Page 111 - Navy Journal 219

Fig 4: Types of surface erosion control measures against landslide

Anti-erosion Solutions

Drainage Technique. Drainage systems reduce the water level inside a poten-
tially unstable hillside, which leads to reduction in pore water pressures in the
ground and an increase in the shear strength within the slope. The reduction in
pore pressure by drainage can be achieved by shallow and/or deep drains,
depending on hillside morphology, the kinematics of movement predicted and
the depth of creep surfaces. Usually, shallow drainage is adopted where the
potential hillside movement is shallow, affecting a depth of 5-6m. Where there
are deeper slippage surfaces, deep drainage must be introduced, but shallow
drainage systems may also be installed, with the aim of running off surface water.

Fig 5: Shallow drainage and Deep drainage technique

Geocomposito
drenante

Tubo di fondo

Reinforcement Measure. Stabilization of a hillside by increasing the
mechanical strength of the unstable ground can be achieved in two ways. Firstly,
insertion of reinforcement elements into the ground and secondly improvement
of the mechanical characteristics of the ground through chemical, thermal or
mechanical treatment. Types of mechanical reinforcement include large diameter
wells supported by one or more crowns of consolidated and possibly reinforced

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