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Most rock slope stability analysis methods are based on the Hoke–Brown criterion under a two‐dimensional state of stress, which somewhat ignores the effect of intermediate principal stress. In this paper, by introducing the improved three‐dimensional H‐B criterion into the Meridian plane, the tangent line of a point on the H‐B strength envelope is regarded as its instantaneous equivalent M‐C parameter. Based on this, a formula for solving the equivalent M‐C strength parameters under a three‐dimensional stress state is established to describe the shear strength parameters of rock mass, considering different stress states. Taking three kinds of rocks as examples, the influence of the intermediate principal stress on their strength parameters is analyzed. On this basis, the realization scheme of the nonlinear strength reduction method is established, the stability of the slope is studied, and an example verifies the feasibility of this method. This method fully considers the nonlinear characteristics of rock slope strength parameters under a three‐dimensional stress state and provides a solid basis for slope stability analysis. [ABSTRACT FROM AUTHOR]

Gas hydrate has gradually become a new potential energy resource. However, some engineering and environmental problems related to the mechanical properties of gas hydrate-bearing sediments (GHBS) during gas recovery may occur. Many studies have been carried out on the basic mechanical properties of GHBS samples based on laboratory tests, but their evolution characteristics and suitable models require further research. Based on a series of data analyses of published laboratory experimental results on GHBS samples with different hydrate saturations under various confining pressures, the evolution characteristics of strength and dilation parameters were investigated. It was found that cohesion (c) increases quickly to a peak value and then decreases gradually to a residual value with an increasing plastic shear strain, and the samples with higher hydrate saturations have higher initial values, peak values, and residual values of cohesion (c). The internal friction angle ( φ ) increases quickly with increasing plastic shear strain and then becomes stable at a residual value for all the samples with different hydrate saturations. The dilation angle ( ψ ) increases from negative to positive values with increasing plastic shear strain and then becomes stable at a residual value. These characteristics are likely to be related to the compaction occurring at the early stage of compression before expansion due to dilation. In this paper, a non-linearly fitted model is proposed considering the evolution of the mechanical parameters, and the verification tests show that the proposed model can simulate the stress–strain behaviors of the GHBS samples well. This model is also adopted in the stability analysis of submarine slopes containing hydrate reservoirs. The analytical approach is developed, accompanied by the strength reduction method. [ABSTRACT FROM AUTHOR]

Based on the conventional triaxial compression test of marble, the microscopic parameters corresponding to the macroscopic mechanical properties of marble were obtained by PFC2D, and on this basis, discrete element method models were established to conduct numerical tests of triaxial compression of marble under different confining pressures and loading rates to study the effect of loading rates on the rock specimens. Under the same confining pressure, brittle damage occurs in marble when the loading rate is low, and the damage type transforms from brittle to ductile as the loading rate increases. The peak strength, cracking stress, damage stress, cohesion, and internal friction angle of marble appear to increase with the increase in the loading rate under the same confining pressure. The characteristic stresses and strength parameters are linearly related to the loading rate. The influence of the loading rate on the peak strength is the most significant. With the increase in the confining pressure, the fitting coefficient of the linear relationship between initiation stress and loading rate decreases from 18.9 to 15.4 for different confining pressures, indicating that the growth rate of initiation stress decreases with the increase in the confining pressure when the loading rate is increased, and the increase in confining pressure suppresses the growth rate of initiation stress with loading rate.

Gas hydrate has gradually become a new potential energy resource. However, some engineering and environmental problems related to the mechanical properties of gas hydrate-bearing sediments (GHBS) during gas recovery may occur. Many studies have been carried out on the basic mechanical properties of GHBS samples based on laboratory tests, but their evolution characteristics and suitable models require further research. Based on a series of data analyses of published laboratory experimental results on GHBS samples with different hydrate saturations under various confining pressures, the evolution characteristics of strength and dilation parameters were investigated. It was found that cohesion (c) increases quickly to a peak value and then decreases gradually to a residual value with an increasing plastic shear strain, and the samples with higher hydrate saturations have higher initial values, peak values, and residual values of cohesion (c). The internal friction angle (φ) increases quickly with increasing plastic shear strain and then becomes stable at a residual value for all the samples with different hydrate saturations. The dilation angle (ψ) increases from negative to positive values with increasing plastic shear strain and then becomes stable at a residual value. These characteristics are likely to be related to the compaction occurring at the early stage of compression before expansion due to dilation. In this paper, a non-linearly fitted model is proposed considering the evolution of the mechanical parameters, and the verification tests show that the proposed model can simulate the stress–strain behaviors of the GHBS samples well. This model is also adopted in the stability analysis of submarine slopes containing hydrate reservoirs. The analytical approach is developed, accompanied by the strength reduction method.

To study the strain hardening and softening mechanism for hard brittle rocks, a strain hardening and softening constitutive model for hard brittle rocks is developed. First, the normalised hardening and softening factors are defined, which characterise the yield state of rock at the stages of pre-peak hardening and post-peak softening, respectively. Then, a unified strength parameter evolution model is established that can describe the nonlinear characteristics of cohesion and the internal friction angle under different confining pressures. Based on the Mohr–Coulomb criterion, a strain hardening and softening constitutive model is proposed. Finally, the proposed model was implemented in FLAC3D, and triaxial compression numerical tests of granite and diabase were conducted. The results show that the constitutive model can characterise the nonlinear mechanical behaviour of the pre-peak hardening stage and post-peak softening stage of hard brittle rock. The model was also able to satisfactorily capture the transition from brittle failure to plastic failure for hard brittle rock under high confining pressures. [ABSTRACT FROM AUTHOR]

We investigate the shape and strength of the magnetic fabrics (anisotropy of magnetic susceptibility (AMS) data) of various massive granitic plutons from different parts of India, using the eigenvalue method. The study aims to analyse eigenvalues and establish their relationship with various deformational attributes. It involves: (1) calculating eigenvectors and their corresponding eigenvalues from magnetic fabric datasets; (2) finding a link between the geometrical appearance of eigenvectors and the mechanistic issues involved with a specific deformation scenario; and (3) determining shape and strength parameters from the magnetic foliation data distribution. The statistical analysis for the unimodal magnetic fabric dataset of orthorhombic symmetry class implies that the plane, consisting of intermediate (V2) and minimum (V3) eigenvectors with pole V1, accurately traces the instantaneous stretching axis (ISAmax) of a particular material flow system under a pure shear regime. Moreover, for the distributions of similar symmetry and modality, we infer that the rotational characteristics of eigenvectors with respect to a fixed coordinate cause a distinct shift of such planes (V2–V3) from the ISAmax of a steady-state flow system under simple shear, where a substantial amount of rotational strain is involved. However, our findings also suggest that variation in symmetry and modality of magnetic fabric data distribution of different studied granitoids can directly influence the relative disposition of V2–V3 with respect to the direction of ISAmax. We conclude that eigenvalue analysis of magnetic fabrics is a powerful approach, which can be utilized while studying the salient deformational aspects of any syntectonic massive granitic body. [ABSTRACT FROM AUTHOR]

Cemented sand and gravel (CSG) has a wide range of applications in dam construction, and its properties are between rockfill and roller compacted concrete (RCC). A difference in gel content will result in a variance in CSG's structure and mechanical properties. To investigate the intricate structural mechanical properties of CSG, this study conducted a series of laboratory tests and associated discrete element analyses. Accordingly, the evolution law of the strength parameters of CSG is explored and a statistical damage constitutive model suitable for CSG is established. The main contributions of this study are as follows: (1) The failure mechanism of the CSG was described from the microscopic level, and the evolution law of the strength parameter cohesion and friction angle of the CSG was analyzed and summarized. (2) Based on the particle flow model, the energy development law and the spatiotemporal distribution law of acoustic emission (AE) provide illustrations of the strain hardening–softening transition features and the interaction between cohesion and friction of CSG. (3) The evolution function between the strength parameter and the strain softening parameter was built, and the critical strain softening parameter was determined by the microcrack evolution law of the particle flow model. (4) The accuracy of the evolution curve was confirmed by comparing it to experimental results. (5) Based on the relationship between cohesion loss and material damage, a statistical damage constitutive model was developed using the improved Mohr–Coulomb strength criterion as the micro strength function. The constitutive model can accurately describe the stress–strain curves of CSG with different gel content. Furthermore, the model reflects the strain hardening–softening properties of CSG and reveals the relationship between the weakening of cohesion and material damage at the microscopic level. These findings provide valuable guidelines for investigating the damage laws and microcosmic failure features of CSG and other relevant materials. [ABSTRACT FROM AUTHOR]

Aiming at the influence factors and their action regulation of the slope stability in the coal measure strata of Beijing–Hong Kong & Macao Expressway, the influence characteristics of injection dip angle of rock stratum, thickness and strength parameters of the soft interlayer, slope height and size of slope angle on the slope safety factor are systematically studied by using the limit equilibrium method theory. The influence of slope height, thickness of weak interlayer and shear strength parameters on the stability of slope in coal measure strata with different dip angles is that the safety factor decreases first and then increases with the increase of strata dip angle. The minimum safety factor of slope under the action of each factor is near the strata dip angle of 30°, which indicates that the stability of slope in coal measure strata is poor when the dip angle of rock stratum is about 30°. With the increase of slope angle, the minimum safety factor decreases. However, when the slope angle is less than 40°, the slope is in a stable state and the dip angle of the strata do not affect the stability of the slope. Slopes with different slope angles have the minimum safety factor that is not affected by slope height. The difference between analytical solution and numerical solution is analyzed. The research provides a theoretical basis for the treatment of slopes in coal measure strata and has certain practical significance.

The Duku Highway in the study area is located in the high-altitude mountainous region of Xinjiang, China, and it is affected by various environmental factors during construction, among which the influence of freeze–thaw cycles cannot be ignored. In order to study the effect of freeze–thaw cycles on the strength of tuff surrounding rock at high-altitude mountainous areas, uniaxial compressive strength and shear wave velocity tests with different numbers of freeze–thaw cycles were conducted on dry and saturated rock samples from the tunnel entrance of the Duku Highway. The test results showed that the tuff specimens condensed a thin layer of ice on the surface with raised freezing points during the freezing stage, but the thickness of the thin ice and the density of the freezing points did not change with the increase of the number of freeze–thaw cycles. Analysis of the test data showed that the wave velocity, uniaxial compressive strength, breaking strain, modulus of elasticity, and Poisson's ratio of the rock decreased as the number of freeze–thaw cycles increased. We believe that the freeze–thaw cycles caused the deterioration of the rock strength. The reason for this phenomenon is that we believe that the freeze–thaw cycling action changed the rock internally and affected its density, which, in turn, caused the attenuation of strength, etc. However, there is a limit to the effect of freeze–thaw cycling on the strength of the surrounding rock. After exceeding the limit of the effect of freeze–thaw cycling, the strength parameters of the surrounding rock will no longer change with the increase of the number of freeze–thaw cycles. The results of this study can provide a theoretical basis for the prevention and control of the stability of tuff surroundings at high-altitude mountain tunnel openings. [ABSTRACT FROM AUTHOR]

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the strain hardening and softening mechanism for hard brittle rocks, a strain hardening and softening constitutive model for hard brittle rocks is developed. First, the normalised hardening and softening factors are defined, which characterise the yield state of rock at the stages of pre-peak hardening and post-peak softening, respectively. Then, a unified strength parameter evolution model is established that can describe the nonlinear characteristics of cohesion and the internal friction angle under different confining pressures. Based on the Mohr–Coulomb criterion, a strain hardening and softening constitutive model is proposed. Finally, the proposed model was implemented in FLAC3D, and triaxial compression numerical tests of granite and diabase were conducted. The results show that the constitutive model can characterise the nonlinear mechanical behaviour of the pre-peak hardening stage and post-peak softening stage of hard brittle rock. The model was also able to satisfactorily capture the transition from brittle failure to plastic failure for hard brittle rock under high confining pressures.

Cemented sand and gravel (CSG) has a wide range of applications in dam construction, and its properties are between rockfill and roller compacted concrete (RCC). A difference in gel content will result in a variance in CSG’s structure and mechanical properties. To investigate the intricate structural mechanical properties of CSG, this study conducted a series of laboratory tests and associated discrete element analyses. Accordingly, the evolution law of the strength parameters of CSG is explored and a statistical damage constitutive model suitable for CSG is established. The main contributions of this study are as follows: (1) The failure mechanism of the CSG was described from the microscopic level, and the evolution law of the strength parameter cohesion and friction angle of the CSG was analyzed and summarized. (2) Based on the particle flow model, the energy development law and the spatiotemporal distribution law of acoustic emission (AE) provide illustrations of the strain hardening–softening transition features and the interaction between cohesion and friction of CSG. (3) The evolution function between the strength parameter and the strain softening parameter was built, and the critical strain softening parameter was determined by the microcrack evolution law of the particle flow model. (4) The accuracy of the evolution curve was confirmed by comparing it to experimental results. (5) Based on the relationship between cohesion loss and material damage, a statistical damage constitutive model was developed using the improved Mohr–Coulomb strength criterion as the micro strength function. The constitutive model can accurately describe the stress–strain curves of CSG with different gel content. Furthermore, the model reflects the strain hardening–softening properties of CSG and reveals the relationship between the weakening of cohesion and material damage at the microscopic level. These findings provide valuable guidelines for investigating the damage laws and microcosmic failure features of CSG and other relevant materials.

Deposit landslides are one of the most representative geological hazards around the world, and the poor understanding of the mechanical characteristics of the soilrock mixture (S-RM) increases the difficulties in evaluating the stability of the deposit slope subjected to rainfall. This study attempted to propose an innovative strength parameter estimation method of the S-RM based on the concept and format of the generalized HoekBrown criterion. The system of “rock blocks–soil–contact surface” was considered the main source providing resistance to the external force, and the effect of the soil matrix, rock blocks, and the contact surface between them was taken into account. The verification of the estimation method was proved based on the abundant test data. A typical deposit slope located in the Taoyuan region of Yunnan Province, China, was selected as a case study, and the estimation method was applied to provide the shear parameters of the S-RM. The slope stability subjected to different types of rainfall was analyzed considering the parameter deteriorations, and the results show that the deposit landslide is more prone to the wave-type rainfall, which shows a deeper response depth of pore water pressure and a smaller safety factor. The present study suggests a simple estimation method for the shear parameters of the S-RM using a few parameters for the engineers and provides an understanding of the deposit slope stability during the rainfall process.

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Maltose is an essential derivative of starch. To understand the processability and stability of maltose‐containing foods, material characterization of the phase and state transition from its amorphous state is required. Although the crystallization of amorphous maltose is well understood, few studies have reported the relationship between the crystallization and the glass transition temperature (Tg)‐related molecular mobility. In this study, water sorption, crystallization, Tg‐related α‐relaxation, and the corresponding time factor for amorphous maltose and maltose / whey protein isolate (WPI) mixtures are measured at various water activity (aw) levels and 25 °C. RESULTS: The water‐additive principle for maltose / WPI mixtures was observed at aw ≤ 0.440 at the molecular level, whereas the crystallization of amorphous maltose occurred at high aw values (≥0.534). The crystal formation and crystallization kinetics of amorphous maltose were affected by water and WPI at aw ≥ 0.534 and 25 °C, as determined by X‐ray diffraction. The relationship between Tg and the water content was fitted by the Gordon–Taylor model, and its constant showed a compositional dependence for the maltose / WPI mixtures. The α‐relaxation temperature of the amorphous samples decreased due to water plasticization, but increased with an increase in the WPI quantity. The Strength (S) value for amorphous maltose, which was a quantitative estimate of the compositional effects on molecular mobility, was based on the William–Landel–Ferry (WLF) equation. CONCLUSION: The S concept exhibits considerable potential for application in controlling the crystallization of amorphous maltose and improving the processability and stability of maltose‐containing foods. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A deep understanding of the behavior and specifications of grouting materials between soil particles is required to increase the applications of various grouting technologies. Out of the different grouts that can be injected in fine-grained soils, colloidal silica has been selected in this study due to its unknown effects on fine-grained soils. In this study, the effects of colloidal silica on silty sand with different amounts of silt were studied, and the strength parameters (c, ϕ) of stabilized samples under long-term static loading was evaluated. A total of 42 uniaxial compression tests and 75 consolidated-drained triaxial tests were done on the samples. Uniaxial compression tests were conducted to determine the most suitable age of the samples for testing, which was three days. The results of the triaxial tests indicate an increase in the drained cohesion parameter in all samples, while changing the drained internal friction angle in silty sands decreases. [ABSTRACT FROM AUTHOR]

The Jinpingzi landslide is an old landslide to the arch dam of Wudongde Hydropower Station in the downstream direction on the right bank of Jinsha River. The displacement monitoring data shows that the landslide zone II presents an overall creep slip with a nonconstant rate. In order to study the rule of strength change of landslide slip zone, its active zone Ⅱwas studied. A series of ring shear tests under different shear rates, moisture content and normal pressure was employed. Its strength characteristics were studied. It could provide reference for the protection and management of similar landslides. It is found that the phenomenon of sliding soil strain softening is obvious. The strength of the sliding zone increases with the change of shear rate and the greater the positive stress, the greater the magnitude of strength recovery. The reason may be that the shear rate changes its shear mode. The cohesion and internal friction angle of the peak strength parameters decrease linearly with the increase of moisture content and the change range of cohesion is greater than the internal friction angle. Residual cohesion is negatively correlated with moisture content and the residual internal friction angle has little change. [ABSTRACT FROM AUTHOR]

Abstract A ameliorative criterion for predicting the glass-forming ability of metallic glasses was presented. The coefficient of determination (R 2) of experimental log 10 (R c) versus the predicted log 10 { R c l i n e a r (T r g , D) } is 0.72. When the predicted log 10 { R c l i n e a r (T r g , D) } is replaced with our predicted log 10 { R c l i n e a r (T r g , 1 D) } , the coefficient of determination (R 2) will increase from 0.72 to 0.94, which is a great improvement for evaluating glass-forming ability (GFA). Highlights • A ameliorative criterion for predicting the glass-forming ability was presented. • The coefficient of determination (R 2) of experimental log 10 (R c) versus log 10 { R c l i n e a r (T r g , D) } is 0.72. • R 2 will increase from 0.72 to 0.94, when log 10 { R c l i n e a r (T r g , D) } is replaced with log 10 { R c l i n e a r (T r g , 1 D) }. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The glass transition and corresponding glass transition temperature ( T ) as found for food solids have received considerable attention, and their relationships with food solid behavior in various processes and food storage have been disputed. However, understanding glass transition-associated relaxations and their coupling with physicochemical properties of food materials is still a challenging and developing area of food material science. This review shows the improved understanding of the glass transition, structural relaxations, and corresponding relaxation times ( τ) as well as their relevant applications on glassy food solids. Above information contributes to understanding of physical changes, molecular mobility, and solid flow characteristics of food components around their glass transition during processing and storage. We also emphasized the limitations of 'fragile' concept in food solids and introduced a 'strength, S' parameter to measure and describe solid flow characteristics of amorphous food mixtures by using a William-Landel-Ferry (WLF)-based approach for the analysis of α-relaxation derived τ above T . The use of the S concept, therefore, can provide a quantitative measure to estimate compositional effects on τ and the control of solid properties, such as stickiness, caking, collapse, and crystallization. [ABSTRACT FROM AUTHOR]

We report on the role of density ratio for granular column collapse experimentally and numerically by demonstrating the fundamental changes using a two-particle approach. The influence of the density ratio for the different profile arrangements on the velocity distribution, interface, and energy transition is described using the Moving Particle Semi-Implicit method (MPS). A constitutive equation utilizing the granular material strength is formulated using the elasto-viscoplastic model under the μ (I) rheology framework by replacing the frictional coefficient with the internal friction angle. The dense state of the granular materials results in a linear relationship between the length scale and inertia constant, which makes the shear strength the driving parameter. Experimental data are compared with numerical simulation for granular collapse with varying density profile configurations to validate the method. We found that the density ratio does not influence the velocity and free surface profile. The interface is maintained similarly to a single-phased granular flow except for erosive configurations where a penetrating regime is evident. The rate at which the granular kinetic energy transforms to the potential energy when the lower density material is on top and at the left of the higher granular materials is similar compared to other profile arrangements. The results demonstrated that the density ratio for different profile arrangements could significantly influence the deformation of the granular materials depending on the particle arrangements. The numerical investigation for the granular column collapse agrees well with experimental studies. Collapse mechanisms of varying density ratio configuration. [Display omitted] • Flow dynamics and energy evolution in density ratio granular column collapse. • Replacement of the μ (I) rheology model parameters with the material strength parameters. • Effective phase-change for high-density ratio for single and two-phase granular flow. • Relationship between the inertia constant and wave front. • The meshfree particle method, MPS, shows excellent agreement with the experiment. [ABSTRACT FROM AUTHOR]

Water sorption, crystallization, calorimetric glass transition temperature ( T g ), structural relaxations and relaxation times ( τ ) of freeze-dried sugars (lactose and trehalose) and whey protein isolates (WPI) in mixed systems were measured at various water activities ( a w ≤ 0.76, and 25 °C). The results indicated that sugar/WPI mixtures showed fractional water sorption behavior. The crystallization and crystalline forms of lactose were affected by trehalose and WPI based on XRD analysis. DMA analysis showed that the α-relaxation temperatures ( T α ) at loss modulus peak at frequency of 0.5 Hz for sugar/protein systems were affected by the presence of water and WPI. The τ and T α −T g relationships in sugar/WPI systems were successfully modeled by using the WLF model. The WLF-type structural strength ( S ), indicating decrease of τ from 10 2 to 10 −2 s, of trehalose decreased with a w up to 0.44 (from 15.8 to 12.1 °C) but WPI increased S . Moreover, a relationship for S and water content for glass forming sugar systems at a w ≥ 0.56 was established. The S concept gave a quantitative measure to estimate compositional effects on τ and could be used to estimate crystallization of food solids components. [ABSTRACT FROM AUTHOR]

Nano-sized bubble dispersion in copper was achieved by a powder metallurgy method based on ball milling and spark plasma sintering. The microstructure of bubbles was evaluated by using Transmission Electron Microscopy (TEM), and the bubble size and interspacing were further quantitatively determined from small-angle X-ray scattering (SAXS) measurement. From TEM observation, the average radius of bubbles is 2 nm and their interspacing is 75 nm, while according to SAXS measurement, the radius is found to be 1.5 nm and the interspacing is 54 nm. By combining those parameters with the bubble distribution and Vickers hardness, the obstacle strength factor was evaluated as 0.23 by using TEM result, and 0.16 by using SAXS data. This suggested that bubbles could impede dislocation motion. [ABSTRACT FROM AUTHOR]

Measurement of tensile strength of soil by direct methods can be challenging due to difficulties in sample preparation and in fixing the specimen while applying uniaxial tension forces. However the tensile strength of soil samples can be measured by indirect tests, such as the Brazilian and double punch tests, assuming that tensile stress is distributed uniformly on the failure plane. In this study, the tensile strength of statically-compacted sand bentonite and cement-enhanced sand bentonite mixtures is measured in varying curing time periods using the “double punch” test. The compressive strengths of samples are also measured using the unconfined compression test, and the correlation between tensile and compressive strength is discussed in relation to curing time. A simple method is also applied to determine the undrained cohesion and internal friction angle of samples through the Mohr-Coulomb circle method, using the double punch tensile strength and unconfined compressive strength. The results show that cohesion increases in both sand bentonite and sand bentonite-cement samples along with curing time. [ABSTRACT FROM AUTHOR]

Structural relaxations and relaxation times, τ , of lactose in freeze-dried amorphous lactose and lactose-WPI mixture systems were studied with glass transition data. The results indicated that T g , enthalpy relaxation and α-relaxation temperature, T α , of amorphous lactose was affected by the presence of lactose crystals and WPI at 0.33 a w (25 °C) due to water migration. The τ and T α −T g relationship of the materials was successfully modeled by the WLF equation with the material-special constants (− C 1 and C 2 ). A strength parameter, S , indicating decrease of τ from 10 2 to 10 −2 s, could be used to measure the structural stability of lactose systems above their glass transition. The strength of amorphous lactose decreased with a w increasing up to 0.44 and enhanced by α lactose crystals and WPI in storage at 0.33 a w . Hence, the strength parameter provided a simple and convenient means to measure compositional effects on structure formation in food processing. [ABSTRACT FROM AUTHOR]

The strength and the related parameters of unsaturated soil are the key issues in unsaturated soil mechanics. The triaxial or direct shear apparatus with suction control is used to measure the related parameters in the strength formulas proposed by Bishop and Fredlund. However, the technique is time-consuming for cohesive soils because it takes a long time to achieve a water–air equilibrium condition under a given suction state. In addition, the feasibility of the technique is also doubted. Lu et al. proposed the concept of suction stress and expressed the unsaturated strength as a function of suction stress which can be determined by the conventional triaxial test. The method can avoid measuring matric suction and is convenient in engineering application. In this paper, conventional triaxial CU tests with different moisture contents were utilized to obtain the effective steady state strength parameters and then the suction stress characteristic curves were obtained. To compare Lu et al.’s strength formula with Bishop’s and Fredlund’s, the soil–water characteristic curve of the same loess sample was also measured by the tensiometer. Theoretically, the three strength theories are different in physical mechanisms, but they can transform to each other mathematically. From the point of view of engineering applications, Lu et al.’s shear strength theory based on suction stress is more convenient to apply in engineering. [ABSTRACT FROM AUTHOR]