Environmental Engineering Reference
In-Depth Information
12
Sustainable Ground Improvement
Technique for Geo-Disaster Mitigation
12.1 Introduction
One of the major set of challenges in the constructed environment is the problem of
ground incompetence such as inability of the natural ground to provide proper support-
ing capability for overlying structures, and vulnerability of slopes and ground to cata-
strophic ground movement due to metastability of the soil mantle. Failure to recognize the
challenges or failure to properly account for potential hazardous and catastrophic natural
or anthropogenic events can lead to geo-disasters. Chapter 10 has deined geo-disasters as
disasters that occur in the land compartment of the geoenvironment as a result of natural
and human-associated catastrophic events such as earthquakes, loods, hurricanes, land-
slides, embankment and dam failures, etc.
To overcome deiciencies in ground support capability, or to strengthen the capability of
the soil mantle to withstand the physical forces resulting from hazardous and catastrophic
events, ground improvement techniques have been devised—the intent of which are to
strengthen the ground (soil mantle) so as to provide the proper resistance to undesirable
and unplanned ground and soil movement. The discussion in this chapter is the use of
a new innovative and sustainable technique for ground improvement to withstand the
stressors resulting from the geo-disasters, and hence to prevent or mitigate geo-disasters.
The basis for the new innovative technique discussed in this chapter requires a brief
review of the natural processes involved in producing the type of ground conditions that
are resistant or vulnerable to geo-disaster stressors.
12.2 Soil Origin and Stability
The underlying basis for the new innovative technique for sustainable ground improve-
ment is the phenomenon of diagenesis . Diagenesis is a critical factor in a geological cycle that
one could call rock-soil-rock cycle. To understand what natural processes are involved in
soil formation from rocks and how these processes can be exploited to improve ground
stability, it is useful to take note of the three processes that are involved in the formation
of soil from rocks and the formation of rocks from soils, i.e., weathering, diagenesis, and
metamorphism. The relationship between the three processes—weathering, diagenesis,
and metamorphism—for rock and soil are shown in schematic illustration in Figure 12.1.
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