CN118531844A - Three-dimensional periodic foundation shock insulation structure using waste rubber as base material - Google Patents

Abstract

The invention relates to the technical field of vibration isolation, and provides a three-dimensional periodic metamaterial foundation vibration isolation structure using waste rubber as a base material, which comprises a periodic structure layer, wherein the periodic structure layer is formed by arranging a unit structure according to a certain periodic rule, the unit structure comprises paved vibrator units, rubber sand B, rubber sand C and geocells, the vibrator units are paved in a foundation pit at equal intervals, rubber sand B is paved between the vibrator units, the geocells are paved at the upper ends of the vibrator units, the geocells are filled with the rubber sand C, the periodic structure layer, a foundation, the rubber sand A and the foundation are paved in the foundation pit, and an upper building structure and a foundation thereof are built on the periodic structure layer. Under the action of earthquake, the periodic structure layer has scattering and forbidden band shielding effects on earthquake waves, so that the upper building structure can be effectively protected. The three-dimensional vibration isolation technology can solve the technical defects of high cost and complex structure of the existing three-dimensional vibration isolation technology.

Description

A three-dimensional periodic foundation isolation structure using waste rubber as a base material

The invention relates to the technical field of seismic isolation structures, and in particular to a three-dimensional seismic isolation periodic foundation structure based on waste rubber.

Background Art

my country's earthquake zones are widely distributed, earthquakes occur frequently, the epicenter is shallow, and earthquake disasters are serious. The Regulations on Seismic Management of Construction Projects clearly stipulate that earthquake resistance should adhere to the principles of people-oriented, comprehensive defense, and highlighting key points. It is encouraged to use seismic isolation and shock absorption technologies in construction projects to improve seismic performance. At present, in order to prevent and reduce the impact of earthquake disasters, in addition to exploring earthquake prediction and strengthening earthquake monitoring, more energy and investment are spent on strengthening the seismic resistance of buildings. In the context of my country becoming a country with the largest automobile production and sales in the world, how to achieve the beneficial consumption and low-carbon recycling of waste tires has become an important issue that green development must consider. Studies have shown that a mixture of waste tire rubber fragments or particles and conventional sand (i.e., rubber sand) has mechanical properties such as low density, low modulus, and high damping, and can be used as a low-carbon, environmentally friendly, artificial energy-consuming, shock-absorbing filler. The old traditional idea of earthquake resistance is to "use rigidity to overcome rigidity", increase the reinforcement of buildings and improve the grade of concrete, and add shear walls, seismic columns, ring beams, etc. to the structure. In short, it is to increase the investment in buildings in exchange for earthquake resistance. With the transformation of the earthquake resistance idea to "using softness to overcome rigidity", seismic isolation technology represented by rubber bearings has achieved many results, but there are still shortcomings such as large horizontal deformation force and poor fire resistance. Research on new seismic isolation technology is both a greater practical need and a need for scientific progress.

In response to the above problems, researchers have done a lot of work on new seismic isolation technologies. The traditional laminated rubber seismic isolation bearings have good horizontal shock absorption effects, but poor vertical shock absorption effects. In addition, other existing three-dimensional seismic isolation bearings, such as friction pendulums and spring seismic isolation bearings, have problems such as complex structures and high manufacturing precision, which result in their inability to fully exert their shock absorption effects in practical applications. High-damping rubber seismic isolation bearings have good seismic isolation effects on high-frequency waves, but poor seismic isolation effects on low-frequency waves, and have high requirements on the performance of rubber materials, which will increase the cost of seismic isolation. There are many factors that affect the seismic isolation performance of the bearings. The above-mentioned seismic isolation bearings all have an attenuation effect on the horizontal seismic motion response of the upper structure, but because of their small horizontal stiffness, they are prone to large horizontal displacements, thereby causing damage to the upper structure.

Nature always follows a simple and regular repetition (periodicity), and because of its periodic repetition, it obtains the characteristics of bandgap (attenuation domain). Based on the principle of phononic crystals, relevant researchers proposed to arrange a periodically distributed structure composed of multiple conventional materials in the foundation of the site to achieve bandgap blocking of seismic waves, and named it seismic metamaterial. Seismic metamaterials can be divided into periodic wave barriers and periodic seismic isolation foundations according to their locations. The periodic seismic isolation foundation can filter seismic waves of any direction in the attenuation domain. Compared with the periodic wave barrier structure, it can be used as a lower load-bearing structure and does not occupy the ground space, providing a new research idea for structural seismic isolation and vibration reduction.

In general, the current research on periodic structures for seismic isolation technology is still in its infancy. Although the existing periodic seismic isolation devices have their highlights, they are still rare in engineering practice. How to go further on the existing basis and propose a new type of periodic seismic isolation structure? Waste tire rubber particles-sand mixture can be used as a low-carbon and environmentally friendly artificial energy-consuming seismic isolation filler. Seismic metamaterials have broad prospects as a rock and soil seismic isolation method that can reduce the accumulation of structural damage. Low cost, small size, and ultra-low frequency band gap are important directions for the development of seismic metamaterials in the future.

Summary of the invention

The purpose of the present invention is to provide a three-dimensional periodic composite metamaterial foundation seismic isolation structure using waste rubber as a base material. When a building encounters an earthquake, the three-dimensional periodic metamaterial foundation seismic isolation structure of the present invention can attenuate the earthquake through the band gap, so that the seismic waves within the band gap frequency range cannot be transmitted to the building, thereby achieving a seismic reduction and isolation effect, and improving the seismic resistance of the upper building.

The present invention provides a three-dimensional periodic composite metamaterial foundation seismic isolation structure using waste rubber as a base material. Combining the technical innovation needs of low-carbon recycling of solid waste tires and the new idea of metamaterial seismic isolation technology, it is proposed to use rubber sand artificial soil as a matrix material, and periodically arranged vibrator units and geocells as reinforcements to form a seismic metamaterial composite foundation, so as to solve the defects of the prior art such as high cost, poor seismic isolation effect for low-frequency waves, and poor three-dimensional body wave seismic isolation effect, and realize low-cost maintenance-free three-dimensional seismic isolation for engineering structures.

To achieve the above object, the present invention provides the following technical solutions:

A three-dimensional periodic foundation seismic isolation structure using waste rubber as a base material comprises a periodic structure layer. A foundation pit is dug on a site. The periodic structure layer, the foundation and rubber sand A are laid in the foundation pit. An upper building structure and its foundation are built on the periodic structure layer.

Furthermore, the periodic structural layer capable of improving the seismic resistance of the building structure is composed of single-cell structures arranged according to a certain periodic pattern, and the single-cell structure includes laid vibrator units, rubber sand B, rubber sand C and geocells. The vibrator units are laid at equal intervals in the foundation pit, rubber sand B is laid between the vibrator units, geocells are laid on the upper ends of the vibrator units, and the geocells are filled with rubber sand C. The vibrator units and geocells are laid in three layers respectively, and the vibrator units and geocells are laid alternately in layers up and down under the foundation and rubber sand A.

Furthermore, the vibrator unit includes a rigid soil box, a rigid cover plate and rubber sand D, wherein the rigid cover plate is located in the middle of the rigid soil box and the two do not interfere with each other; the upper end surface of the rigid soil box is flush with the upper end surface of the rubber sand D, and the upper end of the rigid cover plate protrudes from the upper end surface of the rigid soil box.

Furthermore, the uppermost layer of the foundation pit is paved with rubber sand A and a foundation, and the foundation is flush with the upper and lower ends of the rubber sand A.

Furthermore, the rubber sand A, rubber sand B, rubber sand C and rubber sand D are all formed by mixing rubber particles and sand.

Furthermore, the rigid cover plate is in the shape of a quadrangular pyramid, and the bottom of the rigid cover plate is hollowed out and filled with rubber sand D.

Furthermore, the geocell is a mesh plate structure, and the thickness of the geocell is 2 mm and the height is 20 cm.

Furthermore, the mesh holes on the geocell are arranged opposite to the vibrator unit.

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

1. The present invention constructs the foundation and the upper building structure on a periodic structure. The periodic structure itself has a bandgap characteristic, which can effectively attenuate seismic waves within the bandgap range, thereby greatly reducing the shaking amplitude of the upper building structure caused by earthquakes, and can effectively protect the building structure. Secondly, by introducing geocell reinforced rubber sand, while further enhancing the bearing capacity and integrity of the foundation, a macroscopic layered periodic structure is formed with the soil layer reinforced by the oscillator unit, generating a scattering bandgap, thereby forming an ultra-low frequency bandgap with a macroscopic large-size periodic structure, thereby achieving a better seismic isolation effect. The superposition of bandgap characteristics of multiple periodic structures is achieved.

2. The three-dimensional periodic foundation isolation structure of the present invention combines the scattering type band gap and the local resonance type band gap, and then combines it with the macroscopic periodic structure to form a wider, deeper and lower frequency band gap, thereby realizing the superposition of multiple periodic structures for isolation. The structural size is more suitable than that of the scattering type structure, and it is easy to produce, more applicable and more economical. The materials for making the three-dimensional periodic foundation isolation structure are simple and easy to obtain. The materials used have environmental advantages and a wide range of applications. They can effectively attenuate vibrations within the frequency range and caused by various reasons.

3. The three-dimensional periodic ground-based seismic isolation structure of the present invention can achieve an ultra-low frequency wide band gap by adjusting the size of the oscillator unit (unit cell structure), Poisson's ratio and elastic modulus, the number of periods, the properties of the component materials, the thickness of the geocell, etc., thereby achieving a better seismic isolation effect.

4. The material properties of the rubber sand used in each part of the present invention are independent of each other. By adjusting the rubber sand ratio and density of rubber sand A, rubber sand B, rubber sand C, and rubber sand D respectively, the three-dimensional periodic foundation isolation structure can achieve an ultra-low frequency wide band gap, thereby achieving a better isolation effect.

The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic structural diagram of a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG. 2 is a disassembled diagram of a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG3 is a front view of a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG. 4 is a schematic structural diagram of a periodic structural layer in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG5 is a top view of a periodic structure layer in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG6 is a top view of a geocell in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG. 7 is a cross-sectional view of a vibrator unit in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG8 is a combination diagram of a vibrator unit in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG. 9 is a schematic diagram of a unit cell structure in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG10 is a cross-sectional view of a unit cell structure in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 1 of the present invention.

FIG. 11 is a schematic diagram of the local structure of a periodic structure layer in a three-dimensional seismic isolation periodic foundation structure described in Embodiment 2 of the present invention.

Figure numerals: 1. site; 2. upper building structure; 3. foundation; 4. rubber sand A; 5. geocell; 6. oscillator unit; 7. rubber sand B; 8. rubber sand C; 9. rigid soil box; 10. rigid cover plate; 11. rubber sand D; 12. foundation pit; 13. periodic structural layer; 14. concrete rigid thin plate; 15. unit cell structure.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. 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.

The present invention proposes to use rubber soil, a low-cost artificial soft soil that is a recycled solid waste resource, and common building materials (concrete, geocell) elements to periodically arrange and construct a new type of seismic metamaterial, which is filled around the seismically isolated structure. The seismic reduction and isolation of the engineering structure is achieved through the band gap attenuation and filtering effect of the metamaterial.

Example

In conjunction with FIG. 1 to FIG. 10 , a three-dimensional periodic composite metamaterial foundation seismic isolation structure using waste rubber as a substrate provided by the present invention is described in detail:

A three-dimensional periodic foundation seismic isolation structure using waste rubber as a base material, comprising a periodic structure layer 13, a foundation pit 12 is dug on a site 1, a foundation 3, rubber sand A4, and a periodic structure layer 13 are all laid in the foundation pit 12, the uppermost layer of the foundation pit 12 is laid with rubber sand A4 and the foundation 3, the upper and lower ends of the foundation 3 and the rubber sand A4 are flush, the rubber sand A4 consumes the residual seismic energy attenuated by the periodic seismic isolation structure and plays a role in filling the site, and the upper building structure 2 and the foundation 3 are built on the periodic structure layer;

The periodic structural layer 13 capable of improving the seismic resistance of the building structure is formed by a unit cell structure 15 arranged according to a certain periodic law, and the unit cell structure 15 includes a vibrator unit 6, rubber sand B7, rubber sand C8 and a geocell 5 laid in the foundation pit 12; the vibrator unit 6 is further explained as follows: the vibrator unit 6 includes a rigid soil box 9, a rigid cover plate 10 and rubber sand D11, the rigid cover plate 10 is located in the rigid soil box 9 and the upper end of the rigid cover plate 10 is protruding from the upper end surface of the rigid soil box 9, the rigid cover plate 10 is located in the middle of the rigid soil box 9 and the two do not offset each other, the rigid cover plate 10 is in the shape of a quadrangular pyramid, the bottom of the rigid cover plate 10 is hollowed out and is filled with rubber sand D11 between the rigid soil box 9, the upper end surface of the rigid soil box 9 is flush with the upper end surface of the rubber sand D11, and the seismic isolation and energy dissipation performance inside the vibrator unit 6 is increased by the rubber sand D11;

As shown in FIGS. 9 and 10 , the unit cell structure 15 is further explained: rubber sand B7 is laid between the oscillator units 6 in the unit cell structure 15 and is alternately arranged in layers with the geocell 5 in the foundation pit 12. The oscillator units 6 and the geocell 5 are laid in three layers respectively, so that the overall structure realizes scattering-type periodic structural seismic isolation; the oscillator units 6 are laid at equal intervals, and the seismic isolation performance between the oscillator units 6 can be increased by laying rubber sand B7; the geocell 5 is a mesh plate structure, the mesh holes on the geocell 5 are arranged opposite to the oscillator units 6, and the thickness of the geocell 5 is greater than 2 mm and the height is 20 cm. By setting the geocell 5, the bearing capacity and other mechanical properties of the seismic isolation layer can be increased; the geocell 5 is filled with rubber sand C8, and the rubber sand C8 can increase the seismic isolation performance of the geocell 5. The geocell 5 and the rubber sand C8 work together to form a geocell 5 reinforced rubber sand layer, which can not only improve the structural stiffness but also have seismic isolation capability;

The rubber sand A4, rubber sand B7, rubber sand C8 and rubber sand D11 in this embodiment are all made of a mixture of waste rubber particles and sand. The rubber sand materials used in the rubber sand A4, rubber sand B7, rubber sand C8 and rubber sand D11 have different properties. The rigid cover plate 10 and the rigid soil box 9 are made of concrete. The rubber sand has mechanical properties such as low density, low modulus and high damping. The mixture of rubber particles and sand is used as a filling and buffer material to improve the earthquake resistance effect.

Seismic metamaterials are artificial materials formed by arranging a periodic unit cell structure composed of multiple conventional materials in the foundation of the site. Their properties similar to phononic crystals can achieve bandgap blocking of seismic waves. This embodiment is a metamaterial composed of waste tire particle-sand mixture (rubber sand) as the matrix material, small-sized concrete rigid body and flexible geocell 5 as periodically arranged reinforcement and oscillator unit 6. It has the characteristics of scattering type, local resonance type and macroscopic large-scale double-layer periodic structure, and has the advantages of low cost, small size and ultra-low frequency wide bandgap.

The present invention provides a three-dimensional periodic composite metamaterial foundation seismic isolation structure using waste rubber as a base material, and its seismic isolation mechanism is as follows: first, artificial energy-consuming soft soil rubber sand is replaced around the structure foundation to form a rock and soil seismic isolation layer; secondly, periodically arranged vibrator units 6 are added to the rubber sand artificial soft cushion layer, and the vibrator increases the bearing capacity of the soft soil cushion foundation while also generating an ultra-low frequency band gap through elastic scattering and local resonance of the vibrator unit 6, and because the rubber sand is softer than the original site soil, the band gap frequency is further reduced; and then geocell 5 is introduced to reinforce the rubber sand, and while further enhancing the bearing capacity and integrity of the foundation, a macroscopic double-layer periodic structure is formed with the soil layer reinforced by the vibrator unit 6, generating a scattering band gap, thereby forming an ultra-low frequency band gap with a macroscopic large-size periodic structure, thereby achieving a better seismic isolation effect.

As mentioned above, the present invention constructs the foundation 3 and the upper building structure 2 on the periodic structure layer 13, and uses the band gap characteristics of the periodic structure to attenuate seismic waves within the band gap range, which can effectively alleviate the vibrations generated during an earthquake and can greatly reduce the shaking amplitude of the upper building structure 2 caused by the earthquake, thereby effectively protecting the upper building structure 2.

Example

As shown in Figure 11, the mesh holes on the geocell 5 are arranged opposite to the vibrator unit 6, and the geocell 5 is filled with rubber sand C8. When the rigidity of the geocell 5 is insufficient, the overall stability of the periodic structure layer 13 will be insufficient, thereby posing a safety hazard, which limits the application of the three-dimensional periodic composite metamaterial foundation seismic isolation structure in engineering. Therefore, in the second embodiment disclosed in the present invention, it is proposed to add a layer of concrete rigid thin plate between the geocell 5 and the vibrator unit 6 layer, while further enhancing the bearing capacity and integrity of the foundation, forming a macroscopic three-layer layered periodic structure with the soil layer and the geocell 5 layer reinforced by the vibrator unit 6, generating a scattering bandgap; the unit cell structure 15 in the periodic structure layer 13 generates a local resonance bandgap, and scattering resonance and local resonance occur under the action of seismic waves, widening the bandgap with a macroscopic large-size periodic structure to form an ultra-low frequency bandgap, thereby achieving a better seismic isolation effect.

In order to facilitate understanding of the three-dimensional periodic ground-based seismic isolation structure using waste rubber as the base material provided in the embodiment of the present application, its application scenario is first introduced below. The three-dimensional periodic ground-based seismic isolation structure provided in the embodiment of the present application can be applied to various structures. This original small-scale seismic metamaterial can be used for seismic isolation of ground engineering structures and buried structures, such as lifeline projects, urban underground pipe corridors, subway tunnels and stations, etc.; in addition to having a significant attenuation effect on seismic waves within the band gap range, it also effectively attenuates vibrations in this frequency range caused by other reasons, such as subway train track vibrations, artificial construction or machine use and other environmental vibrations. The application prospects are broad. To this end, the present invention application proposes a three-dimensional periodic ground-based seismic isolation structure using waste rubber as the base material.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (7)

1. A three-dimensional periodic metamaterial foundation seismic isolation structure using waste rubber as a base material, comprising a periodic structure layer (13), characterized in that: A foundation pit (12) is excavated on the site (1), the periodic structure layer (13), the foundation (3), and the rubber sand A (4) are all laid in the foundation pit (12), and the upper building structure (2) and the foundation (3) are built on the periodic structure layer (13). 2. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claim 1, characterized in that: The periodic structural layer (13) capable of improving the earthquake resistance of the building structure is composed of unit cell structures (15) arranged according to a certain periodic pattern, wherein the unit cell structure (15) comprises laid oscillator units (6), rubber sand B (7), rubber sand C (8) and geocells (5). 3. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claim 2, characterized in that: The vibrator units (6) are laid at equal intervals in the foundation pit (12), rubber sand B (7) is laid between the vibrator units (6), geocells (5) are laid on the upper ends of the vibrator units (6), and the geocells (5) are filled with rubber sand C (8). The vibrator units (6) and geocells (5) are laid in three layers respectively, and the vibrator units (6) and geocells (5) are laid alternately in layers up and down under the foundation (3) and the rubber sand A (4). 4. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claim 3, characterized in that: The vibrator unit (6) comprises a rigid soil box (9), a rigid cover plate (10) and rubber sand D (11); the rigid soil box (9) is a square concrete hollow box with a bottom plate, the size of which is between 300 mm×300 mm×300 mm and 500 mm×500 mm×500 mm, and the box thickness is between 20 mm and 30 mm; the rigid cover plate (10) is a hollow structure in the shape of an inverted prism with a closed upper portion and an open lower portion, and is made of reinforced concrete; the space between the rigid cover plate (10) and the rigid soil box (9) is filled with rubber sand D (11), and it is ensured that there is no contact between the rigid cover plate (10) and the rigid soil box (9); the upper end surface of the rigid soil box (9) is flush with the upper end surface of the rubber sand D (11), and the upper end of the rigid cover plate (10) protrudes from the upper end surface of the rigid soil box (9). 5. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claim 1, characterized in that: The uppermost layer of the foundation pit (12) is paved with rubber sand A (4) and a foundation (3), and the thickness of the foundation (3) and the rubber sand A (4) are consistent and flush. 6. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claims 1, 2, 3, and 4, characterized in that: The rubber sand A (4), rubber sand B (7), rubber sand C (8) and rubber sand D (11) are all made of a mixture of waste tire rubber particles and sand, with a mass ratio of 3:7 to 5:5. 7. The three-dimensional periodic metamaterial ground-based seismic isolation structure using waste rubber as a base material according to claim 3, characterized in that: The geocell (5) is in the form of a mesh plate structure, and the height of the geocell (5) is between 200 mm and 300 mm, the thickness of the cell sheet is 1 to 2 mm, and the cell grid size is between 300 mm×300 mm and 400 mm×400 mm.