A Study on the Analysis Method of Soil Layer Seismic Response in Seasonal Frozen Site

2012 ◽  
Vol 238 ◽  
pp. 872-875
Author(s):  
Zhuo Shi Chen ◽  
Shang Jiu Meng ◽  
Yu Run Li ◽  
Long Wei Chen

The analysis of ground motion on seasonal frozen soil mainly focused on the conventional soil, neglecting the impact of the permafrost which causes the obvious defeats in the existed calculation procedure. In this paper, the author proposed that we should apply the field test of shear wave velocity to the soil layer response calculation, improve the test method of dynamic shear modulus, and adopt the regular analysis method of soil layer response to the calculation of frozen soil site.

1996 ◽  
Vol 33 (3) ◽  
pp. 510-514 ◽  
Author(s):  
M O Al-Hunaidi ◽  
P A Chen ◽  
J H Rainer ◽  
M Tremblay

The resonant-column test method was used in this study to determine the dynamic shear moduli and damping ratios of frozen and unfrozen soil samples. Naturally frozen soil specimens were obtained in-situ during the winter. A series of tests were carried out on the frozen soil specimens in a cold room at –9°C. The same specimens, after allowing them to thaw, were then tested at room temperature. Test results show that at low-amplitude shear stains the damping ratio of frozen soil specimens is roughly twice that of unfrozen samples. In addition, the dynamic shear modulus for soil specimens while frozen is significantly greater (30 or 50 times) than that of unfrozen specimens. These results provide a basis for explaining an observation that bus-induced vibrations in buildings while the top soil is frozen in winter are about one-half those induced while the soil is not frozen. Key words: resonant-column test, shear modulus, damping ratio, frozen soil, ground vibration.


2011 ◽  
Vol 243-249 ◽  
pp. 2250-2253 ◽  
Author(s):  
Jing Sun ◽  
Xiao Ming Yuan ◽  
Mao Sheng Gong

The dynamic shear modulus (DSM) is the most basic soil parameter in earthquake or other dynamic loading conditions and can be obtained through testing in the field and in the laboratory. By using the resonant column tests, the effect of the consolidation ratios on the nonlinear behavior of DSM versus the shear strain, G/Gmax-γ, for two types of sands and fourteen types of undisturbed silty soil is investigated and its effect on the surface response spectrum is presented in the paper. The results here indicate that consolidation ratios have certain effect on the shape of the nonlinear behavior of DSM versus the shear strain and G/Gmax increases with increasing of the consolidation ratios. By comparing to the isotropic consolidation, the consideration for the actual anisotropic consolidation makes the acceleration peak amplitude increase and makes the characteristic period decrease. For the incidence of the strong seismic excitation, the effect of the anisotropic consolidation on earthquake ground motion should be considered.


2011 ◽  
Vol 105-107 ◽  
pp. 1426-1432 ◽  
Author(s):  
De Gao Zou ◽  
Tao Gong ◽  
Jing Mao Liu ◽  
Xian Jing Kong

Two of the most important parameters in dynamic analysis involving soils are the dynamic shear modulus and the damping ratio. In this study, a series of tests were performed on gravels. For comparison, some other tests carried out by other researchers were also collected. The test results show that normalized shear modulus and damping ratio vary with the shear strain amplitude, (1) normalized shear modulus decreases with the increase of dynamic shear strain amplitude, and as the confining pressure increases, the test data points move from the low end toward the high end; (2) damping ratio increases with the increase of shear strain amplitude, damping ratio is dependent on confining pressure where an increase in confining pressure decreased damping ratio. According to the test results, a reference formula is proposed to evaluate the maximum dynamic shear modulus, the best-fit curve and standard deviation bounds for the range of data points are also proposed.


2017 ◽  
Vol 14 (5) ◽  
pp. 1072-1086 ◽  
Author(s):  
Dongqing Li ◽  
Jianxin Wei ◽  
Bangrang Di ◽  
Pinbo Ding ◽  
Da Shuai

2011 ◽  
Vol 374-377 ◽  
pp. 1391-1395
Author(s):  
Xue Song Lu ◽  
Wei Xiang

Based on the red clay of Wuhan reinforced by Ionic Soil Stabilizer, the red clay soil is treated by different matches of ISS at first, then is tested in the Atterberg limits test and dynamic triaxia test. The results show that the plastic index decreases, and the red clay were greatly improved under the dynamic condition, the maximum dynamic shear modulus ratio acquired an incensement of 27.72% on average after mixing the ISS into the red clay. In addition, It was concluded that the confining pressure influenced the dynamic shear modulus and damping ratio to a certain extent. Given the same strain conditions, with the incensement of confining pressure increases, the dynamic shear modulus increased and the damping ratio decreased. Moreover, when plotting the dynamic shear modulus versus the dynamic shear strain, the similar curve can be formed for both the natural soil and the modified one, the dynamic shear modulus monotonously decreased with the incensement of the dynamic shear strain. However, the value of dynamic shear modulus differed in the same shear strain between the natural soil and the soil modified by ISS.


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