Geoscience Reference
In-Depth Information
Volumetric strain pent.qpc
10
1
Consolidated
under 50 kPa
10
0
100 kPa
10
−1
Sequence 1
2
3
4
10
−2
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Explosives (kg)
Fig. 15.16. Comparison of volumetric strainafter undrained cyclic loading
and dissipationof excess pore water pressure
Fig. 15.17. Distortionof liquid storage tanks due tosubsoilliquefaction (Kobe, 1995)
Being different from cement mixing, the use of grouting for soil improvement has been
limitedtoshort-termimprovement.Thereasonswhyitspermanentusewasdifficultwere
weathering and deterioration of the properties of improved soil, accidents in the past
that injected liquid contaminated well water and affected human health, and difficulty in
uniform seeping.
Among these, the third issue means that concerned soil has to be improved uniformly
(Figure 15.18); improvement only in cracks is not accepted. After 1990s, a new kind of
colloidal silica emerged in the market and overcame the abovementioned problems. For
example, Figure15.19 illustrates the long-term stability of the mechanical properties of
grouted sand.
