*
Prone to occur on steep slope and cliff.
Figure 5.3
Typical Rock Slope Collapse
5 - 6
Guidebook for Road Construction and Maintenance Management
5.2.3 Landslide
Landslide refers to all types of slope failures and defined as movement of a large mass of
soil and/or rocks.
Charateristics of a landslide are as follows:
*
A portion of the road bulges up by an inch or more.
*
It is triggered by water infiltration and/or earthquake.
*
Materials are soil and highly weathered rocks.
*
It usually occurs on a gentle and irregular mountain slopes.
*
The volume involved is generally more than 5000 cubic meters.
Figure 5.4
Typical Landslide
Guidebook for Road Construction and Maintenance Management
5 - 7
5.2.4 Road Slip
*
Road
slip
occurs
because
of
the
collapse/scouring/caving-in of the valley side
slope of the roadway.
*
Occurs mostly on road shoulder.
*
Occurs mostly along stream bends.
*
Mostly induced by infiltration/leakage of water
from road surface/damaged drainage facilities.
*
Materials are soil and highly weathered rocks.
Figure 5.5
Road Slip
Figure 5.6
Typical Road Slip
5.2.4.1 Road Slip Process
Infiltration of rainfall through the cracks accelerates the process of slipping.
Monitoring of these cracks and preventive measures to reduce road slip risks are
necessary such as filling of cracks with impervious materials. A typical process of the
development of open cracks on a shoulder slope is shown in Figure 5.7.
Expansion
→
Sliding/displacement
→
Compression
Figure 5.7
Stages of Road Slip
