CN115162403A

CN115162403A - Light high-energy-consumption rockfall protection geotextile bag cushion layer and construction method thereof

Info

Publication number: CN115162403A
Application number: CN202210796272.1A
Authority: CN
Inventors: 任非凡; 刘佳豪; 黄强强
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2022-07-06
Filing date: 2022-07-06
Publication date: 2022-10-11

Abstract

The invention relates to a light high-energy-consumption rock fall protection geotechnical bag cushion layer and a construction method thereof. Compared with the prior art, the novel EPS bead-plain filled soil geotechnical composite material is used as the buffer layer filler, is filled in the geotechnical bag and is piled up according to a certain structural form to form the protective cushion layer, and the cushion layer structure has the characteristics of light weight, high damping, remarkable energy consumption effect, convenience in construction, low cost, convenience in maintenance, environment friendliness and the like. The cushion layer greatly reduces the rock falling impact force through the deformation of the flexible structure, blocks the transmission of the partition impact force between the independent soil engineering bags, and has better stress diffusion effect. The cushion structure can be applied to horizontally laid cushions such as a shed cave, can be applied to vertically laid cushions such as stone blocking walls and piers, and has wide application space.

Description

Light high-energy-consumption rockfall protection geotextile bag cushion layer and construction method thereof

Technical Field

The invention relates to the technical field of civil engineering, in particular to a light high-energy-consumption rock fall protection geotextile bag cushion layer and a construction method thereof.

Background

The collapse and rock fall geological disaster is a geological disaster with high occurrence frequency, large damage and strong uncertainty, and seriously threatens the safe use of the building in the mountainous area. For the protection of rockfall geological disasters, various protection measures suitable for different conditions are developed, and active protection and passive protection can be summarized. The use of the adit and the stone blocking wall in the passive protective measures is more, the common adit and the stone blocking wall with the concrete structure are easy to be damaged under the rockfall impact, the use for a long time is not facilitated, and meanwhile, the bridge pier of the bridge road engineering in the mountainous area also has the threat of rockfall impact. The buffer cushion layer is arranged on the surface of the concrete structure threatened by falling rocks impact, the concrete structure can be prevented from being damaged, the buffer cushion layer of the shelter develops for a long time, and the commonly used cushion layers mainly comprise: (1) directly backfilling plain filling soil as a cushion layer; (2) a layer of backfill soil and a layer of shock-resistant plate are paved at intervals to form a sandwich structure; (3) laying a sand layer on the upper part, and laying an EPS plate on the lower part to form a cushion layer; (4) fabricated rubber energy-dissipating plates are used as cushion layers. However, these protective cushion layers all have certain problems, the pure filling has poor buffering effect, thick filling is needed to achieve the buffering effect, but the self weight of the filling is large, and large load can be generated for the lower structure; although the backfill soil and the impact-resistant plate are used together, the buffer effect is better, the construction is complex, the cost is higher, and the plastic deformation and the damage of the impact-resistant plate can be caused under the impact of high-energy falling rocks; the sand layer and the EPS plate cushion layer have good buffering effect, but the EPS plate can be subjected to plastic deformation under the action of large-energy impact, the EPS plate has poor stress diffusion effect, stress is easily concentrated below an impact point, the EPS plate is extremely inconvenient to transport, and the cushion layer has high structural cost; use assembled rubber energy dissipation board buffering effect better, but directly bear the falling rocks and strike and can produce the damage to the bed course structure, use and maintenance cost are higher. Except the assembled rubber energy dissipation bed course, other bed course structures all have the inconvenient scheduling problem of maintenance above structure, and the bed course structure takes place to damage if not maintenance protective effect can discount greatly in time.

The protective layers of the structures such as the stone blocking walls and the piers are not uniformly known at present, plain filling soil is commonly used for naturally accumulating the stone blocking walls to serve as buffer layers at present, but the plain filling soil has poor buffer effect and large natural repose angle, no enough space is available for placing the plain filling soil protective layers in mountain engineering, the slope toe of the plain filling soil protective layers is small, and rolling stones easily cross the retaining structures.

Disclosure of Invention

The invention aims to provide a light high-energy-consumption rock fall protection geotextile bag cushion layer and a construction method thereof, which can be applied to not only horizontally laid cushion layers such as a shed cave and the like, but also vertically laid cushion layers such as a stone blocking wall, a pier and the like, and have wide application space.

The purpose of the invention can be realized by the following technical scheme: a light and high-energy-consumption rock fall protection geotextile bag buffer layer comprises a plurality of geotextile bags and EPS bead-plain filling mixture filled in the geotextile bags.

The EPS bead-plain filling mixture has the characteristics of light weight, high damping, high energy consumption and the like, and has excellent performance in the aspects of vibration damping and energy consumption. However, the shear modulus of the composite material is low, the EPS beads are mixed with plain filling soil as a foreign matter, the bonding property with the plain filling soil is poor, and the possibility of segregation exists. When the buffer composite filler is directly used as a buffer layer, particles may splash under the impact action, large impact pits may be generated, the stress diffusion effect is poor, and the impact stress is mainly concentrated below the impact position. As a 'flexible' reinforced material, the geotextile bag can consume energy through self flexible deformation, has the vertical acceleration attenuation rate of over 70 percent under the same condition, and has the advantages of high compressive strength, local material availability, good anti-freezing and anti-swelling performance, economy, environmental protection and the like. Compared with common filling, the earth bag has high shear strength, remarkable damping energy consumption effect and better characteristic under the action of static and dynamic load.

Preferably, the EPS bead-plain soil filling mixture is formed by mixing EPS beads and a plain soil filling mixture, and the addition amount of the EPS beads is 1.5-2% of the mass of the plain soil filling.

Preferably, the EPS beads have a diameter of 3-5 mm.

Preferably, the volume of the EPS bead-plain soil filling mixture accounts for 75-80% of the volume of the geotextile bag.

A construction method of the light high-energy-consumption rock fall protection geotextile bag cushion layer comprises the following steps:

(1) Laying a geomembrane as a water-resisting layer on the roof of the shed cave;

(2) Laying a drainage plate as a drainage layer on the geomembrane;

(3) Assembling the earthwork bag to form a cushion layer with a slope;

(4) Plain soil filling is paved at the step of the geotextile bag at the top of the cushion layer for transition.

Preferably, the step (3) of assembling the geotextile bag comprises the following steps: the upper geotechnical bags are stacked in the middle of the four geotechnical bags in the lower layer, and are pressed at the 1/4 position of each geotechnical bag in the lower layer.

Preferably, step (4) is implemented by paving plain soil filling transition and scattering grass seeds to form the environment-friendly cushion layer.

A construction method of the light and high-energy-consumption rock fall protection geotechnical bag cushion layer is characterized in that a plurality of iron wire nets piled with geotechnical bags are tied to a stone blocking wall.

Preferably, 3-4 layers of soil engineering bags are piled in each wire mesh, the lower parts of the wire meshes are fixed firstly, then the soil engineering bags are piled, the adjacent soil engineering bags are paved in a crossed mode, and then the upper sections of the wire meshes are fixed.

A construction method of the light high-energy-consumption rockfall protection geotextile bag cushion layer is characterized in that circular-arc geotextile bags are piled around piers.

Preferably, the earth work bags are piled up in a crossed mode, and the outer rings of the earth work bags are fixed through iron wires.

The rockfall protection cushion layer is an indispensable part of the rockfall protection structure, is laid on the rockfall impact side of the protection structure, and absorbs impact energy through self deformation, and meanwhile, impact stress is diffused, so that excessive concentration of impact force on the support structure is reduced. The novel EPS bead-plain filled soil geotechnical composite material is used as the buffer layer filler and filled in the geotechnical bag, and the protective cushion layer is formed by piling according to a certain structural form. The cushion layer greatly reduces the rock fall impact force through the deformation of the flexible structure, blocks the transmission of the partition impact force between the independent soil engineering bags, and has better stress diffusion effect. The cushion structure can be applied to horizontally laid cushions such as a shed cave and the like, can be applied to vertically laid cushions such as a stone blocking wall, a pier and the like, and has wide application space.

Compared with the prior art, the invention has the following advantages:

1. the cushion layer is light, high in damping and good in vibration and energy consumption effects, can consume falling rock impact energy through self compaction, deformation and interface friction, and the EPS beads are used as small particle units and have good deformation restorability under the action of impact force;

2. the cushion layer consists of a plurality of modular geotextile bags, has strong flexibility and good deformation coordination, and has remarkable acceleration attenuation and reduced impact force under the action of impact load;

3. the geotechnical bag is used as an independent unit of the cushion layer, can obstruct the transmission of rock fall impact force, has certain constraint effect on EPS bead-plain filling mixture, avoids deep impact pits generated under the rock fall impact effect, materials are separated, stress is concentrated below impact points, and the diffusion of impact stress is increased;

4. the geotextile bag filler can be prepared from local mixed EPS beads, is simple to construct, can be filled in advance or in situ, has high mechanical construction degree, can be directly stacked on the surface of a retaining structure needing to be protected without influencing the prior building, is used normally for a line, and has strong construction flexibility;

5. the geotechnical bag has high compressive strength, good antifreezing performance, economy and environmental protection;

6. the invention has wide application range, not only can be applied to cushion layers paved in horizontal directions such as a shed cave and the like, but also can be applied to cushion layers paved in vertical directions such as a stone blocking wall, a pier and the like;

7. the drainage performance is good, rainwater in the soil engineering bag can be drained in time, and the influence on the retaining structure is avoided;

8. the invention has convenient repair, the large impact energy rock falls to damage the cushion pad layer, and the repair of the cushion pad layer can be completed only by replacing the soil engineering bag in the damaged area.

Drawings

FIG. 1 is a schematic view of the geotextile bag filling process of the present invention;

FIG. 2 is a schematic view of the equi-horizontal geotechnical bag cushion of the shedder of the present invention;

fig. 3 is a top view of the upper and lower geotechnical bag cushion layers of the shelter cave of the present invention;

FIG. 4 is a schematic view of the vertical geotextile bag cushion layers laid on the stone blocking wall and the like according to the invention;

fig. 5 is a sectional view of a pier geotextile bag cushion of the present invention;

FIG. 6 is a top view of a pier geotextile bag cushion of the present invention;

in the figure: 1-adit, 2-geomembrane, 3-geotechnical drainage plate, 4-drainage pipe, 5-EPS bead-plain filling mixture, 6-geotextile bag, 7-plain filling, 8-grass, 9-geotextile bag of first layer, 10-geotextile bag of second layer, 11-concrete stone blocking wall, 12-prefabricated hook or expansion screw, 13-wire netting, 14-rock, 15-pier.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation procedures are given, but the scope of the invention is not limited to the following examples.

The geotechnical bag cushion layer can be applied to cushion layers paved in the horizontal direction of a shed cave and the like, and can also be applied to cushion layers paved in the vertical direction of a stone blocking wall, a pier and the like. The concrete construction process is as follows:

(1) The size and the arrangement mode of the geobags are determined according to the actual situation of the site, the geobags are selected to be filled in advance or filled in the site, and the thickness of the buffer layer is determined according to the level of the rock falling level in the site. The number of the layers of the soil engineering bags in the buffer layer is controlled within a reasonable range, so that the buffer layer can play a better role, and the number of the layers is not less than three. The size and dimensions of the geotextile bag can be selected according to the size which is easy to purchase in the market.

(2) The earth bag filling filler is selected according to field conditions, and the selection principle is that sandy soil is considered firstly, silt and cohesive soil are considered secondly, and small-particle-size broken stones are considered finally. Mixing with EPS beads in a certain proportion, and filling the earthwork bag.

As shown in figure 1, local common plain filling soil is selected to be mixed with EPS beads, the mixing amount of the EPS beads is 1.5% -2% of the mass of the plain filling soil, the diameter of the EPS beads is 3-5 mm, the EPS bead-plain filling soil mixture is filled into a geotextile bag, and the geotextile bag is stacked according to a certain mode to form a buffer cushion layer.

The following are specific embodiments:

example 1

Referring to fig. 2, the cushion layer of the shelter is installed, and (1) a geomembrane 2 is laid on the top of the shelter 1 and is a water-proof layer; (2) laying a layer of geotechnical drainage plate 3 as a drainage layer; (3) the upper and lower layers are cross-assembled according to the figure 2 to form a graded buffer layer, wherein the geotextile bags 6 are filled with EPS bead-plain filling mixture 5; (4) upper and lower geotextile bags are assembled, referring to fig. 3, an upper geotextile bag (a second geotextile bag 10) is stacked in the middle of four geotextile bags (a first geotextile bag 9) of a lower geotextile bag, and the upper geotextile bag is pressed at 1/4 position of each geotextile bag of the lower geotextile bag; (5) plain filling soil 7 is paved at the step of the geotextile bag at the top of the buffer layer for transition, and grass seeds are scattered to form the environment-friendly buffer cushion layer.

Maintaining a cushion layer: the geotechnical bag can be damaged under the impact action of high-energy falling rocks, and only the geotechnical bag in the damaged area needs to be replaced for repairing the cushion layer, so that the maintenance cost of the cushion layer is greatly reduced.

Example 2

A cushion for greenhouse cave is characterized in that a drainage layer is connected with a drainage pipe 4, grass 8 grows on plain filling 7, and the rest of the structure is the same as that of the cushion in embodiment 1.

Example 3

Referring to fig. 4, the cushion pad layer of the stone blocking wall is installed, wherein (1) a geotechnical bag in a certain size range is selected as a unit according to the size of local rockfall and the impact energy, generally, 3-4 layers of geotechnical bags are selected as a unit, hooks are pre-buried in the wall or expansion screws 12 are driven into the built wall during construction, the small units of the cushion pad layer are tied to the stone blocking wall 11 through iron wires 13, and the stability of the cushion pad layer is guaranteed in the impact process of rolling stones 14. (2) According to the structure shown in fig. 4, the lower part of each layer of the iron wire mesh is fixed, then the soil engineering bags 6 are piled, the adjacent soil engineering bags are also paved in a crossed manner, then the upper sections of the iron wire meshes are fixed, and the buffer layer piling is completed according to the step.

Maintaining a cushion layer: the geotechnical bag can take place the damage under the high energy rock fall striking effect, only need change damaged area's geotechnical bag to the restoration of bed course, greatly reduced bed course maintenance cost.

Example 4

The buffer layer of the geotechnical bags for the piers is installed and referred to fig. 5-6, the buffer layer of the geotechnical bags for the piers adopts the arc-shaped geotechnical bags 6, the buffer layer is piled as shown in fig. 5-6 and is built around the piers 15, a circle of iron wire meshes 13 are adopted to fix the buffer layer, and the stability of the buffer layer is ensured in the falling rock impact process.

Two factors should be considered for the design of the cushion layer, namely the buffering effect on impact force firstly and the stress diffusion effect secondly, so that the impact stress is prevented from being concentrated below the impact point. Aiming at the problems of the existing cushion layer, the invention provides the cushion layer which is good in buffering performance, convenient to construct, capable of taking local materials, low in cost, convenient to repair and environment-friendly, and the structure not only can be applied to the cushion layer paved horizontally in a shed cave (shown in a figure 2), but also can be applied to the cushion layer paved horizontally in a concrete stone blocking wall (shown in a figure 4), piers (shown in figures 5 to 6) and the like in the vertical direction.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The light high-energy-consumption rock fall protection geotextile bag cushion layer is characterized by comprising a geotextile bag and an EPS bead-plain filling mixture filled in the geotextile bag.

2. The light high-energy-consumption rock fall protection geotextile bag buffer layer as claimed in claim 1, wherein the EPS bead-plain filling soil mixture is formed by mixing EPS beads and the plain filling soil mixture, and the EPS beads are added in an amount of 1.5-2% of the mass of the plain filling soil.

3. The light high-energy-consumption rock fall protection geotextile bag cushion layer of claim 1, wherein the EPS bead-plain soil-filling mixture accounts for 75-80% of the volume of the geotextile bag.

4. A construction method of the light-weight high-energy-consumption rock fall protection geotextile bag cushion layer as claimed in any one of claims 1 to 3, characterized by comprising the following steps:

(2) Laying a drainage plate as a drainage layer on the geomembrane;

(3) Assembling the geotextile bags to form a cushion layer with a slope;

5. The construction method of the light weight and high energy consumption rock fall protection geotextile bag cushion layer according to claim 4, wherein the assembling method of the geotextile bag in the step (3) is as follows: the upper layer of the geotextile bags are stacked in the middle positions of the four geotextile bags in the lower layer, and the upper layer of the geotextile bags are pressed at the 1/4 position of each geotextile bag in the lower layer.

6. The construction method of the light high-energy-consumption rock-fall protection geotechnical bag cushion layer according to claim 4, wherein step (4) is implemented by laying plain soil filling for transition and spreading grass seeds to form an environment-friendly cushion layer.

7. A construction method of a light weight high energy consumption rock fall protection geotextile bag cushion as claimed in any one of claims 1 to 3, wherein a plurality of the geotextile bag piled wire nets are tied to the rock-arresting wall.

8. The method for constructing a lightweight high energy consumption rock fall protection geotextile bag cushion as claimed in claim 7, wherein 3 to 4 geotextile bags are stacked in each woven wire net, the lower part of the woven wire net is fixed, and then the geotextile bags are stacked, and the geotextile bags adjacent to each geotextile bag are alternately laid, and then the upper part of the woven wire net is fixed.

9. A construction method of the light-weight high-energy-consumption rock-fall protection geotextile bag cushion layer as claimed in any one of claims 1 to 3, wherein the circular arc-shaped geotextile bags are piled around the pier.

10. The construction method of the light weight and high energy consumption rock fall protection geotextile bag cushion layer as claimed in claim 9, wherein the geotextile bags are piled up in a crossing manner and fixed by an iron wire net.