CN111233406A

CN111233406A - High polymer-based composite material for earth and rockfill dam reinforcement and preparation method thereof

Info

Publication number: CN111233406A
Application number: CN202010063323.0A
Authority: CN
Inventors: 杨才千; 潘婷; 马雯波; 赵艳兵
Original assignee: Nanjing Menglianqiao Material Technology Co Ltd; Xiangtan University
Current assignee: Nanjing Menglianqiao Material Technology Co Ltd; Xiangtan University
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2020-06-05

Abstract

The invention provides a high polymer matrix composite material for reinforcing earth and rockfill dams and a preparation method thereof, wherein the high polymer matrix composite material is prepared from the following raw materials in parts by weight: 1.8-4.5 parts of polyurethane resin; 0 to 18 portions of cement; 180 parts of dry plain soil; 40.5 to 43.2 portions of water. The high polymer-based composite material provided by the invention has the characteristics of good early mechanical property, excellent later mechanical property, good durability, rapid water and leakage stopping and the like according to different proportions, adopts the combination of polyurethane and cement, greatly improves the coordinated deformation performance, the cracking resistance and the early strength of the existing earth and rockfill dam compared with the existing cement-based earth and rockfill dam treatment material, has higher strength and water and leakage stopping functions after reinforcement is carried out for 10-15 minutes, and is suitable for repairing diseases such as cracks, leakage and the like of the earth and rockfill dam and various earth and rockfill side slopes and stopping water and leakage.

Description

High polymer-based composite material for earth and rockfill dam reinforcement and preparation method thereof

Technical Field

The invention belongs to the technical field of reinforcement of earth and rockfill dams and earth and rockfill side slopes, and particularly relates to a high polymer matrix composite material for earth and rockfill dam reinforcement and a preparation method thereof.

Background

The safety inspection of the earth and rock dam shows that the main problems of ① dam body is single thin, the width of the dam top is insufficient, the dam slope is steep, the dam height of some reservoir earth and rock dams is more than 15m, the backwater slope ratio is only 1: 1.5, the width of the dam top is only 3m, ② dam body is poor in filling quality, soil body is loose, the permeability of the dam body is strong, the seepage is serious around the dam, a backwater slope is prone to generate cow leather expansion, even a phenomenon of piping and flowing soil when a high water level is sunk, ③ slope is poor in quality, a dry water slope is mostly turf, a water slope is quite a slope protection, a quite part of the slope protection is serious, a water level is seriously leaked, a cowhide expansion phenomenon is generated, even a phenomenon of piping and flowing soil is generated, a water discharge culvert is not easy to crack, a water discharge culvert is not easy to open, and the water discharge culvert is not easy to open, the water discharge culvert is not open, the water is not.

The existing modified soil materials are mainly divided into clay slurry, cement slurry, chemical slurry and the like. In the reinforcing operation of dam body and non-lithologic earth-rock dam, clay slurry or clay cement slurry is generally adopted, and the technical effect of reinforcing treatment is enhanced when the rock foundation is damaged greatly. When the leakage phenomenon of the foundation dam is severe, chemical grout is generally used. The clay slurry and the cement slurry can not meet the strength requirement, the effect of improving the geological environment of a working face is achieved, a set of mature experimental proportioning data of each slurry component is not formed, and the general chemical slurry can pollute the ecological environment.

Application number CN201710030302.7 discloses an impermeable and corrosion-resistant cement-clay solidified slurry, which comprises the following raw materials: common clay, kaolin, cement, active silicon oxide, industrial waste residue, lime, an early strength agent, an organic stabilizer and water. After the curing agent, the early strength agent and the stabilizing agent are added into the clay-cement slurry, the clay slurry with poor bonding becomes the seepage-proofing corrosion-resisting clay curing slurry with short setting time, strong anti-erosion capability, good fluidity and simple and cheap construction, but the slurry has too many components and overlarge density, so the permeability is poor and the grouting is not facilitated.

According to the situations, aiming at the problems of piping, soil flowing and the like of earth and rockfill dams and earth and rockfill side slopes, a novel reinforcing material which is deep in penetration and moderate in strength is required to be developed, the reinforcing material is prevented from being accumulated on the surface of a soil body, a hard shell is formed between a soil body surface reinforcing layer and an unreinforced layer, and the soil body surface reinforcing layer can be integrally cracked or even fall off after a long time; meanwhile, the geological environment cannot be damaged and the ecological environment is polluted.

Disclosure of Invention

Aiming at the technical problems, the invention provides a high polymer matrix composite material for reinforcing an earth and rockfill dam and a preparation method thereof. The invention improves the problems of piping, soil flowing and the like of earth and rockfill dams and earth and rockfill side slopes, mainly aims at preventing seepage and stopping leakage and improving the rigidity and brittleness of the earth and rockfill dams and the earth and rockfill side slopes. Compared with the existing earth and rockfill dam and cement-based earth and rockfill slope treatment materials, the high polymer-based composite material cement reinforced soil for reinforcing the earth and rockfill dam, disclosed by the invention, has the advantages that the strength and the stability are improved; compared with the simple organic grouting material, the early strength and the stability of the grouting material are improved.

The invention provides a high polymer-based composite material for reinforcing earth and rockfill dams, which comprises dry plain soil, polyurethane, cement and water, wherein the high polymer-based composite material comprises the following components in parts by weight: 1.8 to 4.5 portions of polyurethane resin, 0 to 18 portions of cement, 180 portions of dry plain soil and 40.5 to 43.2 portions of water.

Preferably, the cement is 9 to 18 parts.

Preferably, the particle size of the dry vegetable soil is less than 2 mm.

The polyurethane resin is hydrophilic polyurethane resin which can be polymerized with water.

The invention also provides a preparation method of the high polymer-based composite material for reinforcing the earth and rockfill dam, which comprises the following steps:

(1) weighing polyurethane resin, cement, dry plain soil and water;

(2) adding water into polyurethane resin, and fully stirring and mixing to obtain a polyurethane resin solution;

(3) adding cement into the polyurethane resin solution, and fully stirring and mixing to obtain a mixed solution;

(4) and pouring dry plain soil into a stirrer, pouring the mixed solution into the stirrer, and stirring until the mixed solution is fully and uniformly mixed to obtain the high polymer-based composite material for reinforcing the earth-rock dam.

Has the advantages that:

(1) the high polymer matrix composite material for reinforcing the earth and rockfill dam, prepared by the invention, can effectively inhibit or treat the leakage problems of piping, soil flow and the like of the earth and rockfill dam, and simultaneously improves the strength, ductility and durability of the earth and rockfill dam; by adopting the combination of polyurethane and cement, compared with the existing cement-based earth-rock dam treatment material, the coordinated deformation performance, the anti-cracking performance and the early strength of the material and the existing earth-rock dam are greatly improved, and the material has higher strength and water-stopping and leakage-stopping effects after reinforcement is carried out for 10-15 minutes; compared with the simple use of organic high polymer materials, the early strength and the stability of the material are improved;

(2) the reinforced soil provided by the invention not only can have early compressive strength, but also has the characteristics of later compressive strength, good durability, high water stopping speed and the like according to different proportions, and can be suitable for earth-rock dams with the phenomena of cracks, leakage, slope protection damage and the like;

(3) the technical scheme provided by the invention provides a new idea and construction technical reference for solving the leakage problems of piping, soil flow and the like of the earth-rock dam.

Drawings

Fig. 1 is a scanning electron microscope image of a reinforced soil sample provided by the present invention (where a is the reinforced soil sample prepared in example 4, b is the reinforced soil sample prepared in example 9, and c is the reinforced soil sample prepared in example 2);

FIG. 2 is a graph showing the effect of the compressive properties of reinforced soil samples prepared in examples 1 to 3 (the concentration of the hydrophilic polyurethane resin is 6%);

FIG. 3 is a graph showing the effect of the compressive properties of reinforced soil samples prepared in examples 3, 7, 8 and 9 (no cement in the grouting liquid, only hydrophilic polyurethane resin);

FIG. 4 is a graph showing the effect of the compressive properties of reinforced soil samples prepared in examples 1, 4, 5 and 6 (the mass ratio of soil to cement is 100: 5).

Detailed Description

The invention will be further illustrated with reference to specific examples, to which the present invention is not at all restricted.

The polyurethane material in the following raw materials is a hydrophilic polyurethane material, a product produced by Jiangsu Jiekey New Material science and technology company Limited is selected, and the density of the polyurethane material is about 1.8g/cm³The solid content is 85%; the cement is quick-hardening sulphoaluminate cement and is selected from products produced by engineering materials division of Shandong Lucheng cement Co. The dry plain soil is obtained by drying soil bodies on earth and rockfill dams or natural soil bodies at the temperature of 105 ℃ and then crushing the dried plain soil, and the crushed soil bodies pass through a soil engineering sieve of 2mm without special requirements.

The high polymer-based composite material for reinforcing the earth-rock dam can be directly poured on the surface of a soil body to form a reinforced soil body, and can also be injected into subsidence, cracks and fracture parts of the soil body through a high-pressure grouting machine for seepage prevention and leakage stoppage.

Example 1

(1) Taking 180g of dry plain soil, 9g of cement, 2.7g of hydrophilic polyurethane resin and 42.3g of water, wherein the mass ratio of the dry plain soil to the hydrophilic polyurethane resin solution is 4: 1, the cement is quick-hardening sulphoaluminate cement, the cement accounts for 0.05 mass of dry plain soil, the hydrophilic polyurethane resin accounts for 0.015 mass of dry plain soil, and the water accounts for 0.235 mass of dry plain soil;

(2) stirring and mixing cement and hydrophilic polyurethane resin uniformly, pouring water into the mixture, and stirring and mixing uniformly to form a hydrophilic polyurethane resin cement solution;

(3) and (3) uniformly stirring and mixing the dry plain soil and the hydrophilic polyurethane resin cement solution to obtain the high polymer matrix composite material for reinforcing the earth-rock dam.

Example 2

(1) Taking 180g of dry plain soil, 18g of cement, 2.7g of hydrophilic polyurethane resin and 42.3g of water; the mass of the cement is 0.1 of that of dry plain soil;

Example 3

(1) Taking 180g of dry plain soil, 2.7g of hydrophilic polyurethane resin and 42.3g of water; the mass of the cement is 0g, namely the mass of the cement is 0 of that of dry plain soil;

(2) pouring water into hydrophilic polyurethane resin, and uniformly stirring and mixing to form hydrophilic polyurethane resin solution;

(3) and (3) uniformly stirring and mixing the dry plain soil and the hydrophilic polyurethane resin solution to obtain the high polymer matrix composite material for reinforcing the earth-rock dam.

Example 4 (comparative group)

(1) Taking 180g of dry plain soil, 9g of cement and 45g of water; the mass of the hydrophilic polyurethane resin is 0g, namely the mass of the hydrophilic polyurethane resin is 0 of that of dry plain soil; the water accounts for 0.25 of the mass of the dry plain soil;

(2) pouring water into cement, and stirring and mixing uniformly to form a cement solution;

(3) the dry vegetable soil and the cement solution are stirred and mixed evenly.

Example 5

(1) Taking 180g of dry plain soil, 9g of cement, 1.8g of hydrophilic polyurethane resin and 43.2g of water; the mass of the hydrophilic polyurethane resin is 0.01 of that of dry plain soil; the water accounts for 0.24 of the mass of the dry plain soil;

Example 6

(1) Taking 180g of dry plain soil, 9g of cement, 3.6g of hydrophilic polyurethane resin and 41.4g of water; the mass of the hydrophilic polyurethane resin is 0.02 of that of dry plain soil; the water accounts for 0.23 of the mass of the dry plain soil;

Example 7

(1) Taking 180g of dry plain soil, 1.8g of hydrophilic polyurethane resin and 43.2g of water; the mass of the cement is 0, namely the mass of the cement is 0 of the mass of dry plain soil; namely, the mass of the hydrophilic polyurethane resin is 0.01 of that of dry plain soil; the water accounts for 0.24 of the mass of the dry plain soil;

Example 8

(1) Taking 180g of dry plain soil, 3.6g of hydrophilic polyurethane resin and 41.4g of water; the mass of the cement is 0, namely the mass of the cement is 0 of the mass of dry plain soil; the mass of the hydrophilic polyurethane resin is 0.02 of that of dry plain soil; the water accounts for 0.23 of the mass of the dry plain soil;

Example 9

(1) Taking 180g of dry plain soil, 4.5g of hydrophilic polyurethane resin and 40.5g of water; the mass of the cement is 0, namely the mass of the cement is 0 of the mass of dry plain soil; the mass of the hydrophilic polyurethane resin is 0.025 of that of dry plain soil; the water accounts for 0.225 of the dry soil;

Performance detection

Operating according to geotechnical experiment specifications, respectively preparing reinforcing materials according to the methods of the embodiments 1-9, and then pouring 9 groups of reinforcing materials into a mold (phi 39.1x80mm) for casting molding to obtain a reinforced soil sample; demolding after one day, and maintaining for one day, seven days and twenty-eight days; and when the set age is reached, performing unconfined compressive strength tests on the soil sample. The reinforced soil body samples prepared in the embodiments are placed in a universal testing machine, an unconfined compressive strength test is carried out according to a standard loading rate, the peak compressive strength is observed and recorded, three groups of the same unconfined compressive strength tests are carried out, and the average value of the test results is taken to avoid the discreteness of a single group of test data.

1. The compressive properties of the reinforced soil samples of examples 1-3 are shown in table 1.

TABLE 1 compressive Strength of reinforced soil samples of examples 1-3

In examples 1 to 3, the reinforced soil sample is prepared by using a hydrophilic polyurethane resin cement solution (the concentration of the hydrophilic polyurethane resin is 6%) and dry plain soil, and it can be seen from the data that the addition of the cement can improve the early compressive strength of the high polymer reinforced soil, and the later compressive strength of the high polymer reinforced soil is not improved; the longer the age, the higher the compressive strength of the stabilized soil, as shown in fig. 2 and the preparation method thereof.

2. The compressive properties of the reinforced soil samples of examples 3, 7, 8 and 9 are shown in table 2.

Table 2 shows the compressive strength of the reinforced soil samples of examples 3, 7, 8 and 9

Examples 3, 7, 8 and 9 are reinforced soil samples prepared from a hydrophilic polyurethane resin solution and dry plain soil, and it can be seen from the data that: the early compressive strength of the reinforced soil is not obviously improved and the later compressive strength is obviously improved along with the increase of the concentration of the hydrophilic polyurethane resin when no cement is contained and only the hydrophilic polyurethane resin is contained; the longer the age, the higher the compressive strength of the stabilized soil, as shown in fig. 3.

3. The compressive properties of the reinforced soil samples of examples 1, 4, 5, and 6 are shown in table 3.

Table 3 shows the compressive strength of the reinforced soil samples of examples 1, 4, 5 and 6

Examples 1, 4, 5, 6 (soil to cement mass ratio of 100: 5) produced reinforced soil samples from which it can be seen: when the cement content is unchanged and the content of the hydrophilic polyurethane resin is 4%, the compressive strength of the reinforced soil is not obviously improved; when the cement content is unchanged and the concentration of the hydrophilic polyurethane resin exceeds 4%, the compressive strength of the reinforced soil is obviously improved along with the increase of the concentration of the hydrophilic polyurethane resin. The longer the age, the higher the compressive strength of the stabilized soil, as shown in fig. 4.

The reinforced soil samples prepared in examples 2, 4 and 9 were selected for scanning by electron microscopy, wherein fig. 1 (a) is a scanning electron microscopy of the reinforced soil sample (only cement, no hydrophilic polyurethane) prepared in example 4 (comparative group), and it can be seen that: particles are attached to the soil particles, but the pores are many and the structure is loose; FIG. 1 (b) is a scanning electron micrograph of the reinforced soil sample (hydrophilic polyurethane only, no cement) prepared in example 9, showing that: the floccules are adhered to the surfaces of the soil particles, so that the adhesion among the soil particles is enhanced, the pores are few, and the structure is compact; FIG. 1 (c) is a scanning electron micrograph of the reinforced soil sample (both cement and hydrophilic polyurethane) prepared in example 2, showing that: the flocs are attached to the surface of the soil particles, but each floc is not as large in area as in example 9, so the bonding between the soil particles is not as strong as in example 9, indicating that the cement breaks down the extension of the flocs.

The above experimental studies show that: the hydrophilic polyurethane composite material can be rapidly polymerized to form elastic gel through reaction with water, and has strong adhesive force, the hydrophilic polyurethane solution is solidified with soil to form a solidified body I, the solidified body I shows excellent deformation capacity and water retention in the early stage, and the deformation capacity and the water retention are poor in the later stage, so that the early compressive strength of the hydrophilic polyurethane solution and the soil solidified body is poor, and the later compressive strength is excellent; secondly, cement is added into the hydrophilic polyurethane solution with the same concentration and then is consolidated with soil to form a consolidated body II, the compressive strength of the consolidated body II at the early stage is obviously superior to that of the consolidated body I, which indicates that the cement is filled in soil particle gaps and is consolidated to form a concretion body, so that the early compressive strength of the consolidated body II is superior to that of the consolidated body I; the later-stage compressive strength of the consolidation body II is lower than that of the consolidation body I, which shows that when the hydrophilic polyurethane material and the cement are compounded for use, the two materials have antagonistic action and have adverse effect on the strength of the consolidation body; and (III) whether the hydrophilic polyurethane material is compounded with the cement or not, the compressive strength of the solidified body is increased along with the increase of the concentration of the hydrophilic polyurethane material, because when the concentration of the hydrophilic polyurethane material is increased, the viscosity of the solution is increased, and the bonding strength among particles is increased when the soil body is solidified, so that the compressive strength is increased. Therefore, in practical engineering, if the formula is used for emergency repair and water stopping and plugging, the formula consisting of dry plain soil, polyurethane, cement and water is selected, and the instant unconfined compressive strength of the soil body of the formula is 403-450 kPa; if the dry plain soil is not used for emergency repair and plugging, selecting a formula consisting of dry plain soil, polyurethane and water, wherein the minimum 28-day unconfined compressive strength of the soil body under the formula is 1669-3710 kPa; all the proportions follow the mass ratio of the dry soil to the polyurethane solution to be 4: 1.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The high polymer-based composite material for reinforcing the earth and rockfill dam is characterized by comprising polyurethane resin, cement, dry plain soil and water, wherein the components in parts by weight are as follows: 1.8 to 4.5 portions of polyurethane resin, 0 to 18 portions of cement, 180 portions of dry plain soil and 40.5 to 43.2 portions of water.

2. The polymer-based composite material for reinforcing an earth and rockfill dam according to claim 1, wherein the cement is 9 to 18 parts.

3. The polymer-based composite material for reinforcing an earth and rockfill dam according to claim 1, wherein the polyurethane resin used is a hydrophilic polyurethane resin which can be polymerized with water.

4. The high polymer-based composite material for reinforcing an earth and rockfill dam according to claim 1, wherein the dry plain soil has a particle size of less than 2 mm.

5. The method for preparing a high polymer-based composite material for reinforcing an earth and rockfill dam according to any one of claims 1 to 4, wherein the method comprises the steps of:

(1) weighing polyurethane resin, cement, dry plain soil and water;