| Summary: | 碩士 === 國立中央大學 === 土木工程學系 === 85 === The method of quicklime pile has been proved to be very
effective instabilizing the soft soil ground with high water
content.The bearing capacity of the soil ground can be raised ,
the settlementcan be reduced and the mechanical properties can
be improved.Despiteof these facts,the theoretical study of this
method is still not enough. In particular,there are few
literatures about the variationsof pore water pressure of the
composite soil and the lateral expansionpressure and
displacement of the pile during the chemical and mechanical
reactions of the quicklime pile.Besides, the residue settlement
of the soil ground can*t be estimatedeffectively in analytic and
designing process. So, this research describesexperimental
results about expansion consolidation behavior of composite soil
treated by quicklime piles, and provides a method to estimate
the settlement of ground. We can apply the results for analysis
and in situ construction. The soil we study in this research
is the silty clay of the Taipei basin and the material used in
the soil improvement is thequicklime powder.A series of
laboratory tests are carried out. The remolded soil sample is
firstly preconsolidated, and it is drilled to creat a
cylindrical hole in the center. The quicklime powder is filled
into the hole and the slaked reaction starts. Then the test data
is collected and a series of analyses isdone according to
different conditions of improvement. The experimental data shows
that the improvement effects of the quicklime plie on the soil
sample is obvious. These include the reduction of the resiude
settlement and improve the consolidationproperties . Even if the
soil sample is subjected to the stress increase and is drown
with water, the total improvement effect of it is still
satisfactory. This shows that the quicklime pile has a high
stability in treating soft soil ground. The stability is gained
from the slaked reaction, which makes the bonding forces between
the soil grains increase.Moreover, the gel of calcium silicate
created in the slaked reaction can help to solidify the soil and
raise its stiffness, such that the affinity between the soil and
the water as well as the sensitivity of the stress variationare
reduced. In this way the engineering properties of the
soilsample are improved. In addition, this research also
includes a theoretical study, which considering the chemical
reaction of the quicklime material, the phase reaction of the
soil, and the improvement conditions A theoretical model for
estimating the resuide settlement is proposedafter we have
considered the water content reductions. The estimatingequation
can be used in design and construction.
|
|---|
