Relationship between Young’s modulus and effective Young’s modulus|岩土工程数值方法与理论 - Page 2 - 领先的岩土技术社区，岩土领域的媒体、社区与应用平台！

离线daniellb1023

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只看该作者 12楼发表于: 2007-09-01

引用第10楼mano于2007-09-01 05:06发表的 : @f`s%o
The soil displacement is mainly based on the soil stiffness (Young's Modulus E), drainage condition and stress distribution.
For Clay, the poisson's ratio varies from 0.4 to 0.2 (soft clay to stiff clay), meanwhile the stiffness(E) from 1-15MPa to 30-100MPa. The poisson's ratio decrease with stiffness increase, the dispalcement will be smaller with the same stress level;
For sand, the poisson's ratio varies from 0.15 to 0.35 (loose sand to dense sand), the E from 10-20 MPa to 40-80 MPa, obviously, the settlement is bigger in loose sand with smaller poisson's ratio. sjG@4Or
.......

oh, thanks..... it does help me a lot.

so from your explaination. i can understand the value for "v" clearly.
i understand if the soil is "sand" the "v" value is increase if the soil is better. however the value is decrease in "clay" soil.

but may i know, if is undrain condition. what is the standard/typical "v" value ?

i understand the soil displacement is gover by a lot of condition. However, my opinion is, if "v" can also change this, i will play on it. because minor people here will question on this value, However, if i change the "E" value,they may comment on it.

thanks

离线mano

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只看该作者 13楼发表于: 2007-09-01

To daniellb1023:

The undrained condition, the soil is uncompressible, what's the value for "v"?

You may take a look some textbook and find out!

离线daniellb1023

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只看该作者 14楼发表于: 2007-09-01

i understand if the soil is undrained saturated clays/silts, the v value is 0.5, however, if the soil is not 100% saturated, what is the suggested value ? below 0.5 but larger than the drain value..? or.....?

thanks

离线daniellb1023

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只看该作者 15楼发表于: 2007-09-01

and .....

i understand that the saturated undrain soil is uncompressiable, the volume no change. However, may i know how to calculate step to get the "v" value is 0.5? (i know v = ey/ex.........but how to get ey/ex = 0.5 based on "uncompressiable" defination.)
\
thanks

离线mano

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只看该作者 16楼发表于: 2007-09-02

From Hook's law:
Total volume change=ex+ey+ez=(1-2v)ex
If Total volume change=0, ----->1-2v=0
So, v=0.5

离线mano

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只看该作者 17楼发表于: 2007-09-02

Whether the soil is saturated or not is related to water table, not the water content in the original soil.

Remember, the drained and undrained condition are based on time(drainage time, rate of applying external load).

离线yabby

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只看该作者 18楼发表于: 2007-10-15

看看，学学英文

I'm from GeoHohai.

离线gcoast

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只看该作者 19楼发表于: 2008-05-27

good artical to read, Many thanks

离线georgexue

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只看该作者 20楼发表于: 2008-05-27

E and E' will depend on the v value. meanwhile, these two value are all related to the current stress status. modified cam clay model may explain it very well.

离线wangshimin

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只看该作者 21楼发表于: 2008-06-03

thanks ....may i know what is the reference book's name?

may i conclude that, the "v "value is related to soil parameter, and for good soil "v" value is smaller? and in Plaxis input, if the "v" value is smaller, the soil deformation is samller?

thanks