scholarly journals The Shear Strength of Granite Weathered Soil Under Different Hydraulic Paths

2020 ◽  
Vol 10 (18) ◽  
pp. 6615
Author(s):  
Youqian Lu ◽  
Guoqing Cai ◽  
Chenggang Zhao
Keyword(s):  
Shear Strength ◽  
Direct Contact ◽  
Clear Understanding ◽  
Soil Mineral ◽  
Strength Index ◽  
Soil Particles ◽  
Weathered Soils ◽  
Weathered Soil ◽  
The Difference ◽  
Strength Models

At present, there is no clear understanding of the influence of differences in soil mineral composition, particle size grading, and hydraulic paths on the shear strength of unsaturated soil, and the related strength models are not applicable. The shear strength characteristics of different saturation specimens under different hydraulic paths were studied on two granite weathered soils. The experimental results show that the shear strength index of the prepared specimen is “arched” with the increase of saturation, and the dehydration specimen decreases linearly with the saturation. As considering the cementation of free oxides in soils and the interaction among soil particles at different saturations, it is assumed that there are three different contact modes among soil particles: direct contact, meniscus contact, and cement contact. The difference in contact modes will reflect the different laws of shear strength. A shear strength model capable of distinguishing between the capillary effect and the adsorptive effect was established. The model predicted and verified the shear strength data of granite weathered soil under different hydraulic paths well, and then theoretically explained the evolution law of the shear strength of granite weathering soil under the change of saturation.

scholarly journals Shear Strength of Internal Reinforced Concrete Beam-Column Joints: Intelligent Modeling Approach and Sensitivity Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
De-Cheng Feng ◽  
Bo Fu
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Influence Factors ◽  
Regression Tree ◽  
Reinforced Concrete Beam ◽  
Gradient Boosting ◽  
Intelligent Modeling ◽  
Modeling Approach ◽  
Ensemble Machine Learning ◽  
Strength Models

In this paper, an intelligent modeling approach is presented to predict the shear strength of the internal reinforced concrete (RC) beam-column joints and used to analyze the sensitivity of the influence factors on the shear strength. The proposed approach is established based on the famous boosting-family ensemble machine learning (ML) algorithms, i.e., gradient boosting regression tree (GBRT), which generates a strong predictive model by integrating several weak predictors, which are obtained by the well-known individual ML algorithms, e.g., DT, ANN, and SVM. The strong model is boosted as each weak predictor has its own weight in the final combination according to the performance. Compared with the conventional mechanical-driven shear strength models, e.g., the well-known modified compression field theory (MCFT), the proposed model can avoid the complicated derivation process of shear mechanism and calibration of the involved empirical parameters; thus, it provides a more convenient, fast, and robust alternative way for predicting the shear strength of the internal RC joints. To train and test the GBRT model, a total of 86 internal RC joint specimens are collected from the literatures, and four traditional ML models and the MCFT model are also employed as comparisons. The results indicate that the GBRT model is superior to both the traditional ML models and MCFT model, as its degree-of-fitting is the highest and the predicting dispersion is the lowest. Finally, the model is used to investigate the influences of different parameters on the shear strength of the internal RC joint, and the sensitivity and importance of the corresponding parameters are obtained.

scholarly journals The Shear Strength Characteristics of Frozen Coarse Granular Debris

1984 ◽  
Vol 30 (106) ◽  
pp. 348-357 ◽  
Author(s):  
W.G. Nickling ◽  
L. Bennett
Keyword(s):  
Shear Strength ◽  
Normal Load ◽  
Strength Characteristics ◽  
Shear Tests ◽  
Critical Limit ◽  
Load Rate ◽  
Polycrystalline Ice ◽  
Saturated Sample ◽  
The Difference ◽  
Ice Content

AbstractThe effect of ice content and normal load on the shear strength characteristics of a frozen coarse granular debris was investigated. 31 shear tests were carried out in a modified shearbox allowing a sample temperature of (–1.0 ± 0.2)° C and a load rate of 9.63 × 10−4 cm/min. The tests showed that as the ice content of the frozen debris was increased from 0% (under-saturated) to 25% (saturated), sample shear strength was markedly increased. In contrast, sample shear strength was reduced as ice content was increased from 25% (saturated) to 100% (supersaturated). The changes in shear strength with increasing ice content were attributed directly to changes in internal friction and the cohesive effects of the pore ice. The shear tests also indicate that shear strength increases with increasing normal load up to a critical limit. Above this limit, dilatancy is suppressed causing the shear strength to decrease or remain relatively constant with increased normal load.The stress-strain curves of the 31 tests indicated that samples with higher ice contents tended to reach peak strength (τP) with less displacement during shear. Moreover, the difference between τp and τr (residual strength) was lowest for pure polycrystalline ice and highest for ice-saturated samples. The Mohr-Coulomb failure envelopes displayed very distinctive parabolic curvilinearity. The degree of curvature is thought to be a function of ice creep at low normal loads and particle fracture and crushing at high normal loads.

scholarly journals ‘B-M MODEL’ FOR FARMERS’ KNOWLEDGE MANAGEMENT IN INCREASING RICE PRODUCTION

2021 ◽  
Vol 2 (1) ◽  
pp. 30-45
Author(s):  
BK Mahalder ◽  
◽  
MB Ahmed ◽  
H Bhandari ◽  
MU Salam ◽  
...  
Keyword(s):  
Knowledge Management ◽  
Field Data ◽  
Production Systems ◽  
Rice Yield ◽  
Rice Production ◽  
Practice Change ◽  
Clear Understanding ◽  
Data Set ◽  
Production Practices ◽  
The Difference

Quantifying knowledge on agriculture can have many benefits to stakeholders. While many knowledge-based systems exist in modern days for farmers’ decision support, specific models are lacking on how knowledge traits can impact on agricultural production systems. This study employed modelling technique, supported by field data, to provide a clear understanding and quantifying how knowledge management in production practices can contribute to rice productivity in the environmentally stressed southwest Bangladesh. This research accounted for ‘Boro’ rice as the target crop and ‘BRRI dhan28’ as the test variety. The ‘B-M Model’ was developed following the principle and procedure from published literature, ‘brainstorming’ and data from field surveys. Three knowledge management traits (KMT) were defined and quantified as the inputs of the model. Those are: self-experience and observation (SEO), extension advisory services (EAS) and accessed information sources (AIS). The yield influencing process (YIP), the intermediate state variable of the model, was deduced by accounting for the two dominant agronomic practices, seedling age for transplanting and triple superphosphate (TSP) application. ‘Knowledge drives farmers’ practice change which in turn influences yield’ was composed as the theoretical framework of the ‘B-M Model’. The model performed strongly against an independently collected field data set. Across the 180 farmers’ data, the average relative rice yield (RRY) predicted by the model (0.705) and observed in the field (0.716) was close (root mean squared deviation (RMSD) = 0.018). The difference between predicted and observed RRY was not statistically different (LSD = 0.03), indicating the model fully captured the field data. A regression of predicted and observed RRY explained 96% variance in observation, further proving the model’s strength in estimating RRY in a wider range of farmers’ rice yield. In a normative analysis, the practicality and usefulness of the model to stakeholders were simulated for the understanding of how much achievable yield could be expected by changing farmers’ knowledge pool (the sum of three KMT) on rice production practices, and at what combination(s) of KMT to be considered at strategic hierarchy to materialize a targeted achievable yield. To the best of the knowledge, a model quantifying rice yield in relation to knowledge management trait does not exist in literature. Upon successful testing under diverse yield scenarios using multiple and sophisticated statistical tools that enhanced the credibility of the model, it is concluded that the model has the potential to be used for identifying quantitative pathways of farmers’ knowledge acquisition for practice change leading to improved productivity of rice in the southwest region of Bangladesh.

Shear strength of interfaces in natural and in recycled aggregate concrete

2017 ◽  
Vol 44 (3) ◽  
pp. 212-222
Author(s):  
Shakeel Ahmad Waseem ◽  
Bhupinder Singh
Keyword(s):  
Shear Strength ◽  
Shear Plane ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Failure Envelope ◽  
Interface Shear ◽  
Aggregate Concrete ◽  
Normal Strength ◽  
Strength Models

Shear strength of interfaces in natural aggregate concrete and in recycled aggregate concrete has been investigated using initially uncracked push-off specimens by varying the following parameters: replacement level of the recycled aggregates (0%, 50%, and 100%), concrete grade (normal-strength and medium-strength), and clamping force on the shear plane. Development of truss action for resisting interface shear was indicated by the observed crack patterns in the tested specimens and a truss-based analysis recommended in the literature in combination with a simplified failure envelope for concrete subjected to biaxial stresses has been used for shear strength predictions of the tested specimens. The proposed methodology, which is considered to be more rational than the empirical shear strength models available in the literature was calibrated for both the concrete types and gave conservative and reasonably accurate shear strength predictions for selected experiments taken from the literature.

Study on the Relationship between Supervisors' Remuneration in Listed Companies and Tobacco Control Measures

2021 ◽  
Vol 7 (6) ◽  
pp. 5074-5086
Author(s):  
Miao Wang ◽  
Pengfei Li
Keyword(s):  
Theoretical Study ◽  
Company Law ◽  
Theory And Practice ◽  
Control Measures ◽  
Clear Understanding ◽  
Corporation Governance ◽  
Legal Principle ◽  
Self Consistent ◽  
The Difference ◽  
The Relationship

Objectives: At present, the theoretical study on supervisors' remuneration under the Company Law is still too principled, and many "chaos" occur in the remuneration practices for supervisors. First, the lack of clear understanding of the incentive function and institutional specificities of supervisors' remuneration results in many problems in the application of supervisors' remuneration in practice, as well as the ignoration of the Board of Supervisors in corporation governance. Second, rather than reaching the intended effect, the legislative approach of authorized "blank" intentionally adopted under the Company Law leaves an inducement for the ineffective supervision of supervisors in practice. Third, there is not only a lack of theoretically self-consistent discussion on the special problems of concurrent supervisors and employee supervisors' remuneration, but also a divorce of the institutional structure and application from good expectations. If the research background of the problem is placed in "tobacco regulatory science", it will be found that there is no inevitable connection between supervisors' compliance expectations and remuneration, but mainly depends on the provisions of legislation. Going back and forth between theory and practice of supervisors' remuneration, this paper combs and interprets the issue of supervisors' remuneration from the perspective of the legislative provisions and theoretical study under the Company Law, and analyzes the difference between the reality and the necessity of the Company Law with respect to the issue of supervisors' remuneration in the light of the legal principle of the Company Law, with the view to improvement of the rules of the Company Law.

THE ANALYSIS OF SHEAR STRENGTH OF FLEXURAL RC ELEMENTS ACCORDING TO EC2 AND STR / LENKIAMŲJŲ GELŽBETONINIŲ ELEMENTŲ ĮSTRIŽOJO PJŪVIO STIPRUMO PAGAL STR IR EC2 ANALIZĖ

2013 ◽  
Vol 4 (4) ◽  
pp. 133-144 ◽  
Author(s):  
Šarūnas Kelpša ◽  
Mindaugas Augonis
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Shear Force ◽  
Bending Moment ◽  
Intersection Point ◽  
Shear Reinforcement ◽  
Truss Model ◽  
Calculation Results ◽  
The Difference

When the various reinforced concrete structures are designed according to EC2 and STR, the difference of calculation results, is quite significant. In this article the calculations of shear strength of bending reinforced concrete elements are investigated according to these standards. The comparison of such calculations is also significant in the sense that the shear strength calculations are carried out according to different principles. The STR regulations are based on work of the shear reinforcement crossing the oblique section and the compressed concrete at the end of the section. In this case, at the supporting zone, the external bending moment and shear force should be in equilibrium with the internal forces in reinforcement and compressed concrete, i.e., the cross section must be checked not only from the external shear force, but also from bending moment. In EC2 standard, the shear strengths are calculated according to simplified truss model, which consists of the tension shear reinforcement bars and compressed concrete struts. The bending moment is not estimated. After calculation analysis of these two methods the relationships between shear strength and various element parameters are presented. The elements reinforced with stirrups and bends are investigated additionally because in EC2 this case is not presented. According to EC2 the simplified truss model solution depends on the compression strut angle value θ, which is limited in certain interval. Since the component of tension reinforcement bar directly depends on the angle θ and the component of compression strut depends on it conversely, then exists some value θ when the both components are equal. So the angle θ can be found when such two components will be equated. However, such calculation of angle θ became complicated if the load is uniform, because then the components of tension bar are estimated not in support cross section but in cross section that are displaced by distance d. So, the cube equation should be solved. For simplification of such solution the graphical method to find out the angle θ and the shear strength are presented. In these graphics the intersection point of two components (shear reinforcement and concrete) curves describes the shear strength of element. Santrauka Straipsnyje apžvelgtos ir palygintos STR ir EC2 įstrižojo pjūvio stiprumo skaičiavimo metodikos stačiakampio skerspjūvio elementams. Normatyve neapibrėžtas EC2 metodikos santvaros modelio spyrių posvyrio kampo skaičiavimas, lemiantis galutinį įstrižojo pjūvio stiprumą. Straipsnyje pateikiamos kampo θ apskaičiavimo lygtys, atsižvelgiant į apkrovimo pobūdį. Norint supaprastinti pateiktų lygčių sprendimą siūlomas grafoanalitinis sprendimo būdas, pritaikant papildomus koeficientus. EC2 neapibrėžia skaičiavimo išraiškų, kai skersinis armavimas yra apkabos ir atlankos. Minėtos išraiškos suformuluotos ir pateiktos straipsnyje. Nustačius EC2 metodikos dėsningumus siūlomas alternatyvus apytikslis skaičiavimo būdas atlankomis ir apkabomis armuotiems elementams. Straipsnyje apžvelgtos abi – STR ir EC2 – metodikos, išskiriant pagrindinius skirtumus ir dėsningumus.

The Shear Strength Characteristics of Frozen Coarse Granular Debris

1984 ◽  
Vol 30 (106) ◽  
pp. 348-357 ◽  
Author(s):  
W.G. Nickling ◽  
L. Bennett
Keyword(s):  
Shear Strength ◽  
Normal Load ◽  
Strength Characteristics ◽  
Shear Tests ◽  
Critical Limit ◽  
Load Rate ◽  
Polycrystalline Ice ◽  
Saturated Sample ◽  
The Difference ◽  
Ice Content

Abstract The effect of ice content and normal load on the shear strength characteristics of a frozen coarse granular debris was investigated. 31 shear tests were carried out in a modified shearbox allowing a sample temperature of (–1.0 ± 0.2)° C and a load rate of 9.63 × 10−4 cm/min. The tests showed that as the ice content of the frozen debris was increased from 0% (under-saturated) to 25% (saturated), sample shear strength was markedly increased. In contrast, sample shear strength was reduced as ice content was increased from 25% (saturated) to 100% (supersaturated). The changes in shear strength with increasing ice content were attributed directly to changes in internal friction and the cohesive effects of the pore ice. The shear tests also indicate that shear strength increases with increasing normal load up to a critical limit. Above this limit, dilatancy is suppressed causing the shear strength to decrease or remain relatively constant with increased normal load. The stress-strain curves of the 31 tests indicated that samples with higher ice contents tended to reach peak strength (τP) with less displacement during shear. Moreover, the difference between τp and τr (residual strength) was lowest for pure polycrystalline ice and highest for ice-saturated samples. The Mohr-Coulomb failure envelopes displayed very distinctive parabolic curvilinearity. The degree of curvature is thought to be a function of ice creep at low normal loads and particle fracture and crushing at high normal loads.

scholarly journals The ARMR Classification System and the Modified Hoek-Brown Failure Criterion Compared to Directional Shear Strength Models for Anisotropic Rock Masses

2019 ◽  
Author(s):  
Neil Bar ◽  
Charalampos Saroglou
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Failure Criterion ◽  
Classification System ◽  
Failure Criteria ◽  
Rock Masses ◽  
Anisotropic Rock ◽  
Anisotropic Rock Mass ◽  
Degree Of Anisotropy ◽  
Strength Models

The anisotropic rock mass rating classification system, ARMR, has been developed in conjunction with the Modified Hoek-Brown failure to deal with varying shear strength with respect to the orientation and degree of anisotropy within an anisotropic rock mass. Conventionally, ubiquitous-joint or directional shear strength models have assumed a general rock mass strength, typically estimated using the Hoek-Brown failure criterion, and applied a directional weakness in a given orientation depending on the anisotropic nature of the rock mass. Shear strength of the directional weakness is typically estimated using the Barton-Bandis failure criterion, or on occasion, the Mohr-Coulomb failure criteria. Directional shear strength models such as these often formed the basis of continuum models for slopes and underground excavations in anisotropic rock masses. This paper compares ARMR and the Modified Hoek-Brown failure criterion to the conventional directional shear strength models using a case study from Western Australia.

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