A torsional shear box for determining the shear strength of agricultural soils

Soil Research ◽  
1982 ◽  
Vol 20 (3) ◽  
pp. 203 ◽  
Author(s):  
JE Lloyd ◽  
N Collis-George
Keyword(s):  
Shear Strength ◽  
Agricultural Soils ◽  
Field Studies ◽  
Soil Strength ◽  
Field Conditions ◽  
Soil Conditions ◽  
Strength Parameters ◽  
Torsional Shear ◽  
Wide Range ◽  
Shear Box

A hand-held torsional shear box, suitable for direct measurements of the in situ soil strength (�o) under field conditions and for laboratory determinations of shear strength parameters, is described. A field procedure is given, and the errors in the method are discussed. Under field conditions, it is simple to operate and requires a single measurement to determine �o. Field studies indicate that it is suitable for a wide range of soil conditions which occur in agricultural soils. Results are presented, which show that both moisture status and structure influence the value of �o, as well as the nature of the failure plane. Agricultural soils have a number of characteristics which make it difficult to design methods for determining soil strength parameters or to interpret empirical estimates of soil strength. Chief amongst these are: (1) marked changes in most soil physical properties with depth; (2) a polymodal distribution of pore sizes. Because the measurement is on a surface which is nearly horizontal and is of an area to allow for all forms of failure, the described torsional shear box largely overcomes these problems, and provides a value of �o which is physically interpretable and relevant to studies concerned with soil failure.

scholarly journals Plane strain shear strength of unsaturated fiber-reinforced fine-grained soils

2021 ◽  
Author(s):  
Houman Soleimani-Fard ◽  
Diethard König ◽  
Meisam Goudarzy
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Hydraulic Conductivity ◽  
Soil Conditions ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Fine Grained ◽  
Vapor Equilibrium ◽  
Wide Range ◽  
Ductile Behavior

AbstractDiscrete randomly distributed fibers are commonly used to improve the engineering characteristics of the soil and thus soil properties such as shear strength, compressibility, density, and hydraulic conductivity. Most studies have so far focused on describing the behavior of soils containing randomly distributed fibers under dried or saturated conditions. However, the water table may seasonally fluctuate, thus generating unsaturated soil conditions. Therefore, a better understanding of the hydro-mechanical properties of unsaturated improved soils is of high necessity. In this research, the shear strength parameters of fine-grained soils were evaluated using the biaxial device available at Ruhr Universität Bochum. The applied device was modified to test unsaturated fine-grained soils with various degrees of saturation using axis translation and vapor equilibrium techniques. The experiments were conducted on fine soils containing 0, 0.5, and 1% fiber contents under a wide range of matric suctions. The ductile behavior was more noticeable in samples with lower suctions and higher straw contents. Furthermore, the shear strength of both unreinforced and reinforced fine-grained soils considerably increased by an increase in the suction. Finally, shear band inclination increased by the suction while decreasing by straw content.

scholarly journals Experimental Study on Shear Strength Parameters of Soil Mixed with Glass Fiber

2019 ◽  
Vol 4 (6) ◽  
pp. 124-128
Author(s):  
Mohamad Farouk Abd-elmagied
Keyword(s):  
Shear Strength ◽  
Strength Properties ◽  
Vital Role ◽  
Peak Shear Strength ◽  
Shear Strength Parameters ◽  
Fiber Glass ◽  
Strength Parameters ◽  
Sample Weight ◽  
Strain Behavior ◽  
Shear Box

Determining the shear strength properties of the soil is a vital step in investigation its stress-strain behavior. Moreover, suction plays a vital role in the shear strength of the unsaturated soil. This paper investigates the influence of the fiber glass on the shear strength parameters of (c-ɸ) soil with different ratios. To achieve this purpose, the samples of (c- ɸ) soil from El-Fardos gardens housing compound, Benha city, Egypt, were prepared at their maximum dry densities with corresponding optimum moisture content. Direct shear box test of 60 x 60 mm under a relentless rate of 1 mm/min was employed with the proposed range of ASTM D 3080. Different fiber glass ratios of 0.1, 0.50 and 1.00 % of soil sample weight were used. The results confirmed that the peak shear strength parameters increased with increasing the fiber ratio.

Reliability of Shear-Box Tests Upon Soaking Process on the Sand Soil in Al-Najaf City

2020 ◽  
Vol 857 ◽  
pp. 212-220
Author(s):  
Mohammed Sh. Mahmood ◽  
Waseem H. Al-Baghdadi ◽  
Asaad M. Rabee ◽  
Suhad H. Almahbobi
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Sandy Soil ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Engineering Structures ◽  
Angle Of Internal Friction ◽  
Shear Box ◽  
Testing Condition ◽  
Direct Shear Apparatus

Accurate prediction of the soil shear strength parameters is essential in the reliable geotechnical design of civil engineering structures. This recent paper investigates the effect of the dry testing condition on the shear strength parameters of the sandy soil using the direct shear apparatus and compared with the saturated condition tests in previous researches on the same soil. The dry soil, usually above the water table, is the principal condition of the Al-Najaf city soil in Iraq. Samples are selected from the site of the University of Kufa, which represents the sandy soil of the city. For reliability purposes, the soil is exposed to different pre-soaking durations (one, two, and four weeks) then air-dried for shear tests. The main results revealed that the angle of internal friction (Φ) tested as a dry sample decreases about -6% up to two-weeks soaking then recovered upon four-week soaking about +6%. Compared to the saturated testing, there are increases in F between 6%-17% from saturated tests. Finally, it is recommended to aware in the selection of testing conditions for calculations of the angle of internal friction.

Preliminary report on a new method for determining the shear strength of a soil surface - the resin plate method

Soil Research ◽  
1993 ◽  
Vol 31 (5) ◽  
pp. 539 ◽  
Author(s):  
N Collis-George ◽  
PE Tolmie ◽  
H Moahansyah
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Preliminary Report ◽  
Soil Surface ◽  
Horizontal Stress ◽  
Rigid Plate ◽  
Plate Method ◽  
Torsional Shear ◽  
Box Method ◽  
Shear Box

The proposed method consists of pouring a thin layer of resin onto the soil surface. This impregnates the soil to approx. 2 mm regardless of moisture content. The resultant rigid plate of resin and soil is detached from the soil beneath by applying a horizontal stress. Results for three sands and one soil are compared with those from the torsional shear box method. The method is quick, inexpensive and the results are highly reproducible. The implications of the method are discussed.

The basis for a procedure to specify soil physical properties of a seed bed for wheat

1979 ◽  
Vol 30 (5) ◽  
pp. 831 ◽  
Author(s):  
N Collis-George ◽  
JE Lloyd
Keyword(s):  
Shear Strength ◽  
Physical Properties ◽  
Temperature Regime ◽  
In Situ Stress ◽  
Soil Physical Properties ◽  
Soil Conditions ◽  
Wide Range ◽  
The Mean ◽  
Small Increments

The rationale of characterizing seed beds prepared for wheat by describing the environment at a distance from the plant/soil interface by a selected number of measurements on a bulk basis in the horizontal plane at small increments of depth is discussed. A field procedure is described of in situ measurements to specify the soil conditions of biological consequence to germination and emergence. Measurements at small increments of depth are made to determine: (i) moisture status by moisture content and by moisture potential; (ii) aeration status by air-filled porosity; (iii) temperature regime by monitoring the soil temperature profile with depth; (iv) soil strength by the bulk shear strength of the soil under in situ stress conditions. Field results suggest that the described field procedure is suitable for the routine study of soils involving a wide range of moisture contents, of moisture potentials and of structure. The results show that, within the top 15 cm of a prepared seed bed, soil physical properties change markedly with depth. In particular, tenfold increases of bulk shear strength were measured. Results also showed that bulk shear strength could not be predicted from penetrometer readings and that the mean aerial temperature at 1.2 m is not sufficient to define the mean temperature regime of the developing seedling. The field procedure described is recommended for the characterization of seed beds.

scholarly journals Numerical study on bearing capacity of a pile group next to a slope in unsaturated soils

2020 ◽  
Vol 195 ◽  
pp. 01006
Author(s):  
Amirreza Pourfatollah ◽  
Ali Pirjalili ◽  
Aliakbar Golshani
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Numerical Study ◽  
Pile Group ◽  
Soil Strength ◽  
Strength Parameters ◽  
Water Characteristics ◽  
Soil Shear Strength

The bearing capacity of a pile group mostly depends on parameters of the soil shear strength affected by the soil-water characteristics, especially in unsaturated soils. The soil shear strength is entirely affected by hydraulic stresses in unsaturated soil, such as precipitation and evaporation. Further, the bearing capacity of the pile installed on unsaturated soil depends on hydraulic stresses applied to the soil. Furthermore, slope vicinity may cause a severe decline in the pile bearing capacity. The present study aimed to investigate a pile group in unsaturated soil adjacent to a slope and analyzed the effect of the rainfall on the soil strength parameters. Thus, a numerical study has been performed using a finite difference software,i.e., FLAC2D. Besides, to investigate the model in a real situation, the intensity and duration of rainfall are considered to evaluate changes in hydraulic stresses. Finally, the results show that the rainfall causes a considerable decrease in soil strength parameters in unsaturated soil, leading to the reduction of the pile group bearing capacity and slope stability.

scholarly journals Stability analysis of construction and demolition waste (CDW) deposits in theabandoned quarry of Profitis Ilias, Kozani, Greece.

2013 ◽  
Vol 47 (4) ◽  
pp. 1706
Author(s):  
G. Konstantopoulou ◽  
N. Spanou
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Back Analysis ◽  
Field Tests ◽  
Construction And Demolition Waste ◽  
Shear Strength Parameters ◽  
Strength Parameters ◽  
Demolition Waste ◽  
Waste Dumps ◽  
Wide Range

Abandoned quarries become favourable sites for uncontrolled waste dumps, causing major safety hazards because of potential mass movements. An old quarry, near the town of Kozani, is filled with 772.000 m3 Construction and Demolition Wastes (CDW), containing a variety of materials (aggregates, wood, metals, plastics, bricks, soil etc.), in a wide range of fragment sizes, from clay to boulders. The size of particles and voids influence the behaviour of the filled slope, affecting both shear strength and drainage characteristics. Major factors that should be considered in a stability analysis for CDW, include waste material and soil cover composition, overall degree of compaction, moisture contented, permeability, pore pressure and shear strength parameters. Shear strength parameters were chosen by bibliographic references based on specialized field tests of similar materials. The analyzed profiles computed slip zones of low thickness and range. Therefore, successive back analysis was conducted to the sites of mapped cracks, aimed to determinate the mechanical properties of the slope during the failure. Since, friction angle and bulk density were retained for back analysis, the cohesion was examined. Although deposits are composed of loose heterogeneous materials, which have not been condensed, cohesion exists owing to the "interlocking" of the varying particle size of materials.

Effect of Sample Size on TDA Shear Strength Parameters in Direct Shear Tests

2020 ◽  
Vol 2674 (9) ◽  
pp. 1110-1119 ◽  
Author(s):  
Khaled Zahran ◽  
Hany El Naggar
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Direct Shear ◽  
Shear Strength Parameters ◽  
Shear Tests ◽  
Strength Parameters ◽  
Angle Of Internal Friction ◽  
Direct Shear Tests ◽  
Shear Box ◽  
Box Dimensions

Tire-derived aggregate (TDA), a relatively new construction material, has been gaining acceptance as a backfill material for embankments, trenches, and earth-retaining structures because of its lightweight and excellent geotechnical properties. Type A TDA has a basic geometric shape, with particles approximately 12 to 100 mm in size. As a result of the simplicity and accuracy of the direct shear test, most laboratories choose this test in preference to more complex tests. However, TDA requires large-scale direct shear apparatus because of the consistently large size of its particles, and few facilities own this type of apparatus. Depending on the shear box dimensions, the aspect ratio of the particle size to the box dimensions may lead to variations in the shear strength results of the sample being evaluated. This research focuses on studying the effect of TDA sample size on the shear strength results of direct shear tests by using five different shear box sizes. The findings show that the angle of internal friction increases slightly as the dimensions of the shear box decrease. It was found that the maximum variation in the angle of internal friction and the cohesion results of the different shear boxes was only 1.9° and 2.4 kPa, respectively. These differences should be taken into consideration when TDA shear test results are used in the geotechnical design. It is recommended that a shear box with an aspect ratio (W/Dmax) greater than or equal to 4 should be used when evaluating the shear strength parameters of TDA.

scholarly journals Aerodynamic roughness length related to non-aggregated tillage ridges

2005 ◽  
Vol 23 (10) ◽  
pp. 3187-3193 ◽  
Author(s):  
M. Kardous ◽  
G. Bergametti ◽  
B. Marticorena
Keyword(s):  
Roughness Length ◽  
Agricultural Soils ◽  
Strong Relationship ◽  
Soil Conditions ◽  
Aerodynamic Roughness Length ◽  
North African ◽  
The North ◽  
Ridge Height ◽  
Wide Range ◽  
Aerodynamic Roughness

Abstract. Wind erosion in agricultural soils is dependent, in part, on the aerodynamic roughness length (z0) produced by tillage ridges. Although previous studies have related z0 to ridge characteristics (ridge height (RH) and spacing (RS)), these relationships have not been tested for tillage ridges observed in the North African agricultural fields. In these regions, due to climate and soil conditions, small plowing tools are largely used. Most of these tools produce non-aggregated and closely-spaced small ridges. Thus, experiments were conducted in a 7-m long wind tunnel to measure z0 for 11 ridge types covering the range of geometric characteristics frequently observed in south Tunisia. Experimental results suggest that RH2/RS is the first order parameter controlling z0. A strong relationship between z0 and RH2/RS is proposed for a wide range of ridge characteristics.

CENTRI-CAST GRAY IRON 50

Alloy Digest ◽  
1981 ◽  
Vol 30 (8) ◽  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Physical Properties ◽  
Machine Tools ◽  
Heat Treating ◽  
Gray Iron ◽  
Centrifugally Cast ◽  
Wide Range ◽  
Nominal Tensile Strength ◽  
Cast Gray Iron

Abstract CENTRI-CAST GRAY IRON 50 is a centrifugally cast gray iron with a nominal tensile strength of 50,000 psi. It is cast in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Among its many applications are farm machinery, seals, bushings, machine tools and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-51. Producer or source: Federal Bronze Products Inc..

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