EP1065319A1

EP1065319A1 - Vegetation wall and process for its erection

Info

Publication number: EP1065319A1
Application number: EP00500134A
Authority: EP
Inventors: Fernando P.A.E. Casablanca 1 Garcia Marin
Original assignee: Teconma SA
Current assignee: Teconma SA
Priority date: 1999-06-30
Filing date: 2000-06-23
Publication date: 2001-01-03
Also published as: ES2179710B1; ES2179710A1

Abstract

Vegetation wall and process of use thereof. The invention is comprised by variable formworks (1) of tiers (height) and slope arranged one on top of the other and closed. Inside them the filler is placed. Closure is achieved on the basis of geosynthetics, in the front part as vegetation support (7) and in the lower part of the formwork anchored to the same and in the middle of the filter tier, in this case, by means of a biaxial geonet. The system is interlocking and is completed with a vegetable covering on the outside front. Of application in the contention and covering of bowled floors, of civil and public works (routes, highways, railways, etc.).

Description

Field of the Invention

The invention is related to the field of contention or covering of all types of bowled floor, including embankments, by means of vegetation systems called green walls and is basically applied in the field of public and civil works, particularly related to infrastructures: roads, motorways, railway lines, etc.

State of the Art

Support reinforcements are described for inclined embankments in patent number ES2023736. Said reinforcements include a vegetation padding but do not incorporate a geosynthetic material, resulting in less aeration of the leaf mold and therefore less plant growth. Moreover, said structures are designed for inclinations up to 60°, with tier distances (height of each reinforcement tier) of up to 0.5 m. Therefore, this type of structure is not so efficient regarding growth of the vegetable component of the green wall of the invention and as previously described has operational limits regarding the tier height and the inclination angle.
The present invention solves some of the previously mentioned problems or drawbacks, being effective for greater inclinations and allowing a greater tier distance. Likewise, it supports tiers with improved vegetable growths.
For purposes of a better understanding of the used terms, some of the most specific ones are defined below.

Extrados: Interior of the vegetable wall where, for example, the filling and leaf mold are incorporated.
Tier: height between two layers; in this case, between layers of the reinforcement geonet. It also represents the formwork height.
Proctor: compactation unit.
Leaf mold: filling material based on fines and organic material conforming the ground for vegetation development.
Mulch: protection layer for the seeds.
NPK Fertilizer: fertilizer based on nitrogen, phosphorous and potassium, which varies in the proportion of its components, according to the season, climate, type of plants, etc.
Micro and macro-nutrients: basic elements for vegetable nutrition which are respectively found in small or large proportions.
Fixing agent and soil stabilizer: products of synthetic origin, permitting seeds to be fixed or stabilized in soils with considerable gradients, without becoming detached by rain until their germination.

A first invention would be the green wall itself. A second invention would be a method for settling embankments or inclined surfaces in general, using said green wall.

Detailed Description of the Invention

The green wall consists of the following components:

Filling material of variable granulometry (2). Among the materials to be selected, the following may be mentioned: sands, clays, ballast (loam), gravel, stones, etc.
Reinforcement geosynthetic materials. At least two and preferably in the form of thermosealed geonets, whose mesh prevent the exit of fines. One extends horizontally throughout the lower length of the formwork (1) and another intermediate one is placed in the middle of the tier (3). The geosynthetic materials are usually based on high density polyethylene or polypropylene. The intermediate geosynthetic material must have the same tensile strength in the transversal plane as in the longitudinal one (biaxial). The tensile strength range varies between 40 and 200 kN. This type of geonet permits to obtain tiers of up to 1 m between reinforcing layers with an interlocking system.
Vegetation geosynthetic material. Three-dimensional geonet type (7) with less tensile strength (greater than 3 kN). In another embodiment the invention, a flat geonet may be used with an opening diameter preventing the exit of fines. In both cases, the geosynthetic materials to be used should permit the passage of the plant roots. It is arranged on the wall face. The geosynthetic materials used have high stability to ultraviolet light (UV), on incorporating in their composition finely divided black carbon. Moreover, the polymers forming these commercial geosynthetic materials are inert to the soil chemical agents and are not degraded by the microorganisms present in it. Its operating temperature range varies from -50° to +80°.
Fastening mesh or formwork: Forms a lost type form, that is, non-recoverable. It may be of the round electrowelded steel, polymeric or glass fiber type with sufficient bending diameter to prevent bending due to the filling weight.
Fastening means: Between the geosynthetic materials and the mesh or fastening formwork. It may be made by means of a plastic pin or by means of an electrowelded steel round (6) which interlocks with the system (figure 4). The formwork fastenings (4) are conventional.
Vegetable covering. Consist of leaf mold, seeds and plants to grow over it. Its arrangement is such that there is no settling along the leaf mold line (5).

The green wall consisting of the components described above permit the contention and complete vegetation of reinforced soil cores, with variable height and inclination. The invention is preferably used with gradients between 60-81°.
A process for using the green wall is described below for a green wall with the features described in the containment and covering of embankments.
First of all, the soil base is leveled with variable steps of 75 cm high, being adapted to the natural soil. The geosynthetic layer is spread over the leveled base along the entire wall length. The lost forms are placed over this geosynthetic material, being fastened to the geosynthetic material and to each other. Then, they are covered with the vegetation geosynthetic and the extrados is filled until half the tier. The first 30 or 40 cm are filled with fine granulometry earths or preferably with leaf mold. The initial incorporation of the leaf mold, prior to the incorporation of the remaining filling materials, prevents settling along the vegetation line. This arrangement does not create a continuous line, preventing differential settlements on the wall face. After mechanically compacting the leaf mold layer to at least 97% of the normal proctor, biaxial geosynthetic is placed in the middle of the tier. Once fitted, refilling is carried out with leaf mold and other filling materials and compacted as in the previous step until obtaining for example a height of 75 cm.
Then, the same operations are carried out for a new reinforcement layer, formwork, etc., and so on until reaching the total embankment height established.
Once the construction is finished the vegetable covering is carried out either by mechanical means or by planting. The vegetable covering represents an advantageous improvement over the known state of the art by providing for example a high filling stability, allowing the sowing of grass, which provides an aesthetic beauty to the assembly and creates a vegetation that integrates the construction within the environment. Over this wall, houses, roads, railways, etc., may be constructed on a bad quality and with important unevenness.
Some specific constructional aspects of the invention are described below as examples.

Example 1: Formwork and Fastenings.

A lost form is arranged, folded at 60° with a weight comprised between 35-65 kg. The formwork is made of 8 mm diameter electrowelded steel in the transversal elements and 10 mm in the longitudinal ones. It has a length of 5.15 m to give 5 useful m and the rest for overlapping, with a height of 0.85 m. 5 to 12 hooks, 10 mm diameter and 500-1000 mm variable lengths with curved ends, are used for its fastening. The fastening round of the reinforcing geosynthetic has 10 mm diameter and a length between 0.75 and 2 m.

Example 2. Vegetable Seeding.

This is carried out by projection, comprising (per m²):

4-9 1 of water.
0.4-1 kg short fiber mulch, with vegetable fibers shorter than 30 mm.
slow release NPK fertilizer.
micro and macro-nutrients.
fixing agent and soil stabilizer.
2-4 l organic material, favoring moisture and serving as initial soil for the germinated plants.
25-50 g herbaceous plant seeds selected according to the rainfall and mean temperature of the area where the wall is to be installed, as well as its orientation.

A vegetable covering of 1-2 cm thick is obtained with this seeding.

Brief Description of the Drawings

Figure 1: Partial view of two successive formworks (A and B).
Figure 2: Closing of the system with reinforcement and vegetation geosynthetics.
Figure 3: Detail of the formwork fastenings between each other and with the reinforcement geosynthetic material.
Figure 4. Detail of the fastening between the geonet and the formwork round.

Claims

A green wall to contain and cover bowled floors, preferably embankments, comprising formworks with variable inclination and variable tiers, successively arranged one on top of the other and/or adjacent, to which filling materials are incorporated, characterized by comprising at least two reinforcement geosynthetic materials interlocking with the formworks and at least one vegetation geosynthetic material over which the vegetable covering is sown.
A green wall according to claim 1, characterized in that at least one of the reinforcement geosynthetic materials is arranged in the lower part of the formworks fastened to them.
A green wall according to claims 1 and 2, characterized in that at least one geosynthetic material is arranged in the middle of the formwork tier, being fastened to them.
A green wall according to claim 3, characterized in that the geosynthetic material is a biaxial geonet with the same tensile strength in the longitudinal and transversal planes.
A green wall according to claims 1 to 4, characterized in that the vegetation geosynthetic material is arranged in the front plane of the formworks, being fastened to them.
A green wall according to claim 5, characterized in that the vegetation geosynthetic material is a three-dimensional net with a tensile strength between 1.5 and 5 kN/m.
A green wall according to claims 1 to 4, characterized in that the reinforcement geosynthetics are preferably high density polyethylene or polypropylene.
A green wall according to claims 1 to 4 and 7, characterized in that the reinforcement geosynthetics have a tensile strength between 40 kN and 200 kN.
A green wall according to claims 1 to 8, characterized in that the fastening between the geosynthetic materials and the formwork is by means of pins or by means of a steel round rod crossing the geosynthetic itself.
Process for using a green wall as described in claims 1 to 9, in the contention and/or covering of inclined land surfaces, characterized by the following steps:

Placing at least a first longitudinal reinforcement geosynthetic.

Placing the formworks on top, fastening them to the geosynthetic and to each other.

Placing at least one vegetation geosynthetic.

Filling the formwork first with leaf mold and then with other filling materials and compacting it until the middle of the tier.

Placing at least a second preferably biaxial reinforcement geosynthetic on top and fastening it to the formwork.

Refilling until reaching the required height.

Sowing over the front surface of the wall formed by the vegetation geosynthetic.