Acrylic polymer grouting material and application thereof in prevention and treatment of surface layer pulverization of earthen ruins in humid environment

Abstract

The invention discloses an acrylic polymer grouting material and application of the acrylic polymer grouting material in prevention and treatment of surface layer pulverization of an earthen site in a humid environment, and belongs to the field of cultural relic restoration. Through the modification effect of a water-based polymer material with good diffusivity on the surfaces of ruins and the filling effect of pores, based on the shape of the excavated earthen ruins, the surface layer pulverization of the earthen ruins in the humid environment is prevented and controlled by adopting a stepped distribution micro drilling grouting technology and utilizing a polymer stepped grouting mode; the acrylic polymer liquid is diffused to a certain range of the surface layer of the earthen ruins to prevent internal water from seeping to the surface layer in summer and maintain certain humidity of the surface layer in other seasons, so that internal stress of the surface layer of the earthen ruins caused by water change is reduced, generation of surface layer cracks is reduced, and the pulverization resistance of the earthen ruins is enhanced; the purposes of reducing the permeability coefficient of the earthen ruins and improving the weather resistance of the surface layers of the earthen ruins are achieved.

Description

Technical Field

[0001] The invention relates to a grouting material and application thereof, in particular to an acrylic polymer grouting material and application thereof in preventing and controlling surface pulverization of earthen ruins in a humid environment, belonging to the field of cultural relics restoration. Background Art

[0002] Earthen sites are relics left over from various activities throughout human history, including production and daily life. They not only carry a wealth of historical information but also represent the wisdom of human development. They are a vital cultural heritage and are widely distributed around the world. Wet earthen sites are often found in environments with heavy rainfall and shallow groundwater levels, where the soil itself holds a high water content. Water is soil's nemesis. The water environment of wet earthen sites, composed of atmospheric precipitation, air vapor, and groundwater capillary water, creates a harsher and more complex living environment, making their preservation more urgent and challenging.

[0003] Pulverization refers to the process by which the surface material of an earthen site gradually loosens and flakes off under the influence of physical, chemical, and biological factors, ultimately forming powder-like particles. This condition can reduce the structural strength of earthen sites, alter their surface morphology, and in severe cases, even affect their stability and safety.

[0004] The study on the prevention of pulverization of wet earthen sites is an important and complex task in the field of cultural relics protection. It can delay or prevent the pulverization of the surface of the earthen sites due to environmental factors by improving the overall water repellency of the site soil.

[0005] Among the existing technologies for preventing the pulverization of earthen sites, some scholars use surface spraying, which can effectively protect the surface layer of earthen sites. However, since the water content in a humid environment is generally high, the surface of the earthen site is severely eroded by water, the protection effect is poor, and the penetration depth is not enough to completely penetrate the shell layer and the powder layer, which often fails to protect the surface layer of the earthen site; some scholars use plant covering technology, the plant roots can solidify the soil and reduce rainwater erosion, and the selection and configuration of plants are relatively tedious and complex, rigorous and scientific, to ensure that their protective effect on the site is greater than their destructive effect, but the presence of vegetation will also have a certain impact on the original appearance of the earthen site, and the effect of restoring the old to its original state cannot be achieved; some scholars also use chemical grouting methods, the drilling diameter is large, which can easily cause greater disturbance to the earthen site and leave more obvious marks on the surface of the site. Most of them are grouting protection of cracks in the earthen site, and there are problems such as insufficient reinforcement gradient range and insufficient overall strength; therefore, these methods cannot fundamentally prevent and control the pulverization of the surface of wet earthen sites.

[0006] It can be seen that no single existing method can ideally prevent and control the surface pulverization of moist earthen sites, and innovation is urgently needed in the method of preventing the surface pulverization of moist earthen sites. Summary of the Invention

[0007] Therefore, starting from the site soil itself and from the perspective of the formation mechanism of pulverization of moist soil sites, improving the overall water repellency of the soil site is the key to preventing pulverization of moist soil sites.

[0008] In view of this, the present invention provides an acrylic polymer grouting material and its application in preventing and controlling the surface pulverization of earthen ruins in humid environments. Based on the idea of ​​in-situ modification of the hydrophysical properties of earthen ruins and control of the path of water diffusion, the surface of the ruins particles is modified and the pores are filled by a water-based polymer material with good diffusivity. Based on the shape of the excavated earthen ruins, a stepped micro-drilling grouting technology is adopted. The polymer stepped grouting method is used to prevent and control the surface pulverization of earthen ruins in humid environments, and the acrylic polymer liquid is diffused to a certain range of the surface of the earthen ruins, so as to prevent internal water from seeping into the surface in summer and maintain a certain humidity of the surface in other seasons, so as to reduce the internal stress of the surface of the ruins caused by water changes, reduce the generation of surface cracks, enhance the anti-pulverization ability of the earthen ruins, and achieve the purpose of reducing the permeability coefficient of the earthen ruins and improving the weather resistance of the surface of the earthen ruins.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] An acrylic polymer grouting material comprises the following raw materials in parts by weight:

[0011] 96.88-99.399 parts of magnesium acrylate solution, 0.001-0.02 parts of initiator, 0.1-0.6 parts of cross-linking agent, and 0.5-2.5 parts of catalyst.

[0012] The initiator is a persulfate, including ammonium persulfate, potassium persulfate, sodium persulfate, peroxymonosulfate, peroxydisulfate, etc., to promote the polymerization reaction of the magnesium acrylate solution at 50-90°C.

[0013] The cross-linking agent is any one of N,N'-methylenebisacrylamide, diethylene glycol diacrylate, dimethylaminoethyl methacrylate and polyvinyl alcohol or a mixture of several thereof, so as to enhance the mechanical properties and stability of magnesium acrylate polymer.

[0014] The catalyst is sodium bisulfite and / or triethanolamine.

[0015] The application of the acrylic polymer grouting material in preventing and controlling the surface pulverization of earthen ruins in a humid environment comprises the following steps:

[0016] (1) Calculate the grouting volume and drilling depth based on the environment of the earthen ruins. Weigh the raw materials according to the grouting volume. Mix the magnesium acrylate solution, initiator, and cross-linking agent evenly as material A, and the catalyst as material B. Then, grouting holes are opened in layers on the earthen ruins. Because the earthen ruins are sloped or stepped in shape, and the water level or water content in the lower part is higher, which has an adverse effect on the earthen ruins, the grouting depth at the bottom of the earthen ruins is usually deeper than that at the upper part.

[0017] (2) Use a dual-channel grouting machine to absorb material A and material B respectively. After mixing material A and material B in the grouting machine, start from the grouting hole at the bottom of the earthen site and inject them into the grouting holes of each layer from bottom to top. The grouting speed of each layer is controlled according to the environment of the earthen site. In order to ensure the grouting effect and the stability of the earthen site, the grouting time interval between adjacent layers is 0.5-1h;

[0018] (3) After each layer of grouting is completed, material A, material B and the fallen ruins soil are mixed and stirred, and filled into the grouting hole until the surface is flat and there is no bulge around it. Finally, the grouting project is completed and the ruins soil filled in the grouting hole forms a whole with the surrounding soil ruins.

[0019] On the basis of the above technical solution, the present invention further defines the solution as follows:

[0020] Furthermore, the environment of the earthen site includes the stability of the earthen site, the surface humidity of the earthen site, the moisture content of the earthen site, the permeability coefficient of the earthen site and the water level around the earthen site. Among them, the permeability coefficient of the earthen site is tested by variable head or constant head method according to the nature of the earthen site.

[0021] Furthermore, the calculation formula for grouting volume is Q = π·λ·r 2 ·p,

[0022] Among them, Q is the grouting volume, λ is the empirical coefficient, r is the grouting diffusion radius, p is the grouting pressure, and the empirical coefficient is 1.5-2.0;

[0023] The calculation formula for the grouting diffusion radius is:

[0024] Among them, k is the soil permeability coefficient, p is the grouting pressure, t is the expected grouting time, n is the soil porosity, β is the grouting slurry density, r0 is the grouting pipe radius, r n is the final diffusion radius of the slurry in the soil layer;

[0025] The estimated grouting time is also an important reference for the curing time when designing the polymer mix ratio.

[0026] Furthermore, the grouting speed is based on the fact that there is no grouting or damage to the surface of the earthen ruins.

[0027] The beneficial effects of the present invention are:

[0028] (1) The micro-grouting method has little impact on the stability of the earthen ruins. The present invention aims to prevent the internal water of the earthen ruins from diffusing outward within the grouting range. After testing and calculation analysis, the micro-grouting depth is 60-80 cm, that is, the grouting diffusion radius is about 30-40 cm, and the grouting hole diameter is 0.5 cm-1.5 cm. Due to the small grouting depth and hole diameter, according to the principle of small hole stress, the grouting hole has a small impact on the earthen ruins.

[0029] (2) The in-situ modification method of the polymer soil ruins surface layer improves the weather resistance of the soil ruins surface layer. Acrylic hydrogel itself has excellent elasticity, swelling properties, self-healing properties, and anti-freeze properties. After grouting, the anti-shrinkage performance, freeze-thaw performance, and salt crystallization resistance of the soil ruins surface layer are significantly enhanced, reducing the stress accumulation of the soil ruins surface layer and improving the weather resistance of the soil ruins surface layer.

[0030] (3) The bottom-up stepped grouting design ensures the stability of the earthen site and improves the diffusion range of the polymer. Due to the poor hydraulic properties of the earthen site itself, the mechanical properties of the surface layer of the earthen site and its own stability decrease during the grouting process. In particular, the stress at the bottom is large, which is prone to collapse. At the same time, the water pressure at the bottom of the earthen site is large. The bottom-up stepped grouting design method, that is, the method of grouting and reinforcing at the same time, can effectively improve the mechanical properties of the earthen site itself and enhance its stability. At the same time, under the action of gravity and grouting pressure, the diffusion depth of the grouting material will be rapidly increased, thereby improving the quality and effect of the earthen site reinforcement. This design method helps to improve the utilization efficiency of grouting materials and reduce material waste.

[0031] (4) The polymer improves the permeability coefficient of the earthen site, prevents the diffusion of groundwater from the interior to the surface during the rainy season, reduces the evaporation of the surface layer, and reduces the accumulation of salt in the surface layer. The polymer can form a network structure, fill the large pores between soil particles, play a cementing role, and increase the overall density of the soil, thereby reducing the permeability coefficient of the soil and preventing the migration of water inside the earthen site. Because salt usually moves with water, when water penetration decreases, the accumulation of salt will also decrease accordingly, thereby reducing the occurrence of surface alkali powdering. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Flowchart of the present invention;

[0033] Figure 2 This is a cross-sectional view of the stepped earthen ruins grouting structure of the present invention.

[0034] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0035] 1. Surface layer of earthen ruins, 2. Steps of earthen ruins, 3. Drilling holes in the upper layer, 4. Diffusion range, 5. Drilling holes in the middle layer, 6. Drilling holes in the lower layer, 7. Drilling holes in the bottom layer. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In the following examples, the calculation formula for the grouting amount is Q = π·λ·r 2 ·p,

[0038] Among them, Q is the grouting volume, λ is the empirical coefficient, r is the grouting diffusion radius, p is the grouting pressure, and the empirical coefficient is 1.5-2.0;

[0039] The calculation formula for the grouting diffusion radius is:

[0040] Among them, k is the soil permeability coefficient, p is the grouting pressure, t is the expected grouting time, n is the soil porosity, β is the grouting slurry density, r0 is the grouting pipe radius, r n is the final diffusion radius of the slurry in the soil layer.

[0041] Example 1

[0042] like Figure 1 、 Figure 2 As shown in the figure, the step grouting method for preventing the surface pulverization of earthen ruins in humid environments includes two parts: the preparation of acrylic polymer grouting materials and the step grouting technology;

[0043] The preparation of polymer grouting materials includes the following steps:

[0044] (1) Weigh magnesium acrylate solution, initiator ammonium persulfate, crosslinker N,N'-methylenebisacrylamide, and catalyst sodium bisulfite.

[0045] (2) Testing the permeability coefficient of earthen sites: According to the nature of the earthen sites, when the clay content is greater than 30%, the variable head test method is used.

[0046] (3) Prepare polymer grouting materials: Based on the stability, moisture content, permeability coefficient and other parameters of the earthen site, control the curing time and volume stability of the magnesium acrylate solution as key indicators, control the amount of initiator, cross-linker and catalyst, and form the polymer material mix ratio of the earthen site. When the slope of the earthen site is large, the curing time of the polymer can be appropriately extended to increase the diffusion range of the polymer. The polymer mix ratio is as follows: 99.399 parts of magnesium acrylate solution, 0.001 parts of initiator, 0.1 parts of cross-linker and 0.5 parts of catalyst.

[0047] Step grouting includes the following steps:

[0048] (1) The grouting depth is designed based on the stability of the earthen site and the surrounding water level. Since the earthen site is sloped and the water level or water content in the lower part is relatively high, it is divided into four parts according to the bottom and height range of the earthen site, namely the bottom (ground), lower part, middle part, and upper part. From the bottom to the upper part, the grouting depth and range decrease successively.

[0049] (2) Calculation of the diffusion range of grouting: Based on the permeability coefficient of the earthen ruins and the pressure of the grouting machine measured above, the diffusion radius of the grouting machine and the grouting time are calculated. In the radius calculation formula, r = 31 cm, k = 2.3 × 10 -5 cm / s, p=1Mpa, t=300s, n=0.29, β=1.15g / cm 3 , r0=1cm, r n =60cm.

[0050] (3) Weigh the various components of the polymer, mix the magnesium acrylate solution, cross-linking agent, and cross-linking agent evenly as material A, and the catalyst as material B, and place them in two containers respectively.

[0051] (4) Start grouting: First, grouting is carried out at the bottom of the earthen site. A dual-channel grouting machine is used to absorb material A and material B respectively, and the mixture is evenly mixed in the grouting machine. The time of each grouting hole is controlled according to the time t of step (2) and the humidity of the surface of the earthen site. Secondly, according to the design parameters of step (1), grouting holes 7, 6, 5, and 3 are grouted in layers from bottom to top. In order to ensure the grouting effect and the stability of the earthen site, the grouting time interval of each layer is 0.5-1h. The grouting speed is mainly based on the fact that there is no grouting or surface shedding damage on the surface of the earthen site.

[0052] (5) Repair of grouting holes: After each layer of grouting is completed, material A and material B are selected and mixed with the fallen ruins soil, and the modified ruins soil is filled into the grouting holes. The filling is stopped when the surface is flat and there is no bulging around. Finally, the grouting project is completed and the ruins soil filled in the grouting holes is consistent with the surrounding soil ruins.

[0053] Example 2

[0054] like Figure 1 、 Figure 2 As shown in the figure, the step grouting method for preventing the surface pulverization of earthen ruins in humid environments includes two parts: the preparation of acrylic polymer grouting materials and the step grouting technology;

[0055] The preparation of polymer grouting materials includes the following steps:

[0056] (1) Weigh magnesium acrylate solution, initiator permonosulfate, crosslinker diethylene glycol diacrylate, and catalyst triethanolamine.

[0057] (2) Testing the permeability coefficient of earthen sites: According to the nature of the earthen sites, when the clay content is less than 15%, the constant head test method is selected.

[0058] (3) Prepare polymer grouting materials: Based on the stability, moisture content, permeability coefficient and other parameters of the earthen site, control the curing time and volume stability of the magnesium acrylate solution as key indicators, control the amount of initiator, cross-linker and catalyst, and form the polymer material mix ratio of the earthen site. When the slope of the earthen site is small, the curing time of the polymer can be appropriately shortened to increase the diffusion range of the polymer. The polymer mix ratio is as follows: 96.88 parts of magnesium acrylate solution, 0.02 parts of initiator, 0.6 parts of cross-linker and 2.5 parts of catalyst.

[0059] Step grouting includes the following steps:

[0060] (1) The grouting depth is designed based on the stability of the earthen site and the surrounding water level. Since the earthen site is in a stepped shape and the water level or water content in the lower part is higher, it is divided into four parts according to the bottom and height range of the earthen site, namely the bottom (ground), lower part, middle part, and upper part. From the bottom to the upper part, the grouting depth and range decrease in sequence, and the grouting holes are arranged in the horizontal plane of the steps.

[0061] (2) Calculate the diffusion range of grouting. According to the permeability coefficient of the earthen ruins and the pressure of the grouting machine, calculate the diffusion radius of the grouting machine and the grouting time. In the radius calculation formula, r = 31 cm, k = 2.6 × 10 -5 cm / s, p=1Mpa, t=480s, n=0.29, β=1.15g / cm 3 , r0=0.8cm, r n =60cm.

[0062] (3) Weigh the various components of the polymer, mix the magnesium acrylate solution, cross-linking agent, and cross-linking agent evenly as material A, and the catalyst as material B, and place them in two containers respectively.

[0063] (4) Start grouting: First, grouting is carried out at the bottom of the earthen site. A dual-channel grouting machine is used to absorb material A and material B respectively, and the mixture is evenly mixed in the grouting machine. The time of each grouting hole is controlled according to the calculated time of step (2) and the humidity of the surface of the earthen site. Secondly, according to the design parameters of step (1), grouting holes 7, 6, 5, and 3 are grouted in layers from bottom to top. In order to ensure the grouting effect and the stability of the earthen site, the grouting time interval of each layer is 0.5-1h. The grouting speed is mainly based on the fact that the surface of the earthen site does not have grouting and surface shedding damage.

[0064] (5) Repair of grouting holes: After each layer of grouting is completed, material A and material B are selected and mixed with the fallen ruins soil, and the modified ruins soil is filled into the grouting holes. The filling is stopped when the surface is flat and there is no bulging around. Finally, the grouting project is completed and the ruins soil filled in the grouting holes is consistent with the surrounding soil ruins.

Claims

1. An acrylic polymer grouting material, characterized in that: The invention comprises the following raw materials in parts by weight: 96.88-99.399 parts of magnesium acrylate solution, 0.001-0.02 parts of initiator, 0.1-0.6 parts of cross-linking agent, and 0.5-2.5 parts of catalyst.

2. The acrylic polymer grouting material according to claim 1, characterized in that The initiator is persulfate.

3. The acrylic polymer grouting material according to claim 1, characterized in that The cross-linking agent is any one of N,N'-methylenebisacrylamide, diethylene glycol diacrylate, dimethylaminoethyl methacrylate, and polyvinyl alcohol, or a mixture of several of them.

4. The acrylic polymer grouting material according to claim 1, characterized in that The catalyst is sodium bisulfite and / or triethanolamine.

5. Application of an acrylic polymer grouting material in preventing and controlling the surface pulverization of earthen ruins in humid environments.

6. The use according to claim 5, characterized in that The following steps are involved: (1) Calculate the grouting volume and drilling depth according to the environment of the earthen ruins, weigh the raw materials according to the grouting volume, mix the magnesium acrylate solution, initiator, and cross-linking agent evenly as material A, and use the catalyst as material B, and open grouting holes in layers on the earthen ruins; (2) After mixing material A and material B, start from the grouting hole at the bottom of the earthen site and inject them into the grouting holes of each layer from bottom to top. The grouting speed of each layer is controlled according to the environment of the earthen site. The time interval between grouting of adjacent layers is 0.5-1h. (3) After each layer of grouting is completed, material A, material B and the fallen ruins soil are mixed and stirred, and filled into the grouting hole until the surface is flat and there is no bulge around it.

7. The use according to claim 6, characterized in that The environment of earthen sites includes the stability of earthen sites, surface humidity of earthen sites, moisture content of earthen sites, permeability coefficient of earthen sites and water level around earthen sites.

8. The use according to claim 6, characterized in that The calculation formula for grouting volume is Q = π·λ·r 2 ·p, Among them, Q is the grouting volume, λ is the empirical coefficient, r is the grouting diffusion radius, p is the grouting pressure, and the empirical coefficient is 1.5-2.0; The calculation formula for the grouting diffusion radius is: Among them, k is the soil permeability coefficient, p is the grouting pressure, t is the expected grouting time, n is the soil porosity, β is the grouting slurry density, r0 is the grouting pipe radius, r n is the final diffusion radius of the slurry in the soil layer.

9. The use according to claim 6, characterized in that The grouting speed shall be based on the fact that there is no grouting or damage to the surface of the earthen ruins.

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