Cohesion Coefficient Research Articles

Stability analysis of ultra-high and steep reinforced soil fills slopes based on strength reduction

The research focuses on solving the important problem of slope stability in the field of civil engineering. The study adopted an advanced strength double reduction coefficient method for slope stability analysis, which considers the different influence weights of cohesion and internal friction angle, and reduces them with different reduction coefficients to describe the stability of the slope. The simulation experiment results indicate that the attenuation degree of cohesion and internal friction angle affects slope stability. When the reduction coefficient of cohesion increases to 1.737 and the reduction coefficient of internal friction angle increases to 1.201, the slope is prone to instability and failure, and the safety factor of the calculated result is 1.493. Moreover, when the anti-slip pile is set in the middle of the slope (1/2), and the slope is in a critical state, the bending moment and shear force suffered by the anti-slip pile are both maximum, so the reinforcement effect is also the best.

Compression creep characteristics of crushed sugarcane end-leaves

The creep behavior of crushed sugarcane end-leaf (SEL) was studied, with consideration of different loading force, moisture content, and feeding amount. Statistical analysis software was used to develop and fit the regression data to a strain change law as a function of time. The four-element Burgers model was used. A further goal was to analyze the effect of different test conditions on the fitted creep characteristic parameters. The instantaneous elasticity coefficient E0 was found to increase when the loading force increased; the value of delayed elasticity coefficient E1 increased and the value of cohesion coefficient η0 decreased when the feeding amount increased; the value of delayed elasticity coefficient E1 and cohesion coefficient η0 decreased when the moisture content was increased. Therefore, the loading force, moisture content, and feeding amount of crushed SEL all affected the creep capacity of crushed SEL in compression. The results can provide substantial theoretical reference for the silage production of crushed SEL.

Multi-objective genetic algorithm calibration of colored self-compacting concrete using DEM: an integrated parallel approach.

A detailed numerical simulation of Colored Self-Compacting Concrete (CSCC) was conducted in this research. Emphasis was placed on an innovative calibration methodology tailored for ten unique CSCC mix designs. Through the incorporation of multi-objective optimization, MATLAB's Genetic Algorithm (GA) was seamlessly integrated with PFC3D, a prominent Discrete Element Modeling (DEM) software package. This integration facilitates the exchange of micro-parameter values, where MATLAB's GA optimizes these parameters, which are then input into PFC3D to simulate the behavior of CSCC mix designs. The calibration process is fully automated through a MATLAB script, complemented by a fish script in PFC, allowing for an efficient and precise calibration mechanism that automatically terminates based on predefined criteria. Central to this approach is the Uniaxial Compressive Strength (UCS) test, which forms the foundation of the calibration process. A distinguishing aspect of this study was the incorporation of pigment effects, reflecting the cohesive behavior of cementitious components, into the micro-parameters influencing the cohesion coefficient within DEM. This innovative approach ensured significant alignment between simulations and observed macro properties, as evidenced by fitness values consistently exceeding 0.94. This investigation not only expanded the understanding of CSCC dynamics but also contributed significantly to the discourse on advanced concrete simulation methodologies, underscoring the importance of multi-objective optimization in such studies.

Modeling rainfall-induced landslide using the concept of local factor of safety: Uncertainty propagation and sensitivity analysis

Rainfall-induced landslides (RILS) are commonly investigated using hydro-mechanical models with the concept of local factor of safety. The inputs of these models are usually prone to uncertainties. An uncertainty analysis is required to investigate how uncertainties propagate through the model and impact the predictions. An appropriate strategy for uncertainty propagation analysis is suggested in this work to deal with nonlinearity and high dimensionality of RILS problems. It proceeds by performing a sensitivity analysis in two steps. A screening technique is first applied to eliminate insignificant parameters. Then, a global sensitivity analysis is performed to rank the parameters by order of importance. The Sobol indices are used as sensitivity metrics. The polynomial chaos expansion is used to compute the Sobol indices. The proposed strategy is first applied to a hypothetical benchmark and then to a more realistic configuration where prior knowledge of parameters and type of soil are considered. The results show that, when prior knowledge of soil is available, the most important parameters are the coefficient of cohesion, friction angle and air entry pressure head, respectively. The results also show that 10% uncertainty on these parameters leads to about 20% uncertainty on the prediction of slope stability.

Estimation of geomechanical rock characteristics from specific energy data using combination of wavelet transform with ANFIS-PSO algorithm

The geomechanical characteristics of a drill formation are uncontrollable factors that are crucial to determining the optimal controllable parameters for a drilling operation. In the present study, data collected in wells drilled in the Marun oilfield of southwestern Iran were used to develop adaptive network-based fuzzy inference system (ANFIS) models of geomechanical parameters. The drilling specific energy (DSE) of the formation was calculated using drilling parameters such as weight-on-bit (WOB), rate of penetration (ROP), rotational speed of drilling string (RPM), torque, bit section area, bit hydraulic factor, and bit hydraulic power. A stationary wavelet transform was subsequently used to decompose the DSE signal to the fourth level. The approximation values and details of each level served as inputs for ANFIS models using particle swarm optimization (PSO) algorithm and genetic algorithm (GA). As model outputs, the Young’s Modulus, uniaxial compressive strength (UCS), cohesion coefficient, Poisson’s ratio, and internal friction angle were compared to the geomechanical parameters obtained from petrophysical logs using laboratory-developed empirical relationships. Both models predicted the Young’s modulus, UCS, and cohesion coefficient with high accuracy, but lacked accuracy in predicting the internal friction angle and Poisson’s ratio. The root mean square error (RMSE) and determination coefficient (R2) were lower for the ANFIS-PSO model than for the ANFIS-GA model, indicating that the ANFIS-PSO model presents higher accuracy and better generalization capability than the ANFIS-GA model. As drilling parameters are readily available, the proposed method can provide valuable information for strategizing a drilling operation in the absence of petrophysical logs.

A New Approach for Analyzing Circular Tunnels in Nonlinear Strain-Softening Rock Masses Considering Seepage Force

Accurate calculation of the stresses and deformations of tunnels is of great importance for practical engineering applications. In this study, a three-region model for tunnels considering seepage force was established. A new nonlinear strain-softening model is proposed. Then, a unified solution for the stresses and deformations of tunnels is deduced. Through a series of discussions, the effects of seepage force, softening modulus coefficient of cohesion, and initial support resistance on the stress distribution, radii of the post-peak zone, and surface displacement around the tunnel are discussed. Results show that the tangential stresses are always larger than the radial stresses. As the distance from the tunnel center increases, the radial stress continues to increase, while the tangential stress first increases and then decreases. With the increases in seepage force, the radii of the post-peak zone and surface displacement all increase. With the increases in softening modulus coefficient of cohesion, the radii of the post-peak zone increase while the surface displacement decreases. Tunnels with a higher initial support resistance experience lower radii of the post-peak zone and surface displacement.

Development of model and analysis of one-dimensional movement of ploughshare of subsoiler

Soil medium changes its structure and deforms when the actuating tool of an agricultural machine interacts with the soil. The effect of soil on the performance of the actuating tool can be taken into account through soil density and tensile strength. The model of a plastic medium proposed by Academician Kh.A. Rakhmatulin and simplified equations obtained based on the hypothesis of plane sections were used to describe the movement of soil near the point under finite deformations. It was stated that, depending on the coefficient of internal friction and cohesion of soil, a zone of high soil density could form near the actuating tool of the subsoiler ploughshare, where a significant increase in the resistance force is observed.

Dynamic Community Detection Method of a Social Network Based on Node Embedding Representation

The node embedding method enables network structure feature learning and representation for social network community detection. However, the traditional node embedding method only focuses on a node’s individual feature representation and ignores the global topological feature representation of the network. Traditional community detection methods cannot use the static node vector from the traditional node embedding method to calculate the dynamic features of the topological structure. In this study, an incremental dynamic community detection model based on a graph neural network node embedding representation is proposed, comprising the following aspects. A node embedding model based on influence random walk improves the information enrichment of the node feature vector representation, which improves the performance of the initial static community detection, whose results are used as the original structure of dynamic community detection. By combining a cohesion coefficient and ordinary modularity, a new modularity calculation method is proposed that uses an incremental training method to obtain node vector representation to detect a dynamic community from the perspectives of coarse- and fine-grained adjustments. A performance analysis based on two dynamic network datasets shows that the proposed method performs better than benchmark algorithms based on time complexity, community detection accuracy, and other indicators.

Taxonomy of cohesion coefficients for weighted and directed multilayer networks

Clustering and closure coefficients are among the most widely applied indicators in the description of the topological structure of a network. Many distinct definitions have been proposed over time, particularly in the case of weighted networks, where the choice of the weight attributed to the triangles is a crucial aspect. In the present work, in the framework of weighted directed multilayer networks, we extend the classical clustering and closure coefficients through the introduction of the clumping coefficient, which generalizes them to incomplete triangles of any type. We then organize the class of these coefficients in a systematic taxonomy in the more general context of weighted directed multilayer networks. Such cohesion coefficients have also been adapted to the different scales that characterize a multilayer network, in order to grasp their structure from different perspectives. We also show how the tensor formalism allows incorporating the new definitions, as well as all those existing in the literature, in a single unified writing, in such a way that a suitable choice of the involved adjacency tensors allows obtaining each of them. Finally, through some applications to simulated networks, we show the effectiveness of the proposed coefficients in capturing different peculiarities of the network structure on different scales.

Evaluation of Surface Properties of Chitosan and Scale Gelatin Coatings on Shrimp Fillets (Litopenaeus vannamei)

ABSTRACT This study aimed to evaluate the wettability of edible coatings based on chitosan or the gelatin of Nile tilapia (Oreochromis niloticus) scales on the surface of shrimp fillets (Litopenaeus vannamei) with glycerol as a plasticizer. Initially, the surface was characterized according to Zisman’s methodology. The surface tension and dispersive and polar components of the shrimp fillet was 59.93 (low-energy surface), 14.14, and 45.79 mN/m, respectively. The mathematical modeling applied to experimental design 32 showed that the minimum concentration of biopolymers favored wettability, among other observations about the interactions between the components of the coatings and the surface of the shrimp fillet. The behavior of the plasticizer was influenced by the biopolymer; as the concentration of the plasticizer increased, the cohesion coefficient of chitosan coatings decreased, while the opposite effect was observed for gelatin coatings. The coating compositions with optimized wettability were 1.0% chitosan and 0% glycerol (W s = −12.934 mN/m), and 1.0% gelatin and 0% glycerol (W s = −5.588 mN/m).

Bonding properties and mechanism of the interface between precast UHPC and post-cast UHPC

In the application of UHPC joints between the precast UHPC segmental bridges, the bonding behavior of UHPC-to-UHPC interface can influence the overall integrity and the performance of the structures. The current study used the direct shear test, splitting tensile test and slant shear test to clarify the bonding properties and mechanism of the interface between precast UHPC and post-cast UHPC. The different surface preparations, including as-cast, chiseled and grooved, were considered and discussed. DIC technique was employed to observe the failure process of UHPC bond specimens. The cohesion coefficient and friction coefficient were recommended by data analysis. The results demonstrated that the UHPC bond specimens presented adhesive failure along the bonding interface without any failure was observed in the precast UHPC or post-cast UHPC. The surface preparation showed various effects on the bond strength of interface under different stress states. The bond strength of the interface is ranked from lowest to highest as follows: as-cast interface, chiseled interface and grooved interface. The interface shear bond strength increased little with chiseled preparation, but the tensile bond strength increased significantly. The interface with grooved preparation showed a greater improvement in shear bond strength than in tensile bond strength. The correlations between the interface bond strength and chemical bonding force, Van der Waals force, mechanical interlocking force and the bridge effect and dowel action of steel fibers were discussed. The values of cohesion coefficient were 0.983 MPa, 0.995 MPa and 11.818 MPa for as-cast interface, chiseled interface and grooved interface, respectively. The corresponding friction coefficient for each surface preparation was 1.065, 1.126 and 1.190, respectively.

Ballast Stabilization with Polyurethane for Use in Desert Areas

Sand dune accumulation in the railways passing through desert areas leads to ballast softening and settlement, which is one of the major challenges in the ballast maintenance operation. In this regard, ballast infilling with polyurethane could be mentioned as a novel solution that has been less attentional in previous studies. In this matter, in present study using a domestic cost-effective polyurethane, the ballast stabilization has been accomplished and the relevant shear strength parameters have been investigated via a series of large-scale direct shear tests. Since the utilized polyurethane has composed of two different components, in the first stage, the best weight ratios of components have been investigated via a series of compression tests. In this matter, the ratio of 1.5 units polyol to 1 unit isocyanate has been adopted as the best composition. Then, the resulting polyurethane was injected into the ballast to perform large-scale direct shear tests. According to the measurement results, the maximum shear stress, the internal friction angle, and the cohesion coefficient increased by 109%, 9.5%, and 162.5% with respect to the non-stabilized ballast (NSB), respectively. In addition, the dilation angle decreased by 66.4% with the injection of polyurethane into the ballast. Hence, the results indicate increased shear strength and lateral track resistance in the presence of polyurethane, which can prevent lateral deflection and improve track safety. In other words, the mentioned polyurethane has improved the shear parameters of the ballast more significantly than other polyurethanes and has shown its performance in increasing the bearing capacity.

Improvement of lateritic soil using shredded plastic bottles for road construction in Jos-South, Plateau State of Nigeria

Some geotechnical properties of lateritic soil treated with plastic shred were assessed. The test method employed involves treating lateritic soil with Plastic shreds in the percentages of 0%, 0.5%, 1.0%, 1.5%, and 2.0% by dry weight of soil. Test carried out include preliminary test, compaction test using British Standard light (BSL) and Unconfined compressive strength (UCS) test and shear strength test. One-way analysis of variance (ANOVA) and Regression Analysis was carried out using Microsoft Office Excel software. Percentage passing BS No 200 sieve (%) was 19.34. The MDD initially increased from its natural value of 1.70 Mg/m3 to 1.77 Mg/m3 at 0.5% PS content, while OMC increased with increase in PS. The UCS increased from 51 kN/m2 for the natural soil to 72 kN/m2 at 0.5% shredded plastic content and thereafter, a decrease in UCS was observed with further increase in the percentage of shredded plastic (1%, 1.5%, and 2%). The angle of internal friction increased by about 11% and the cohesion coefficient increased by 12%; bearing capacity increased generally with an increase in PS from 147 kN/m2 natural to 215 kN/m2 at 2%. ANOVA analysis shows that shredded plastic has a significant effect on the treated lateritic soil. Based on the result obtained, an optimal 2% of PS content improved the index and strength characteristics of the treated soil and is recommended for geotechnical engineering application based on regulatory standards.

Interface Shear Behaviour between Precast and New Concrete in Composite Concrete Members: Effect of Grooved Surface Roughness

A major condition for the quality performance of connected-concrete layers is enough shear strength at the interface. Research shows that the interface shear behaviour is highly dependent on the texture of its interface. Although, several research on the effect of surface roughness on the interface shear behaviour of concrete to concrete connection using different interface patterns exists; however, there is scant literature on studies using quantitatively controlled interface texture, especially studies considering the roughness tooth geometrical parameters. In this study, seven different interface roughness geometries were designed and utilised as the study parameters for the interface shear behaviour, as well as the initial confining pressure. The double-sided shear test was used to determine the shear behaviour, failure mode, shear transfer mechanism, alongside the friction and cohesion values for all the studied interface types. The test results showed that both the interface roughness geometry and the magnitude of the confining pressure have a significant effect on the interfacial shear behaviour. Using different formations of the interface geometry provided a 15.4% difference in interfacial shear strength. For most of the interface geometries, interface cracking load increases linearly with the increase of initial confining pressure, while for the shear strength, the increase in confining pressure is more effective at lower pressure values. The friction and cohesion coefficients are influenced by the roughness tooth angle and tooth distribution.

Artificial neural network models for wall parameters on plug-1 flow characteristics through pipelines

Dense phase pneumatic conveying is a preferable method for transportation of a friable, fragile, abrasive, or agglomerated in nature material through pipeline with comparatively less wear and tear of the system and product as well. A fine particulate material moves as a single entity due to its cohesion in vertical or thin horizontal pipes in Plug-1 flow. A model based on mechanics was created and later modified using experiments for this type of flow. In this work Artificial Neural Networks (ANNs) models are used to study the effect of wall friction coefficient and coefficient of wall cohesion on the pressure drop. Three different datasets having 50000, 250000, and 500000 data points were used to test 19, 21, and 25 ANN architectures respectively. The best architecture was found to be t50-t40-r1 architecture with Adamax optimizer, with mean absolute percentage error (MAPE) being close to 0.00402% when tested on the 500000 samples dataset with 25000 test values, 0.0043% when tested on the dataset with 250000 samples and 25000 test values, and 0.0035% on the 50000 samples dataset with 10000 test values. The s20-s20-r1 architecture with Adam optimizer was quick and gave second best results with MAPE being close to 0.009% when tested on the 500000 samples dataset, 0.00988% when tested on the dataset with 250000 samples,and 0.00408% when tested on the 50000 samples dataset. The t40-t40-t40-t40-r1 with Adamax optimizer was slow but gave the third best results with MAPE being close to 0.0166% when tested on the 500000 samples dataset, 0.00496% when tested on the dataset with 250000 samples, and 0.00480% when tested on the 50000 samples dataset.

Determination of fundamental mechanical properties of biomass using the cubical triaxial tester to model biomass flow

The flowability of biomass is an indicator of how amenable biomass is to handling. The flowability measurements are often determined with empirical or tertiary experiments. This status quo impedes employing engineering principles to advance the design and operation of biomass handling systems. It is imperative to establish an experimental protocol minimizing empirical aspects of flowability characterization to account for the variability of biomass. This study demonstrates the operational principles of the large chamber cubical triaxial tester and the procedure of triaxial tests to quantify bulk flow behaviors of two milled biomass feedstocks, namely corn stover 2 mm (CS) and Douglas fir 1 mm (DF). The Mohr-Coulomb (MC), Drucker-Prager (DP) and modified Cam-Clay (mCC) models are calibrated for both biomasses. Analysis indicates that CS will exhibit a cohesive flow with a larger cohesion coefficient of MC (3.8 ± 3.5 kPa) than DF (0.42 ± 0.9 kPa) and a larger d value of DP (6.9 kPa) than DF (0.0 kPa), respectively. CS exhibits a higher spring-back index of mCC (0.39 ± 0.05) than DF (0.27 ± 0.05) also suggesting handling issues, which agrees with the experiences in the industry. This study demonstrates the capability of a CTT in a quantitative investigation of biomass handling characteristics.

Rheological Properties of Date Juice, Pomegranate Juice and their Concentrates: A Review

This review aims to investigate the rheological properties of date juice, pomegranate juice and their concentrates and to identify their flow behaviour. There are many rheological properties that have been studied, including viscosity, coefficient of flow behaviour index, type, and cohesion coefficient. Knowing the rheological properties of date juice and pomegranate and their concentrates is of paramount importance in various food processing operations. The flow behaviour index, activation energy and cohesion coefficient of date and pomegranate juices ranged between 0.605–0.988 and 0.776–1.45 J/mol, 1.9*104–3.3*104 and 32200–54430, 0.002–0.102 and 0.0013-0.075 Pa.sn, respectively. Both date juice and pomegranate juice with their distinct concentrations, have a non-Newtonian, semi-plastic behaviour that varies according to the type and variety of the fruit. There are several models have been used to describe the flow behaviour of date and pomegranate juices. The most important factors that affect the rheological properties and flow behaviour of the date and pomegranate juices are the temperature and the concentration of dissolved solids in the juice. Arrhenius equation is used to express the effect of temperature on the rheological properties of date and pomegranate juice and their various concentrates. Also, the apparent viscosity increases with rising concentration of dissolved solids and decreasing temperature. KEYWORDS Date juice, pomegranate juice, rheological properties, flow behaviour, cohesion coefficient

Measurement and simulation validation of numerical model parameters of fresh concrete

Abstract In the numerical simulation of the macroscopic flow of the concrete, it can optimize the performance indicators of the screw conveyor and improve the uniformity of the material to be discharged in the batch production. The discrete element method is effective. The accuracy of physical parameters of this method is a key issue for the reliability of the simulation results of concrete. In this study, we measured the parameters describing the interaction between gravel, mortar, as well as between these two materials and the wall (steel). The experimentally determined parameters include the particle density, size, shape, coefficient of restitution, coefficients of static, and rolling friction. The cohesion coefficient of mortar particles for batch time was obtained by comparing the spread diameter and flow time in V-funnel experiments and simulation. After these calibration steps, the DEM parameters were validated by comparison of the mass flow rate and driving power by the batch production of screw conveying in simulations and experiments. The calculated results are proved to be close to the experimental data, which demonstrates that the measured DEM parameters are of sufficient accuracy to be used in the simulation of concrete flow performance (mass flow rate, energy consumption) in the screw conveyors.

Seismic Bearing Capacity of Shallow Foundations Placed on an Anisotropic and Nonhomogeneous Inclined Ground

In the present study, the limit equilibrium method combined with the pseudo-static seismic loading approach and applying the simplified Coulomb failure mechanism were employed for calculating the bearing capacity of nonhomogeneous and anisotropic soils on slopes. It was assumed that the cohesion coefficient was nonhomogeneous and anisotropic and anisotropy effect was ignored for the friction angle. For estimating optimal bearing capacity values, the particle swarm optimization algorithm was used. Comparing the results of previous researchers with those of the present study for isotropic and homogeneous soils indicated that the present solution provided acceptable values for the bearing capacity of shallow foundations. The effect of anisotropy ratio and the nonhomogeneous coefficient on the seismic bearing capacity was evaluated and found that decreasing the anisotropy ratio and increasing the nonhomogeneous coefficient cause an increase in the seismic bearing capacity. Furthermore, the results showed that the depth of the failure zone decreases with increasing the nonhomogeneous coefficient, the anisotropy ratio, and the seismic acceleration coefficient, while the depth of the failure zone increases with an increase in the slope inclination.

Study on the stability of highway slope in cold region under freeze-thaw cycles

Based on thermo-mechanical coupling and elastoplastic theory, a finite element (FE) numerical simulation was adopted to study the stability of slopes in cold regions under freeze-thaw cycles. And the prediction of slope landslide was also studied through the calculation of strength reduction coefficients combination. The result shows that the development of the slope vertical displacement under freeze-thaw cycles can be divided into two stages: rapid stage and stable stage. After combining the two reduction coefficients of cohesion and internal friction of the soil, the maximum vertical displacement on the top of the slope in this region can be calculated as a reference for predicting the slope landslides. Meanwhile, the corresponding safety factor of the slope in the cold region can be obtained according to the reduction coefficients. .