Foamed polyacrylamide jacking pipe warehouse pressure improver applicable to water-rich sand layer and preparation method of foamed polyacrylamide jacking pipe warehouse pressure improver

Abstract

The invention discloses a foamed polyacrylamide jacking pipe warehouse pressure improver applicable to a water-rich sand layer and a preparation method of the foamed polyacrylamide jacking pipe warehouse pressure improver. The foamed polyacrylamide jacking pipe warehouse pressure improver is prepared from water, a foaming agent, polyacrylamide and epoxy resin. The concrete foaming agent comprises the following components in parts by weight: 1000 parts of water, 150-215 parts of a foaming agent, 25-35 parts of polyacrylamide and 10-25 parts of epoxy resin. Dissolving a foaming agent in water to prepare a foaming solution, then introducing air into the bottom of the sealed stirrer, and carrying out rotary physical foaming to obtain a foam solution; and adding polyacrylamide and epoxy resin into the foam solution, and uniformly mixing to obtain the warehouse pressure modifier. And the improvement effect on the water-rich sand layer muck is good.

Description

Technical Field

[0001] The invention belongs to the technical field of underground engineering pipe jacking construction, and particularly relates to a foamed polyacrylamide pipe jacking warehouse pressure improver suitable for water-rich sand layers and a preparation method thereof. Background Art

[0002] In the construction of pipe jacking in water-rich sand layers, due to the high groundwater level, loose sandy soil structure and high permeability, it is difficult to control the pressure during pipe jacking to maintain a dynamic balance with the water and soil pressure at the face. It is difficult to control the pressure with traditional bentonite-based pressure improvers, which either easily cause sand and water spraying, resulting in large-scale settlement of the surrounding area, or blockage and cake formation, resulting in poor excavation of the mud pumping pipe. In addition, the dehydration of traditional bentonite-based pressure improvers mixed with slag waste is slow, difficult to separate, and has high environmental disposal costs. Therefore, developing a pressure improver suitable for pipe jacking in water-rich sand layers is a key pipe jacking construction problem that needs to be solved urgently.

[0003] CN 109749748 A discloses a method for improving shield slag in water-rich gravel strata and a slag improver. The slag improver of the invention is prepared from the following raw materials in parts by weight: 0.25-0.33 parts of sodium bentonite, 0.01-0.015 parts of carboxymethyl cellulose, and 1 part of water; the composition and weight of liquid B are: 0.001-0.003 parts of polyacrylamide and 1 part of water. Liquid A is pumped into the soil bin in front of the cutter disc through a bentonite pipeline, and then liquid B is pumped into the soil bin through a polymer pipeline. Liquid A and liquid B in the soil bin are mixed and stirred with slag to improve the slag. The invention requires a lot of manpower and material resources, and is difficult to apply on a large scale. In addition, the improver made from sodium bentonite has problems such as slow dehydration, difficult separation, and high environmental protection disposal costs of the mixed waste of the improver and slag.

[0004] CN 111663948 A discloses a shield slag improvement admixture for water-rich sand and gravel formations. The improver of the invention is prepared from the following raw materials in parts by weight: 0.1-1wt% of thickener A, 0.025-1wt% of thickener B, 0.025-0.5wt% of surfactant, 1-10wt% of pumping agent, 0.01-0.06wt% of pH regulator, 5-15wt% of mineral improver and water. The thickener A is anionic polyacrylamide, the thickener B is hexadecyl hydroxyethyl cellulose, the surfactant is sodium lauryl polyoxyethylene ether sulfate, the pumping agent is polyethylene glycol, the pH regulator is a soda solution or a caustic soda solution, and the mineral improver is bentonite. The patent has difficulty in controlling the silo pressure, which easily causes the mud pumping pipe to be unsmooth, and the improver made of sodium bentonite has problems such as slow dehydration, difficult separation, and high environmental protection disposal costs when the improver and slag are mixed with waste. Summary of the invention

[0005] The object of the present invention is to provide a foamed polyacrylamide pipe jacking warehouse pressure improver suitable for water-rich sand layers and a preparation method thereof in view of the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present application provides a foamed polyacrylamide pipe jacking bin pressure improver suitable for water-rich sand layers, wherein the foamed polyacrylamide pipe jacking bin pressure improver is prepared from water, a foaming agent, polyacrylamide and an epoxy resin; the components are calculated by weight as follows: 1000 parts of water, 150 to 215 parts of a foaming agent, 25 to 35 parts of polyacrylamide, and 10 to 25 parts of an epoxy resin.

[0008] In some embodiments, the foaming agent is prepared by compounding sodium α-olefin sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of 1:2:1.

[0009] Furthermore, in some embodiments, the sodium α-olefin sulfonate is selected from one or more sodium α-olefin sulfonates with a carbon number ranging from 12 to 16.

[0010] Furthermore, in some embodiments, the active matter content in the sodium dodecyl sulfate is not less than 94 wt %, and the petroleum ether soluble matter content is not greater than 1.0 wt %.

[0011] Furthermore, in some embodiments, the alkylphenol polyoxyethylene ether is selected from at least one of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether.

[0012] Furthermore, in some embodiments, the molecular weight of the polyacrylamide is 4 million to 7 million.

[0013] Furthermore, in some embodiments, the molecular weight of the epoxy resin is 200,000 to 500,000.

[0014] The present application also provides a method for preparing a foamed polyacrylamide pipe jacking warehouse pressure improver suitable for use in water-rich sand layers, comprising:

[0015] S1. Foaming solution preparation

[0016] Firstly, the foaming agent and water are weighed according to the weight proportions of each component, and then the foaming agent is dissolved in water to prepare a foaming solution;

[0017] S2. Foam solution preparation

[0018] First, add the foaming solution obtained in step S1 into the sealed mixer, then introduce air into the bottom of the sealed mixer to rotate and physically foam to obtain a foam solution;

[0019] S3. Modifier Preparation

[0020] Weigh polyacrylamide and epoxy resin in parts by weight, add them to the foam solution prepared in step S2, and mix them evenly to prepare a foamed polyacrylamide pipe jacking warehouse pressure improver.

[0021] In a second aspect, the present application provides a foamed polyacrylamide pipe jacking warehouse pressure improver suitable for use in water-rich sand layers, which is prepared by the above-mentioned preparation method.

[0022] In a third aspect, the present application provides the use of the above-mentioned foamed polyacrylamide pipe jacking bin pressure improver in pipe jacking construction in water-rich sand layers.

[0023] In some embodiments, the application includes: adding the foamed polyacrylamide pipe jacking silo pressure improver into the water-rich sand layer slag.

[0024] Furthermore, the injection rate of the foamed polyacrylamide pipe jacking bunker pressure improver is 30wt% of the water-rich sand layer slag.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention uses water, a foaming agent, polyacrylamide and an epoxy resin to prepare a foamed polyacrylamide pipe jacking bunker pressure improver for a water-rich sand layer. The foam solution acts as a lubricant, the epoxy resin acts as a plugging agent to cut off groundwater recharge, and the polyacrylamide acts as a consistency adjuster for the mixture in the bunker.

[0027] (2) The present invention adopts water, foaming agent, polyacrylamide and epoxy resin to prepare foam polyacrylamide pipe jacking bunker pressure improver for water-rich sand layer. After construction, the waste contains foam solution, polyacrylamide and epoxy resin, which can be naturally dissipated and degraded, eliminating the separation process, solving the problems of difficult disposal of slag and high disposal cost. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0029] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] Example 1: A foamed polyacrylamide pipe jacking warehouse pressure improver for a water-rich sand layer in this example is prepared from water, a foaming agent, polyacrylamide and an epoxy resin. The weights of its components are as follows: 1000 grams of water, 150 grams of a foaming agent, 25 grams of polyacrylamide, and 10 grams of an epoxy resin. The foaming agent is compounded from sodium α-olefin sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of 1:2:1. The preparation process is as follows:

[0032] S1. Foaming solution preparation

[0033] Firstly, sodium α-olefin sulfonate, sodium dodecyl sulfate, alkylphenol polyoxyethylene ether and water are weighed according to the weight of each component, and then the sodium α-olefin sulfonate, sodium dodecyl sulfate and alkylphenol polyoxyethylene ether are uniformly mixed and dissolved in water to prepare a foaming solution.

[0034] S2. Foam solution preparation

[0035] First, add the foaming solution obtained in step S1 into the sealed mixer, then introduce air into the bottom of the sealed mixer to perform high-speed rotation and physical foaming to obtain the foam solution.

[0036] S3. Modifier Preparation

[0037] Finally, the polyacrylamide and epoxy resin are weighed and added into the foam solution at one time to prepare the warehouse pressure improver.

[0038] S4. Improver performance test

[0039] (1) The fluidity test of the mixture of improver and slag soil was conducted by slump test. Before the experiment, the mixer and the inner wall of the slump cylinder were soaked to prevent the inner wall from drying and absorbing the moisture of the soil, which would cause errors in the experimental results. After the slag soil in the water-rich sand layer to be improved was mixed with the silo-pressed improver with an injection rate of 30 wt%, the slag soil was loaded into the slag soil in three times, with each layer filling one-third of the height. After each layer was filled, a tamping hammer was used to evenly tamp the wall of the barrel from the outside to the inside in a spiral manner for 25 times. After tamping, the slump barrel was lifted. The height of the sand soil after collapse was measured with a ruler. The slump was the height of the barrel minus the reading of the ruler. Each group of tests was performed three times and the average value was taken in mm.

[0040] (2) Test the cohesion and internal friction angle of the mixture of modifier and slag soil. Direct shear test is used. The modified soil sample is placed in the fixed upper box and movable lower box of the direct shear apparatus. During the test, vertical pressure is first applied to the soil sample, and then horizontal thrust is applied to the lower box. The displacement between the upper and lower boxes causes the soil sample to be sheared and damaged. The shear stress at the time of damage is obtained, and then the shear strength of the soil is determined according to Coulomb's law. Then a curve of the relationship between shear strength and vertical pressure is drawn. The inclination angle of the straight line is the internal friction angle, and the unit is °. The intercept of the straight line on the ordinate is the cohesion, and the unit is kPa.

[0041] (3) The permeability coefficient of the mixture of improver and slag soil is tested by permeability test. During the test, a saturated sample with a cross-section of A and a length of L is filled in a transparent plastic cylinder. The water valve is opened to allow water to flow through the sample from top to bottom and be discharged from the outlet. After the head difference △h and the seepage flow rate Q are stable, the amount of water V flowing through the sample within a certain period of time t is measured. The permeability coefficient is calculated according to the formula K= Calculation, unit is cm / s.

[0042] According to the test method of the above preparation process, the main performance indicators of the slag after the foamed polyacrylamide pipe jacking warehouse pressure improver of the water-rich sand layer prepared in this example are as follows: slump is 182mm, permeability coefficient is 1.2× , the cohesion is 0.549 kPa, and the internal friction angle is 40.83°.

[0043] Example 2: Raw materials were weighed according to the following weights: 1000 g of water, 165 g of foaming agent, 30 g of polyacrylamide, and 12 g of epoxy resin. A foamed polyacrylamide pipe jacking warehouse pressure improver for water-rich sand layer was prepared according to the preparation method in Example 1.

[0044] The main performance indicators of the slag after being improved by the foamed polyacrylamide pipe jacking warehouse pressure improver of the water-rich sand layer prepared in this example were tested according to the test method in Example 1: slump was 194mm, permeability coefficient was 1.4× , the cohesion is 0.471 kPa, and the internal friction angle is 39.45°.

[0045] Example 3: Raw materials were weighed according to the following weights: 1000 g of water, 180 g of foaming agent, 35 g of polyacrylamide, and 20 g of epoxy resin. A foamed polyacrylamide pipe jacking warehouse pressure improver for water-rich sand layer was prepared according to the preparation method in Example 1.

[0046] The main performance indicators of the slag after being improved by the foamed polyacrylamide pipe jacking warehouse pressure improver of the water-rich sand layer prepared in this example were tested by the test method in Example 1: the slump was 206mm, the permeability coefficient was 1.7× , the cohesion is 0.432 kPa, and the internal friction angle is 38.31°.

[0047] Example 4: Raw materials were weighed according to the following weights: 1000 g of water, 195 g of foaming agent, 35 g of polyacrylamide, and 23 g of epoxy resin. A foamed polyacrylamide pipe jacking warehouse pressure improver for water-rich sand layer was prepared according to the preparation method in Example 1.

[0048] The main performance indicators of the slag soil after being improved by the foamed polyacrylamide pipe jacking bunker pressure improver of the water-rich sand layer prepared in this example were tested by the test method in Example 1: the slump was 217mm, the permeability coefficient was 2.3× , the cohesion is 0.392 kPa, and the internal friction angle is 38.04°.

[0049] Example 5: The raw materials were weighed according to the following weights: 1000 g of water, 215 g of foaming agent, 30 g of polyacrylamide, and 25 g of epoxy resin. The foamed polyacrylamide pipe jacking warehouse pressure improver for water-rich sand layer was prepared according to the preparation method in Example 1.

[0050] The main performance indicators of the slag after being improved by the foamed polyacrylamide pipe jacking warehouse pressure improver of the water-rich sand layer prepared in this example were tested according to the test method in Example 1: the slump was 231 mm, the permeability coefficient was 2.8× , the cohesion is 0.366 kPa, and the internal friction angle is 37.56°.

[0051] The performance test summary table of Examples 1-5 is shown in Table 1:

[0052] Table 1

[0053]

[0054] It can be seen from Table 1 that the foaming agent, polyacrylamide and epoxy resin can improve the water-rich sand layer slag very well. The slump after improvement reaches 231mm and the permeability coefficient reaches 2.4× , the cohesion is 0.549, the internal friction angle is 37.56°, and its performance has been significantly improved to meet the needs of the project. From the above table, it can be seen that the permeability coefficient decreases rapidly at the beginning and decreases slowly in the later period. With the continuous increase of the improver, the cohesion of the slag increases and the internal friction angle decreases.

[0055] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A foamed polyacrylamide pipe jacking bunker pressure improver suitable for water-rich sand layers, characterized in that: The foamed polyacrylamide pipe silo pressure improver is prepared from water, a foaming agent, polyacrylamide and an epoxy resin; the components are calculated by weight as follows: 1000 parts of water, 150-215 parts of a foaming agent, 25-35 parts of polyacrylamide and 10-25 parts of an epoxy resin.

2. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 1, characterized in that: The foaming agent is prepared by compounding sodium α-olefin sulfonate, sodium lauryl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of 1:2:

1.

3. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 2, characterized in that: The sodium α-olefin sulfonate is selected from one or more sodium α-olefin sulfonates with a carbon number ranging from 12 to 16.

4. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 2, characterized in that: The active matter content in the sodium lauryl sulfate is not less than 94wt%, and the petroleum ether soluble matter content is not more than 1.0wt%.

5. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 2, characterized in that: The alkylphenol polyoxyethylene ether is selected from at least one of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether.

6. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 1 or 2, characterized in that: The molecular weight of the polyacrylamide is 4 million to 7 million.

7. The foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 1 or 2, characterized in that: The molecular weight of the epoxy resin is 200,000 to 500,000.

8. The method for preparing the foamed polyacrylamide pipe jacking warehouse pressure improver according to any one of claims 1 to 7, characterized in that: include: S1. Foaming solution preparation Firstly, the foaming agent and water are weighed according to the weight proportions of each component, and then the foaming agent is dissolved in water to prepare a foaming solution; S2. Foam solution preparation First, add the foaming solution obtained in step S1 into the sealed mixer, then introduce air into the bottom of the sealed mixer to rotate and physically foam to obtain a foam solution; S3. Modifier Preparation Weigh polyacrylamide and epoxy resin in parts by weight, add them to the foam solution prepared in step S2, and mix them evenly to prepare a foamed polyacrylamide pipe jacking warehouse pressure improver.

9. A foamed polyacrylamide pipe jacking warehouse pressure improver suitable for use in water-rich sand layers, prepared by the preparation method described in claim 8.

10. Use of the foamed polyacrylamide pipe jacking warehouse pressure improver according to claim 9 and any one of claims 1 to 7 in pipe jacking construction in water-rich sand layers.

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