scholarly journals Strength and Compressibility of Ammonia-Soda Residue from the Solvay Sodium Plant

2021 ◽  
Vol 11 (23) ◽  
pp. 11305
Author(s):  
Jakub Zięba ◽  
Przemysław Rzepka ◽  
Bartłomiej Szczepan Olek
Keyword(s):  
Confining Pressure ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Initial Void Ratio ◽  
Undisturbed Samples ◽  
Constant Rate ◽  
Natural Water Content ◽  
Engineering Parameters ◽  
Strain Space ◽  
Different Levels

This work presents the discussion of the results for an experimental study conducted to characterise the mechanical behaviour of ammonia-soda residue (ASR). The calcareous sludge is an alkaline waste formed during the production of soda ash and deposited at the area of the former Solvay Sodium Plant factory in Krakow, Poland. Isotropically consolidation drained (CID) triaxial tests and constant rate of strain (CRS) consolidation tests include the full saturation with water, completion of the consolidation, and the loading/strain rate choice. For this purpose, ASR undisturbed samples were collected from the ground and submitted to laboratory experiments. These samples show a distinct difference in the initial bulk density, the initial level of compaction, initial void ratio, and the natural water content. The CD triaxial tests were conducted under three different levels of confining pressure; in turn, CRS tests were run with two appropriate input strain rates. According to the physical state of ASR and the depth of sampling, two different evolutions of the critical state in the stress–strain space were observed. In the light of the assessed stress–strain–strength behaviour, key design engineering parameters of ASR were calculated.

Stress–strain behaviour of weathered weak rock in middle-sized triaxial tests

2006 ◽  
Vol 43 (10) ◽  
pp. 1096-1104 ◽  
Author(s):  
De'an Sun ◽  
Tugen Feng ◽  
Hajime Matsuoka
Keyword(s):  
Triaxial Test ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Weak Rock ◽  
Test Results ◽  
Compression Tests ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Undisturbed Samples ◽  
Strain Relationship

A middle-sized triaxial test apparatus for a specimen 20 cm in height and 10 cm in diameter was developed to measure the deformation and strength of weak rock or gravel. High-quality undisturbed samples of a weathered weak rock were taken from a dam site by a core drilling method. To avoid damage to the structure of the weak rock due to saturation of specimens as a result of measuring volume change through the water change in a burette, the lateral deformation of specimens was directly measured in the unsaturated condition using three rings mounted on the specimen. Using the developed triaxial test apparatus, isotropic compression tests and consolidated–drained triaxial compression tests were performed on unsaturated or saturated undisturbed samples under confining pressures of 49, 98, 196, 392, 539, and 683 kPa. The test results show that the stress–strain relationship of the weathered weak rock under both unsaturated and saturated conditions is strongly influenced by the confining pressure when the confining pressure is less than 392 kPa, and the stress–strain behaviour becomes similar to that of normally consolidated clay when the confining pressure is greater than 392 kPa. Comparison of results of triaxial tests on unsaturated and saturated specimens shows that the saturated samples become somewhat weak. The test results also show that the bonding and stress history largely influence the stress–strain relationship at small strain levels.Key words: weathered weak rock, microstructure, undisturbed sample, deformation, strength, triaxial test, unsaturated sample.

Experimental Study on Parameters of Duncan-Chang Model for Cement-Soil

2013 ◽  
Vol 641-642 ◽  
pp. 403-409
Author(s):  
Cai Fu Qian ◽  
Xin Jiang Song ◽  
Jie Wu ◽  
Wei Li
Keyword(s):  
Experimental Study ◽  
Calculation Method ◽  
Confining Pressure ◽  
Elastic Theory ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Pressure Decrease ◽  
Cement Soil ◽  
Nonlinear Elastic ◽  
Chang Model

The conventional triaxial tests for cement-soil show stronger soften characteristics of cement-soil under low confining pressure. The soften character is weaken as confining pressure decrease. For adopting Duncan-Chang hyperbola model to obtain parameters of cement-soil, the model cannot include the stress-strain soften characteristics of cement-soil, and must be discussed. The paper studies on parameters of Duncan-Chang model using generalized Hooke law and nonlinear elastic theory. The researches show the parameters of k and n are unrelated to soften characteristics of cement-soil; the relation of Rf and σ3 is given by the soften characteristics, Rf influence the soften process directly. The calculation method could be used in E-u model, and has good practical value.

scholarly journals A Nonlinear Constitutive Model for Disintegrated Carbonaceous Mudstone Based on Logarithmic Functions

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiang Qiu ◽  
Jinhong Li ◽  
Huangbin Jiang ◽  
Hongyuan Fu ◽  
Shun Yang
Keyword(s):  
Constitutive Model ◽  
Axial Strain ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Triaxial Tests ◽  
Lateral Strain ◽  
Logarithmic Function ◽  
Stress Strain ◽  
Nonlinear Constitutive Model ◽  
Nonlinear Stress

To study the mechanical characteristics of the disintegrated carbonaceous mudstone (DCM), consolidated drained triaxial tests were conducted on the DCM with three degrees of compaction (i.e., 90%, 93%, and 96%). Then, the nonlinear constitutive model suitable for the DCM was established based on test results using a logarithmic function. The stress-strain characteristics of the DCM were analyzed. The results revealed that the axial strain of the DCM was positively correlated with the deviatoric stress and lateral strain. The slopes of deviatoric stress-axial strain curves decreased with the increase of axial strain and so did the slopes of the axial strain-volumetric strain curves. The strength of the DCM increased with the increase of the confining pressure and the degree of compaction. In addition, the axial strain induced by dilatancy was also positively correlated with the degree of compaction and the confining pressure. Furthermore, under triaxial loading conditions, the relationship between the stress and strain of the DCM can be expressed by a logarithmic function; based on this, a nonlinear constitutive model with ten material parameters was derived. In addition, the results of numerical tests using the model showed similar stress-strain characteristics of the DCM comparing with the triaxial tests. Hence, it indicated that the nonlinear constitutive model based on the logarithmic function can reflect the nonlinear stress-strain characteristics of the DCM.

Modified Duncan-Chang Model Considering Physical Properties of Saturated Clays

2013 ◽  
Vol 416-417 ◽  
pp. 1746-1752
Author(s):  
Xing Chen Wang ◽  
Ri Qing Xu ◽  
Jing Lin Qian
Keyword(s):  
Physical Properties ◽  
Void Ratio ◽  
Confining Pressure ◽  
Deviatoric Stress ◽  
Plasticity Index ◽  
Test Results ◽  
Stress Strain ◽  
Initial Void Ratio ◽  
Proposed Model ◽  
Chang Model

A series of undrained triaxial compression tests of saturated clays under different conditions were performed to study whether it is possible to determine parameters specifying Duncan-Chang model simply by using the physical parameters. The test results show that both the initial tangent modulus and peak deviatoric stress decrease with increasing initial void ratio and plasticity index of the soil under the same confining pressure. Whereas, they increase with increasing confining pressure of the soil with the same initial void ratio and plasticity index. A new synthesized physical parameter λ is defined based on the test results in this work. The functional relationships among the parameters K, peak deviatoric stress in Duncan-Chang model and the parameter λ are established to develop a modified Duncan-Chang model by considering physical properties of soil. In this model, only two input parameters, i.e., λ and the damage ratio Rf, are needed to predict the stress-strain relationships of the soil. In order to check the accuracy of the proposed model, laboratory tests were conducted to evaluate against the predicted results. The results show that the stress-strain relationships of saturated clays can be well described by the proposed model.

Experimental Study on Shear Strength Characteristics and Stress-Strain Relationship of Loess

2013 ◽  
Vol 535-536 ◽  
pp. 574-577 ◽  
Author(s):  
Bo Han ◽  
Hong Jian Liao ◽  
Hang Zhou Li ◽  
Zheng Hua Xiao
Keyword(s):  
Experimental Study ◽  
Residual Strength ◽  
Failure Modes ◽  
Confining Pressure ◽  
Strength Characteristics ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Triaxial Apparatus ◽  
Strain Relationship ◽  
Relationship Of

This paper mainly concerns the non-linear strength characteristics of the loess. A series of consolidated undrained triaxial tests(CU test) and consolidated drained triaxial tests (CD test) of normal consolidation and over consolidation loess specimens are carried out by using the normal triaxial apparatus of strain control. The stress-strain relationship curves and strength characteristics of loess are investigated and analyzed. The results show that the stress-strain relationship obtained by CU tests appears strain softening, while the stress-strain relationship for CD tests appears strain hardening. Different failure modes have different stress-strain relationships. Furthermore, the results also show that the peak strength, residual strength and residual strength ratio change with the different confining pressure. Based on the triaxial shear tests of normal consolidated loess, the influences of over-consolidated loess on the stress-strain relationships and strength characteristic are discussed. Several conclusions obtained in this paper can be referenced for the loess experimental study.

GRANULAR FAILURE: THE ORIGIN OF EARTHQUAKES?

2009 ◽  
Vol 23 (28n29) ◽  
pp. 5374-5382 ◽  
Author(s):  
MASSIMO PICA CIAMARRA ◽  
LUCILLA DE ARCANGELIS ◽  
EUGENIO LIPPIELLO ◽  
CATALDO GODANO
Keyword(s):  
Confining Pressure ◽  
Stick Slip ◽  
Slip Regime ◽  
Constant Rate ◽  
Large Fluctuations ◽  
System Flow ◽  
System Phase Diagram ◽  
Dynamics Simulations ◽  
Stick Slip Motion ◽  
System Phase

Via Molecular Dynamics simulations, we investigate the stick-slip motion in a model of fault, where two surfaces subject to a constant confining pressure P, and enclosing granular particles, are subject a shear stress σ. When the system sticks, the stress increases with a constant rate [Formula: see text], while the stress decreases when the system flow. We dermine the system 'phase diagram' in the pressure P load velocity [Formula: see text] plane, locating the transition form the continuos flow regime to the stick-slip regimes, and show that the transition between these two regimes is characterized by the presence of large fluctuations. In the stick-slip regime, the system reproduces the behaviour of a segment of a fault of fixed lenght.

Study on Constitutive Mode of Three Typical Rocks Based on Triaxial Compression Test

2012 ◽  
Vol 170-173 ◽  
pp. 322-326
Author(s):  
Kui Chen ◽  
Ren Hua Yang ◽  
Tao Xu ◽  
Ya Jing Qi
Keyword(s):  
Residual Strength ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Digital Design ◽  
Peak Strength ◽  
Design Parameters ◽  
Stress Strain ◽  
Red Sandstone ◽  
Constitutive Mode ◽  
Shield Machine

In order to study the relationship between the design parameters of the shield machine and the strength of rock, the behaviours of rocks under the conventional triaxial compression, the complete stress-strain curves under different confining pressures of three typical rocks, i.e. granite, limestone and red sandstone, were taken out for analysis. From the curves, the values of elastic modulus E and Poisson's ratio μ were gained and the relationships between the following parameters were figured out, which are peak strength versus confining pressure, residual strength versus confining pressure, strain at peak strength versus confining pressure, and strain at residual strength versus confining pressure. According to the values and relationships, the complete stress-strain curves were divided into three parts. For each part, a constitutive equation was established by using the strain softening trilinear elastic-brittle-plastic constitutive model, and all the related parameters in the constitutive equations were also presented, which provide a theoretical foundation for the digital design of the cutter head and cutters of Shield machine.

A Change of Undrain Shear Strength of Soft Ground during Consolidation Process

2014 ◽  
Vol 513-517 ◽  
pp. 269-272
Author(s):  
Yeong Mog Park ◽  
Ik Joo Um ◽  
Norihiko Miura ◽  
Seung Cheol Baek
Keyword(s):  
Shear Strength ◽  
Soft Clay ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Test Results ◽  
Exponential Equation ◽  
Consolidation Process ◽  
Degree Of Consolidation ◽  
Clay Ground ◽  
Strength Increment

The purpose of this study is to investigate the undrain shear strength increment during consolidation process of soft clayey soils. Thirty kinds of laboratory triaxial tests have been performed using undisturbed and remolded Ariake clay samples with different degree of consolidation and 5 kinds of confining pressure. Test results show that well known linear equation proposed by Yamanouchi et al.(1982) is overestimated the strength of undisturbed soft clay ground in the process of consolidation. A new simple and reasonable exponential equation proposed in this paper.

Research on Hydraulic Conductivity of Coarse Sandstone under Triaxial Compression

2011 ◽  
Vol 94-96 ◽  
pp. 1146-1151 ◽  
Author(s):  
Guan Rong ◽  
Xiao Jiang Wang
Keyword(s):  
Hydraulic Conductivity ◽  
Circumferential Strain ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Test Results ◽  
Stress Strain ◽  
Deformation And Failure ◽  
Maximum Value ◽  
Strain Process ◽  
Peak Value

Permeability test for complete stress-strain process of coarse sandstone were carried out in triaxial test instrument. On the basis of test results, the influence of confining pressure and strain on the hydraulic conductivity was discussed. It is shown that in the complete stress-strain process, hydraulic conductivity changes in the law that presents the same character with the curve of stress-strain. The hydraulic conductivity reduces slightly with the increase of deviatoric stress in the stage of micro fracture compressing and elastic; In the elastoplastic stage, along with the expansion of new fractures, the hydraulic conductivity increases slowly at first and then reaches sharply to the maximum value after peak point; In the post-peak stage, the fracture which controls the hydraulic conductivity of coarse sandstone is compressed because of the confining pressure and the hydraulic conductivity decreases. During the process of deformation and failure, the hydraulic conductivity is more sensitive to the change of circumferential strain. With the increase of confining pressure, the increased value from initial to peak value and the decreased value from peak to residual value decreases.

Large-scale triaxial tests of dense gravel material at low confining pressure

2012 ◽  
pp. 587-592
Author(s):  
S Lenart ◽  
J Koseki ◽  
T Sato ◽  
Y Miyashita ◽  
H Thang
Keyword(s):  
Large Scale ◽  
Confining Pressure ◽  
Triaxial Tests
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