scholarly journals Empirical Method for Evaluating Resilient Modulus of Saturated Silty Clay under Cyclic Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhen Zhang ◽  
Yong Chen ◽  
Guanbao Ye ◽  
Peilin Xiang ◽  
Yan Xiao ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Stress Ratio ◽  
Resilient Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Empirical Method ◽  
Traffic Load ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Test Results

Resilient modulus of soil is crucial for the design of a structure on a foundation subjected to a cyclic loading (e.g., traffic load or machine vibration load). This paper conducted a series of dynamic triaxial tests of saturated silty clay, considering the influence of the factors of cyclic stress ratio (CSR), static deviatoric stress ratio (SDR), and overconsolidation ratio (OCR) on the resilient modulus and dynamic damping ratio of the soil. A cyclic loading with a form of half sine wave was used to model the traffic loading. The results showed that the soil was prone to failure under a higher SDR, even though the applied CSR was less than the critical CSR. The saturated silty clay performed a strain softening behavior and its dynamic properties deteriorated significantly when higher CSR and SDR and lower OCR were involved. Based on the test results, an empirical method with a form of exponential function was proposed to evaluate the resilient modulus of the soil, considering the combined effects of CSR and SDR and OCR. The proposed method was verified through a comparison with the test results in this study and from literatures, and some recommendations for its application were offered.

ANALYSIS OF DYNAMIC STRESS-STRAIN RELATIONSHIP OF LOESS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5559-5565
Author(s):  
HONGJIAN LIAO ◽  
ZHIGANG ZHANG ◽  
CHUNMING NING ◽  
JIAN LIU ◽  
LI SONG
Keyword(s):  
Residual Strain ◽  
Dynamic Stress ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Constitutive Relationship ◽  
Triaxial Tests ◽  
Stress And Strain ◽  
Test Results ◽  
Relationship Model ◽  
Strain Relationship

This paper aims to study dynamic properties of loess. This study is helpful to the subject on how to avoid or decrease the seismic disasters on loess ground. Dynamic triaxial tests are carried out with saturated remoulded soil samples taken form loess sites in Xi'an, China. Dynamic stress and strain relationship as well as the rule of the accumulated residual strain are obtained from the test results. Linear relationship between accumulated residual strain and vibration circle under constant amplitude circular loading is presented. A hypothesis about the accumulated residual strain is proposed. 1D dynamic constitutive relationship model which can well describe the real relationship between dynamic stress and strain under irregular dynamic loading is established. Numerical program with this model is developed and an example is tested. Numerical results of hysteresis loop, accumulated residual strain, amplitude of dynamic stress and damping ratio show good agreement with test results. It is indicated that the hypothesis of accumulated residual strain and the 1D dynamic constitutive relationship model can accurately simulate the dynamic triaxial tests of saturated remoulded loess.

scholarly journals Multi-Scale Study of The Small-Strain Damping Ratio of Fiber-Sand Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2476
Author(s):  
Haiwen Li ◽  
Sathwik S. Kasyap ◽  
Kostas Senetakis
Keyword(s):  
Dynamic Properties ◽  
Wide Spectrum ◽  
Damping Ratio ◽  
Polypropylene Fiber ◽  
Small Strain ◽  
Treatment Method ◽  
Fiber Content ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Fiber Reinforced

The use of polypropylene fibers as a geosynthetic in infrastructures is a promising ground treatment method with applications in the enhancement of the bearing capacity of foundations, slope rehabilitation, strengthening of backfills, as well as the improvement of the seismic behavior of geo-systems. Despite the large number of studies published in the literature investigating the properties of fiber-reinforced soils, less attention has been given in the evaluation of the dynamic properties of these composites, especially in examining damping characteristics and the influence of fiber inclusion and content. In the present study, the effect of polypropylene fiber inclusion on the small-strain damping ratio of sands with different gradations and various particle shapes was investigated through resonant column (macroscopic) experiments. The macroscopic test results suggested that the damping ratio of the mixtures tended to increase with increasing fiber content. Accordingly, a new expression was proposed which considers the influence of fiber content in the estimation of the small-strain damping of polypropylene fiber-sand mixtures and it can be complementary of damping modeling from small-to-medium strains based on previously developed expressions in the regime of medium strains. Additional insights were attempted to be obtained on the energy dissipation and contribution of fibers of these composite materials by performing grain-scale tests which further supported the macroscopic experimental test results. It was also attempted to interpret, based on the grain-scale tests results, the influence of fiber inclusion in a wide spectrum of properties for fiber-reinforced sands providing some general inferences on the contribution of polypropylene fibers on the constitutive behavior of granular materials.

scholarly journals Resilient modulus and cumulative plastic strain of frozen silty clay under dynamic aircraft loading

2021 ◽  
Vol 3 (10) ◽  
Author(s):  
Xiaolan Liu ◽  
Xianmin Zhang ◽  
Xiaojiang Wang
Keyword(s):  
Plastic Strain ◽  
Resilient Modulus ◽  
Confining Pressure ◽  
Frozen Soil ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Research Findings ◽  
Cumulative Plastic Strain ◽  
Construction Operation ◽  
Compaction Degree

AbstractThis paper describes an investigation into the factors influencing the resilient modulus and cumulative plastic strain of frozen silty clay. A series of dynamic triaxial tests are conducted to analyze the influence of the temperature, confining pressure, frequency, and compaction degree on the resilient modulus and cumulative plastic strain of frozen silty clay samples. The results show that when the temperature is below − 5 °C, the resilient modulus decreases linearly, whereas when the temperature is above − 5 °C, the resilient modulus decreases according to a power function. The resilient modulus increases logarithmically when the frequency is less than 2 Hz and increases linearly once the frequency exceeds 2 Hz. The resilient modulus increases as the confining pressure and compaction degree increase. The cumulative plastic strain decreases as the temperature decreases and as the confining pressure, frequency, and compaction degree increase. The research findings provide valuable information for the design, construction, operation, maintenance, safety, and management of airport engineering in frozen soil regions.

A Study on Dynamic Properties of Cement-Stabilized Soils

2011 ◽  
Vol 243-249 ◽  
pp. 2050-2054 ◽  
Author(s):  
Pei Hsun Tsai ◽  
Sheng Huoo Ni
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Test Results ◽  
Resonant Column Test ◽  
Stabilized Soil ◽  
Shearing Strain ◽  
Relationship Of ◽  
The Relationship

In this paper the dynamic property (shear modulus and damping ratio) of cement-stabilized soil is studied with using the resonant column test. The amount of cement admixed, the magnitude of confining pressure, and shearing strain amplitude are the parameters considered. Test results show that the maximum shear modulus of cement-stabilized soil increases with increasing confining pressure, the minimum damping ratio decreases with increasing confining pressure. The shear modulus of cement-stabilized soil decreases with increasing shearing strain while the damping ratio increases with increasing shearing strain. In the paper the relationship of shear modulus versus shearing strain is fitted into the Ramberg-Osgood equations using regression analysis.

scholarly journals Experimental and Estimation Studies of Resilient Modulus of Marine Coral Sand under Cyclic Loading

2020 ◽  
Vol 8 (4) ◽  
pp. 287 ◽  
Author(s):  
Shao-Heng He ◽  
Qiong-Fang Zhang ◽  
Zhi Ding ◽  
Tang-Dai Xia ◽  
Xiao-Lu Gan
Keyword(s):  
Cyclic Loading ◽  
South China Sea ◽  
Effective Stress ◽  
South China ◽  
Stress Ratio ◽  
Resilient Modulus ◽  
Cyclic Stress ◽  
Marine Transportation ◽  
Cyclic Stress Ratio ◽  
Coral Sand

Coral sand is an important filler resource that can solve the shortage of terrestrial fillers in coastal areas. Recently, the foundations of many infrastructures in the South China Sea have been built with coral sand as fillers, which have been subjected to wave and traffic cyclic loads. Resilient modulus (Mr) is an important design parameter in marine engineering, but there are few studies on the resilient modulus response of coral sand under cyclic loading. A series of drained cyclic triaxial tests were carried out to investigate the effects of the initial mean effective stress (p0) and cyclic stress ratio (ζ) on the resilient modulus response of the coral sand from the South China Sea. The change of fractal dimension (αc) can reflect the rule of particle breakage evolution. The αc of coral sand shows a tendency of almost maintaining stable and then increasing rapidly with the increase of mean effective stress p0 under each cyclic stress ratio ζ. There is a threshold of p0, when the p0 exceeds this threshold, αc will increase significantly with the increase of p0. The increase of p0 has a beneficial effect on the improvement of the Mr, while the increase of ζ has both beneficial and detrimental effects on the improvement of the Mr. A new prediction model of the Mr considering particle breakage was established, which can better predict the Mr of coral sand in the whole stress interval. The research results can provide guidance for the design of marine transportation infrastructures, which can promote the development of marine transportation industry and energy utilization.

scholarly journals Enhancing Vibration Reduction on Lightweight Lower Control Arm

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Alessandro Messana ◽  
Alessandro Ferraris ◽  
Andrea G. Airale ◽  
Alessandro Fasana ◽  
Massimiliana Carello
Keyword(s):  
Mechanical Performance ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Vibration Reduction ◽  
Design Procedure ◽  
Test Results ◽  
Hybrid Lca ◽  
Original Solution ◽  
Lower Control Arm ◽  
Real Behavior

This paper describes the design procedure to enhance the damping properties of a multimaterial lightweight suspension arm for a C-segment vehicle. An innovative viscoelastic material has been used to join carbon fiber with steel that has a function of passive constrained layer damper and adhesive simultaneously. Therefore, the hybrid technology applied has been focused on reducing the LCA mass, diminishing the steel thickness, and adding a CFRP tailored cover without compromising the global mechanical performance. Particular attention has been paid to the investigation of the dynamic response in terms of vibration reduction, especially in the range of structure-borne frequencies of 0–600 Hz. Two different viscoelastic materials have been evaluated in such a way to compare their stiffness, damping, and dynamic properties. The experimental test results have been virtually correlated with a commercial FEM code to create the respective material card and predict the real behavior of the LCAs (original and hybrid). The experimental modal analysis has been performed and compared on both the arms highlighting a very good correlation between virtual and experimental results. In particular, the hybrid LCA allows an interesting improvement of damping ratio, about 3,5 times higher for each eigenmode than in the original solution.

scholarly journals Dynamics of Biochar-Silty Clay Interaction Using In-House Fabricated Cyclic Loading Apparatus: A Case Study of Coastal Clay and Novel Peach Biochar from the Qingdao Region of China

2020 ◽  
Vol 12 (7) ◽  
pp. 2599 ◽  
Author(s):  
Junwei Liu ◽  
Suriya Prakash Ganesan ◽  
Xin Li ◽  
Ankit Garg ◽  
Aman Singhal ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Shear Modulus ◽  
Dynamic Behavior ◽  
Void Ratio ◽  
Water Pressure ◽  
Damping Ratio ◽  
Cyclic Strength ◽  
Silty Clay ◽  
Amended Soils ◽  
Amended Soil

Biochar has been recently investigated as an eco-friendly material in bio-engineered slopes/landfill covers. A majority of recent studies have focused on analyzing water retention behavior while very few have examined dynamic behavior (i.e., cyclic loading due to earthquake, wind, or wave) of biochar amended soil. As far as the authors are aware, there is no study on the dynamic behavior of biochar amended soils. Considering the above mentioned study as a major objective, field excavated soil was collected and mixed with in-house produced biochar from peach endocarps, at three amendment rates (5%, 10%, and 15%). The un-amended bare soil and biochar amended soil were imposed to a cyclic load in a self-designed apparatus and the corresponding stress-strain parameters were measured. Dynamic parameters such as shear modulus and damping ratio were computed and the results were compared between bare and biochar amended soil. Furthermore, the residual cyclic strength of each soil types were correlated with an estimated void ratio to understand the interrelation between dynamic loading responses and biochar amended soils. The major outcomes of this study show that the addition of biochar decreases the void ratio, thereby increasing the shear modulus and residual cyclic strength. However, the modulus and strength values attenuates after 15 cycles due to an increase in pore water pressure. In contrary, at higher amendment rates, Biochar Amended Soils (BAS) forms clay-carbon complex and decreases both shear modulus and residual cyclic strength.

scholarly journals Laboratory Characterization of a Compacted–Unsaturated Silty Sand with Special Attention to Dynamic Behavior

2020 ◽  
Vol 10 (7) ◽  
pp. 2559
Author(s):  
Andrzej Głuchowski ◽  
Zdzisław Skutnik ◽  
Marcin Biliniak ◽  
Wojciech Sas ◽  
Diego Lo Presti
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Silty Sand ◽  
Triaxial Tests ◽  
Bender Element ◽  
State Dependent ◽  
Laboratory Characterization ◽  
Dynamic Excitations

The dynamic properties of compacted non-cohesive soils are desired not only because of the risk of natural sources of dynamic excitations such as earthquakes, but mostly because of the anthropogenic impact of machines that are working on such soils. These soils are often unsaturated, which positively affects the soil’s mechanical properties. The information about the values of these parameters is highly desirable for engineers. In this article, we performed a series of tests, including oedometric tests, resonant column tests, bender element tests, and unsaturated triaxial tests, to evaluate those characteristic parameters. The results showed that sandy silt soil has a typical reaction to dynamic loading in terms of shear modulus degradation and the damping ratio curves’ characteristics, which can be modeled by using empirical equations. We found that the compaction procedure caused an over-consolidation state dependent on the moisture content during compaction effort. The article analyzed the soil properties that impact the maximum shear modulus G0 value. Those properties were suction s, confining pressure σ3, and compaction degree represented by the void ratio function f(e).

scholarly journals Effect of Sand Fouling on the Dynamic Properties and Volume Change of Gravel During Cyclic Loadings

2020 ◽  
Author(s):  
Meysam Bayat
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Dynamic Behavior ◽  
Volume Change ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Practical Applications ◽  
Large Shear Strain

Understanding the factors that influence the dynamic behavior of granular soils during cyclic loading is critical to infrastructure design. Previous research has lacked quantitative study of the effects of fouling index (FI), mean effective confining pressure, relative density, shear strain level and anisotropic consolidation, especially when the effective vertical stress is lower than the effective horizontal stress on the dynamic behavior of gravelly soils. The objective of the present study was to evaluate the dynamic behavior and volume change of both clean and fouled specimens for practical applications. To this end, cyclic triaxial tests with local strain measurements under both isotropic and anisotropic confining conditions were conducted. It is found that the fouled specimen with 50 % sand (i.e. the specimen which contains 50 % gravel and 50 % sand) has the highest shear modulus at low shear strain levels and the largest volume reduction and damping ratio at large shear strain levels. The results of tests indicate that the effect of fouling index on the shear modulus is reduced at large shear strain levels. Volumetric contraction due to the increase in mean effective confining pressure is more significant at large shear strain levels. The results also indicate that the stiffness of the specimens under anisotropic compression mode are larger than those in extension or isotropic mode.

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