Sand passing through gabion cages on M13 off-ramp

HIGHWAY residents have raised concerns about the gabion cages on the M13 off-ramp to Dawncliffe, Westville, following the recent heavy rains. According to community members, the cages were fitted after the April floods, however, with the recent heavy rainfalls, there was sand passing through the gabions and obstructing traffic on the M13 off-ramp.

“The heavy rains last week just spilt over the curb stones on the N3 and washed most of the soil back onto the M13 off-ramp. Now, we had to push the soil back up the hill,” said a community member. The community said it is only a matter of time before another incident could lead to the soil falling onto the road again.

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Professor Mohamed, who is a lecturer in Civil Engineering, gave an objective insight on how gabions should be constructed to avoid sand from passing through, and how this can be fixed.

“Gabions should be properly or sufficiently filled. They are typically filled with rocks or other suitable materials to provide stability and prevent erosion. If the filling is inadequate or not done correctly, there may be gaps or voids in the structure, allowing sand to pass through.

“Gabions consist of wire mesh or cages that hold the filling materials together. If the mesh or wire used is not strong enough or of low quality, it may fail to retain the filling, leading to sand leakage.

“They should be properly positioned and aligned during construction to ensure they can withstand the forces exerted on them, such as soil pressure. If the gabion is not positioned correctly, it may become unstable and allow sand to pass through,” he said.

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“If the gabion structure is not designed with adequate drainage, water pressure can build up behind it, leading to erosion and weakening of the structure, eventually causing sand to pass through.

“If the construction process is not carried out with proper attention to detail and precision, it can result in a poorly built gabion that fails to retain the filling material effectively.
Extreme weather conditions, such as heavy rainfall or flooding, can put additional stress on the gabion, potentially leading to failure and sand leakage.

“Over time, gabions may deteriorate due to natural wear and tear. If the structure is not adequately maintained, it can lead to issues like gaps or breaks, allowing sand to pass through.

“To address the sand-leakage issue, a thorough inspection of the gabion’s construction and an identification of the specific problem areas will be necessary. Repairs or reconstruction may be required to ensure the gabion functions as intended and prevents further sand erosion. Consulting with experienced engineers or construction professionals can help in assessing the situation and finding appropriate solutions,” he added.

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