The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Enlong Liu - One of the best experts on this subject based on the ideXlab platform.
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new twin shear unified Strength Criterion
Geotechnique Letters, 2020Co-Authors: Xingyan Liu, Enlong Liu, Bingtang Song, Ping WangAbstract:In this paper, by modifying the relationship between shear stress τ and normal stress σ on the plane subjected to twin-shear (T-S) stresses and the adverse judgement conditions of T-S stresses comb...
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application of new twin shear unified Strength Criterion to frozen soil
Cold Regions Science and Technology, 2019Co-Authors: Xingyan Liu, Enlong LiuAbstract:Abstract A new twin-shear unified Strength Criterion is proposed in this study. This Criterion reveals the relationship among single-shear, twin-shear, and triple-shear Strength criteria. All known linear and nonlinear Strength criteria—such as Huber–von Mises, Drucker–Prager, Mohr–Coulomb, Tresca, and twin-shear series—are special cases of the new twin-shear unified Strength Criterion. The proposed unified Strength Criterion was employed to study the Strength characteristics in the compressed meridional plane (where the stress Lode angle, θσ = − 30°) of frozen soil, based on the soil's nonlinear and asymmetric properties. In the Criterion, β and C, which denote the relationship between the shear stress τ and normal stress σ on the twin-shear stress acting plane, are deemed variable; they vary with the change in normal stress σ or mean stress p. Through a comparison of results, we found that the results obtained with the proposed Strength Criterion were in good agreement with the results of tests on frozen soil. On this basis, expressions for the cohesive force and the internal friction angle of frozen soil were derived and discussed.
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a Strength Criterion for frozen moraine soils
Cold Regions Science and Technology, 2019Co-Authors: Enlong Liu, Fei Luo, Zhanyuan ZhuAbstract:Abstract The Strength behavior of frozen soils has been extensively investigated in frozen soils mechanics for many years. In order to study the Strength properties of frozen moraine soils, a series of cryogenic tri-axial compression tests are carried out under confining pressures ranging from 0.5 MPa to 16 MPa at the temperatures of −0.5 °C, −2.0 °C and −6.0 °C, respectively. The test results show that when the mean stress is less than the consolidation yield pressure defined as a boundary stress of the Strength envelope, the Strength envelope is nonlinear, while when the mean stress is greater than the consolidation yield pressure, the Strength envelope becomes linear approximately and can be described by the Mohr-Coulomb Strength Criterion. According to the test results, a new Strength Criterion is proposed based on the concept of binary medium model to describe the nonlinear Strength behavior of frozen moraine soils. The proposed Strength Criterion has taken the heterogeneous characteristics of frozen moraine soils into account and can describe the nonlinear Strength behavior on the hypothesis of that a representative volume element (RVE) of frozen moraine soils is a binary medium consisting of some bonded elements and frictional elements, and the bonded elements will be gradually broken and transformed into frictional elements under certain stress conditions. Finally, compared with test results, it is demonstrated that the proposed new Strength Criterion could well reflect the Strength behavior of frozen moraine soils at the temperatures of −0.5 °C, −2.0 °C and −6.0 °C, respectively.
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Study on Strength Criterion for frozen soil
Cold Regions Science and Technology, 2019Co-Authors: Xingyan Liu, De Zhang, Enlong Liu, Ge Zhang, Bingtang SongAbstract:Abstract It is established that the Strength of frozen soil exhibits apparent nonlinearity in the p–q plane. As the mean stress p increases, in certain experimental conditions, the Strength of frozen soil increases rapidly and then reduces gradually; however, in certain other conditions, the Strength increases gradually and then reduces rapidly. The former phenomenon is said to be of the “front peak” type, and its critical confining pressure is relatively smaller. The latter phenomenon is said to be of the “back peak” type, and its critical confining pressure is relatively higher. Only a few cases are considered as “symmetric”; these exhibit forms analogous to a parabola opening downward. Based on these observations, it is determined that the temperature, soil type, salt content, strain rate, thawing cycle times, and particle size of the sample determine the type of the Strength curve. With the present level of research, most of the Strength criteria can consider only one of the three types. Thus, a new Strength Criterion that can be simultaneously applied to the three types of Strength-changes, and the corresponding Strength Criterion in the deviatoric plane are proposed. Moreover, two concepts—“calculated cohesive force (c0)” and “calculated internal frictional angle (φ)” of frozen soil—are proposed as fundamental mechanical parameters for various Strength criteria.
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A new Strength Criterion for frozen soils considering the influence of temperature and coarse-grained contents
Cold Regions Science and Technology, 2017Co-Authors: De Zhang, Enlong Liu, Xingyan Liu, Ge Zhang, Bingtang SongAbstract:Abstract Strength of frozen soils is a hot topic, which has been being extensively investigated in frozen soil mechanics. In order to describe the effects of temperature and coarse-grained contents on the Strength properties of frozen soils, a series of cryogenic triaxial compression tests for frozen soils are analyzed at different temperatures, and different coarse-grained contents at − 6 °C. A new Strength Criterion is proposed based upon the modified slope method of downward CSL (critical state line) curve in the meridian plane, in which the various parameters as well as their physical meanings are analyzed and discussed in detail, with their variations expressed by temperature and coarse-grained contents. In addition, on the basis of envelope theorem, the internal frictional angle is investigated and introduced to Lade-Duncan model in the deviatoric plane. Compared with test results, it is demonstrated that the proposed new Strength Criterion could well reflect the Strength varying rules at different confining pressures ranging from lower to higher pressures for frozen soils. For frozen mixed soils with different coarse-grained contents, the Strength decreases first and then increases with increasing coarse-grained content, which can also be predicted by the proposed Strength Criterion well.
Chong Wang - One of the best experts on this subject based on the ideXlab platform.
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a nonlinear Strength Criterion for frozen sulfate saline silty clay with different salt contents
Advances in Materials Science and Engineering, 2018Co-Authors: Yanhu Zhao, Yuanming Lai, Jing Zhang, Chong WangAbstract:It has been proven that the mechanical properties of frozen saline soils are different from frozen soils and unfrozen saline soils. In this paper, in order to study the effects of the salt contents on the Strength characteristics of frozen soils, a series of conventional triaxial compression tests are carried out for frozen saline silty clay with Na2SO4 contents 0.0, 0.5, 1.5, and 2.5% under confining pressures from 0 MPa to 18 MPa at −6°C, respectively. The experimental results show that the Strength of frozen saline silty clay presents obvious nonlinearity, the Strength of frozen saline silty clay increases with increasing confining pressures at first, but with a further increase in confining pressures, the Strength decreases because of pressure melting and crushing phenomena under high confining pressures, and salt contents have an important influence on Strength of frozen saline silty clay. A Strength Criterion is proposed on the basis of the experimental results. The Strength Criterion could well reflect the nonlinear Strength characteristic of frozen saline silty clay and the influence of salt contents on frozen saline silty clay.
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a Strength Criterion for frozen sodium sulfate saline soil
Canadian Geotechnical Journal, 2016Co-Authors: Mengke Liao, Yuanming Lai, Chong WangAbstract:Salt content has been proven to be an important influencing factor on the mechanical properties of frozen saline soils, whose Strength Criterion is different from that of unfrozen saline soils or f...
Yuanming Lai - One of the best experts on this subject based on the ideXlab platform.
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a heuristic elastoplastic damage constitutive modeling method for geomaterials from Strength Criterion to analytical full spectrum stress strain curves
International Journal of Geomechanics, 2021Co-Authors: Lunyang Zhao, Yuanming Lai, Wanlu Zhang, Fujun Niu, Qizhi Zhu, Jianfu ShaoAbstract:Abstract This paper presents an elastoplastic damage constitutive modeling method in the thermodynamic framework for geomaterials. The model within this method starts from a Strength Criterion and ...
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a dynamic Strength Criterion for frozen sulfate saline silty clay under cyclic loading
Cold Regions Science and Technology, 2020Co-Authors: Yanhu Zhao, Yuanming Lai, Jing Zhang, Mengke LiaoAbstract:Abstract The Strength properties of frozen saline soils under cyclic loading are more complex than those of unfrozen soils and frozen salt-free soils due to the existence of salt crystals in soil matrix. In this paper, a serious of tri-axial cyclic loading tests are conducted for frozen sulfate saline silty clay (FSSSC) with different Na2SO4 contents under different confining pressures and loading dynamic stress ratios at the temperature of −6 °C, respectively. The experimental results illustrate that the dynamic Strength of FSSSC decreases with the increase of axial strain. The critical state line of FSSSC under cyclic loading is moving constantly. The dynamic critical state lines of FSSSC with different salt contents are different under same axial strains. The dynamic friction angle of FSSSC is related to salt content, loading dynamic stress ratio and confining pressure. Based on the experimental results, a dynamic Strength Criterion for FSSSC under cyclic loading is proposed, and the method of determining dynamic Strength parameters is given. This Strength Criterion not only can reflect the effect of loading dynamic stress ratio and salt content on dynamic Strength, but also can describe the influence of high confining pressure on dynamic Strength.
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a nonlinear Strength Criterion for frozen sulfate saline silty clay with different salt contents
Advances in Materials Science and Engineering, 2018Co-Authors: Yanhu Zhao, Yuanming Lai, Jing Zhang, Chong WangAbstract:It has been proven that the mechanical properties of frozen saline soils are different from frozen soils and unfrozen saline soils. In this paper, in order to study the effects of the salt contents on the Strength characteristics of frozen soils, a series of conventional triaxial compression tests are carried out for frozen saline silty clay with Na2SO4 contents 0.0, 0.5, 1.5, and 2.5% under confining pressures from 0 MPa to 18 MPa at −6°C, respectively. The experimental results show that the Strength of frozen saline silty clay presents obvious nonlinearity, the Strength of frozen saline silty clay increases with increasing confining pressures at first, but with a further increase in confining pressures, the Strength decreases because of pressure melting and crushing phenomena under high confining pressures, and salt contents have an important influence on Strength of frozen saline silty clay. A Strength Criterion is proposed on the basis of the experimental results. The Strength Criterion could well reflect the nonlinear Strength characteristic of frozen saline silty clay and the influence of salt contents on frozen saline silty clay.
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a Strength Criterion for frozen sodium sulfate saline soil
Canadian Geotechnical Journal, 2016Co-Authors: Mengke Liao, Yuanming Lai, Chong WangAbstract:Salt content has been proven to be an important influencing factor on the mechanical properties of frozen saline soils, whose Strength Criterion is different from that of unfrozen saline soils or f...
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modified hoek brown Criterion for nonlinear Strength of frozen soil
Cold Regions Science and Technology, 2013Co-Authors: Yugui Yang, Feng Gao, Yuanming LaiAbstract:Abstract The Strength of frozen soil presents obvious nonlinearity, which makes many theoretical criteria unable to accurately predict failure. The Hoek–Brown Criterion, which is one of the most widely used Strength criteria in geotechnical engineering, could predict the Strength of frozen soil subjected to low confining pressure. For high values of confining pressure, the predicted results do not agree well with experimental data. In the present study, the Criterion was modified by incorporating a new parameter to account for the nonlinearity of frozen soil under high confining pressures. The parameter and instantaneous friction angle for the nonlinear failure envelope were also analyzed. To describe the failure mechanism of frozen soil under complicated stress state, the deviatoric section of Strength Criterion for frozen soil, in which the Mohr–Coulomb Criterion forms the low bound, and the Drucker–Prager Criterion forms the upper bound, was obtained, and a united Strength Criterion was established to take the effect of intermediate principal stress on Strength behavior into account. The Strength Criterion could well reflect the nonlinear Strength characteristic of frozen soil under the influence of pressure melting and crushing phenomena.
Dezhi Zeng - One of the best experts on this subject based on the ideXlab platform.
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through wall yield collapse pressure of casing based on unified Strength theory
Petroleum Exploration and Development, 2016Co-Authors: Kuanhai Deng, Dezhi ZengAbstract:Abstract The unified algorithm of through-wall yield collapse pressure for casing with due consideration of Strength differential (SD), yield-to-tensile Strength ratio, material hardening and intermediate principal stress, which is suitable to calculate collapse Strength of all casing has been obtained based on unified Strength theory, and four classical through-wall yield collapse formulas of casing have been presented based on the L. Von Mises, TRESCA, GM and twin yield Strength Criterion. The calculated value is maximum based on the twin yield Strength Criterion, which can be used as upper limit of through-wall yield collapse pressure, and the calculated value is minimum based on the TRESCA Strength Criterion, which can be used as lower limit of through-wall yield collapse pressure in the design process. Numerical and experimental comparisons show that the equation proposed by this paper is much closer to the collapse testing values than that of other equations.
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Through-wall yield collapse pressure of casing based on unified Strength theory
KeAi Communications Co. Ltd., 2016Co-Authors: Yuanhua Lin, Kuanhai Deng, Dezhi Zeng, Yongxing Sun, Tianguo XiaAbstract:The unified algorithm of through-wall yield collapse pressure for casing with due consideration of Strength differential (SD), yield-to-tensile Strength ratio, material hardening and intermediate principal stress, which is suitable to calculate collapse Strength of all casing has been obtained based on unified Strength theory, and four classical through-wall yield collapse formulas of casing have been presented based on the L. Von Mises, TRESCA, GM and twin yield Strength Criterion. The calculated value is maximum based on the twin yield Strength Criterion, which can be used as upper limit of through-wall yield collapse pressure, and the calculated value is minimum based on the TRESCA Strength Criterion, which can be used as lower limit of through-wall yield collapse pressure in the design process. Numerical and experimental comparisons show that the equation proposed by this paper is much closer to the collapse testing values than that of other equations. Key words: unified Strength theory, casing collapse, through-wall yield, collapse pressure, Strength differential, intermediate principal stres
Xingli Wang - One of the best experts on this subject based on the ideXlab platform.
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elasto plastic analysis of the surrounding rock mass in circular tunnel based on the generalized nonlinear unified Strength theory
International journal of mining science and technology, 2016Co-Authors: Xiujie Huang, Jixun Zhang, Ling Yang, Shikou Yang, Xingli WangAbstract:Abstract The present paper aims to establish a versatile Strength theory suitable for elasto-plastic analysis of underground tunnel surrounding rock. In order to analyze the effects of intermediate principal stress and the rock properties on its deformation and failure of rock mass, the generalized nonlinear unified Strength theory and elasto-plastic mechanics are used to deduce analytic solution of the radius and stress of tunnel plastic zone and the periphery displacement of tunnel under uniform ground stress field. The results show that: intermediate principal stress coefficient b has significant effect on the plastic range, the magnitude of stress and surrounding rock pressure. Then, the results are compared with the unified Strength Criterion solution and Mohr–Coulomb Criterion solution, and concluded that the generalized nonlinear unified Strength Criterion is more applicable to elasto-plastic analysis of underground tunnel surrounding rock.
