scholarly journals FRICTION ANGLE OF POLISHED SURFACES OF SANDSTONE AND CONGLOMERATE FROM THE SEMANGGOL FORMATION, BERIS DAM, KEDAH DARUL AMAN

2020 ◽  
Vol 4 (1) ◽  
pp. 09-12
Author(s):  
J. K. Raj
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Friction Angle ◽  
Normal Displacement ◽  
Test Conditions ◽  
Apparent Cohesion ◽  
Shear Box

The Beris Dam is founded on a sequence of thick bedded to massive conglomerate and gritstone with some sandstone and mudstone, mapped as the Semanggol Formation of Triassic age. Portable shear box tests on polished surfaces of a sandstone, and a conglomerate, core yield friction angles of 18.0o and 20.8o, respectively. These friction angles are comparable with residual friction angles of between 17.5o and 19.0o determined in field and laboratory tests on sheared mudstone surfaces of the Semanggol Formation at the Muda Dam. Apparent cohesion values determined in the portable shear box tests result from the restricted normal displacement test conditions and should not be considered in shear strength calculations.

scholarly journals Comparative Study between Silica Fume and Nano Silica Fume in Improving the Shear Strength and Collapsibility of Highly Gypseous Soil

2020 ◽  
Vol 27 (1) ◽  
pp. 72-78
Author(s):  
Ahmed Al-Obaidi ◽  
Marwa Al-Mukhtar ◽  
Omar Al-Dikhil ◽  
Saeed Hannona
Keyword(s):  
Shear Strength ◽  
Silica Fume ◽  
Friction Angle ◽  
Engineering Properties ◽  
Nano Silica ◽  
Direct Shear Tests ◽  
Apparent Cohesion ◽  
Gypsum Content ◽  
Wet Condition ◽  
Gypseous Soil

Soils with highly gypsum content signify known as soils that exhibit collapsibility and sudden failure when being submerged to wetting. Many of the constructions built on this soil showed cracked and/or collapsed at some parts as these soils immersed or leached with water. The utilization of extremely fine materials, for example, Microscale or Nanoscale, is generally utilized these days. This research compared the use of Silica fume (SF) (micro material) and Nano Silica fume (NSF) (Nanomaterial) to explore the capability of these very fine materials to mend the shear strength and collapsibility properties of highly gypseous soils. The soil as Poorly Graded Sand (SP) was used, with a gypsum amount equal to 62%. A succession of direct shear tests and double odometer tests were carried on dry and submarined specimens of soil at various percentages of SF and NSF. The obtained results indicate that mixing the highly gypseous soils with SF or NSF improved the engineering properties of these soils, especially for the wet condition. The average increment in apparent cohesion when adding SF (5-20) percentage varies between (140-310) % in dry soil and (20-40) % in soaked soil. Same results obtained when mixing the gypseous soils with (1-5) % of NSF. Also, the Nanomaterial provided an improvement of the friction angle in dry and submerged cases respectively. Considering that, the SF gives adverse results upon the friction angle of the soil. The SF and the NSF both condensed the dangers of gypseous soil collapsibility. Consequently, the use of NSF can be assertively suggested to improve the engineering characteristics of highly gypseous soils when compared with SF, where only mixing of 3% of NSF gives the best results.

Numerical Simulation for Shear Characteristics of Rock-Mass Structural Plane

2013 ◽  
Vol 734-737 ◽  
pp. 574-578
Author(s):  
Bao Yuan Yuan ◽  
Qi Wang ◽  
Hai Feng Lu
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Friction Angle ◽  
Normal Displacement ◽  
Displacement Curve ◽  
Peak Shear Strength ◽  
Structural Plane ◽  
Linear Feature ◽  
Stress And Deformation ◽  
The Stability

The characteristics of structural plane are very important to the stability of rock mass.In this paper,the stress and deformation characteristics of structural plane under direct shear conditions are analyzed based on FLAC3D code.And the influence of structural plane inhomogeneity to shear test was discussed.The results obtained in this paper indicate that, with the increase of normal stress, the shear strength of structural plane is constantly increasing,and the tow of them presents linear feature significantly. The normal displacement and shear displacement increase with the rise of the normal stress too. The peak shear strength increases gradually on the condition of uneven friction angle in the interface. This situation changes smaller when the discrete degree of friction angle is small. The peak shear strength increases significantly when the discrete degree of friction angle is big,and the stress-displacement curve exhibits a nonlinear characteristics before yield.

scholarly journals Effect of Grain Size and Distribution on Mechanical Behavior of Dune Sand

2021 ◽  
Vol 7 (8) ◽  
pp. 1355-1377
Author(s):  
Amel Boudia ◽  
Abdelmadjid Berga
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Shear Strength ◽  
Mechanical Behavior ◽  
Friction Angle ◽  
Experimental Program ◽  
Dune Sand ◽  
Natural Sand ◽  
Direct Shear Tests ◽  
Shear Box

Sand is a major component of soils. It is widely used in manufacturing and construction. In geomechanics, one characterizes sand according to various aims. This paper investigates, for local sands, the effect of grain size and granular distribution on the mechanical behavior in terms of strength and stress-strain relationship. For this purpose, dune sands of the great Occidental Erg, from Algeria, are analyzed, according to the Mohr-Coulomb criterion. The study uses three kinds of sands. Every kind is divided into three sizes classes. Then, the experimental program conducts a set of direct shear tests, under various vertical stresses, using the small shear box (60 × 60 mm). The results show that the particle size and distribution have a direct effect on the mechanical behavior of the dune sand. Then, the dominant size class governs the natural sand behavior. Moreover, the peak shear strength increases as particle size increases. This indicates that there is an increase in peak friction angle with the increase of particles size and the sands consider as a purely cohesionless material. In addition, the experimental analysis shows that density and confinement stress is not sufficient to interpret the mechanical behavior. Indeed, mineralogy and surface state can influence the shear strength. These conclusions lead to the relevance of the sand genesis and the importance of the local materials thematic. Doi: 10.28991/cej-2021-03091730 Full Text: PDF

Shear strength of Athabasca Oil Sands

1978 ◽  
Vol 15 (2) ◽  
pp. 216-238 ◽  
Author(s):  
Maurice B. Dusseault ◽  
Norbert R. Morgenstern
Keyword(s):  
Shear Strength ◽  
Oil Sands ◽  
Published Data ◽  
Oil Sand ◽  
Initial Portion ◽  
Apparent Cohesion ◽  
Geophysical Logs ◽  
Shear Box ◽  
Grain Surface ◽  
Dilation Rate

Previously published data are inadequate to explain the high natural shear strength of oil sand. Dissolved gas comes out of solution when confining stresses are removed rapidly, and this results in an internal pressure that expands the oil sand specimens disrupting their fabric. Geophysical logs indicate that in situ densities are much higher than those determined from conventionally cored specimens.Although the behavior of slopes in oil sands suggests that the shear strength is high, the source of strength of the oil sand has not been explained. Therefore detailed oil sand strength testing was undertaken on samples obtained in a special manner. Down-hole refrigeration of cored sections resulted in relatively high-quality specimens, and these were shaped on a lathe to provide triaxial and shear-box test samples.Strength tests on dense Ottawa sand, oil sand tailings and densely recompacted oil sand were performed: standard behavior was observed throughout. A series of triaxial and shear-box tests on undisturbed oil sands demonstrated a Mohr failure envelope that is highly curved, which displays no cohesion intercept and which is extremely steep for the initial portion of the envelope. Optical and scanning electron microscope investigations have revealed a dense interpenetrative structure and a considerable degree of grain surface rugosity. These factors give rise to a very high dilation rate before failure, and the dilation rate is suppressed as normal stress increases. The suppression of dilation results in shear of grains and grain asperities, giving rise to an apparent cohesion intercept at higher normal stresses. The curvilinear failure envelopes may be conveniently expressed as power-law relationships, and this form of expression will prove useful in stability analysis.

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

scholarly journals Stabilization of Algerian Clayey Soils with Natural Pozzolana and Lime

2017 ◽  
Author(s):  
Khelifa Harichane ◽  
Mohamed Ghrici ◽  
Said Kenai
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Plasticity Index ◽  
Engineering Properties ◽  
High Plasticity ◽  
Expansive Clay ◽  
Clayey Soils ◽  
Natural Pozzolana

Cohesive soils with a high plasticity index present difficulties in construction operations because they usually contain expansive clay minerals. However, the engineering properties of soils can be improved by different techniques. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both lime and natural pozzolana on plasticity, compaction and shear strength of two clayey soils classified as CH and CL according to the unified soil classification system (USCS). The obtained results indicated that for CH class clay soil, the plasticity index decreased significantly for samples stabilized with lime. On the other hand, for the soil classified as CL class clay, a high decrease in the plasticity index value was observed for samples stabilized with natural pozzolana compared to those stabilized with lime. Also, both the cohesion and internal friction angle in lime added samples were demonstrated to increase with time. The combination of lime and natural pozzolana exhibits a significant effect on the enhancement of both the cohesion and  internal friction angle at later stages. The lime-natural pozzolana combination appears to produce higher shear strength parameters than lime or natural pozzolana used alone.

scholarly journals Shear Strength Characterization of Bauxite Deposits in Kuantan, East Coast Malaysia

2019 ◽  
Vol 8 (3S3) ◽  
pp. 404-407
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
East Coast ◽  
Field Performance ◽  
Friction Angle ◽  
Parent Rock ◽  
Index Tests ◽  
Strength Characterization ◽  
The Relationship

Engineering characterization which are useful for "temperate" zone soils usually fail to predict the field performance of bauxitic soils, because the index tests upon which the characterization are based are not always reproducible for bauxitic soils. Fifteen (15) bauxitic soil of undisturbed and disturbed samples from 3 distinct sites in Kuantan, all derived from basalt parent rock but representing various stages of weathering were subjected to engineering and mineralogic tests. Values for cohesion and friction angles are evaluated. Soils from Semambu has the highest moisture content of 33.27%, the cohesion value is however lower compared to Bukit Goh which has moisture content of 21.74%. Study are further done to discover the relationship with cohesion and friction angles. Thus, by measuring the cohesion and friction angle can evaluate the performance of bauxite shear strength.

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