Landslide Mitigation - Semi-quantitative Approaches for Landslide Assessment and Prediction - page 232

Fig. 8.5 Jhora training at
Paglajhora

The main problem in the Jhora Training is the clearance of seepage water from
the interior mass. The conduits or the holes made for the clearance of seepage water
is mainly clogged with clay and thus water cannot be allowed to drain due to lack of
proper maintenance. The subsidence and sinking of the materials are facilitated due
to storage of seepage water at the back of the concrete structure being facilitated by
the weight of the overlying materials.

8.3.3 Retaining Wall

Retaining walls are made to resist the pressure of dislodged materials or to resist the
pressure of earth filling deposited behind it after its formation. The retaining wall

should conform to the repose angle of the constituent slope materials. The repose
angle in dry condition can be easily measured by pouring the sun-dry materials
from vertical position on a near horizontal surface. At the time of the construction
of the retaining walls, the possible pressure from the back

ll, the nature of base-
ment, angle of repose and hydraulic character of the slope forming materials are to
be studied for the

fixation of depth of foundation, width and height of the berms

(steps) of the wall.
The further re ned concept of angle of internal friction may be introduced which

is approximately equal to angle of repose (Van Burkalow 1945 ) but not exactly
same as it includes the inter-granular friction as well as interlocking. The steep, high