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The volume of tailings in the world has increased rapidly in recent years, which poses a substantial ecological threat. With the objective of reducing negative impacts on environment and reuse the abandoned slate tailings, the possibility of making eco-friendly unburned bricks by using slate tailings from Shaanxi Province of China was investigated. Raw materials included slate tailings, fly ash and cement, and bricks were produced through the process of mixing, molding, and curing. The optimal compressive strength of the product was found at the slate tailings: fly ash: cement = 5:2:3(wt.%) with 7-day curing at room temperature and 1-day curing in oven, and the forming water content is 15 wt.%. Under these conditions, the compressive strength and water absorption rate were 26 MPa and 14.32% respectively. Other physical properties and durability conform to the Chinese GB/T4111-2013 standard for test methods for concrete blocks and bricks and the Chinese JC/T422-2007 standard for unfired bricks made of tailings. In addition, a variety of methods were combined to explore the formation mechanism. The phase composition, chemical structure and microstructure of the brick are analyzed by XRD, SEM and AFM. Finally, molecular dynamics (MD) was used to simulate main cementation component, the hydrated calcium silicate(C-S-H) gel, to advance the understanding of mechanical properties of brick at the nanoscale. The results show that the C-S-H gel formed in the curing process acted as the main adhesive component, and the slate tailings are mainly worked as aggregate skeleton to provide support strength for unburned bricks.
Weijin Wang; Yuxiang Gan; Xin Kang. Synthesis and Characterization of Sustainable Eco-friendly Unburned Bricks from Slate Tailings. Journal of Materials Research and Technology 2021, 1 .
AMA StyleWeijin Wang, Yuxiang Gan, Xin Kang. Synthesis and Characterization of Sustainable Eco-friendly Unburned Bricks from Slate Tailings. Journal of Materials Research and Technology. 2021; ():1.
Chicago/Turabian StyleWeijin Wang; Yuxiang Gan; Xin Kang. 2021. "Synthesis and Characterization of Sustainable Eco-friendly Unburned Bricks from Slate Tailings." Journal of Materials Research and Technology , no. : 1.
The stress-dependent K0, Vs, and Vs anisotropy and their correlations with sand for 1D consolidation stress were tested with a custom-designed floating-wall consolidometer-type Bender Element (BE) testing apparatus. K0 of a soil sample was calculated using stress measurements through soil pressure transducers installed at the midsection of the consolidometer. The Vs and Vs anisotropy were measured by the bender elements installed in three orthogonal directions in the consolidometer, i.e., vh, hv, and hh. Granular soils with different sizes and shapes were tested. The effects of the stress level, overconsolidation ratio (OCR), particle size and shape on the Vs anisotropy, and K0 of the granular soils during one-dimensional consolidation were investigated. The laboratory investigations suggested (1) the K0 showed a constant value during loading, while it increased as the OCR increased during unloading, (2) soils with smaller particle sizes, rough surfaces, and angular geometry tended to have a lower value of K0, and vice versa, (3) both the anisotropic stress state and the anisotropic fabric (geometry) could lead to the Vs anisotropy, but the Vs anisotropy was manifested due to the horizontal stress-lock during unloading stage, and (4) the published correlation between Vs and K0 was modified by introducing the influence of the OCR, which could effectively reduce the variation and improve the prediction accuracy. Therefore, the modified correlation could be used as a robust approach to estimate K0 for both normally consolidated and highly overly consolidated granular soils.
Guangbo Du; Nina Liu; Zhao Xia; Xin Kang. Laboratory Investigation on the Stress-Dependent Anisotropic Shear Wave Velocity (Vs) and Coefficient of Lateral Earth Pressure at Rest (K0) of Granular Materials. Advances in Civil Engineering 2021, 2021, 1 -13.
AMA StyleGuangbo Du, Nina Liu, Zhao Xia, Xin Kang. Laboratory Investigation on the Stress-Dependent Anisotropic Shear Wave Velocity (Vs) and Coefficient of Lateral Earth Pressure at Rest (K0) of Granular Materials. Advances in Civil Engineering. 2021; 2021 ():1-13.
Chicago/Turabian StyleGuangbo Du; Nina Liu; Zhao Xia; Xin Kang. 2021. "Laboratory Investigation on the Stress-Dependent Anisotropic Shear Wave Velocity (Vs) and Coefficient of Lateral Earth Pressure at Rest (K0) of Granular Materials." Advances in Civil Engineering 2021, no. : 1-13.
Clay particles are usually associated in flocculates or aggregates with different microfabric manners, which will govern the macroscale mechanical behaviors of clayey soils. In this study, the characteristics of different microfabric manners of defect-free kaolinite were explored applying large-scale full-atomistic molecular dynamics simulations. Due to the special crystal structure, kaolinite particles were more likely to flocculate in Edge-to-Face (EF) and Edge-to-Edge (EE) manners than aggregate in Face-to-Face (FF) manner when analyzed from the system energy point of view. For EF and EE manners, the 1st layer of adsorbed water of every single kaolinite particle was complete while the 2nd and the 3rd layers of adsorbed water arranged in T-, L-/inverted L- or cross-shape according to the wettability performance of surrounding kaolinite particles' surfaces. A series of new schematic diagrams of different microfabric manners with adsorbed water structures were developed according to the corresponding equilibrium topologies and physicochemical characteristics. The conceptual hypothesis of the kaolinite sedimentary process was verified and improved based on the simulation results analysis. The research results enhanced the comprehension of microfabric characteristics of clay colloids. The simulation method applied in this work would foster future investigations into clay colloids in various physicochemical environments.
He-Mei Sun; Wei Yang; Ren-Peng Chen; Xin Kang. Microfabric characteristics of kaolinite flocculates and aggregates — Insights from large-scale molecular dynamics simulations. Applied Clay Science 2021, 206, 106073 .
AMA StyleHe-Mei Sun, Wei Yang, Ren-Peng Chen, Xin Kang. Microfabric characteristics of kaolinite flocculates and aggregates — Insights from large-scale molecular dynamics simulations. Applied Clay Science. 2021; 206 ():106073.
Chicago/Turabian StyleHe-Mei Sun; Wei Yang; Ren-Peng Chen; Xin Kang. 2021. "Microfabric characteristics of kaolinite flocculates and aggregates — Insights from large-scale molecular dynamics simulations." Applied Clay Science 206, no. : 106073.
With the objective of decreasing the adverse impact on the environment and recycling the waste of tailings, the possibility of producing eco-friendly building materials by utilizing the slate tailings (ST) was investigated. Besides ST, the fly ash (FA) and metakaolin (MK) mixtures were added to the raw materials through geopolymerization to improve the brick quality. The mechanical performance of the geopolymer brick was characterized by unconfined compression tests, and the physical properties, microstructure and geopolymerization processes were evaluated using X-ray diffraction (XRD), Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that at different ST contents, the variations of the compressive strength are attributed to the coupling effects of pore filling and geopolymer gelation. Higher alkaline activator/solid ratio and extended curing time generally lead to higher strength and bulk density while reduce the water absorption rate. Atomic force microscopy (AFM) was utilized to offer detailed information of geopolymer gels at higher resolutions for obtaining both surface morphology and nano-mechanical properties. The optimum conditions are found to be that the ST is 50%, alkali content and forming days are respectively 14% and 28 days. Under these conditions, the compressive strength and water absorption of the brick samples are 20.47 MPa and 13.4%, respectively, and the other physical properties meet the Chinese Non-sintered Waste Tailing Brick Standard (JC/T 422-2007).
Xin Kang; Yuxiang Gan; Renpeng Chen; Chao Zhang. Sustainable eco-friendly bricks from slate tailings through geopolymerization: synthesis and characterization analysis. Construction and Building Materials 2021, 278, 122337 .
AMA StyleXin Kang, Yuxiang Gan, Renpeng Chen, Chao Zhang. Sustainable eco-friendly bricks from slate tailings through geopolymerization: synthesis and characterization analysis. Construction and Building Materials. 2021; 278 ():122337.
Chicago/Turabian StyleXin Kang; Yuxiang Gan; Renpeng Chen; Chao Zhang. 2021. "Sustainable eco-friendly bricks from slate tailings through geopolymerization: synthesis and characterization analysis." Construction and Building Materials 278, no. : 122337.
The influence of surface topography on the mechanical behavior of soil-structure interfaces over a range of particle sizes and shapes is systematically investigated in this research. 3D printed interfaces with different topographies and uniformly graded 3D printed soil particles and two types of natural sands (Ottawa sand 20/30 and Dolomite sand #1, #2 and #3) were employed and tested. Laboratory investigations showed that the shear strength and volume change responses of the 3D printed interfaces are positively influenced with the increase of the inclination of asperities. The proposed wedge friction model successfully explained the distinct mechanical behaviors of soil-structure interfaces under shearing. A “turning point” was found for the interface shear resistance with the increase of the inclination of asperities. When the surface topography produces passive resistance to the soil, the change of the surface topography has little effect on the interface mechanical behavior. The findings from this research will provide insights for soil-structure interface design and discrete element method (DEM) simulations in considering the mechanical behavior of soil-structure interfaces.
Xin Kang; Hang Lei; Renpeng Chen. Examination of Interface Asperity and Particle Shape on the Mechanical Behavior of Soil-Structure Interfaces Using 3D Printed Models. KSCE Journal of Civil Engineering 2020, 25, 386 -397.
AMA StyleXin Kang, Hang Lei, Renpeng Chen. Examination of Interface Asperity and Particle Shape on the Mechanical Behavior of Soil-Structure Interfaces Using 3D Printed Models. KSCE Journal of Civil Engineering. 2020; 25 (2):386-397.
Chicago/Turabian StyleXin Kang; Hang Lei; Renpeng Chen. 2020. "Examination of Interface Asperity and Particle Shape on the Mechanical Behavior of Soil-Structure Interfaces Using 3D Printed Models." KSCE Journal of Civil Engineering 25, no. 2: 386-397.
This study aims to advance the understanding of particle shape effects on the mechanical behaviours of granular materials by using 3D printed soil. A holistic particle geometry parameter (Sh), which integrated the 3D information of a particle (i.e. volume, surface area, and size) was developed to describe the particle shape and correlate with the granule’s shear behaviours. Test results revealed that higher Sh had positive correlations with the shear strength and dilation angle but exhibited negative correlations with packing densities. Under a constant relative density, particle shape showed coupled effects on the mechanical and volumetric behaviours of granular materials. The Regular Hexahedron (RH) granules exhibited the highest shear strength with the optimal shape parameter. In addition, an empirical correlation between Sh and maximum mobilised friction angle (ϕmax) was established, which provided insights for discrete element method (DEM) simulations in considering the influences of particle shape.
Hang Lei; Zhixin Chen; Xin Kang. Examination of particle shape on the shear behaviours of granules using 3D printed soil. European Journal of Environmental and Civil Engineering 2020, 1 -20.
AMA StyleHang Lei, Zhixin Chen, Xin Kang. Examination of particle shape on the shear behaviours of granules using 3D printed soil. European Journal of Environmental and Civil Engineering. 2020; ():1-20.
Chicago/Turabian StyleHang Lei; Zhixin Chen; Xin Kang. 2020. "Examination of particle shape on the shear behaviours of granules using 3D printed soil." European Journal of Environmental and Civil Engineering , no. : 1-20.
A portable bender element-double cone penetration (BE-DCP) testing equipment, which is invented as a prototype model for measuring the small-strain stiffness (shear wave velocity, Vs) and shear strength of in-situ soft soil deposits (loose sand and soft clay) is developed in this study. The shear wave velocity in two orthogonal directions (Vs-hv and Vs-hh) of the in-situ soils is measured from paired bender elements (BE) installed on the side of the cone shaft. The bender elements are housed in a mechanically controlled sliding block in the shaft which not only protects bender elements while the BE-DCP apparatus is being pushed into the ground, but also ensures a good contact between adjacent soil particles and benders when the target depth is reached. The real-time relationship of the pushing force and penetration depth is recorded by force transducer and laser displacement sensor and graphed in LabVIEW. Based on the cone penetration testing (CPT) theory, two formulas are derived to calculate the shear strength parameters of the in-situ soils. Test results obtained from both the portable bender element-double cone penetration (BE-DCP) testing apparatus and conventional laboratory experiments on Ottawa sand 20/30, four different sizes of Dolomite sands in various packing densities and Kaolinite under different water contents and densities as well as a field testing were compared and validated, indicating that the novel designed portable bender elementdouble cone penetration (BE-DCP) apparatus is robust, fast, and cost-efficient for measurement of small-strain stiffness and shear strength of in-situ soils.
Xin Kang; He-Mei Sun; Hong Luo; Tian Dai; Ren-Peng Chen. A Portable Bender Element-Double Cone Penetration Testing Equipment for Measuring Stiffness and Shear Strength of In-Situ Soft Soil Deposits. KSCE Journal of Civil Engineering 2020, 24, 3546 -3560.
AMA StyleXin Kang, He-Mei Sun, Hong Luo, Tian Dai, Ren-Peng Chen. A Portable Bender Element-Double Cone Penetration Testing Equipment for Measuring Stiffness and Shear Strength of In-Situ Soft Soil Deposits. KSCE Journal of Civil Engineering. 2020; 24 (12):3546-3560.
Chicago/Turabian StyleXin Kang; He-Mei Sun; Hong Luo; Tian Dai; Ren-Peng Chen. 2020. "A Portable Bender Element-Double Cone Penetration Testing Equipment for Measuring Stiffness and Shear Strength of In-Situ Soft Soil Deposits." KSCE Journal of Civil Engineering 24, no. 12: 3546-3560.
We compared the catalytic effects of two polymers (soluble starch and apple pectin) on the flocculation of kaolinite suspension. Moreover, the relationship between the zeta potential value and the time when kaolin particle sedimentation occurred was verified, and the mechanism of flocculation was analyzed. Additionally, a constitutive model was proposed to simulate the non-ideal sedimentation of clay particles in an aqueous system under constant gravity. This model not only considers the inhomogeneity of the solute but also simulates the change in clay concentration with time during the deposition process. This model proposes a decay constant (α) and sedimentation coefficient (s). The model can also be used to calculate the instantaneous sedimentation rate of the clay suspensions at any time and any depth for the settling cylinder. These sedimentary characteristics were simulated by adopting the established deposition model. The results show that the model is capable of predicting the time required for the complete sedimentation of particles in the aqueous system, suggesting the feasibility of engineering wastewater treatment, site dredging, etc.
Jianfu Wang; Xin Kang; Chunyin Peng. Modelling and Experimental Investigation on the Settling Rate of Kaolinite Particles in Non-Ideal Sedimentation Stage under Constant Gravity. Materials 2020, 13, 3785 .
AMA StyleJianfu Wang, Xin Kang, Chunyin Peng. Modelling and Experimental Investigation on the Settling Rate of Kaolinite Particles in Non-Ideal Sedimentation Stage under Constant Gravity. Materials. 2020; 13 (17):3785.
Chicago/Turabian StyleJianfu Wang; Xin Kang; Chunyin Peng. 2020. "Modelling and Experimental Investigation on the Settling Rate of Kaolinite Particles in Non-Ideal Sedimentation Stage under Constant Gravity." Materials 13, no. 17: 3785.
Coarse-grained molecular dynamic (CGMD) simulations are the most popular technique in mesoscale modeling. In the fields of applied clay science, significant progresses have been made in coarse-graining clay particles. Meanwhile, various kinds of coarse-grained water models have been developed in the fields of environmental science, chemical physics and biological science to advance the basic understanding of chemical and biological reaction processes in the presence of water. The coarse-grained clay model (Gay-Berne clay model) that has the highest coarsening degree and the most reasonable coarsening theory, however, requires a unique potential function, which is found not compatible with previous coarse-grained water models. In order to simulate mesoscale clay-water interactions using Gay-Berne clay model, a completely new coarse-grained water model was proposed in this study. Five water molecules were embedded into one pseudo spherical water particle. The model parametrization was determined by thermodynamic perturbation method and was verified by comparing the nine physical, mechanical and thermodynamic properties with previous published studies in experiments, full-atomistic water models and other coarse-grained water models. Comparison analysis showed that the properties of water were well reproduced by the newly developed simple coarse-grained water model. In addition, the new coarse-grained water model showed a speed-up factor of 520 in reference with full-atomistic water model. Therefore, the new coarse-grained water model is suitable for coarse-grained simulations and could bridge the gap toward probing the clay-water interaction mechanisms from nano to mesoscale.
He-Mei Sun; Wei Yang; Ren-Peng Chen; Xin Kang. A coarse-grained water model for mesoscale simulation of clay-water interaction. Journal of Molecular Liquids 2020, 318, 114085 .
AMA StyleHe-Mei Sun, Wei Yang, Ren-Peng Chen, Xin Kang. A coarse-grained water model for mesoscale simulation of clay-water interaction. Journal of Molecular Liquids. 2020; 318 ():114085.
Chicago/Turabian StyleHe-Mei Sun; Wei Yang; Ren-Peng Chen; Xin Kang. 2020. "A coarse-grained water model for mesoscale simulation of clay-water interaction." Journal of Molecular Liquids 318, no. : 114085.
Shear wave velocity (Vs) anisotropy of kaolinite mixed with sodium chloride (NaCl) and organic polymer (polyethylene oxide, xanthan gum, and chitosan) solutions was investigated using a custom-made floating wall consolidometer-type bender element testing system. The addition of salt and polymers influenced the microfabric anisoopy of platy kaolinite particles, thus resulted in the increment or decrement in the Vs anisotropy. The Vs of kaolinite in all three orthogonal directions increased as the NaCl concentration increased; however, the Vs anisotropy decreased. PEO and chitosan increased the Vs of kaolinite, while xanthan gum exhibited counter-effects. Vs anisotropy (Vs−hh/Vs−vh and Vs−hv/Vs−vh) of polymer amended kaolinite was found to decrease. In addition, both salt- and polymer-modified kaolinite did not show Vs cross-anisotropy.
X. Kang; J. Cao; B. Bate. Shear wave velocity anisotropy of salt- and polymer-amended kaolinite. Acta Geotechnica 2020, 15, 3605 -3611.
AMA StyleX. Kang, J. Cao, B. Bate. Shear wave velocity anisotropy of salt- and polymer-amended kaolinite. Acta Geotechnica. 2020; 15 (12):3605-3611.
Chicago/Turabian StyleX. Kang; J. Cao; B. Bate. 2020. "Shear wave velocity anisotropy of salt- and polymer-amended kaolinite." Acta Geotechnica 15, no. 12: 3605-3611.
Additional void ratio and yield stress that can be easily determined by one-dimensional consolidation test are two representative parameters for the assessment of clayey soil structure. In this paper, a “structural parameter” that defined as the normalization of the integral of additional void ratio times effective vertical stress until yield stress was proposed to evaluate the disturbance induced by soil structure changes. By conducting oedometer tests on Hangzhou clay at various disturbed states, the compression index, yield stress, and structural parameter were obtained. The evolution of normalized additional void ratio during one-dimensional loading is presented to establish the soil structural indexing strategies for assessment of clay structure disturbances. Based on the laboratory investigations, a linear relationship between the normalized structural parameter and normalized yield additional void ratio was obtained. For a certain soil, specimens with the same initial void ratio but different disturbed state have a nearly constant void ratio when yielding. It is also found that soils with a higher plasticity index exhibit stronger structure and lower compressibility. In addition, quick direct shear tests were carried out to examine the undrained shear strength of soils at different disturbed states. The soil disturbance degree quantified from the undrained shear strength is found slightly higher than that from the structural parameter. This study can provide a reference for assessing the clayey soil structure.
Fanyan Meng; Renpeng Chen; Xin Kang; Zhongchao Li. e-p curve-based structural parameter for assessing clayey soil structure disturbance. Bulletin of Engineering Geology and the Environment 2020, 79, 4387 -4398.
AMA StyleFanyan Meng, Renpeng Chen, Xin Kang, Zhongchao Li. e-p curve-based structural parameter for assessing clayey soil structure disturbance. Bulletin of Engineering Geology and the Environment. 2020; 79 (8):4387-4398.
Chicago/Turabian StyleFanyan Meng; Renpeng Chen; Xin Kang; Zhongchao Li. 2020. "e-p curve-based structural parameter for assessing clayey soil structure disturbance." Bulletin of Engineering Geology and the Environment 79, no. 8: 4387-4398.
Setting time is a critical parameter that limits the workability of cement-based materials and is generally determined using a Vicat needle test for cement paste, or by measuring the penetration resistance for mortar and concrete. The Vicat needle and penetration tests, however, are either adequate for cement paste or mortars, instead of all types of cementitious materials. Therefore, a modified fall cone method (FCM) was developed to serve as a unified test protocol for measuring the setting time of both cement paste and mortars while the semi-adiabatic calorimetry (SAC) was employed for a comparative study. Mortar samples with various mix proportions and aggregate sizes were tested by both methods. Two models were established to fit the FCM and SAC data, and the initial and final setting times were obtained by taking extremums from the derivatives. Test results indicated that the setting time measured by the FCM were consistently shorter than those measured by the SAC and such discrepancy gradually decreased with the increase of cement/sand ratio (wc/ws) and finally disappeared when pure cement paste was achieved. The discrepancy of the setting time measured from different methods is attributed to the mixing of aggregates, which significantly enhances the penetration resistance of mortar but only has a moderate effect on heat evolution at early-age hydration.
Xin Kang; Hang Lei; Zhao Xia. A comparative study of modified fall cone method and semi-adiabatic calorimetry for measurement of setting time of cement based materials. Construction and Building Materials 2020, 248, 118634 .
AMA StyleXin Kang, Hang Lei, Zhao Xia. A comparative study of modified fall cone method and semi-adiabatic calorimetry for measurement of setting time of cement based materials. Construction and Building Materials. 2020; 248 ():118634.
Chicago/Turabian StyleXin Kang; Hang Lei; Zhao Xia. 2020. "A comparative study of modified fall cone method and semi-adiabatic calorimetry for measurement of setting time of cement based materials." Construction and Building Materials 248, no. : 118634.
Excavated soils from tunnel construction need high treatment cost and pollute the environment. To investigate the feasibility of excavated clayey silt reused in back-fill grout, the flowability, stability and strength were taken as measurement indexes of grouting performance. The clayey silt was tested to be reused as substitutes for fly ash, bentonite and sand, respectively. The experimental results indicated that the clayey silt reused as a substitute for fly ash decreased the flowability and strength of grout mixes, and the clayey silt reused as a substitute for bentonite decreased the stability of grout mixes, and neither of them was feasible. The clayey silt reused as a substitute for sand decreased the flowability, but the grouting performance could be improved by adjusting the mix proportion to meet all grouting requirements. After adding the proportion of water to improve the flowability and increasing the cement:fly ash ratio to improve the strength, a scheme of clayey silt reutilization was suggested, which was cement:fly ash:bentonite:clayey silt:water = 280:230:100:680:660. At the end of this paper, the pore structure feature tests, X-ray diffraction (XRD) tests and scanning electron microscope (SEM) tests were performed to analyze the different morphology, microstructure and mineralogy characteristics before and after the clayey silt was reused as a total substitute for sand in grout mixes.
Jun Xu; Chao Xiao; Huai-Na Wu; Xin Kang. Reuse of Excavated Clayey Silt in Cement–Fly Ash–Bentonite Hybrid Back-fill Grouting during Shield Tunneling. Sustainability 2020, 12, 1017 .
AMA StyleJun Xu, Chao Xiao, Huai-Na Wu, Xin Kang. Reuse of Excavated Clayey Silt in Cement–Fly Ash–Bentonite Hybrid Back-fill Grouting during Shield Tunneling. Sustainability. 2020; 12 (3):1017.
Chicago/Turabian StyleJun Xu; Chao Xiao; Huai-Na Wu; Xin Kang. 2020. "Reuse of Excavated Clayey Silt in Cement–Fly Ash–Bentonite Hybrid Back-fill Grouting during Shield Tunneling." Sustainability 12, no. 3: 1017.
Binary soil mixtures are extensively used in the construction of geothermal-related earth structures such as geothermal energy piles (GEP), ground source heat pumps (GSHP) and earth air tunnel heat exchangers (EATHE). An evaluation of the binary soil’s thermal-mechanical properties is the key process in determining the final performance of geothermal-related projects. Therefore, the thermal-mechanical properties of binary soil mixtures were systematically investigated in this paper. A series of thermal and mechanical property tests was conducted on five sand-kaolin clay mixtures with sand contents ranging from 0% to 100% by dry weight. The experimental results indicated that the sand-clay mixtures achieved the theoretically densest state when the sand content reached the critical threshold. The further the binary mixture’s sand content was from the critical threshold, the lower the mixture’s density was. As the sand content increased, the shear stress-strain curves gradually shifted from strain-softening behavior to strain-hardening behavior due to the decrease in suction stress. The relationship between the sand content and the shear strength of the mixtures exhibited an “S” shape, which is attributed to the interaction between the sand and clay particles and varied with the sand contents. The shear wave velocity of the sand clay mixtures was found to decrease continuously with the increase in sand content until the sand skeleton had formed. In addition, the thermal conductivity of the binary mixed soil changed linearly with the sand content, and the upper bound of the critical threshold interval (77%) was found to separate the two different heat conduction modes. Finally, an elastic shear modulus (G0) model, which correlated to the tangent elastic modulus of the binary mixture (Em), and a more generalized thermal conductivity (K) model were formulated for the binary sand-clay mixtures, and the effectiveness and feasibility of the proposed models were validated by comparing the values predicted with the model and the experimental data.
Zhao Xia; Ren-Peng Chen; Xin Kang. Laboratory characterization and modelling of the thermal-mechanical properties of binary soil mixtures. Soils and Foundations 2019, 59, 2167 -2179.
AMA StyleZhao Xia, Ren-Peng Chen, Xin Kang. Laboratory characterization and modelling of the thermal-mechanical properties of binary soil mixtures. Soils and Foundations. 2019; 59 (6):2167-2179.
Chicago/Turabian StyleZhao Xia; Ren-Peng Chen; Xin Kang. 2019. "Laboratory characterization and modelling of the thermal-mechanical properties of binary soil mixtures." Soils and Foundations 59, no. 6: 2167-2179.
Xin Kang; Zhao Xia; Renpeng Chen; Hemei Sun; Wei Yang. Effects of inorganic ions, organic polymers, and fly ashes on the sedimentation characteristics of kaolinite suspensions. Applied Clay Science 2019, 181, 1 .
AMA StyleXin Kang, Zhao Xia, Renpeng Chen, Hemei Sun, Wei Yang. Effects of inorganic ions, organic polymers, and fly ashes on the sedimentation characteristics of kaolinite suspensions. Applied Clay Science. 2019; 181 ():1.
Chicago/Turabian StyleXin Kang; Zhao Xia; Renpeng Chen; Hemei Sun; Wei Yang. 2019. "Effects of inorganic ions, organic polymers, and fly ashes on the sedimentation characteristics of kaolinite suspensions." Applied Clay Science 181, no. : 1.
Yu-Syuan Jhuo; Yu Guan; Louis Ge; Zhao Xia; Xin Kang. Assessment of Direct Tension Tests on Compacted Sand-Clay Mixtures. Journal of Materials in Civil Engineering 2019, 31, 04019236 .
AMA StyleYu-Syuan Jhuo, Yu Guan, Louis Ge, Zhao Xia, Xin Kang. Assessment of Direct Tension Tests on Compacted Sand-Clay Mixtures. Journal of Materials in Civil Engineering. 2019; 31 (10):04019236.
Chicago/Turabian StyleYu-Syuan Jhuo; Yu Guan; Louis Ge; Zhao Xia; Xin Kang. 2019. "Assessment of Direct Tension Tests on Compacted Sand-Clay Mixtures." Journal of Materials in Civil Engineering 31, no. 10: 04019236.
This paper presents a full-scale model study of geosynthetic-reinforced pile-supported (GRPS) track-bed to investigate the effect of geogrid reinforcement and the evolution of pile efficacy (ratio of load borne by the pile cap to the total applied load). Three testing procedures were followed: model construction, static loading and subsoil settlement (simulated by discharging of water bags surrounding the pile caps). The results indicated that partially mobilized soil arching was developed during the first two procedures. When sufficient subsoil settlement was reached, fully mobilized soil arching was established. The geogrid was proven to effectively transfer load from the water bag to the pile cap. The stress difference induced by the geogrid showed lower absolute values for the corresponding sensors above the water bag during loading and settlement procedures, due to the inverse triangular distribution of the vertical-directional geogrid tensile force above the water-bag area. The experimental results of pile efficacy were compared to the estimations of four analytical models. For the present test at partially mobilized arching state, the pile efficacy increased with the construction height increasing and decreased as the static loading increased. The partially mobilized arching also resulted in overestimations of the pile efficacy from all four analytical models. At fully mobilized arching state, the pile efficacy stayed relatively stable, being well predicted by all four analytical models.
Han-Lin Wang; Ren-Peng Chen; Qiwei Liu; Xin Kang. Investigation on geogrid reinforcement and pile efficacy in geosynthetic-reinforced pile-supported track-bed. Geotextiles and Geomembranes 2019, 47, 755 -766.
AMA StyleHan-Lin Wang, Ren-Peng Chen, Qiwei Liu, Xin Kang. Investigation on geogrid reinforcement and pile efficacy in geosynthetic-reinforced pile-supported track-bed. Geotextiles and Geomembranes. 2019; 47 (6):755-766.
Chicago/Turabian StyleHan-Lin Wang; Ren-Peng Chen; Qiwei Liu; Xin Kang. 2019. "Investigation on geogrid reinforcement and pile efficacy in geosynthetic-reinforced pile-supported track-bed." Geotextiles and Geomembranes 47, no. 6: 755-766.
Xin Kang; Zhao Xia; Renpeng Chen; Peng Liu; Wei Yang. Effects of inorganic cations and organic polymers on the physicochemical properties and microfabrics of kaolinite suspensions. Applied Clay Science 2019, 176, 38 -48.
AMA StyleXin Kang, Zhao Xia, Renpeng Chen, Peng Liu, Wei Yang. Effects of inorganic cations and organic polymers on the physicochemical properties and microfabrics of kaolinite suspensions. Applied Clay Science. 2019; 176 ():38-48.
Chicago/Turabian StyleXin Kang; Zhao Xia; Renpeng Chen; Peng Liu; Wei Yang. 2019. "Effects of inorganic cations and organic polymers on the physicochemical properties and microfabrics of kaolinite suspensions." Applied Clay Science 176, no. : 38-48.
The settling curve is commonly used for studying the sedimentation process of a suspension. This paper introduces a mathematical equation (S-model) to simulate the settling curve of a suspension and offers new approaches to calculate the settling velocity, solid volume fraction, and flocs size of suspended particles in dilute range during sedimentation. The proposed S-model was evaluated by both experimental data and literature test data which is shown to accurately represent different types of settling behaviors and provide closer simulation than the previous published models. The proposed S-model also enhanced the representation of the hindered settling and consolidation portions of a settling curve through the introduction of two model parameters that controlling the deflection points of the sedimentation and consolidation. In addition, Computational Fluid Dynamics (CFD) simulation was conducted which indicated that the proposed S-model is a robust tool in modeling and characterizing the sedimentation behaviors of batch sedimentation. The findings from this research may provide new approach in modeling the sedimentation behavior of soil suspensions and bring broad impacts to engineering applications, such as biological secondary treatment process, mineral processing, water purification, sedimentation, soil modification, and ground improvement.
Xin Kang; Zhao Xia; Jianfu Wang; Wei Yang. A novel approach to model the batch sedimentation and estimate the settling velocity, solid volume fraction, and floc size of kaolinite in concentrated solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2019, 579, 123647 .
AMA StyleXin Kang, Zhao Xia, Jianfu Wang, Wei Yang. A novel approach to model the batch sedimentation and estimate the settling velocity, solid volume fraction, and floc size of kaolinite in concentrated solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019; 579 ():123647.
Chicago/Turabian StyleXin Kang; Zhao Xia; Jianfu Wang; Wei Yang. 2019. "A novel approach to model the batch sedimentation and estimate the settling velocity, solid volume fraction, and floc size of kaolinite in concentrated solutions." Colloids and Surfaces A: Physicochemical and Engineering Aspects 579, no. : 123647.
This paper proposed a pore-scale model to simulate the effect of initial soil density on the bimodal soil water characteristic curve (SWCC) of compacted soils. The pore-scale model is developed based on the bimodal pore-size distribution. Soils with bimodal pore-size distribution is assumed to have dual porosity, namely the macropore structure and the micropore structure, and hypothesized that the micropore structure is hard to be compressed under mechanical loading. The water stored in the macropore structure is divided into two parts, the bulk water and the meniscus water, respectively. The deformation of soil (bulk water flow) is obtained by horizontal shifting and vertical scaling of the pore-size distribution (PSD) function. A toroidal model is used to describe the influence of initial density on the meniscus water. The pore structure of compacted coal gangue was qualitatively imaged as an evidence of the pore structure changes, and the SWCC of the compacted coal gangue was quantitatively analyzed. Finally, a numerical method is advised for simulating bimodal permeability function by using the proposed model with Mualem function. Laboratory test results in published literature are employed to validate the proposed model and permeability function, and the model predictions showed good agreement with the experimental data in the literature.
Ren-Peng Chen; Peng Liu; Xiao-Ming Liu; Peng-Fei Wang; Xin Kang. Pore-scale model for estimating the bimodal soil–water characteristic curve and hydraulic conductivity of compacted soils with different initial densities. Engineering Geology 2019, 260, 105199 .
AMA StyleRen-Peng Chen, Peng Liu, Xiao-Ming Liu, Peng-Fei Wang, Xin Kang. Pore-scale model for estimating the bimodal soil–water characteristic curve and hydraulic conductivity of compacted soils with different initial densities. Engineering Geology. 2019; 260 ():105199.
Chicago/Turabian StyleRen-Peng Chen; Peng Liu; Xiao-Ming Liu; Peng-Fei Wang; Xin Kang. 2019. "Pore-scale model for estimating the bimodal soil–water characteristic curve and hydraulic conductivity of compacted soils with different initial densities." Engineering Geology 260, no. : 105199.