method of a wall protection mud for a cast-in-place pile, which adopts the following technical scheme:

[0022] The preparation method of the wall protection mud for the cast-in-place pile comprises the following steps:

[0023] S1, preparing the cementing agent;

[0024] S2, preparing the anti-permeation auxiliary material, mixing the anti-permeation auxiliary material with the cementing agent to obtain the filler;

[0025] S3, stirring the bentonite, the mixing water, the soda ash, the mineral material, the weighting agent and the filler prepared in S3 to obtain the wall protection mud.

[0026] By using the above technical solution, the anti-permeation auxiliary material is mixed with the cementing agent, and then mixed with the bentonite, water and the like, thereby improving the bonding strength of the anti-permeation auxiliary material and the cementing agent, facilitating the fixation of the anti-permeation auxiliary material in the mud skin, improving the anti-permeation performance and support strength of the mud skin, and preventing the surrounding soil from permeating into the cast-in-place pile, thereby prolonging the service life of the cast-in-place pile.

[0027] Optionally, S2 specifically includes the following steps: hydrating the cementing agent raw material and intermittently stirring to obtain the cementing agent.

[0028] By using the above technical solution, the cementing agent raw material is expanded in space after hydration, facilitating the bonding and fixation of the anti-permeation auxiliary material, and facilitating the adhesion of clay particles and mineral material particles after the addition of bentonite, mineral material and barite and the like. When the cementing agent is selected from hydroxyethyl carboxymethyl cellulose and polyacrylamide, the polyacrylamide and the hydroxyethyl carboxymethyl cellulose swell and cross to form a three-dimensional network structure that supports and adheres to each other, and then mixed with the anti-permeation auxiliary material, facilitating the loading of the anti-permeation auxiliary material; part of the nitro humic acid potassium not wrapped by the wrapping agent dilutes and lubricates the three-dimensional network structure, facilitating the uniform mixing of the three-dimensional network structure with the bentonite, the soda ash, the mineral material and the weighting agent. During the preparation of the mud, the groups of water molecules adsorbed by the polyacrylamide hydrate with the hydroxyethyl carboxymethyl cellulose, and the ions decomposed from the hydroxyethyl carboxymethyl cellulose hydrate with the water molecules, the osmotic pressure inside and outside the three-dimensional network structure is enhanced, and the polyacrylamide polyelectrolyte has strong water absorption capacity; after the cast-in-place pile is formed, the surrounding water molecules permeate into the mud skin under the action of rain and vehicle load, the polyacrylamide polyelectrolyte absorbs water, reducing the probability of water molecules entering the cast-in-place pile and corroding the reinforcement cage, thereby prolonging the service life of the cast-in-place pile.

[0029] Optionally, S3 specifically includes the following steps: the bentonite is put into part of the mixing water, stirred after uniform mixing, the remaining mixing water is slowly poured during the stirring process, and then the soda ash, the mineral material, the weighting agent and the filler prepared in S3 are added, stirred for 15-25 min, and the stirring speed is 70-90 r / min, to obtain the wall protection mud.

[0030] By using the above technical solution, the bentonite is first mixed with part of the mixing water to form a slurry, and then the remaining water is added for dilution, thereby reducing the probability of the agglomeration of the bentonite and improving the uniformity of the mud.

[0031] In summary, the present application includes at least one of the following beneficial technical effects:

[0032] 1. The nitro humic acid potassium is loaded on the vaterite, and then coated with the calcium tung oil rosin to form a anti-permeable filler, which is first loaded on the three-dimensional structure of the hydroxyethyl carboxymethyl cellulose and polyacrylamide adhesive, and the presence of calcium ions and potassium ions improves the loading firmness; then mixed with bentonite particles, tailings sand, barite and the like to improve the permeability and adhesion firmness of the mud to the surrounding soil;

[0033] 2. In the process of preparing the mud, the nitro humic acid potassium is coated with the calcium tung oil rosin and is not easily consumed by the reaction. After the cast-in-place pile is formed, under the double action of rainfall and vehicle load, the mud skin on the surface of the cast-in-place pile is impacted by the surrounding soil, air pressure in the soil and water molecules, the calcium tung oil rosin is broken, the nitro humic acid potassium is exposed, the free potassium ions, carboxyl and hydroxyl in the nitro humic acid potassium form negative charged hydration groups, and after absorbing part of the infiltrated water molecules, a tough bonding structure is formed to bond the clay particles in the mud skin together, increase the compactness of the mud skin, block the surrounding soil from permeating into the cast-in-place pile, and at the same time improve the impact resistance of the cast-in-place pile, thereby prolonging the service life of the cast-in-place pile;

[0034] 3. With the passage of time, the vaterite is converted into calcite in a low-temperature and humid environment, in the process, the potassium ions are embedded between adjacent crystal layers of the vaterite and form a bonding effect with the vaterite, which limits the expansion and separation of adjacent crystal layers, improves the formed particle size and formed strength of the calcite, thereby improving the compressive strength of the cast-in-place pile and prolonging the service life of the cast-in-place pile;

[0035] 4. The metal ions in the tailings sand are adsorbed by the hydroxyethyl carboxymethyl cellulose, thereby improving the bonding strength of the tailings sand as a framework material and the adhesive. DETAILED DESCRIPTION

[0036] The application will be further described in detail below in combination with examples and comparative examples.

[0037] In the following examples, the specific conditions not specified are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The raw materials used in the following examples can be sourced from ordinary market sales unless otherwise specified.

[0038] The bentonite is selected from engineering mud bentonite, the mud making rate is ≥18%, the water content is 1.2%, the sand content is 0.12%, the particle size is 200 mesh, and the density is 2.36 g / cm 3 , the expansion ratio is 4 times;

[0039] The soda ash is selected from industrial soda ash, the density is 2.532 g / cm 3 , and the effective ingredient content is ≥98%;

[0040] The tailing sand is selected from iron tailing sand, wherein the content of SiO2 is 61.75wt%, the content of Fe2O3 is 17.95%, the content of CaO is 6.02wt%, the content of MnO is 5.62%, and the content of Al2O3 is 3.61%;

[0041] Barite density 4.3g / cm 3 , particle size 400 mesh, barium sulfate content 90wt%;

[0042] Hydroxyethyl carboxymethyl cellulose viscosity 8000; polyacrylamide density 2.6g / cm 3 , active ingredient content 87%;

[0043] Vaterite, granular, particle size less than 3mm, pore size 30-40nm, density 2.9g / cm 3 ;

[0044] Potassium nitro humic acid moisture ≤15%; fineness 100 mesh; potassium content 10%; water-soluble humic acid ≥45%, pH value 10;

[0045] Tung oil specific gravity (20 / 4℃): 0.9380, moisture volatile ≤0.2; impurities ≤0.15;

[0046] Softening point of rosin 76℃, acid value ≥166mgKOH / g.

[0047] Preparation example

[0048] 5kg of tung oil and 15kg of rosin are mixed, heated to 225℃, and constant temperature stirring is carried out for 8min; 3.5kg of calcium hydroxide is added, heated to 240℃, and constant temperature stirring is carried out for 20-40min to obtain tung oil calcium rosin.

[0049] Example

[0050] Example 1

[0051] S1, 0.3kg of hydroxyethyl carboxymethyl cellulose and 0.05kg of polyacrylamide are uniformly mixed, then slowly poured into 3L of normal temperature distilled water for hydration, stirring while pouring, after all poured in, intermittent stirring is carried out for 24h, stirring for 5min, standing for 6h, and the stirring speed is 100r / min to obtain the cement;

[0052] S2, 13 kg of vaterite and 5 kg of nitro humic acid potassium were put into water, stirred and ultrasonically treated for 15 min; after drying and dehydration, oscillation dispersion was carried out to obtain anti-permeation particles; 5 kg of tung oil calcium rosin prepared by the preparation example was sprayed on the surface of the anti-permeation particles, and anti-permeation adjuvants with a particle size of less than 3 mm were obtained after cooling and oscillation; the above steps were repeated to prepare enough anti-permeation adjuvants; 23 kg of anti-permeation adjuvants were added to 0.4 kg of the cement prepared in S1, and stirred for 5 min at a stirring speed of 80 r / min to obtain the filler;

[0053] S3, 54 kg of bentonite was put into 450 kg of mixing water, mixed uniformly and stirred, and the remaining 450 kg of mixing water was slowly poured into the mixture during the stirring process; after the mixing water was poured, 2.7 kg of soda ash, 7 kg of tailings, 14 kg of barite and the filler prepared in S2 were added, and stirred for 20 min at a stirring speed of 80 r / min to obtain the wall protection mud.

[0054] Example 2

[0055] S1, 0.05 kg of hydroxyethyl carboxymethyl cellulose and 0.08 kg of polyacrylamide were mixed uniformly, and then slowly poured into 3 L of distilled water at room temperature for hydration; the mixture was stirred during pouring, and after all the mixture was poured in, intermittent stirring was carried out for 24 h; the mixture was stirred for 5 min and then statically placed for 6 h at a stirring speed of 100 r / min to obtain the cement;

[0056] S2, 3.2 kg of vaterite and 0.8 kg of nitro humic acid potassium were put into water, stirred and ultrasonically treated for 15 min; after drying and dehydration, oscillation dispersion was carried out to obtain anti-permeation particles; 1 kg of tung oil calcium rosin prepared by the preparation example was sprayed on the surface of the anti-permeation particles, and anti-permeation adjuvants with a particle size of less than 3 mm were obtained after cooling and oscillation; the above steps were repeated to prepare enough anti-permeation adjuvants; 5 kg of anti-permeation adjuvants were added to 0.13 kg of the cement prepared in S1, and stirred for 5 min at a stirring speed of 80 r / min to obtain the filler;

[0057] S3, 54 kg of bentonite was put into 450 kg of mixing water, mixed uniformly and stirred, and the remaining 450 kg of mixing water was slowly poured into the mixture during the stirring process; after the mixing water was poured, 2.7 kg of soda ash, 7 kg of tailings, 14 kg of barite and the filler prepared in S2 were added, and stirred for 20 min at a stirring speed of 80 r / min to obtain the wall protection mud.

[0058] Example 3

[0059] S1, 0.3 kg of hydroxyethyl carboxymethyl cellulose and 0.1 kg of polyacrylamide were mixed uniformly, and then slowly poured into 3 L of distilled water at room temperature for hydration; the mixture was stirred during pouring, and after all the mixture was poured in, intermittent stirring was carried out for 24 h; the mixture was stirred for 5 min and then statically placed for 6 h at a stirring speed of 100 r / min to obtain the cement;

[0060] S2, put 1 kg of ball vaterite and 0.5 kg of nitro humic acid potassium into water, stir and ultrasonic treatment for 15 min; after drying and dehydration, oscillation dispersion, anti-permeable particles are obtained; take 0.5 kg of tung oil calcium rosin prepared in preparation example to spray on the surface of the anti-permeable particles, and after cooling and oscillation, anti-permeable adjuvants with particle size less than 3 mm are obtained, repeat the above steps to prepare enough anti-permeable adjuvants; take 2 kg of anti-permeable adjuvants and add 0.35 kg of the cementing agent prepared in S1, stir for 5 min, and the stirring speed is 80 r / min, to obtain the filler;

[0061] S3, put 60 kg of bentonite into 450 kg of mixing water, mix uniformly, then stir, slowly pour the remaining 450 kg of mixing water during stirring, after the mixing water is poured, add 1.8 kg of soda ash, 8.2 kg of tailings, 24.6 kg of barite and the filler prepared in S2, stir for 20 min, and the stirring speed is 80 r / min, to obtain the wall protection mud.

[0062] Example 4

[0063] The difference from example 2 is that the addition amount of polyacrylamide in S1 is 0.05 kg.

[0064] Example 5

[0065] The difference from example 2 is that the addition amount of polyacrylamide in S1 is 0.1 kg.

[0066] Example 6

[0067] The difference from example 2 is that the addition amount of anti-permeable adjuvants in S2 is 2 kg.

[0068] Example 7

[0069] The difference from example 2 is that the addition amount of anti-permeable adjuvants in S2 is 23 kg.

[0070] Example 8

[0071] The difference from example 2 is that the addition amount of ball vaterite in the preparation of anti-permeable adjuvants in S2 is 1 kg.

[0072] Example 9

[0073] The difference from example 2 is that the addition amount of ball vaterite in the preparation of anti-permeable adjuvants in S2 is 13 kg.

[0074] Example 10

[0075] The difference from example 2 is that the addition amount of nitro humic acid potassium in the preparation of anti-permeable adjuvants in S2 is 0.5 kg.

[0076] Example 11

[0077] The difference from Example 2 is that the amount of potassium nitrohumate added in the preparation of the S2 anti-permeation adjuvant is 5 kg.

[0078] Example 12

[0079] The difference from Example 2 is that the amount of calcium tung oil rosin added in the preparation of the S2 anti-permeation adjuvant is 0.5 kg.

[0080] Example 13

[0081] The difference from Example 2 is that the amount of calcium tung oil rosin added in the preparation of the S2 anti-permeation adjuvant is 5 kg.

[0082] Comparative Example

[0083] Comparative Example 1

[0084] The difference from Example 2 is that hydroxyethyl carboxymethyl cellulose is not added, and the amount of polyacrylamide added is 0.13 kg.

[0085] Comparative Example 2

[0086] The difference from Example 2 is that polyacrylamide is not added, and the amount of hydroxyethyl carboxymethyl cellulose added is 0.13 kg.

[0087] Comparative Example 3

[0088] The difference from Example 2 is that the anti-permeation adjuvant is not added.

[0089] Comparative Example 4

[0090] The difference from Example 2 is that barite is not added in the anti-permeation adjuvant.

[0091] Comparative Example 5

[0092] The difference from Example 2 is that potassium nitrohumate is not added in the anti-permeation adjuvant.

[0093] Comparative Example 6

[0094] The difference from Example 2 is that calcium tung oil rosin is not added in the anti-permeation adjuvant.

[0095] Comparative Example 7

[0096] The difference from Example 2 is that the tailings sand is replaced with river sand having the same particle size and weight.

[0097] Table 1 Raw Material Table of Examples and Comparative Examples

[0098]

[0099]

[0100] Performance test

[0101] Test method

[0102] 1. The viscosity (S) of the mud was determined by using a standard funnel viscometer type 1006, following the steps: 200 mL and 500 mL of mud were measured in two open ended cups, the sand particles with a size greater than 4 mm were filtered out using a sieve, and then the mud was poured into the funnel, allowing the mud to flow out of the funnel until the 500 mL measuring cup was full, the time required was the viscosity (S) of the mud. The test results are shown in Table 2.

[0103] 2. The 30 min water loss (ml) and the mud cake thickness (mm) of the mud were determined by using a gas pressure mud water loss tester type NS-1. The test results are shown in Table 2.

[0104] 3. The permeability of the mud cake formed by the mud was tested, following the steps:

[0105] (1) The soil samples below 10 m of soft soil layer were collected, and a plurality of 1 m x 1 m x 1 m molds were prepared, the molds were pressurized to 20 kPa, a hole with a diameter of 20 cm and a depth of 50 cm was drilled at the center position of the mold;

[0106] (2) The mud was poured into the drilled hole, and was left to stand for 24 h, C25 concrete was poured into the drilled hole, the grouting pressure was 7 MPa, the mud in the drilled hole was replaced, and the test piece was formed by integrating the mold, the mud cake, and the cast-in-place pile after curing for 7 days;

[0107] (3) The same batch of test pieces were divided into two groups, one group was peeled to test the weight S1 (kg) of the mud cake and the cast-in-place pile, and the other group was sealed by coating the top end of the mud cake and the cast-in-place pile with waterproof material, the test piece was placed in a sealed tank containing water, the height of the water was required to be consistent or slightly lower than the height of the test piece, the height difference was not greater than 0.5 cm, the sealed tank was pressurized to 0.7 MPa after sealing, and the test piece was peeled after 30 min, and the weight S2 (kg) of the mud cake and the cast-in-place pile was tested;

[0108] (4) The permeability rate (%) per unit thickness was calculated:

[0109] Permeability rate (%) = (S2-S1) / (S1 x h) x 100%

[0110] The test results are shown in Table 2.

[0111] Table 2: Test results data table of each example and comparative example

[0112]

[0113] In combination with Example 1, Example 2 and Example 3 and in combination with Table 2, by adjusting the amount of mixing water, bentonite, soda ash, tailings sand, barite, hydroxyethyl carboxymethyl cellulose and polyacrylamide in the cementing agent, the amount of ballvitreous, potassium nitrohumate and calcium tung oil rosin in the anti-permeation filler, the anti-permeation mud is prepared, which facilitates the mud to form a mud skin on the inner wall of the borehole to block the surrounding soil from permeating into the bored pile, thereby prolonging the service life of the bored pile.

[0114] In combination with Example 2, Example 4 and Example 5, the weight ratio of hydroxyethyl carboxymethyl cellulose to polyacrylamide in Example 2 is 5:8, the weight ratio of hydroxyethyl carboxymethyl cellulose to polyacrylamide in Example 4 is 1:1, and the weight ratio of hydroxyethyl carboxymethyl cellulose to polyacrylamide in Example 5 is 1:2, and in combination with Table 2, it can be seen that as the weight ratio of hydroxyethyl carboxymethyl cellulose to polyacrylamide increases, the viscosity, water loss and mud skin thickness of the mud have little effect, and the permeability of the mud skin formed by the mud first decreases and then increases.

[0115] In combination with Example 2, Example 6 and Example 7, the amount of anti-permeation auxiliary material added in Example 2 is 5 kg, the amount of anti-permeation auxiliary material added in Example 6 is 2 kg, and the amount of anti-permeation auxiliary material added in Example 7 is 23 kg, and in combination with Table 2, it can be seen that as the amount of anti-permeation auxiliary material increases, the viscosity of the mud decreases, the water loss increases, the mud skin thickness first increases and then decreases, and the permeability of the mud skin formed by the mud decreases. The raw materials for preparing the anti-permeation auxiliary material include ballvitreous, potassium nitrohumate and calcium tung oil rosin, the potassium nitrohumate is loaded on the ballvitreous, and then the calcium tung oil rosin is coated to form the anti-permeation auxiliary material.

[0116] In combination with Example 2, Example 8 and Example 9, the amounts of potassium nitrohumate and calcium tung oil rosin added in the preparation process of the anti-permeation auxiliary material in the three examples are the same, the difference lies in that 3.2 kg of ballvitreous is added in Example 2, 1 kg of ballvitreous is added in Example 8, and 13 kg of ballvitreous is added in Example 9, and in combination with Table 2, it can be seen that as the amount of ballvitreous in the anti-permeation auxiliary material increases, the viscosity of the mud decreases, the water loss increases, and the mud skin thickness has little effect, and the permeability of the mud skin formed by the mud first increases and then decreases.

[0117] In combination with Example 2, Example 10 and Example 11, the adding amount of vaterite and calcium tung oil rosin in the preparation process of the three examples of anti-permeation adjuvant is the same, the difference is that 0.8 kg of nitro humic acid potassium is added in Example 2, the weight ratio of nitro humic acid potassium to hydroxyethyl carboxymethyl cellulose is 16:1; 0.5 kg of nitro humic acid potassium is added in Example 10, the weight ratio of nitro humic acid potassium to hydroxyethyl carboxymethyl cellulose is 10:1; 5 kg of nitro humic acid potassium is added in Example 11, the weight ratio of nitro humic acid potassium to hydroxyethyl carboxymethyl cellulose is 100:1; it can be seen from Table 2 that with the increase of the adding amount of nitro humic acid potassium in the anti-permeation adjuvant, the viscosity of the mud decreases, the water loss increases, the mud cake thickness decreases, and the permeability of the mud cake formed by the mud decreases first and then increases.

[0118] In combination with Example 2, Example 12 and Example 13, the adding amount of vaterite and calcium tung oil rosin in the preparation process of the three examples of anti-permeation adjuvant is the same, the difference is that 1 kg of calcium tung oil rosin is added in Example 2, 0.5 kg of calcium tung oil rosin is added in Example 12, and 5 kg of calcium tung oil rosin is added in Example 13, it can be seen from Table 2 that with the increase of the adding amount of calcium tung oil rosin in the anti-permeation adjuvant, the permeability of the mud cake formed by the mud decreases first and then increases.

[0119] In combination with Example 2 and Comparative Example 1, the difference between Example 2 and Comparative Example 1 is that hydroxyethyl carboxymethyl cellulose is not added in Comparative Example 1, it can be seen from Table 2 that the increase of the adding amount of hydroxyethyl carboxymethyl cellulose makes the viscosity of the mud increase, the water loss decrease, the mud cake thickness thicken, and the permeability decrease.

[0120] In combination with Example 2 and Comparative Example 2, the difference between Example 2 and Comparative Example 2 is that polyacrylamide is not added in Comparative Example 2, it can be seen from Table 2 that the increase of the adding amount of polyacrylamide makes the viscosity of the mud increase, the water loss decrease, the mud cake thickness thicken, and the permeability decrease.

[0121] In combination with Example 2 and Comparative Example 3, the difference between Example 2 and Comparative Example 3 is that the anti-permeation adjuvant is not added in Comparative Example 3, it can be seen from Table 2 that the increase of the adding amount of the anti-permeation adjuvant effectively reduces the permeability of the mud cake.

[0122] In combination with Example 2 and Comparative Example 4, the difference between Example 2 and Comparative Example 4 is that vaterite is not added in the anti-permeation adjuvant in Comparative Example 4, it can be seen from Table 2 that the increase of the adding amount of vaterite effectively reduces the permeability of the mud cake.

[0123] In combination with Example 2 and Comparative Example 5, the difference between Example 2 and Comparative Example 5 is that nitro humic acid potassium is not added in the anti-permeation adjuvant in Comparative Example 5, it can be seen from Table 2 that the increase of the adding amount of nitro humic acid potassium effectively reduces the permeability of the mud cake.

[0124] In combination with Example 2 and Comparative Example 6, the difference between Example 2 and Comparative Example 6 is that no tung oil calcium rosin is added in the anti-seepage adjuvant in Comparative Example 6, and it can be seen from Table 2 that the increase of the amount of tung oil calcium rosin effectively reduces the seepage rate of the mud skin.

[0125] In combination with Example 2 and Comparative Example 7, the difference between Example 2 and Comparative Example 7 is that the tailings sand is replaced by river sand in Comparative Example 7, and it can be seen from Table 2 that the increase of the amount of tailings sand increases the thickness of the mud skin and reduces the seepage rate of the mud skin.

[0126] It is worth noting that in the method for testing the seepage rate in the present application, the presence of water molecules penetrating from the bottom of the cast-in-place pile into the cast-in-place pile is observed, so the seepage rate can only be used as a comparison between the examples and the comparative examples of the present application to reflect the effect of the anti-seepage adjuvant, and there is a deviation from the actual engineering use.

[0127] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the Patent Law.

Claims

1. A wall protection slurry for a cast-in-place pile, characterized by, The raw materials include the following weight parts: mixing water 900 parts; bentonite 54-60 parts; soda ash 1.7-2.7 parts; mineral material 7-8.2 parts; weighting agent 14-24.6 parts; adhesive 0.13-0.4 parts; anti-permeation auxiliary material 2-23 parts; the preparation raw materials of the anti-permeation auxiliary material include porous carrier, nitro humic acid potassium and coating agent, and the weight ratio of the porous carrier, nitro humic acid potassium and coating agent is (10-16):(4-5):5; The anti-permeation auxiliary material is formed by loading nitro humic acid potassium on the porous carrier and then coating the coating agent; The porous carrier is selected from vaterite; the coating agent is selected from tung oil calcium rosin; The adhesive includes hydroxyethyl carboxymethyl cellulose and polyacrylamide, and the weight ratio of the hydroxyethyl carboxymethyl cellulose and polyacrylamide is (5-48):8; The mineral material is selected from tailings sand; When the wall protection mud for bored pile is prepared, the hydroxyethyl carboxymethyl cellulose and polyacrylamide are first hydrated to obtain the adhesive, then the anti-permeation auxiliary material is mixed with the adhesive to obtain the filler, and then the filler is mixed with other raw materials to prepare the wall protection mud.

2. The wall protection slurry for cast-in-place piles according to claim 1, characterized by, The preparation of the tung oil calcium rosin includes the following steps: tung oil and rosin are mixed, heated to 220-230 DEG C, and constant temperature stirring is performed for 5-10 min; calcium hydroxide is added, heated to 240 DEG C-250 DEG C, and constant temperature stirring is performed for 20-40 min to obtain the tung oil calcium rosin.

3. The slurry according to claim 1, wherein The preparation of the anti-permeation auxiliary material includes the following steps: the porous carrier and nitro humic acid potassium are put into water, stirred and ultrasonically treated for 10-20 min; after dehydration, the anti-permeation particles are obtained after dispersion; the coating agent is sprayed on the surface of the anti-permeation particles, and the anti-permeation auxiliary material is obtained after oscillation.

4. The wall protection slurry for cast-in-place piles according to claim 1, characterized by, The weighting agent is selected from barite.

5. The method of preparing a wall protection slurry for cast-in-place piles according to any one of claims 1 to 4, characterized in that, The method includes the following steps: S1, preparing the adhesive; S2, preparing the anti-permeation auxiliary material, and mixing the anti-permeation auxiliary material with the adhesive to obtain the filler; S3, stirring the bentonite, mixing water, soda ash, mineral material, weighting agent and the filler prepared in S2 to obtain the wall protection mud.

6. The method of preparing a wall protection slurry for a cast-in-place pile according to claim 5, characterized by, S1 specifically includes the following steps: the adhesive raw materials are hydrated, and intermittent stirring is performed to obtain the adhesive.

7. The method of preparing a wall protection slurry for a cast-in-place pile according to claim 5, characterized by, S3 specifically includes the following steps: the bentonite is put into part of the mixing water, mixed uniformly and stirred, the remaining mixing water is slowly poured into the stirring process, then the soda ash, mineral material, weighting agent and filler prepared in S2 are added, and stirring is performed for 15-25 min at a stirring speed of 70-90 r / min to obtain the wall protection mud.

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