Construction method of assembled rigid and flexible combined elastic earthquake-resistant reinforced earth retaining wall

Abstract

The present invention belongs to the field of slope protection and earthquake resistance. In order to solve the problems of poor deformation adaptability of rigid joints of existing reinforced retaining wall panels and large occupation area of ​​flexible reinforced earth slopes without panels, the present invention provides a method for constructing an assembled rigid-flexible combined elastic earthquake-resistant reinforced earth retaining wall. The reinforced retaining wall greatly enhances the deformation adaptability of the retaining wall and reduces the occupied area of ​​the project by using geogrids, assembled wall panels and elastic shock-absorbing devices; reduces scouring damage to the slope surface; under the action of earthquake loads, by using the connecting steel plates of the elastic shock-absorbing connection device as a splicing mold, a certain amount of displacement is allowed between the wall panel blocks without damage, thereby reducing damage to the connection between the wall panel and the geogrid; by separating and arranging the upper and lower geogrids, the force is more reasonable, the structure is more stable, and the deformation fatigue life is good.

Description

Technical Field

[0001] The invention belongs to the field of slope protection and earthquake disaster reduction, and specifically relates to a construction method of a rigid and flexible combined geogrid reinforced retaining wall using a spring shock-absorbing connection device, which is a small and medium-sized geosynthetics combined reinforced retaining structure for geotechnical engineering. Background Art

[0002] Reinforced retaining walls have been widely used in the stabilization and reinforcement of hillsides, foundation pit slopes and river banks due to their superior bearing capacity and seismic stability. After years of engineering practice experience at home and abroad, it has been demonstrated that when encountering earthquake disasters, reinforced earth retaining walls can effectively reinforce or block unfavorable geological bodies. For example, they can reinforce landslides, collapses, rock piles, and block falling rocks and mud-rock flows.

[0003] However, according to the post-earthquake survey of reinforced earth retaining walls in recent years, although reinforced earth retaining walls have shown better seismic performance than traditional gravity retaining walls, a large proportion of reinforced earth retaining walls have suffered varying degrees of damage. Among them, one of the main damage phenomena is the fracture of the rigid connection between the retaining wall panel and the reinforcement. The main reason is that the flexible reinforcement has a good deformation adaptability, while the rigid connection at the rigid panel has a poor deformation adaptability, so it is easy to be damaged due to the difference in deformation adaptability.

[0004] The better solution is to use ecological flexible panelless geogrid to reinforce the soil slope. Its advantages are: the construction can be operated by machinery, which is fast and simple; make full use of the original slope soil, reduce the abandoned soil, and be environmentally friendly; at the same time, the slope can be beautifully greened, and the landscape effect is relatively good; the project cost is low; but it also has disadvantages, that is, the area is relatively wide, the amount of earth and stone required is relatively large; the slope surface is prone to scouring and damage under rainfall. Therefore, the land acquisition and material costs of the project are increased, the durability is relatively poor, and it is not suitable for projects with small available areas. Then, based on the construction method of ecological flexible panelless geogrid reinforced soil slope, a prefabricated rigid and flexible combined elastic seismic reinforced soil retaining wall construction method is provided. Summary of the invention

[0005] In order to solve the problems that the rigid joints of existing reinforced retaining wall panels have poor deformation adaptability and the flexible reinforced earth slopes without panels occupy a large area, the present invention provides a construction method for an assembled rigid-flexible combined elastic earthquake-resistant reinforced earth retaining wall.

[0006] The present invention adopts the following technical solution:

[0007] A prefabricated rigid-flexible combined elastic seismic-resistant reinforced earth retaining wall comprises prefabricated wall panel concrete blocks, a waterproof geomembrane, a concrete waterproof sealing top layer, a geogrid device, a foundation and a fill foundation. The geogrid device is flush with the top surface of the fill foundation and is constructed and installed on the foundation. The geogrid device is formed by connecting a plurality of horizontally arranged grid monomers. The grid monomers are parallel to each other, and the head and tail ends of each layer of grid monomers are flush. The gaps between the grid monomers are compacted by backfill soil. The prefabricated wall panel concrete blocks are spliced ​​by an elastic shock-absorbing connection device and vertically connected to the geogrid device to form a rigid-flexible combined elastic seismic-resistant reinforced earth retaining wall.

[0008] An elastic shock-absorbing connection device is arranged at the joint of each assembled wall panel concrete block along the cross section of the retaining wall.

[0009] The elastic shock-absorbing connection device includes a shock-absorbing spring, an embedded connection plate and a fixing rod. The embedded connection plate at the front end of the shock-absorbing spring connects the elastic shock-absorbing connection device to the assembled wall panel concrete block, and the fixing rod at the rear end of the shock-absorbing spring connects the elastic shock-absorbing connection device to the geogrid device.

[0010] The upper and lower sides of the assembled wall panel concrete blocks are provided with reserved grooves for seamlessly splicing the upper and lower assembled wall panel concrete blocks.

[0011] The embedded connecting plate is also a splicing mold for the assembled wall panel concrete blocks. The embedded connecting plate is embedded in the reserved grooves of the upper and lower assembled wall panel concrete blocks and is sealed with anchor glue, so that the upper and lower assembled wall panel concrete blocks are seamlessly and tightly spliced.

[0012] Before the geogrid device is reversed, the fixing rod of the elastic shock-absorbing connection device is passed through the mesh holes of the laid main reinforcement and auxiliary reinforcement grid to connect the geogrid device to the elastic shock-absorbing connection device.

[0013] A construction method for an assembled rigid-flexible combined elastic seismic-resistant reinforced earth retaining wall adopts a spring damping connection device to improve the deformation adaptability of the retaining wall. The specific construction steps of the reinforced earth assembled rigid-flexible combined elastic seismic-resistant reinforced earth retaining wall are as follows:

[0014] 1) Construction foundation: cast-in-place concrete foundation or mortar-laid stone foundation;

[0015] 2) Construction of filling foundation: excavate the original slope joint into steps to form a filling foundation with an inverted trapezoidal step section to increase interface friction;

[0016] 3) Mortar the bottom prefabricated wall foundation base on the above concrete foundation or mortar-laid stone foundation;

[0017] 4) Embed the embedded connection plate of the elastic shock-absorbing connection device into the concrete block of the assembled wall panel, spread the filler behind the concrete block of the assembled wall panel, and then lay the geogrid device. First, lay the main reinforcement grid and the auxiliary reinforcement grid. Before the reverse package, pass the fixing rod through the mesh of the main reinforcement and auxiliary reinforcement grid that have been laid, so that the geogrid device is connected to the elastic shock-absorbing connection device;

[0018] 5) Construction of geogrid device: on the basis of the completed construction, the grid units are laid layer by layer from bottom to top. After each layer of grid units is constructed, the soil is filled and compacted to make it level before the construction of the next layer of grid units is carried out.

[0019] The present invention provides an arrangement and method of an assembled rigid-flexible composite reinforced earth retaining wall for geotechnical engineering that uses a geogrid device (5), an assembled wall panel concrete block (1), and an elastic shock-absorbing connection device (2) to reinforce the soil. By using the geogrid device (5), the assembled wall panel concrete block (1), and the elastic shock-absorbing connection device (2), the deformation adaptability of the earth retaining wall is greatly enhanced and the engineering occupied area is reduced. Under the action of earthquake loads, by using the embedded connection plate (63) of the elastic shock-absorbing connection device (2) as a splicing mold, a certain amount of displacement is allowed between the assembled wall panel concrete blocks (1) without causing damage. At the same time, by using the elastic shock-absorbing connection device The fixing rod (61) of (2) replaces the rigid connection commonly used today between the wall and the geogrid device (5), thereby enhancing the deformation coordination ability between the wall and the geogrid device (5), thereby reducing the brittle failure at the connection between the assembled wall panel concrete block (1) and the geogrid; the geogrid is connected by U-shaped nails and nylon ties (53), making the structure a unified force-bearing whole, which is safer, and the nylon ties (53) are geosynthetics that can resist the potential corrosion and aging risks of traditional steel wire binding, thereby improving the corrosion resistance and durability of the system; by setting up internal and external drainage facilities, it is ensured that the structure still has sufficient durability under the influence of natural environmental factors such as rainfall. In order to study the stress and deformation of the reinforced earth retaining wall under seismic loads and verify its safety, a finite element model of the reinforced earth retaining wall was established as follows: Figure 6 , use vertical uniformly distributed load to simulate the response of reinforced earth retaining wall under the load on the upper part of reinforced earth retaining wall, use EL seismic wave to simulate the dynamic response of reinforced earth retaining wall under the action of seismic load, and conduct dynamic analysis. Consider the stress and deformation of reinforced earth retaining wall under the combined action of dynamic and static loads. Since the deformation is small and the deformation cannot be seen clearly, take the magnification factor of 50 times to get the deformation grid diagram Figure 8 , comprehensive total displacement map Fig. 9It can be seen that the maximum displacement occurs at the top of the wall and decreases from top to bottom. The deformation at the wall foundation is negligible. There is no obvious deformation on the wall surface. Since the elastic shock-absorbing connection device is assumed to bear only axial force, it will produce a small longitudinal displacement with the soil, which has no obvious effect on its working performance. Compared with the traditional reinforced slope, the displacement at the wall surface is smaller, there is no deformation such as wall bulge, and the protection ability is stronger. Fig.10 It can be seen that the horizontal displacement caused by the earthquake load is small, and the maximum displacement occurs in the non-reinforced area. Since the front non-reinforced area is protected by panels, it has no obvious effect on the stability of the wall. Fig.11 It can be seen from the deformation contour map that the wall has no obvious potential sliding surface for outward sliding.

[0020] In summary, it can be seen that the method and structure of the present invention are simple, with good strength, rigidity, deformation adaptability and stability, good deformation fatigue life, and strong anti-scouring ability. In addition, in actual engineering applications, compacting the backfill soil can further reduce the vertical settlement of the wall, and coupled with a solid foundation, the new reinforced earth retaining wall can have superior stability in engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of a reinforced earth retaining wall;

[0022] Figure 2 Schematic diagram of the structure of the geogrid device;

[0023] Figure 3 It is a schematic diagram of the concrete block structure of the assembled wall panel;

[0024] Figure 4 is a schematic diagram of an elastic shock-absorbing connection device;

[0025] Figure 5a , 5b It is a schematic diagram of the detailed dimensions of the elastic shock-absorbing connection device;

[0026] Figure 6 This is a schematic diagram of the finite element model of reinforced soil retaining wall;

[0027] Figure 7 A numerically calculated average stress diagram for the implementation of the present invention;

[0028] Figure 8 A numerically calculated deformed grid diagram implemented in the present invention;

[0029] Fig. 9 A numerically calculated total displacement map for the implementation of the present invention;

[0030] Fig.10 is a numerically calculated horizontal displacement diagram implemented by the present invention;

[0031] Fig.11 It is a contour map of the total displacement calculated numerically according to the present invention.

[0032] In the figure: 1-prefabricated wall panel concrete block, 2-elastic shock-absorbing connection device, 3-waterproof geomembrane, 4-concrete waterproof sealing top layer, 5-geogrid device, 6-foundation, 7-seepage ditch, 8-drainage pipe, 9-backfill gravel, 10-fill foundation, 11-protective layer;

[0033] 51-grid unit, 52-backfill soil, 53-nylon tie, 54-auxiliary tie bar, 55-main tie bar, 56-soil filling bag;

[0034] 61-fixing rod, 62-shock absorbing spring, 63-embedded connecting plate. DETAILED DESCRIPTION

[0035] The present invention uses an elastic shock-absorbing connection device to connect the assembled wall panel and the geogrid, so that the reinforced earth retaining wall has sufficient flexibility and is not prone to rigid damage that is difficult to repair under the action of earthquake loads, and increases the ability of the wall panel to adapt to soil deformation. At the same time, the use of spliced ​​prefabricated block panels makes construction easier. The introduction of waterproof geomembrane makes the reinforced soil difficult to be invaded by water, and the use of the geogrid's fold line reverse packaging technology greatly reduces the deformation of the slope.

[0036] The present invention adopts Figure 1 , 2 The assembled rigid-flexible combined reinforced earth retaining wall shown includes an assembled wall panel concrete block 1, an elastic shock-absorbing connection device 2, a geogrid device 5, a foundation 6 and a fill foundation 10. The assembled wall panel concrete block 1 is perpendicular to the geogrid device 5, and the geogrid device 5 is flush with the top surface of the fill foundation 10 and is constructed and installed on the foundation 6. It is characterized in that: the geogrid device 5 is connected by several layers of horizontally arranged grid monomers 51, the grid monomers 51 are parallel to each other, and the head and tail ends of each layer of grid monomers 51 are flush, the assembled wall panel concrete block 1 is connected to the geogrid through the elastic shock-absorbing connection device 2, forming a rigid-flexible combined elastic seismic reinforced earth retaining wall, and the gaps between the grid monomers 51 are compacted by backfill soil 52.

[0037] The elastic shock-absorbing connection device 2 includes a shock-absorbing spring 62, an embedded connection plate 63, and a fixing rod 61. The embedded connection plate 63 at the front end of the shock-absorbing spring 62 is both a connection device between the elastic shock-absorbing connection device 2 and the assembled wall panel concrete block 1, and also a splicing mold for the assembled wall panel concrete block 1. The embedded connection plate 63 is embedded in the reserved grooves of the upper and lower assembled wall panel concrete blocks 1, and is sealed with anchor glue, so that the upper and lower assembled wall panel concrete blocks 1 are seamlessly and tightly spliced. The fixing rod 61 at the rear end passes through the grille mesh and is placed in the grille to play a connecting and fixing role. An elastic shock-absorbing connection device 2 is set at the splicing position of each assembled wall panel concrete block 1 along the cross section of the retaining wall. Figure 4 shown.

[0038] Taking a certain project as an example, the specific construction method of the assembled rigid-flexible combined elastic seismic reinforced earth retaining wall of the present invention is further described:

[0039] 1) Use cast-in-place concrete foundation or mortar-laid stone foundation.

[0040] 2) The site is leveled. According to the design drawings and the on-site soil conditions, the foundation is leveled and filled. When selecting the cross-section form, the stability of the reinforced soil structure and the surrounding terrain conditions are mainly considered. The present invention uses an inverted trapezoidal cross-section, and the original slope joint is excavated into a step shape to increase the interface friction. Before construction, obstacles and weeds within the reinforcement range are removed, and the poor foundation soil is replaced with the foundation treatment. The bottom layer should be excavated to the design elevation and leveled.

[0041] 3) Lay out lines accurately according to the construction drawings and relevant design requirements.

[0042] 4) The bottom prefabricated wall panel concrete blocks 1 are mortared on the concrete foundation.

[0043] 5) Cut the geogrid according to the design requirements and lay the bottom grid according to the actual position of the construction layout. Along the longitudinal direction of the site, adjacent geogrids are butt-jointed, and the geogrid must be laid according to the position, length and direction required by the design drawings.

[0044] 6) Embed the embedded connection plate 63 of the elastic shock-absorbing connection device 2 into the assembled wall panel concrete block 1, spread the filler at a certain distance behind the assembled wall panel concrete block 1, and then lay the geogrid. First, lay the auxiliary reinforcement grid and the main reinforcement grid. Before the reverse wrapping, pass the fixing rod 61 through the mesh of the main reinforcement and the auxiliary reinforcement grid that have been laid, so that the geogrid device 5 is connected to the elastic shock-absorbing connection device 2, and place the fill bag 56 at the reserved reverse wrapping section grid. Use the fill bag 56 as the front end curve forming mold of the reverse wrapping section, reverse the geogrid close to the fill bag 56, and spread a certain amount of backfill. Fold down and fix the tail of the reverse wrapping section above the main tie 55 at 45° to the horizontal direction, and then tie the reverse wrapping section of the auxiliary tie 54 to the main tie 55 to complete the production of the reinforcement layer of the grid monomer 51;

[0045] In step 5), the main tie bars are made of EGA100100 glass fiber self-adhesive material, and the auxiliary tie bars are made of GSJ150150 warp knitted polyester material.

[0046] In step 6), an elastic shock-absorbing connection device 2 is provided at the joint of each assembled wall panel concrete block 1 along the cross section of the retaining wall.

Claims

1. An assembled rigid-flexible combined elastic seismic reinforced earth retaining wall, comprising assembled wall panel concrete blocks (1), a waterproof geomembrane (3), a concrete waterproof sealing top layer (4), a geogrid device (5), a foundation (6) and a fill foundation (10), wherein the geogrid device (5) is flush with the top surface of the fill foundation (10) and is installed on the foundation (6), wherein the geogrid device (5) is formed by connecting a plurality of horizontally arranged grid monomers (51), wherein the grid monomers (51) are parallel to each other, and the head and tail ends of each layer of grid monomers (51) are flush, and the gaps between the grid monomers (51) are compacted by backfill soil (52), characterized in that: The assembled wall panel concrete blocks (1) are spliced ​​by elastic shock-absorbing connection devices (2) and vertically connected to a geogrid device (5) to form a rigid and flexible combined elastic earthquake-resistant reinforced earth retaining wall; an elastic shock-absorbing connection device (2) is arranged at the splicing position of each assembled wall panel concrete block (1) along the cross section of the retaining wall; the elastic shock-absorbing connection device (2) comprises a shock-absorbing spring (62), an embedded connection plate (63) and a fixing rod (61); the embedded connection plate (63) at the front end of the shock-absorbing spring (62) connects the elastic shock-absorbing connection device (2) to the assembled wall panel concrete block (1) Then, the fixing rod (61) at the rear end of the shock absorbing spring (62) connects the elastic shock absorbing connection device (2) to the geogrid device (5); before the geogrid device (5) is reversed, the fixing rod (61) of the elastic shock absorbing connection device (2) is passed through the grid mesh of the laid main reinforcement (55) and the auxiliary reinforcement (54), so that the geogrid device (5) is connected to the elastic shock absorbing connection device (2); when the geogrid device (5) is reversed, the tail of the reversed section above the main reinforcement is folded downward and fixed at a 45° angle to the horizontal direction, and then the reversed section of the auxiliary reinforcement is tied to the main reinforcement.

2. The assembled rigid-flexible combined elastic seismic reinforced earth retaining wall according to claim 1 is characterized in that The upper and lower sides of the assembled wall panel concrete blocks (1) are provided with reserved grooves for seamlessly splicing the upper and lower assembled wall panel concrete blocks (1).

3. The assembled rigid-flexible combined elastic seismic reinforced earth retaining wall according to claim 2 is characterized in that The embedded connection plate (63) is also a splicing mold for the assembled wall panel concrete blocks (1). The embedded connection plate (63) is embedded in the reserved grooves of the upper and lower assembled wall panel concrete blocks (1) and is sealed with anchor glue, so that the upper and lower assembled wall panel concrete blocks (1) are seamlessly and tightly spliced.

4. A construction method for an assembled rigid-flexible combined elastic seismic reinforced earth retaining wall, characterized in that: The spring damping connection device is used to improve the deformation adaptability of the retaining wall. The specific construction steps of the reinforced earth assembled rigid and flexible combined elastic seismic reinforced earth retaining wall are as follows: 1) Construction foundation: cast-in-place concrete foundation or mortar-laid stone foundation; 2) Construction of filling foundation: excavate the original slope joint into steps to form a filling foundation with an inverted trapezoidal step section to increase interface friction; 3) Mortar the bottom prefabricated wall foundation base on the above concrete foundation or mortar-laid stone foundation; 4) Embed the embedded connection plate of the elastic shock-absorbing connection device into the concrete block of the assembled wall panel, spread the filler behind the concrete block of the assembled wall panel, and then lay the geogrid device. First, lay the main reinforcement grid and the auxiliary reinforcement grid. Before the reverse package, pass the fixing rod through the mesh of the main reinforcement and auxiliary reinforcement grid that have been laid, so that the geogrid device is connected to the elastic shock-absorbing connection device; 5) Construction of geogrid device: on the basis of the completed construction, the grid units are laid layer by layer from bottom to top. After each layer of grid units is constructed, the soil is filled and compacted to make it level before the construction of the next layer of grid units is carried out.

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