Shear modulus and material damping of municipal solid waste based on large-scale cyclic triaxial testing

2008 ◽  
Vol 45 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Dimitrios Zekkos ◽  
Jonathan D. Bray ◽  
Michael F. Riemer
Keyword(s):  
Shear Modulus ◽  
Large Scale ◽  
Dynamic Properties ◽  
Small Strain ◽  
Unit Weight ◽  
Material Damping ◽  
Confining Stress ◽  
Small Strain Shear Modulus ◽  
Waste Composition ◽  
Modulus Reduction

Representative dynamic properties of municipal solid waste (MSW) are required to perform reliable seismic analyses of MSW landfills. A comprehensive large-scale cyclic triaxial laboratory testing program was performed on MSW retrieved from a landfill in the San Francisco Bay area to evaluate the small-strain shear modulus, and strain-dependent normalized shear modulus reduction and material damping ratio relationships of MSW. The effects of waste composition, confining stress, unit weight, time under confinement, and loading frequency on these dynamic properties were evaluated. The small-strain shear modulus depends primarily on waste composition, confining stress, unit weight, and time under confinement. The normalized shear modulus reduction and material damping curves for MSW depend on waste composition and confining stress. Based on the results of this study and a review of literature, strain-dependent shear modulus reduction and material damping relationships are recommended for use in landfill design.

scholarly journals Determining Shrinkage Cracks Based on the Small-Strain Shear Modulus–Suction Relationship

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 362 ◽  
Author(s):  
Avishek Shrestha ◽  
Apiniti Jotisankasa ◽  
Susit Chaiprakaikeow ◽  
Sony Pramusandi ◽  
Suttisak Soralump ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Crack Depth ◽  
Small Strain ◽  
Horizontal Stress ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Confining Stress ◽  
Small Strain Shear Modulus ◽  
Shrinkage Cracks

This research aims to propose the use of spectral analysis of surface wave (SASW) tests along with in-situ suction measurements for non-destructive determination of shrinkage cracks. The underlying principle behind this proposed method is that, while suction and the small-strain shear modulus are positively correlated for intact samples, this is not the case for cracked ground. A series of SASW tests were performed on a clay embankment at different periods, during which the suction, modulus, and shrinkage crack depth varied seasonally. The soil water retention curve (SWRC) of the undisturbed sample collected from the cracked zone was determined, which related the suction-to-moisture content and void ratio of the soil. A free-free resonant frequency (FFR) test in the lab was conducted to determine the small-strain shear modulus (G0) at various moisture contents. The small-strain moduli from the SASW tests on the intact ground were generally higher than those from the FFR tests due to the effect of confining stress. A drop in the small-strain modulus determined using the SASW test was observed as an increase in suction-induced cracks and it relieved the horizontal stress. The crack depth measured in the field was then modelled using a semi-empirical procedure that can be used to predict crack depth relative to suction.

scholarly journals Nonlinear dynamic properties of silty clay from Warsaw area

2016 ◽  
Vol 48 (3) ◽  
pp. 201-220
Author(s):  
Wojciech Sas ◽  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Alojzy Szymański
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Nonlinear Dynamic ◽  
Dynamic Properties ◽  
Small Strain ◽  
Silty Clay ◽  
Resonant Column ◽  
Material Damping ◽  
Nonlinear Dynamic Properties ◽  
Low Amplitude

Abstract In this work, the small-strain and nonlinear dynamic properties of silty clay samples were studied by means of the low- and high-amplitude resonant column (RC) tests at various mean effective stresses (p’). The tested specimens were collected from the centre of Warsaw, district Śródmieście. Initially, the low-amplitude tests (below 0.001%) were conducted. Subsequently, the nonlinear testing was performed, at shearing strains greater than 0.001%. These tests were carried out in order to receive the dynamic properties of silty clay specimens in the nonlinear shear strain range. The small-strain material damping ratios (Dmin) of silty clay samples were also measured during the low-amplitude resonant column testing. The results show that increasing shear strain (γ) above the elastic threshold (γte) causes a decrease of the shear modulus (G) and normalized shear modulus (G/Gmax) of analyzed soil samples. Simultaneously, it is observed a increase of its damping ratio (D) and normalized damping (D/Dmin) with increasing shear strain (γ). Predictive equations for estimating normalized shear modulus and material damping of silty clay soils were presented here as well. The equations are based on a modified hyperbolic model and a statistical analysis of the RC tests results. The influence of unloading process on dynamic properties of the tested material was also discussed in the paper.

Effects of current suction ratio and recent suction history on small-strain behaviour of an unsaturated soil

2012 ◽  
Vol 49 (2) ◽  
pp. 226-243 ◽  
Author(s):  
C.W.W. Ng ◽  
J. Xu
Keyword(s):  
Shear Modulus ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Small Strain ◽  
Triaxial Tests ◽  
Stress History ◽  
Reduction Curve ◽  
Small Strain Shear Modulus ◽  
Suction History ◽  
Modulus Reduction

Although the small-strain shear modulus of saturated soils is known to be significantly affected by stress history, consisting of the overconsolidation ratio (OCR) and recent stress history, the effects of suction history on the small-strain shear modulus of unsaturated soils have rarely been reported. In this study, the effects of suction history, which refers to current suction ratio (CSR) and recent suction history, on both the very-small-strain shear modulus (G0) and shear modulus reduction curve of an unsaturated soil, are investigated by carrying out constant net mean stress compression triaxial tests with bender elements and local strain measurements. In addition, the effect of suction magnitude on G0 and the shear modulus reduction curve is also investigated. At a given suction, G0, elastic threshold strain (εe), and the rate of shear modulus reduction all increase with CSR. On the other hand, the effect of recent suction history on G0 is not significant. The effect of direction of recent suction path (θ) on the shear modulus reduction curve is not distinct. However, the magnitude of recent suction path (l) affects the shear modulus reduction curve significantly when θ = –90°.

Bender Element Measurement for Small-Strain Shear Modulus of Compacted Loess

2021 ◽  
Vol 21 (5) ◽  
pp. 04021063
Author(s):  
Fangtong Wang ◽  
Dianqing Li ◽  
Wenqi Du ◽  
Chia Zarei ◽  
Yong Liu
Keyword(s):  
Shear Modulus ◽  
Small Strain ◽  
Bender Element ◽  
Small Strain Shear Modulus ◽  
Compacted Loess

scholarly journals Temperature-Dependent Model for Small-Strain Shear Modulus of Unsaturated Soils

2020 ◽  
Vol 146 (12) ◽  
pp. 04020136
Author(s):  
Farshid Vahedifard ◽  
Sannith Kumar Thota ◽  
Toan Duc Cao ◽  
Radhavi Abeysiridara Samarakoon ◽  
John S. McCartney
Keyword(s):  
Shear Modulus ◽  
Unsaturated Soils ◽  
Small Strain ◽  
Temperature Dependent ◽  
Small Strain Shear Modulus ◽  
Dependent Model ◽  
Temperature Dependent Model

Shear modulus reduction and damping ratio curves for earth core materials of dams

2019 ◽  
Vol 56 (1) ◽  
pp. 14-22 ◽  
Author(s):  
DongSoon Park ◽  
Tadahiro Kishida
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Empirical Relationship ◽  
Embankment Dams ◽  
In Situ Data ◽  
Earth Core ◽  
Dynamic Analyses ◽  
Modulus Reduction ◽  
Core Materials

It is essential to obtain shear modulus reduction and damping ratio curves to perform dynamic analyses of earth-cored embankment dams. Many studies have been performed for dynamic properties of clayey soils, but they have been limited for earth core materials of dams. This study conducted resonant column tests to obtain shear modulus reduction (G/Gmax) and damping ratio (D) curves for 31 specimens (17 undisturbed and 14 remolded specimens) from 13 earth-cored embankment dams. Empirical G/Gmax and D curves are proposed for dynamic properties of clayey earth core materials. Fitting curves are provided by using the functional forms of the Ramberg–Osgood and Darendeli models. The observation shows that the undisturbed earth cores yield relatively higher G/Gmax and lower D curves than the remolded cores. G/Gmax curves of compacted earth cores are relatively higher than those of Vucetic and Dobry curves for a similar level of plasticity index. Uncertainty and bias are calculated by performing residual analysis, which shows that there is no clear bias in predicting G/Gmax and the uncertainties between undisturbed earth core materials and natural deposits are at a similar level. A proposed empirical relationship of G/Gmax and D curves for earth core materials can be utilized for dynamic analyses of embankment dams for cases where there is insufficient in situ data.

Sign in / Sign up

Export Citation Format

Share Document