| Summary: | 碩士 === 國立中央大學 === 土木工程學系 === 86 === In foundation design, the formation of the mat foundation is a
popular one in Taiwan, especially in urban area. It can reduce
the net soil pressure and foundation settlement, and has deeper
embedment than the embedment of the combined footing. The cells
enclosed by grid floor beams can be used as the tank of drinking
water, fire protecting water, sanitary water, and the space of
parking. Conventional design method treats the mat foundation as
a rigid body, neglects the true flexibility of the mat
foundation, and assumes that the contact soil pressure
distributes linearly. In case of high building structure rests
on soft soil stratum, the result may become conservative. The
foundation design method is gradually replaced by the analysis
of Winkler subgrade model, ( Coefficient of the subgrade
reaction), the stiffness of the soil spring (A is the
distributive area of the spring of soil ), thus we could analyze
the stresses of members of structure when we got the soil and
structure stiffness using computer software after the techniques
of CAD(Computer Aided Design) was well developed.Coefficient of
the subgrade reaction can be obtained by experimental formula or
from site loading test. However, coefficient of the subgrade
reaction is a function that lies between the properties of the
soil and structure. It depends on the soil and structure
stiffness, the depth of the soil stratum, the size of the
foundation, and the distribution of the loads on the
foundation. Moreover, it is not a constant value for the whole
region under the mat foundation. This paper investigates the
distribution of soil reactions in the interaction between soil
and foundation under external loading considering the linear and
nonlinear soil materials by three dimensional finite element
method.
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