Cementation and bond degradation of rubber–sand mixtures

2010 ◽  
Vol 47 (7) ◽  
pp. 763-774 ◽  
Author(s):  
Changho Lee ◽  
Q. Hung Truong ◽  
Jong-Sub Lee
Keyword(s):  
Elastic Wave ◽  
Rubber Particle ◽  
Small Strain ◽  
Vertical Stress ◽  
Body Waves ◽  
Interparticle Contact ◽  
Stress Strain ◽  
Vertical Loading ◽  
Wave Velocities ◽  
Bond Degradation

Cementation influences the mechanical behavior of soils. The effects of cementation and bond degradation are investigated for lightly cemented rigid sand and soft rubber particle mixtures subjected to vertical loading under the K0 condition. Cemented and uncemented specimens were prepared with various sand volume fractions. The propagation velocity of small strain body waves was measured by piezo materials, incorporated within an oedometer. Cemented specimens exhibited a bilinear behavior in the semi-log plot (vertical strain versus log of vertical stress). Vertical strains of a cemented specimen normalized by an uncemented specimen show that the stress–strain behavior is controlled by several different mechanisms and forces: capillary force, cementation bonds, and interparticle contact stresses after bond degradation. The elastic wave velocities dramatically increase due to cementation hardening under fixed vertical stress, and are constant after curing even though vertical stress increases. Additional loading of the vertical effective stress decreases the elastic wave velocities due to bond degradation. The shear wave velocity presents three behavior regions as a function of the sand fraction for both uncemented and cemented specimens: rubber-like, sand-like, and transition behaviors. The vertical stress–strain response and the elastic wave velocities can serve as indicators of cementation and bond degradation.

scholarly journals Evaluation of Compressive Strength and Stiffness of Grouted Soils by Using Elastic Waves

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
In-Mo Lee ◽  
Jong-Sun Kim ◽  
Hyung-Koo Yoon ◽  
Jong-Sub Lee
Keyword(s):  
Elastic Wave ◽  
Elastic Waves ◽  
Large Strain ◽  
Small Strain ◽  
Test Results ◽  
Wave Velocities ◽  
Strength Tests ◽  
Soil Media ◽  
Strength And Stiffness ◽  
Particulate Soil

Cement grouted soils, which consist of particulate soil media and cementation agents, have been widely used for the improvement of the strength and stiffness of weak ground and for the prevention of the leakage of ground water. The strength, elastic modulus, and Poisson’s ratio of grouted soils have been determined by classical destructive methods. However, the performance of grouted soils depends on several parameters such as the distribution of particle size of the particulate soil media, grouting pressure, curing time, curing method, and ground water flow. In this study, elastic wave velocities are used to estimate the strength and elastic modulus, which are generally obtained by classical strength tests. Nondestructive tests by using elastic waves at small strain are conducted before and during classical strength tests at large strain. The test results are compared to identify correlations between the elastic wave velocity measured at small strain and strength and stiffness measured at large strain. The test results show that the strength and stiffness have exponential relationship with elastic wave velocities. This study demonstrates that nondestructive methods by using elastic waves may significantly improve the strength and stiffness evaluation processes of grouted soils.

scholarly journals Estimation of the Small-Strain Stiffness of Clean and Silty Sands using Stress-Strain Curves and CPT Cone Resistance

2009 ◽  
Vol 49 (4) ◽  
pp. 545-556 ◽  
Author(s):  
Junhwan Lee ◽  
Doohyun Kyung ◽  
Bumjoo Kim ◽  
Monica Prezzi
Keyword(s):  
Small Strain ◽  
Stress Strain ◽  
Cone Resistance ◽  
Small Strain Stiffness

Factors affecting at-rest lateral stress in artificially cemented sands

1995 ◽  
Vol 32 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Fanyu Zhu ◽  
Jack I. Clark ◽  
Michael J. Paulin
Keyword(s):  
Cement Content ◽  
Vertical Stress ◽  
Specimen Preparation ◽  
Test Results ◽  
Lateral Stress ◽  
Stress History ◽  
Cemented Sand ◽  
Vertical Loading ◽  
Cemented Sands ◽  
Dry Sand

This paper presents the results of a laboratory study on the at-rest lateral stress and Ko of two artificially cemented sands. A modified oedometer ring was used to measure the lateral stress of cemented and uncemented sands. Test materials were No. 3 Ottawa sand and a marine sand with Portland cement. The specimens were prepared using the method of undercompaction to minimize the influence of specimen preparation on test results. The cement contents were 0, 0.5, 1.0, 2.0, 4.0, and 8.0% by the weight of dry sand. The water content of the specimens was 4% of the weight of dry sand and cement. When the sands were cured under zero confining pressure, the test results indicated the following: the at-rest lateral stress in cemented sands decreases significantly with increasing cement content; the relationship between the vertical and at-rest lateral stress is nonlinear and the value of Ko increases with increasing vertical stress; and the lateral stress decreases with sand density and curing period. When the specimens were cured under vertical stress, the value of Ko during the removal of vertical loading increased with both overconsolidation ratio and cement content. Stress history has a significant influence on the behaviour of at-rest lateral stress in cement sands. Key words : cemented sand, Ko, lateral stress, overconsolidation, stress history.

Assessing rock brittleness and fracability from radial variation of elastic wave velocities from borehole acoustic logging

2016 ◽  
Vol 64 (4) ◽  
pp. 958-966 ◽  
Author(s):  
Xiao-Ming Tang ◽  
Song Xu ◽  
Chun-Xi Zhuang ◽  
Yuan-Da Su ◽  
Xue-Lian Chen
Keyword(s):  
Elastic Wave ◽  
Radial Variation ◽  
Acoustic Logging ◽  
Wave Velocities ◽  
Rock Brittleness

Elastic Wave Velocities in Laminated Media

1954 ◽  
Vol 26 (5) ◽  
pp. 949-949
Author(s):  
J. E. White ◽  
F. A. Angona
Keyword(s):  
Elastic Wave ◽  
Wave Velocities

A New Nonlinear Stress-Strain Model for Soils at Various Strain Levels

2013 ◽  
Vol 631-632 ◽  
pp. 782-788
Author(s):  
Cheng Chen ◽  
Zheng Ming Zhou
Keyword(s):  
Compression Test ◽  
Triaxial Compression ◽  
Small Strain ◽  
Empirical Formulas ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Proposed Model ◽  
Nonlinear Stress ◽  
London Clay ◽  
Strain Model

Soils have nonlinear stiffness and develops irrecoverable strains even at very small strain levels. Accurate modeling of stress-strain behaviour at various strain levels is very important for predicting the deformation of soils. Some existing stress-strain models are reviewed and evaluated firstly. And then a new simple non-linear stress-strain model is proposed. Four undetermined parameters involved in the proposed model can be obtained through maximum Young’s module, deformation module, and limit deviator stress and linearity index of soils that can be measured from experiment directly or calculated by empirical formulas indirectly. The effectiveness of the proposed stress-strain model is examined by predicting stress-strain curves measured in plane-strain compression test on Toyota sand and undrained triaxial compression test on London clay. The fitting results of the proposed model are in good agreement with experimental data, which verify the effectiveness of the model.

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