Anti-seismic square pile for chemical powder production device

Abstract

The application provides an anti-seismic square pile for a chemical powder production device, which comprises a square-section pile body, an internal prestressed steel reinforcement cage and a fiber concrete outer layer which are sequentially arranged outside the square-section pile body, a tenon-and-mortise connecting part and a tenon-and-mortise connecting groove which are used in cooperation and are arranged at the top and the bottom of the pile respectively, and the tenon-and-mortise connecting part comprises a connecting block and high-strength bolts, the connecting block is fixed on the top of the pile through the bolts, and the shape of the connecting block is matched with the shape of the tenon-and-mortise connecting groove. The vertical compression bearing capacity of the anti-seismic square pile for the chemical powder production device is improved compared with that of a traditional pile, the elastic state is maintained when the interlayer displacement angle reaches 1 / 65-1 / 50, the anti-seismic performance is improved, the steam consumption is greatly reduced, the maintenance period is shortened, and the energy consumption is reduced in the production process.

Description

Technical Field

[0001] This invention relates to the field of square pile technology, and specifically to an earthquake-resistant square pile for chemical powder production equipment. Background Technology

[0002] Propylene can be used to prepare a variety of basic organic raw materials, such as propylene oxide, acrolein, allyl alcohol, isopropanol, carbon tetrachloride, butanol, etc. In recent years, the demand for propylene has increased significantly due to the demand from downstream derivatives (especially polypropylene). Given the fierce competition in the international market, the development of propylene and its derivatives must adopt the most advanced environmentally friendly processes and technologies to achieve large-scale, low-cost production. In response to the development prospects of propylene in China, China Tianchen Engineering Co., Ltd. has developed a methanol-to-olefins catalyst, primarily a silica-alumina-phosphorus molecular sieve-based chemical powder. This powder can achieve a methanol conversion rate of 100% or close to 100%, with a selectivity of over 78% for ethylene and propylene, and almost no C5 or higher products. Furthermore, its outstanding hydrothermal stability and suitable pore structure enhance its performance, making it poised for widespread application in the future.

[0003] Concrete square piles, as one of the main forms of building pile foundations for chemical powder production plants, are widely used in geological conditions such as soft soil and liquefiable soil layers. However, existing square pile technologies have significant drawbacks: traditional piles use a uniform cross-section design, resulting in abrupt changes in stiffness between the pile body and the connection, which can easily lead to stress concentration and fracture during earthquakes (failure occurs when the inter-layer displacement angle is greater than 1 / 30); the connection between the pile top and the pile cap relies on ordinary bolts, which have insufficient tensile strength and cannot meet the requirements for seismic resistance and pull-out resistance; the production process relies on traditional steam curing (energy consumption ≥800kg standard coal / batch, cycle ≥24 hours), resulting in high carbon emissions and low efficiency; the material relies solely on concrete strength without incorporating the synergistic effect of fiber reinforcement and prestressing. These problems restrict the application of square piles under real-world working conditions. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a seismic-resistant square pile for chemical powder production equipment.

[0005] An earthquake-resistant square pile for a chemical powder production device includes: a square-section pile body and an inner prestressed steel cage and a fiber-reinforced concrete outer layer arranged sequentially on the outside of the square-section pile body. The pile top and pile bottom are respectively provided with a tenon and mortise joint and a tenon and mortise joint groove for matching use, so that the pile top and pile bottom are connected. The fiber-reinforced concrete outer layer is prepared from raw materials including the following parts by weight: 125-135 parts crushed stone, 350-480 parts medium and coarse sand, 210-250 parts silicate cement, 50-70 parts sulfoaluminate cement, 0.5-1.0 parts nano silica, 18-35 parts silica fume, 20-38 parts anhydrite, 98-102 parts polycarboxylate superplasticizer, 0.3-0.8 parts organosilicon water-repellent agent, 70-80 parts polyacrylamide fiber, 20-30 parts polybutene fiber, 16-26 parts industrial aluminum sulfate, 1-5 parts sodium dodecyl sulfate, and 14-25 parts sulfoaluminate clinker.

[0006] Crushed stone and medium-coarse sand are used as the aggregate system, and the aggregate gradation satisfies the continuous gradation curve.

[0007] As a cementing system, silicate cement and sulfoaluminate cement are used together to form a dual network structure of CSH gel and ettringite (AFt) by hydration products. Silicate cement provides early strength, while sulfoaluminate cement generates expansion substances to compensate for shrinkage and prevent cracking, thus solving the problem of shrinkage and cracking in traditional concrete and making the pile more robust.

[0008] Nano-silica, silica fume, and anhydrite (CaSO4·1 / 2H2O) are used as functional fillers. Among them, nano-silica needs to be surface modified by silane coupling agent (KH-550) to improve the interfacial bonding energy by ≥40%.

[0009] When polycarboxylate superplasticizer and organosilicon water-repellent agent are used as an admixture system, the water reduction rate is ≥35% and the concrete shrinkage rate is ≤125%.

[0010] Polyacryl alcohol fiber and polybutene fiber are used as reinforcing phases.

[0011] Industrial aluminum sulfate and sulfoaluminate clinker synergistically generate early-strength ettringite, increasing the 1-day compressive strength by ≥40%.

[0012] Furthermore, the crushed stone has a continuous gradation of 5-25mm particle size, and the content of needle-like and flaky particles in the crushed stone is ≤5%, the mud content in the sand is ≤1.5%, and the mud lump content is ≤0.5%.

[0013] And / or the fineness modulus of medium-coarse sand is 2.6-3.0, the silicate cement is PO 42.5R, and the nano silica is D. 50 =10-20nm, silica fume specific surface area ≥20000m² 2 / kg, the solid content of polycarboxylate superplasticizer is 20%;

[0014] And / or polyacrylamide fibers are 12-15 mm in length and 30-50 μm in diameter; polybutene fibers are 18-22 μm in diameter and 12-30 mm in length.

[0015] Polyacryl alcohol fibers (PVA fibers) primarily provide tensile strength and toughness, inhibiting early plastic cracking in concrete. Longer fibers (12-15mm) can effectively bridge micro-cracks, creating a "bridging effect" and improving crack resistance. If the length is too short (<12mm), effective bridging is difficult to achieve; if too long (>15mm), clumping is likely, affecting dispersion uniformity. Typically, the diameter of polyacryl alcohol fibers (PVA fibers) ranges from 30-50μm.

[0016] Polybutene fiber (PB fiber) primarily enhances the seismic energy dissipation capacity of concrete by absorbing seismic energy through the plastic deformation of fine fibers. Fine fibers (18-22μm) offer better flexibility, generating more plastic hinges and slowing crack propagation. Excessively coarse fibers (>22μm) become brittle and cannot effectively dissipate energy; excessively fine fibers (<18μm) are prone to breakage, reducing long-term stability. Typically, PB fibers are 12-30mm in length.

[0017] Furthermore, the mass ratio of silicate cement to sulfoaluminate cement is (3.5-4.5):1, and the mass ratio of nano-silica to silica fume is 1:(21-29).

[0018] The volume ratio of polyacrylamide fiber to polybutene fiber is (3.5-4):1, and the total content of the two fibers is controlled at 0.5-1.2 vol.% of the total volume of the raw materials.

[0019] The mass ratio of industrial aluminum sulfate to sulfoaluminate clinker is (1-1.5):1.

[0020] The synergistic effect of nano-silica and silica fume directly affects the microstructure (such as the double network structure of hydration products) and mechanical properties (such as compressive strength, impermeability, and crack resistance) of concrete, and needs to be strictly controlled. The amount of anhydrite is usually adjusted according to the type of cement and process requirements, and its proportion within a certain range (such as 20-38 parts) has little impact on the final performance.

[0021] Nano-silica (SiO2), as an ultrafine active filler, mainly enhances the interfacial bonding energy through modification with silane coupling agents, thereby strengthening the bond strength between the cement matrix and fibers and improving crack resistance.

[0022] Silica fume (SiO2 micro powder) has pozzolanic activity. It reacts with cement hydration products to form CSH gel, which fills pores and increases density, while also compensating for shrinkage.

[0023] Anhydrite (CaSO4·1 / 2H2O), as an auxiliary mineral admixture, mainly functions to regulate setting time and refine pore structure, but its activity is low and its direct impact on mechanical properties is weak.

[0024] Furthermore, the side length of the square cross-section pile ranges from 200mm to 1800mm, and the wall thickness is 1 / 8 to 1 / 6 of the side length.

[0025] Furthermore, the prestressed steel cage is formed by several longitudinal steel bars and several annular stirrups, wherein the longitudinal steel bars are of HRB500E grade or above, and the pretension force is 300-500kN.

[0026] Furthermore, the mortise and tenon joint includes a connecting block and high-strength bolts. The connecting block is fixed to the top of the pile by the bolts, and the shape of the connecting block matches the shape of the mortise and tenon joint groove.

[0027] Preferably, the tenon and mortise joint also includes a pre-embedded steel plate with a thickness of 8-12mm, which is welded and fixed to the prestressed steel bars and the surface is sandblasted.

[0028] Furthermore, the prestressed steel cage also includes spiral stirrups, which are spirally arranged around the outside of the cage-like structure formed by the longitudinal steel bars and the annular stirrups.

[0029] Furthermore, the bolts are M24-M36 in size, made of 42CrMo alloy steel, with a preload range of 250-400kN, and are fitted with epoxy resin adhesive.

[0030] Epoxy resin adhesives are used for bonding high-strength bolts to embedded steel plates and pile concrete interfaces, and are considered auxiliary materials for bolted connections.

[0031] By filling the gap between the bolt and the threaded hole with adhesive, it prevents the bolt from loosening due to vibration; isolates it from moisture and corrosive media, extending the bolt's service life; and improves the adhesion between the bolt and concrete or steel, avoiding connection failure caused by interface debonding.

[0032] Furthermore, there are three connecting blocks: two straight connecting blocks and one L-shaped connecting block. The L-shaped connecting block is located at the included angle at the top of the pile, and the two straight connecting blocks are located on both sides of the L-shaped connecting block. One or both ends of the connecting block are provided with inclined surfaces with an inclination angle of 5°-8°.

[0033] Furthermore, stiffening rings are spaced along the axial direction on the prestressed steel cage, with a thickness of 50-80mm and a spacing of 200-600mm.

[0034] Furthermore, an elastic damping layer is added to the mortise and tenon connection at the pile end. The elastic damping layer is made of polyurethane or rubber material, with a thickness of 20-30mm and a compressive strength ≥20MPa.

[0035] Furthermore, the mix proportions of the fiber-reinforced concrete outer layer meet the following requirements: water-cement ratio ≤ 0.28, chloride ion content ≤ 0.06%, and alkali content ≤ 3.0 kg / m³. 3 Sulfate resistance grade ≥ KS120.

[0036] Advantages and beneficial effects of the present invention:

[0037] The seismic-resistant square piles for chemical powder production equipment described in this invention have improved vertical compressive bearing capacity compared to traditional piles. They maintain an elastic state even when the interlayer displacement angle reaches 1 / 65-1 / 50, thereby improving seismic performance. Furthermore, they significantly reduce steam consumption and shorten the curing cycle during production, thus reducing energy consumption. Attached Figure Description

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0039] Figure 1 This is a connection structure diagram of the earthquake-resistant square piles used in chemical powder production equipment according to the present invention.

[0040] Figure 2 This is an internal structural diagram of the earthquake-resistant square pile used in a chemical powder production device according to the present invention.

[0041] Figure label:

[0042] 1. Square cross-section pile body; 2. Longitudinal reinforcement; 3. Circular stirrups; 4. Fiber-reinforced concrete outer layer; 5. Embedded steel plate; 6. Tenon and mortise joint; 61. Connecting block; 62. Bolt; 7. Tenon and mortise joint groove; 8. Stiffening ring. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0046] Example 1

[0047] A seismic-resistant square pile for a chemical powder production plant, comprising:

[0048] The pile has a square cross-section with sides ranging from 600mm and a wall thickness of 1 / 6 of the side length. The pile top and bottom are equipped with matting mortise and tenon joints and mortise and tenon grooves. The mortise and tenon joints include connecting blocks and bolts. The connecting blocks are fixed to the pile top by bolts. The shape of the connecting blocks matches the shape of the mortise and tenon groove. Specifically, there are three connecting blocks: two straight connecting blocks and one L-shaped connecting block. The L-shaped connecting block is located at the included angle at the pile top, and the two straight connecting blocks are located on either side of the L-shaped connecting block. One or both ends of the connecting blocks have inclined surfaces with an inclination angle of 5°. 8°; The tenon and mortise connection also includes a pre-embedded steel plate with a thickness of 8mm, which is welded and fixed to the prestressed steel cage and the surface is sandblasted; the bolts are M24-M36 specifications, made of 42CrMo alloy steel, with a pre-tightening force range of 250-400kN, and are used with epoxy resin adhesive; stiffening rings are set at intervals along the axial direction on the prestressed steel cage, with a thickness of 50mm and a spacing of 200mm; an elastic damping layer is added to the tenon and mortise connection at the pile end, which is made of polyurethane or rubber material, with a thickness of 20mm and a compressive strength ≥20Mpa;

[0049] The internal prestressed steel cage is formed by several longitudinal steel bars and several ring stirrups. The longitudinal steel bars are of HRB500E grade or above and the pretension force is 350kN.

[0050] The prestressed steel cage may also include spiral stirrups, which are spirally arranged around the outside of the cage-like structure formed by the longitudinal steel bars and the annular stirrups.

[0051] The outer layer of fiber-reinforced concrete is prepared from the following raw materials in parts by weight: 125 parts crushed stone, 355 parts medium and coarse sand, 210 parts silicate cement, 50 parts sulfoaluminate cement, 0.8 parts nano silica, 21 parts silica fume, 21 parts anhydrite, 98 parts polycarboxylate superplasticizer, 0.3 parts organosilicon water-repellent agent, 70 parts polyacryl alcohol fiber, 20 parts polybutene fiber, 17 parts industrial aluminum sulfate, 1 part sodium dodecyl sulfate, and 16 parts sulfoaluminate clinker.

[0052] The crushed stone has a continuous gradation of 5-25mm particle size, with a needle-like and flaky particle content of ≤5%, a mud content of ≤1.5% in the sand, a mud lump content of ≤0.5%, a fineness modulus of 2.6-3.0 for the medium-coarse sand, and uses PO 42.5R silicate cement and nano-silica D. 50 =15nm, silica fume specific surface area ≥20000m² 2 / kg, the solid content of the polycarboxylate superplasticizer is 20%, and the length of the polyacrylamide fiber is 12mm and the diameter is 30. μm The polybutene fiber has a diameter of 18 μm and a length of 13 μm. mm .

[0053] The mix proportions of the fiber-reinforced concrete outer layer meet the following requirements: water-cement ratio of 0.27, chloride ion content of 0.05%, and alkali content of 2.8 kg / m³. 3 Sulfate resistance grade KS130.

[0054] When in use, the square piles are connected and fixed by a tenon-and-mortise structure. The tenon-and-mortise joint groove at the bottom of the upper square pile works in conjunction with the connecting block at the bottom of the lower square pile to connect and fix the two square piles.

[0055] Example 2

[0056] A seismic-resistant square pile for a chemical powder production plant, comprising:

[0057] The pile has a square cross-section with a side length of 1000mm and a wall thickness of 1 / 8 of the side length. The pile top and bottom are equipped with matting mortise and tenon joints and mortise and tenon grooves. The mortise and tenon joints include connecting blocks and bolts. The connecting blocks are fixed to the pile top by bolts. The shape of the connecting blocks matches the shape of the mortise and tenon groove. Specifically, there are three connecting blocks: two straight connecting blocks and one L-shaped connecting block. The L-shaped connecting block is located at the included angle at the pile top, and the two straight connecting blocks are located on either side of the L-shaped connecting block. One or both ends of the connecting blocks have inclined surfaces with an inclination angle of 5°. 8°; The tenon and mortise connection also includes a pre-embedded steel plate with a thickness of 10mm, which is welded and fixed to the prestressed steel cage and the surface is sandblasted; the bolts are M24-M36 specifications, made of 42CrMo alloy steel, with a pre-tightening force range of 250-400kN, and are used with epoxy resin adhesive; stiffening rings are set at intervals along the axial direction on the prestressed steel cage, with a thickness of 60mm and a spacing of 400mm; an elastic damping layer is added to the tenon and mortise connection at the pile end, which is made of polyurethane or rubber material, with a thickness of 24mm and a compressive strength ≥20Mpa;

[0058] The internal prestressed steel cage is formed by several longitudinal steel bars and several ring stirrups. The longitudinal steel bars are HRB600 and the pretension force is 420kN.

[0059] The prestressed steel cage may also include spiral stirrups, which are spirally arranged around the outside of the cage-like structure formed by the longitudinal steel bars and the annular stirrups.

[0060] The outer layer of fiber-reinforced concrete is prepared from the following raw materials in parts by weight: 130 parts crushed stone, 410 parts medium and coarse sand, 230 parts silicate cement, 62 parts sulfoaluminate cement, 1.0 part nano silica, 29 parts silica fume, 25 parts anhydrite, 98-102 parts polycarboxylate superplasticizer, 0.5 parts organosilicon water-repellent agent, 75 parts polyacrylamide fiber, 22 parts polybutene fiber, 23 parts industrial aluminum sulfate, 2 parts sodium dodecyl sulfate, and 21 parts sulfoaluminate clinker.

[0061] The crushed stone has a continuous gradation of 5-25mm particle size, with a needle-like and flaky particle content of ≤5%, a mud content of ≤1.5% in the sand, a mud lump content of ≤0.5%, a fineness modulus of 2.6-3.0 for the medium-coarse sand, and uses PO 42.5R silicate cement and nano-silica D. 50 =15nm, silica fume specific surface area ≥20000m² 2 / kg, the solid content of the polycarboxylate superplasticizer is 20%, and the length of the polyacrylamide fiber is 13mm and the diameter is 37. μm The polybutene fiber has a diameter of 20 μm and a length of 22 μm. mmThe mix proportions of the fiber-reinforced concrete outer layer meet the following requirements: water-cement ratio of 0.26, chloride ion content of 0.04%, and alkali content of 2.7 kg / m³. 3 Sulfate resistance grade KS140.

[0062] control group: traditional square pile

[0063] Configuration: Ordinary Portland cement (PO42.5), no fiber reinforcement, ordinary prestressed steel bars (HRB400), no tenon and mortise joints.

[0064] Test results:

[0065] 1. Vertical compressive bearing capacity

[0066] The vertical compressive bearing capacity of a single traditional square pile is 2300kN, while that of the square pile of this invention is 2800-2950kN, which is an increase of 21-28%.

[0067] 2. Seismic testing

[0068] When the seismic acceleration is 0.1g, the inter-story drift angle of a traditional square pile is 1 / 200, while that of the square pile of the present invention is 1 / 1000 to 1 / 800; when the seismic acceleration is 0.2g, the inter-story drift angle of a traditional square pile is 1 / 100, while that of the square pile of the present invention is 1 / 600 to 1 / 500; when the seismic acceleration is 0.4g, the inter-story drift angle of a traditional square pile is 1 / 35, indicating damage, while that of the square pile of the present invention is 1 / 65 to 1 / 50, indicating an elastic state.

[0069] Comparative Example 1

[0070] The difference from Example 1 above is that the mass ratio of silicate cement to sulfoaluminate cement exceeds the given range, specifically 200 parts of silicate cement and 70 parts of sulfoaluminate cement, with other materials the same as in Example 1.

[0071] Test results:

[0072] The compressive strength decreased to 2200kN, the concrete shrinkage increased, and the interlayer displacement angle reached 1 / 30 at 0.4g (failure).

[0073] Comparative Example 2

[0074] The difference from Example 1 above is that the mass ratio of nano-silica to silica ash exceeds the given range. Specifically, it is 0.2 parts of nano-silica and 36 parts of silica ash, with other materials the same as in Example 1.

[0075] Test results:

[0076] The interface modification effect of nano-silica is weakened, the bond strength between fiber and concrete decreases, and the sulfate resistance grade drops to KS90.

[0077] Comparative Example 3

[0078] The difference from Example 1 above is that only polyacrylamide fiber is used, while other materials are the same as in Example 1.

[0079] Test results:

[0080] Lacking the plastic energy dissipation capacity of polybutene fibers, the interlaminar displacement angle reaches 1 / 100 at 0.2g (insufficient elasticity), resulting in decreased fatigue resistance and an increase in residual deformation to 3‰ after 200 cycles.

[0081] Comparative Example 4

[0082] The difference from Example 1 above is that only polybutene fiber is used, while other materials are the same as in Example 1.

[0083] Test results:

[0084] The lack of bridging effect of long fibers in polyacrylamide fibers reduces macroscopic crack resistance, and the inter-layer displacement angle reaches 1 / 60 under a 0.4g earthquake (due to insufficient toughness).

[0085] Comparative Example 5

[0086] The difference from Example 1 above is that the mass ratio of industrial aluminum sulfate to sulfoaluminate clinker exceeds the given range. Specifically, it is 30 parts of industrial aluminum sulfate and 10 parts of sulfoaluminate clinker, with other materials the same as in Example 1.

[0087] Test results:

[0088] The delayed formation of ettringite leads to insufficient early hydration products, weakening concrete strength development and resulting in reduced concrete strength. Reduced ettringite levels also decrease concrete density and increase sulfate penetration pathways, thereby reducing impermeability.

[0089] The seismic-resistant square piles prepared by this invention have a compressive strength ≥2800kN, and under the action of 0.4g seismic acceleration, the residual deformation is ≤2‰ when the inter-story drift angle reaches 1 / 50, and the sulfate erosion resistance grade is ≥KS120.

[0090] Table 1. Performance comparison of square piles obtained from the examples, comparative examples, and control groups.

[0091]

[0092] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A seismic-resistant square pile for a chemical powder production plant, characterized in that, include: The pile consists of a square-section pile body, an internal prestressed steel cage arranged sequentially on the outside of the square-section pile body, and a fiber-reinforced concrete outer layer. The pile top and bottom are respectively equipped with matching mortise and tenon joints and mortise and tenon joint grooves to connect the pile top and bottom. The fiber-reinforced concrete outer layer is prepared from the following raw materials in parts by weight: 125-135 parts crushed stone, 350-480 parts medium-coarse sand, 210-250 parts silicate cement, 50-70 parts sulfoaluminate cement, 0.5-1.0 parts nano-silica, 18-35 parts silica fume, 20-38 parts anhydrite, 98-102 parts polycarboxylate superplasticizer, 0.3-0.8 parts organosilicon water-repellent agent, 70-80 parts polyacrylamide fiber, 20-30 parts polybutene fiber, 16-26 parts industrial aluminum sulfate, 1-5 parts sodium dodecyl sulfate, and 14-25 parts sulfoaluminate clinker. The polycarboxylate superplasticizer has a solid content of 20%.

2. The seismic-resistant square pile for chemical powder production equipment according to claim 1, characterized in that, The crushed stone has a continuous gradation of 5-25mm particle size, with a needle-like and flaky particle content of ≤5%, a mud content of ≤1.5%, and a clay lump content of ≤0.5%. The fineness modulus of medium-coarse sand is 2.6-3.0, the silicate cement is PO 42.5R, and the nano-silica is D. 50 =10-20nm, silica fume specific surface area ≥20000m² 2 / kg; Polyacryl alcohol fibers are 12-15 mm long and 30-50 μm in diameter; polybutene fibers are 18-22 μm in diameter and 12-30 mm long.

3. The seismic-resistant square pile for chemical powder production equipment according to claim 1, characterized in that, The mass ratio of silicate cement to sulfoaluminate cement is (3.5-4.5):1, and the mass ratio of nano-silica to silica fume is 1:(21-29). The volume ratio of polyacrylamide fiber to polybutene fiber is (3.5-4):1, and the total content of the two fibers is controlled at 0.5-1.2 vol.% of the total raw material volume. The mass ratio of industrial aluminum sulfate to sulfoaluminate clinker is (1-1.5):

1.

4. The seismic-resistant square pile for chemical powder production equipment according to claim 1, characterized in that, The side length of the square cross-section pile ranges from 200mm to 1800mm, and the wall thickness is 1 / 8 to 1 / 6 of the side length.

5. The seismic-resistant square pile for a chemical powder production device according to claim 1, characterized in that, The prestressed steel cage is formed by several longitudinal steel bars and several ring stirrups. The longitudinal steel bars are of HRB500E grade or above, and the pretension force is 300-500kN.

6. The seismic-resistant square pile for a chemical powder production device according to claim 1, characterized in that, The mortise and tenon joint includes a connecting block and bolts. The connecting block is fixed to the top of the pile by bolts, and the shape of the connecting block matches the shape of the mortise and tenon joint groove. The mortise and tenon joint also includes a pre-embedded steel plate with a thickness of 8-12mm, which is welded and fixed to the prestressed steel cage and the surface is sandblasted.

7. The seismic-resistant square pile for a chemical powder production device according to claim 6, characterized in that, There are 3 connecting blocks: 2 straight connecting blocks and 1 L-shaped connecting block. The L-shaped connecting block is located at the angle at the top of the pile, and the 2 straight connecting blocks are located on both sides of the L-shaped connecting block. One or both ends of the connecting block are provided with inclined surfaces with an inclination angle of 5°-8°.

8. The seismic-resistant square pile for a chemical powder production device according to claim 1, characterized in that, Stiffening rings are installed at intervals along the axial direction on the prestressed steel cage. The thickness of the stiffening rings is 50-80mm and the spacing is 200-600mm.

9. The seismic-resistant square pile for a chemical powder production device according to claim 1, characterized in that, An elastic damping layer is added to the mortise and tenon joint at the pile end. The elastic damping layer is made of polyurethane or rubber material, with a thickness of 20-30mm and a compressive strength ≥20MPa.

10. The seismic-resistant square pile for a chemical powder production device according to claim 1, characterized in that, The mix proportions of the fiber-reinforced concrete outer layer must meet the following requirements: water-cement ratio ≤ 0.28, chloride ion content ≤ 0.06%, and alkali content ≤ 3.0 kg / m³. 3 Sulfate resistance grade ≥ KS120.

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