Design and Application of Geocell Retaining Wall in Road Cutting Slope
Abstract: The article first introduces the characteristics of flexible retaining walls by comparing the rigid and flexible walls, and expounds the specific application range of flexible retaining walls. Then through the theoretical knowledge, the design mechanism of the plastic geocells manufacturers flexible retaining wall is briefly introduced. Finally, the slope protection in a northwestern project is taken as an example to demonstrate the feasibility of a combination of a geogrid flexible retaining wall and anti-slide pile and good slope protection effect plastic geocells for sale. This example is also used to provide an effective reference for similar roller-type slope protection methods.
Keywords: plastic geocells manufacturers flexible retaining wall; design mechanism; roller type
With the improvement of the national development level and the improvement of the highway industry, there is an increasing demand for highway construction, and the improvement of the quality of the retaining wall is also imperative. The plastic geocells factory price flexible retaining wall has the characteristics of superior to the rigid retaining structure, that is, the surface can be greened after the completion of the construction, and at the same time, based on the flexible characteristics of the wall itself, when the external force is applied, part of the earth pressure is released wholesale plastic geocells, resulting in the wall The soil pressure of the soil is rearranged, which is in the direction of facilitating the overall stability, so it is born as a new type of retaining wall.
2. Characteristics of flexible retaining walls
The flexible retaining wall has a low modulus. Under the earth pressure, due to its flexibility, the wall can be coordinated with the soil. At the same time, due to a small amount of deformation, part of the earth pressure can be released, making it less prone to breakage. It can relieve local concentration of pressure, which is the biggest difference between the flexible retaining wall and a rigid retaining wall. The characteristics of the plastic geocells manufacturers flexible retaining wall are as follows:
(1) The high quality plastic geocells and the filling material in the three-dimensional network structure constitute the structural layer of the ecological flexible retaining wall of the plastic geocells factory price, which is a new type of design with a certain design gradient (1:0.25-1:0.5). Support structure. The more common supporting structures are gravity retaining wall, light retaining wall, reinforced earth retaining wall, etc., which are characterized by light structure, convenient construction wholesale plastic geocells, and low cost.
(2) With the improvement of highway construction demand, rigid retaining structures are undoubtedly widely used, but due to their labor intensity, engineering cost, number of dirty workers, and their own weight, their limitations are also obvious. The geotechnical ecological flexible retaining wall, which is opposite to the rigid structure, is not only convenient to construct, but also less subject to geographical restrictions, and its wall has a lighter weight and a certain flexibility high quality plastic geocells. Therefore, the bearing capacity of the foundation is relatively low compared to the rigid retaining wall.
(3) Geotechnical format The flexible retaining wall is characterized by the fact that after the completion of the construction, the greening construction can be carried out directly on the wall surface, which not only ensures the quality of the highway engineering but also solves the problems of its aesthetics and environmental protection. (4) A geogrid retaining wall is a kind of flexible retaining wall. Its function is composed of four parts: the wall itself, the reinforced layer, the back wall, and the foundation plastic geocells for sale. The wall is under the action of earth pressure and the soil. Coordinated deformation without cracking, while its flexibility prevents local stress concentration, which is a unique feature of flexible retaining walls.
3. Scope of application of geocell flexible retaining wall
Table 1 List of applicable conditions for plastic geocells manufacturers flexible retaining wall
4. Design mechanism of geocell flexible retaining wall
As a new type of support, the roller-type plastic geocells factory price flexible retaining wall maintains the stability of the structure and also satisfies the function of wall greening, but its stress and deformation are relatively complicated. In this part, we first introduce the working mechanism of the high quality plastic geocells structural layer and then describe the design idea of the plastic geocells for sale flexible retaining wall.
4.1 Working mechanism of the geocell structural layer
Due to the existence of wholesale plastic geocells, the carrying capacity of the internal packing can be greatly improved. The composite body is subjected to the force, and the frictional resistance of the chamber and the soil body and the strength of the body can effectively reduce the lateral deformation of the soil. The unique three-dimensional structure of the plastic geocells for sale makes it different from the traditional reinforced materials, which can effectively reduce the lateral deformation of the soil and improve its bearing capacity. The article mainly introduces the mechanism of action of high quality plastic geocells from the following aspects.
Lateral restraint and friction of the plastic geocells manufacturers to the soil:
The wholesale plastic geocells restraint is mainly reflected in the following two aspects:
(1) The frictional effect of the sidewall of the cell on the filler. Due to the different modulus of the plastic geocells factory price and the soil, different deformations occur when the force is applied together, which causes friction between the interior wall and the soil interface. When the composite is subjected to an external force, frictional resistance is generated, and the frictional force increases as the external force increases and reaches the limit state plastic geocells for sale. The frictional resistance f can be expressed by the following formula:
Where: the coefficient of friction between the μ-cell and the soil; σ3-the horizontal hoop stress of the composite; the contact area of the S-filler with the cell wall.
(2) The tightening effect of the high quality plastic geocells on the soil in the cell unit. The soil inside the grid is subjected to the upper load, and the wall of the chamber is squeezed, which creates a tight-fitting effect on the soil and restrains the lateral displacement trend. According to the rubber film theory of Henkel and Gibert plastic geocells manufacturers, the additional stress Δσ3 increased due to the stress of the cell wall membrane is derived:
Where: film coefficient of M-cell material, kPa; εc-cell hoop strain limit value; εa-cell axial strain limit value wholesale plastic geocells; d-cell initial diameter.
According to More-Coulomb’s law:
Therefore, Δσ1 is an increase in bearing capacity due to lateral restraint.
4.2 Wall width selection of flexible slope retaining wall
Due to the certain flexibility, the wall body is allowed to undergo a certain degree of deformation under the action of the earth pressure behind the wall. Taking into account the strength of the cell using the modulus, the coordinated deformation between the composites, and the reasons for maintaining the integrity of the retaining wall plastic geocells factory price, the article uses the 1.5% of the wall width as the wall to produce the maximum deformation. The limit value is used as the control standard for the wall width.
4.2.1 Determination of earth pressure on the wall. The wall back force of the flexible retaining wall is the same as that of the tilting gravity retaining wall, so it also relies on the integrity of the wall to resist the earth pressure and maintain stability. According to the Coulomb earth pressure theory plastic geocells for sale, the earth pressure distribution on the back of the wall is:
Where: δ-wall back friction angle (°); α-wall back inclination (wall back pitch is positive, vice versa); Ka-Coulomb earth pressure coefficient;
H-strong back height (m); φ-the internal friction angle of the reinforced fill in the geogrid high quality plastic geocells; the bulk density of the γ-undisturbed soil.
4.2.2 Analysis mode. The analysis of the force of the wall is equivalent to the simply supported beam with hinged ends. The model is shown in Figure 1.
Figure 1 Wall calculation mode
Where: σB-the earth pressure stress value (kN/m) received at point B at the bottom of the wall back plastic geocells manufacturers; qn-the earth pressure stress level value (kN/m) received at point B at the bottom of the wall back.
According to the theory, in the upper state of the beam, the maximum deformation of the beam body occurs at the section of the beam span:
Where: the bending stiffness of the EI-beam (kN·m2); the moment of inertia of the I-beam section
Finishing is available:
From ymax ≤ 0.015B1,
4.2.3 Consider wall stability
Figure 2 Retaining wall force diagram
Figure 3 Schematic diagram of the basic section
(1) Anti-sliding stability analysis:
(2) Anti-overturning stability analysis:
(3) Analysis of eccentric moment at the bottom of the wall:
(4) Analysis of base bottom stress and base eccentric moment e:
Among them: HEy-Ey force arm (o) for point o; force arm (m) for HEx-Ex to point o; force arm (m) for HG-wall gravity G to o point; Kc-base anti-sliding stability Coefficient plastic geocells factory price; [Kc]-base anti-sliding safety factor; K0-anti-overturning stability coefficient; γ1-wall body bulk density (kN/m3); [K0]-anti-overturning required safety factor; [σ]-corrected foundation soil Allowable bearing capacity (kPa); the allowable wholesale plastic geocells bearing capacity improvement factor of K-foundation soil.
The two wall thickness design values of B11 and B12 are obtained by the formulas (10) and (11) respectively, and the two are taken as the second value of B1, and then the first value is compared to determine the final design of the wall thickness plastic geocells for sale. value. The above part is the design mechanism of this new type of support structure.
5. Project examples
5.1 Project Overview
In order to ensure the stability of the slope and reduce the erosion of water flow, the KL7 contract section of Kangjiaya to Linxia Expressway in Gansu Province has adopted various forms of slope protection in order to facilitate the greening of the slope and beautify the road capacity. Among them, in section K56+440~580, the route of the section is shallowly excavated (the highest slope of 11.4 meters) passes through the edge of the landslide body. The landslide body is stable overall plastic geocells factory price, and there is a shallow surface collapse and the groundwater is relatively developed. In order to ensure the stability of the subgrade during roadbed excavation and prevent the slope from collapsing and other diseases, the project adopts a combined protection method. Firstly, the anti-slide pile retaining block is installed, the deep seepage trench is buried, and the appropriate load shedding measures are taken at the same time. The flexible retaining wall is arranged on the one hand, so as to effectively wholesale plastic geocells protect and support the sliding of the slope soil, and the greening of the slope can be smoothly implemented.
5.1.1 Setting of anti-slide piles. Reinforced concrete anti-slide piles are set on the left side slope of section K56+440-580. The pile spacing is 5m, the pile diameter is 1.5m, and the pile top is connected with 1.2m×1.0m rectangular reinforced concrete cross-beams to ensure anti-slip plastic geocells manufacturers. The pile can fully exert its anti-sliding effect, and the length of the pile body to be buried in the stable formation should be greater than 1/3 of the length of the whole pile and less than 1/2 of the length of the pile.
5.1.2 Setting of the plastic geocells for sale flexible retaining wall. The retaining wall adopts 1:0.75 slope ratio, which is composed of a retaining wall compartment, high quality plastic geocells compartment and backfilling. The wall width is calculated by the formula (7), formula (10) and formula (11) to meet 3m requirements.
Figure 4 Standard cross-section of plastic geocells factory price flexible retaining wall
Figure 5 cell detail structure
5.2 Effect evaluation
At the beginning of the construction, the flexible retaining wall was continuously monitored, and regular monitoring was carried out after completion. The final statistical results showed that the flexible retaining wall was stable overall, the lateral displacement was small, and the effect was good.
The high quality plastic geocells flexible retaining wall not only satisfies the structural safety, convenient construction, low cost, but also the wall itself can be planted with grass and green walls. This method is in line with the harmonious needs of protecting the ecological and beautifying the landscape and combines these two advantages. A new type of retaining structure is worth promoting. However, due to the short introduction time of this kind of support structure wholesale plastic geocells, the current engineering practice is less, and theoretical research is limited. There are still many problems to be solved, so the system of the flexible retaining wall has not been fully formed, in actual work. The problems exposed need to be further improved.