Rockfall protection fence

Nature Net method

Outline

New type of protective fence that absorbs large rockfall energy with
high-strength and high-toughness net made by fiber

Characteristics

Nature Net method absorbs impact only by the elongation and strength of the fiber net and rope.
There are three main members to exhibit the characteristics of Nature Net method.

Nature Net

Hit receiveing part which is formed with a high-elongation and high-strength rope around the Raschel netting.

Nature Rope

High-strength ropes made of high-elongation polyester and have high shock-absorption performance.
They are used not only for the hit receiving part, but also the  ropes of Nature Net and Nature Sling of holding material.
Nature Belt is used as an auxiliary rope material for the hit receiving part.

Compared to the conventional polyethylene rope (red) with elongation, a wide absorption area is secured even with the same strength.

Pillar material

The piller is fixed by Multi-locks based on the lock bolt. Due to the toughness of the lock bolt and Multi-lock structure, it can be operated 360 ° and it follows flexibly with the net and rope moving against rockfalls.

Multi-lock

These effects enable flexible behavior as shown in the figure.
(CAE analysis by LS-DYNA)

Impact energy absorption mechanism

Since Nature Net absorbs rockfall energy flexibly by deforming flexible structural members, all structural members begin to deform almost at the same time as the rockfall collides.

Just before the collision

Nature Net and the buffer rope are deformed at the same time, and the impact energy is mitigated by the impact force distribution and tensile resistance.

Pillar tilts due to the impact force from Nature Net. The resistance of side belt absorbs impact energy and reduces the load on the end of the pillar.

The motion of Steps 1 to 3 are behaved almost at the same time, the entire fence structure shall be deformed and absorbed the rockfall energy.

Behavior at each stage by high-speed camera (1/200)

Other application

Nature Net can be applied under the following conditions.

 

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