scholarly journals Experimental and Numerical Simulation Study on the Shear Strength Characteristics of Magnolia multiflora Root-Soil Composites

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
ZiFan Sui ◽  
Wen Yi ◽  
YunGang Lu ◽  
Liang Deng
Keyword(s):  
Shear Strength ◽  
Inclination Angle ◽  
Numerical Models ◽  
Shear Resistance ◽  
Enhancement Effect ◽  
Shear Direction ◽  
Multiple Roots ◽  
Shear Tests ◽  
Single Root ◽  
Laboratory Test Results

The shear strength of the soil refers to the ultimate strength of the soil against shear failure, which is one of the important indicators used to measure slope stability. This paper presents a simulation of direct shear tests on root-soil composites with different root embedding angles under different stress conditions. By comparing and analyzing the simulation results of ABAQUS software and the laboratory test results, the enhancement effect of plant roots on soil shear strength was explored. Conclusions can be drawn as follows: the excellent agreement between numerical models and laboratory shear tests suggested that the developed model can quickly and conveniently predict the shear strength of the root-soil composites. The shear strength was related to the rooting arrangement. For a single root system, when the inclination angle of the root was about 64° to the shear direction, the shear resistance of soil was much improved, while the root reinforcement had less effect when the inclination angle was greater than 90°. In the case of multiple roots, the hybrid rooting method can more effectively improve the shear resistance of the root-soil composite. Therefore, in the practical application of using the root to strengthen the soil, the angle of a single root and arrangement of multiple roots should be comprehensively considered.

scholarly journals A study on the effect of grain morphology on shear strength in granular materials

2021 ◽  
Vol 249 ◽  
pp. 06013
Author(s):  
Nicolin Govender ◽  
Patrick Pizette
Keyword(s):  
Shear Strength ◽  
Aspect Ratio ◽  
Rolling Resistance ◽  
Grain Morphology ◽  
Rolling Friction ◽  
Shear Resistance ◽  
Friction Model ◽  
Shear Direction ◽  
Lower Shear ◽  
Shed Light

The Discrete Element Method (DEM) has been successfully used to further understand GM behaviour where experimental means are not possible or limited. However, the vast majority of DEM publications use simplified spheres with rolling friction to account for particle shape, with a few using clumped spheres and super quadratics to better capture grain geometric detail. In this study, we compare the shear strength of packed polyhedral assemblies to spheres with rolling resistance to account for shape. Spheres were found to have the highest shear resistance as the limited rolling friction model could not capture the geometric of rotation grains which caused reordering and dilation. This geometric arrangement causes polyhedra to align faces in the shear direction, reducing the resistance to motion. Conversely, geometric interlocking can cause jamming resulting in a dramatic increase in shear resistance. Particle aspect ratio (elongation and fatness) was found to significantly lower shear resistance, while more uniform aspect ratio’s increased shear resistance with shape non-convexity showing extremes of massive slip or jamming. Thus, while spheres with rolling friction may yield bulk shear strength similar to some polyhedra with a mild aspect ratio, the grain scale effect that leads to compaction and jamming from rotation and interlocking is missed. These results shed light on the complex impact that individual grain shape has on bulk behaviour and its importance.

scholarly journals Material-Dependent Shear Capacity of Threaded Rods

CivilEng ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 351-367
Author(s):  
Nikolai Sklarov ◽  
Catherina Thiele
Keyword(s):  
Shear Strength ◽  
Material Properties ◽  
Tensile Tests ◽  
Shear Resistance ◽  
Good Prognosis ◽  
Shear Capacity ◽  
Shear Tests ◽  
New Correlation ◽  
Adhesive Anchors

Currently, the determination of the shear capacity VRk,s0 of post installed adhesive anchors is already included in the current standardization and approval documents. Considering that EAD 330499-00-0601 allows for determining the shear resistance of a fastener only based on the characteristic steel ultimate tensile strength fuk determined from the material tensile tests, and without considering the actual ductility of the material used, this leads to a severe underestimation of the actual steel shear resistance. In order to efficiently determine the shear strength by calculation based on material characteristics, tensile and shear tests were carried out on metallic threaded rods and rebars to show their correlation with the material properties. A new correlation between tensile and shear strength is presented, which is based on the plasticity module Epl and allows a good prognosis of the shear strength.

Punch-shear tests and size effects for evaluating the shear strength of machinable ceramics

2004 ◽  
Vol 95 (5) ◽  
pp. 372-376 ◽  
Author(s):  
Yiwang Bao ◽  
Haibin Zhang ◽  
Yanchun Zhou
Keyword(s):  
Shear Strength ◽  
Size Effects ◽  
Shear Tests

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 Influence of coarse aggregate on shear resistance of self-consolidating concrete beams

2017 ◽  
Vol 10 (1) ◽  
pp. 30-40
Author(s):  
G. SAVARIS ◽  
R. C. A. PINTO
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Self Consolidating Concrete ◽  
Coarse Aggregates ◽  
Lower Shear ◽  
Nominal Size ◽  
High Flowability

Abstract Self-consolidating concrete is characterized by its high flowability, which can be achieved with the addition of superplasticizer and the reduction of the amount and size of coarse aggregates in the concrete mix. This high flowability allows the concrete to properly fill the formwork without any mechanical vibration. The reduction in volume and particle size of the coarse aggregates may result in lower shear strength of beams due to a reduced aggregate interlock. Therefore, an experimental investigation was conducted to evaluate the influence of the reduction in the volume fraction and the nominal size of coarse aggregate on concrete shear strength of self-consolidating beams. Six concrete mixes were produced, four self-consolidating and two conventionally vibrated. A total of 18 beams, with flexural reinforcement but without shear reinforcement were cast. These beams were tested under a four-point loading condition. Their failure modes, cracking patterns and shear resistances were evaluated. The obtained shear resistances were compared to the theoretical values given by the ACI-318 and EC-2 codes. The results demonstrated a lower shear resistance of self-consolidating concrete beams, caused mainly due to the reduced aggregate size.

scholarly journals Shear Tests and Calculation of Shear Resistance with the PC Program RFEM from Thin Partition Walls of Brick in Old Buildings

2015 ◽  
Vol 10 (2) ◽  
pp. 103-112
Author(s):  
Sinan Korjenic ◽  
Bernhard Nowak ◽  
Philipp Löffler ◽  
Anna Vašková
Keyword(s):  
Horizontal Displacement ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Horizontal Force ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Existing Building ◽  
Material Parameters ◽  
Partition Walls ◽  
Material Studies

Abstract This paper is about the shear capacity of partition walls in old buildings based on shear tests which were carried out under real conditions in an existing building. There were experiments conducted on different floors and in each case, the maximum recordable horizontal force and the horizontal displacement of the respective mortar were measured. At the same time material studies and material investigations were carried out in the laboratory. The material parameters were used for the calculation of the precise shear capacity of each joint. In the shear tests, the maximum displacement of a mortar joint was determined at a maximum of two to four millimetres. Furthermore, no direct linear relationship between the theoretical load (wall above it) and the shear stress occurred could be detected in the analysis of the experiment, as it was previously assumed.

scholarly journals An Experimental Study on a Composite Bonding Structure for Steel Bridge Deck Pavements

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaoguang Zheng ◽  
Qi Ren ◽  
Huan Xiong ◽  
Xiaoming Song
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Epoxy Resin ◽  
Bonding Strength ◽  
Bridge Deck ◽  
Steel Bridge ◽  
Shear Tests ◽  
Bonding Structure ◽  
Asphalt Overlay ◽  
Strength Tests

As one of the major contributors to the early failures of steel bridge deck pavements, the bonding between steel and asphalt overlay has long been a troublesome issue. In this paper, a novel composite bonding structure was introduced consisting of epoxy resin micaceous iron oxide (EMIO) primer, solvent-free epoxy resin waterproof layer, and ethylene-vinyl acetate (EVA) hot melt pellets. A series of strength tests were performed to study its mechanical properties, including pull-off strength tests, dumbbell tensile tests, lap shear tests, direct tension tests, and 45°-inclined shear tests. The results suggested that the bonding structure exhibited fair bonding strength, tensile strength, and shear strength. Anisotropic behaviour was also observed at high temperatures. For epoxy resin waterproof layer, the loss of bonding strength, tensile strength, and shear strength at 60°C was 70%, 35%, and 39%, respectively. Subsequent pavement performance-oriented tests included five-point bending tests and accelerated wheel tracking tests. The impacts of bonding on fatigue resistance and rutting propagation were studied. It was found that the proposed bonding structure could provide a durable and well-bonded interface and was thus beneficial to prolong the fatigue lives of asphalt overlay. The choice of bonding materials was found irrelevant to the ultimate rutting depth of pavements. But the bonding combination of epoxy resin waterproof and EVA pellets could delay the early-stage rutting propagation.

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