The influence of aging on the shear strength behaviour of two fine-grained soils

1979 ◽  
Vol 16 (2) ◽  
pp. 391-397 ◽  
Author(s):  
Mehter Mohamed Allam ◽  
A. Sridharan
Keyword(s):  
Shear Strength ◽  
Tangent Modulus ◽  
Black Cotton Soil ◽  
Shear Tests ◽  
Fine Grained ◽  
Shearing Resistance ◽  
Initial Tangent Modulus

A series of undrained triaxial shear tests was conducted on normally consolidated remoulded black cotton soil and kaolinite, in order to examine the influence of aging on their shear strength behaviour. It was found that apart from an increase in shear strength and brittleness, both soils exhibited an increase in their angles of shearing resistance when aged for a month. The cohesion intercept was found to reduce on aging. The initial tangent modulus increases very significantly (to the extent of even 10 times) especially for black cotton soil after 30 days of aging.

In situ shear tests of soil blocks with roots

1998 ◽  
Vol 35 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Tien H Wu ◽  
Alex Watson
Keyword(s):  
Shear Strength ◽  
Root System ◽  
Tensile Force ◽  
Failure Surface ◽  
Soil Reinforcement ◽  
Shear Tests ◽  
Maximum Displacement ◽  
Shearing Resistance ◽  
Simplified Procedures

In situ shear tests were performed on soil blocks that contained roots to study the contribution of roots to the shear strength in a case where the shear deformation is not constrained to a thin zone. The shearing resistance of the soil-root system, the tensile force in selected roots, and the deformation of the soil block were measured. The roots were exposed after the test and their positions were determined and used to estimate the initial positions. The root force and the shearing resistance of the soil-root system were estimated with known solutions and compared with measured root force and shearing resistance. None of the roots that passed through the shear zone failed in tension at the maximum displacement. As a consequence, the root resistance is much less than that found in a case where the failure surface is restricted to the boundary between a weak soil and a firm base and where roots are anchored in the firm base and fail in tension. Simplified procedures for estimating root forces are suggested for the case of a thick shear zone.Key words: in situ test, roots, shear strength, slope stability, soil reinforcement, soil–root interaction.

Strength behaviour of lime-treated soils in the presence of sulphate

2000 ◽  
Vol 37 (6) ◽  
pp. 1358-1367 ◽  
Author(s):  
P V Sivapullaiah ◽  
A Sridharan ◽  
H N Ramesh
Keyword(s):  
Shear Strength ◽  
Black Cotton Soil ◽  
Strength Development ◽  
Volume Changes ◽  
Treated Soil ◽  
Fine Grained ◽  
Strain Behaviour ◽  
Abnormal Volume ◽  
Stabilized Soil ◽  
Cemented Soils

Lime has been used extensively to improve the shear strength of fine-grained soils. It has been recently reported that the presence of sulphate causes abnormal volume changes in lime-stabilized soil. The paper presents the strength behaviour of lime-treated montmorillonitic natural black cotton soil in the presence of varying sulphate contents after curing for periods of up to 365 days. Alteration of soil–lime reactions in the presence of sulphate affects the strength development by cementation. Consequently, the stress–strain behaviour effective stress paths of soil cured with sulphate are similar to those of normally consolidated soil rather than cemented soils. The reduction in shear strength due to a reduction in effective cohesion intercept occurs for lime-treated soil cured with sulphate for long periods.Key words: clays, cohesion, fabric, friction, 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.

Residual shear strength of fine-grained soils and soil–solid interfaces at low effective normal stresses

2015 ◽  
Vol 52 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Hisham T. Eid ◽  
Ruslan S. Amarasinghe ◽  
Khaled H. Rabie ◽  
Dharma Wijewickreme
Keyword(s):  
Shear Strength ◽  
Large Strain ◽  
Laboratory Research ◽  
Normal Stresses ◽  
Interface Shear ◽  
Residual Shear Strength ◽  
Fine Grained ◽  
Solid Interface ◽  
Wide Range ◽  
Shear Area

A laboratory research program was undertaken to study the large-strain shear strength characteristics of fine-grained soils under low effective normal stresses (∼3–7 kPa). Soils that cover a wide range of plasticity and composition were utilized in the program. The interface shear strength of these soils against a number of solid surfaces having different roughness was also investigated at similar low effective normal stress levels. The findings contribute to advancing the knowledge of the parameters needed for the design of pipelines placed on sea beds and the stability analysis of shallow soil slopes. A Bromhead-type torsional ring-shear apparatus was modified to suit measuring soil–soil and soil–solid interface residual shear strengths at the low effective normal stresses. In consideration of increasing the accuracy of assessment and depicting the full-scale field behavior, the interface residual shear strengths were also measured using a macroscale interface direct shear device with a plan interface shear area of ∼3.0 m2. Correlations are developed to estimate the soil–soil and soil–solid interface residual shear strengths at low effective normal stresses. The correlations are compared with soil–soil and soil–solid interface drained residual shear strengths and correlations presented in the literature.

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.

scholarly journals Engineering properties of fine grained soils of Kathmandu Valley, Nepal

1996 ◽  
Vol 14 ◽  
Author(s):  
T. P. Katel ◽  
B. N. Upreti ◽  
G. S. Pokharel
Keyword(s):  
Geotechnical Properties ◽  
Engineering Properties ◽  
Soil Conditions ◽  
Kathmandu Valley ◽  
Construction Sites ◽  
Engineering Construction ◽  
Fine Grained ◽  
The Past ◽  
Shearing Resistance ◽  
Watershed Boundary

This paper primarily deals with the distribution, and engineering and geotechnical properties of fine grained soils in the Kathmandu Valley. Not much studies have been done on these soils in the past except at some engineering construction sites such as bridges and heavy buildings. Very little data are available on the engineering and geotechnical properties of soils of the valley (IOE, 1983a, 1983b, 1986a, 1986b, 1986c; Koirala et al., 1993; Sadaula, 1993; Shakya, 1987; Soil Test, 1990a, 1990b). The authors conducted detailed laboratory studies on the soils of the Thapathali and Ratnapark areas in the central part of the Kathmandu Valley and the results are presented and discussed. An attempt is also made to broadly evaluate the soil conditions of the valley based on the available data from previous studies conducted by various agencies. The soils of the Kathmandu Valley are mainly produced by weathering of rocks within its watershed boundary. They are in most part lacustrine and fluvial in origin and composed of clayey, silty, sandy and gravely sediments. The maximum thickness of the sediment is found in the central part (550 m at Bhrikutimandap) and southern part (>457m at Harishidhi) of the valley. The engineering properties, basically the index properties such as grain size, natural moisture content specific gravity, Atterberg limits; and the mechanical properties such as penetration resistance, cohesion, unconfined compressive strength, compressibility as well as angle of shearing resistance of fine grained soils were determined and found to vary considerably both in horizontal and vertical directions. The bearing capacity and settlement values of the soils were also determined. It is commonly found that most of the buildings in the Kathmandu Valley are founded on isolated or strip types of foundations and the foundation depth is between 1 and 1.5 m. The study of soil properties of the Kathmandu Valley indicates that the heavy loaded structures should be founded on either raft, mat or pile types of foundation.

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