short info

An automatic system enables performing of Direct Shear and Residual Shear tests through a total computer control. It is a table-mounted model and has stepper motors controlling shearing load. Stress levels can be maintained with in the limits of ±0.5% through set of weights. Vertical and horizontal displacements and shearing load are all displayed in their respective engineering units on LCD display.

Standard

IS2720 Part XXXIX and BS1370

Model

VSLIC-S131

Origin

Indian

Make/ OEM

VERTEX

  • Description

  • SPECIFICATIONS

  • FEATURES

  • VIDEO
  •  New
    WORKING PRINCIPAL

OVERVIEW

The unit is same as VSLIC-S133 except that the transducers like displacement sensors and load cell with micro-processor based touch panel display system are provided instead of dial gauges and proving rings. Total loading capacity of the apparatus is 8 kg/cm². It is provided with standard 60mm shear box assembly. Set of weights to give a normal stress up to 3 kg/cm² on the specimen through lever is provided as standard. Additional weights are to be ordered separately.

Electronic Data Acquisition System For Direct Shear Test Equipment
The three-channel micro controller based signal conditioning and touch panel display unit is suitable to measure Horizontal load, Horizontal Displacement and Vertical displacement directly indicated in their respective engineering units during Direct Shear Testing. The system receives the output signal from the sensors i.e. Load cell and Displacement Sensors attached to the Direct shear Test apparatus. The data of all three channels of Direct Shear Test can be transferred to computer through RS-232/ Ethernet and can be online monitored. The Unit also provides the facility of online monitoring of data of all the sensors on Touch Panel Display provided at the front.

Broadly the following facilities are incorporated in the system:-

  • Touch panel is provided to perform various operations such as TARE, PROGRAMMING, START, STOP etc.
  • Independent Taring of each channel
  • Data transfer interval is programmable (between 1 second to 1 hour)
  • Automatic data saving on stop button.
  • There are 25 set results having a maximum of 200 data points per set can be stored in the electronic unit .The sample number can be programmed.
  • Online date and time of test will be stored along with the data.
  • On line (while the test is in progress) data transfer to the computer through RS-232/ Ethernet.

Sensors Specification:-

1. Load Cell :
•   Capacity : 200kg/ 2000N
•   Resolution : 0.1kg/ 1N

2. LINEAR VARIABLE DIFFERENTIAL TRANSFORM ER (LVDT) 2 No.
•    Stroke : ± 20mm
•    Resolution : 0.01mm

Software Specification

  • Data Acquisition from Signal Conditioning Unit to Computer
  • Off-Line Data Analysis Software that does all the calculations of Direct Shear Test.
  • Has option for manual as well as automatic recording of data.
  • Calculates Area, Volume, Bulk density, Dry density, Moisture content etc. of the specimen
  • Display the following Plots (Graphical)
    (a) Horizontal Displacement vs Shear Force
    (b) Horizontal Displacement vs Vertical Displacement
    (c) Normal stress vs Shear Force
    (d) Maximum value of the Dilation Angle

The software is windows based and user friendly. It is easy to operate and has the flexibility to enter different sizes of test specimen up to 1000mm X 1000mm
Note : Computer does not form part of the supply.



SPECIFICATIONS

An automatic system enables performing of Direct Shear and Residual Shear tests through a total computer control. It is a table-mounted model and has stepper motors controlling shearing load. Stress levels can be maintained with in the limits of ±0.5% through set of weights. Vertical and horizontal displacements and shearing load are all displayed in their respective engineering units on LCD display.

Board specification of the unit are:-

  • Rate of strain: 0.0001-9.9999 mm/min
  • Load range capacity : ±5 kN

Electronic Sensors

The unit includes :-

  • Load cell Universal type : 2000N
  • Displacement sensor horizontal : ± 20mm
  • Displacement sensor vertical : ± 20mm Supplied complete with weight upto 3kg/cm²

COMPUTER
Dedicated Computer with Data Acquisition card with latest configuration will be supplied.

FEATURES

An automatic system enables performing of Direct Shear and Residual Shear tests through a total computer control. It is a table-mounted model and has stepper motors controlling shearing load. Stress levels can be maintained with in the limits of ±0.5% through set of weights. Vertical and horizontal displacements and shearing load are all displayed in their respective engineering units on LCD display.

Board specification of the unit are:-

  • Rate of strain: 0.0001-9.9999 mm/min
  • Load range capacity : ±5 kN

Electronic Sensors

The unit includes :-

  • Load cell Universal type : 2000N
  • Displacement sensor horizontal : ± 20mm
  • Displacement sensor vertical : ± 20mm Supplied complete with weight upto 3kg/cm²

COMPUTER
Dedicated Computer with Data Acquisition card with latest configuration will be supplied.

PRODUCT VIDEO

WORKING PRINCIPALNew

Shear Strength of Soil by Direct Shear Test

Shear strength of a soil is its maximum resistance to shearing stresses. The shear strength is expressed as

Where   C’ = Effective cohesion

= Effective stress        = Effective angle of shearing resistance

Using direct shear test, one can find out the cohesion and angle of internal friction of soil which are useful in many engineering designs such as foundations, retaining walls, etc.

This test can be performed in three different drainage conditions namely unconsolidated-undrained, consolidated-undrained and consolidated-drained conditions. In general, cohesionless soils are tested for direct shear in consolidated drained condition.

Apparatus Required for Direct Shear Test

Apparatus required for conduction direct shear test are

  • Shear box
  • Shear box container
  • Base plate with cross groves on its top
  • Porous stones (2 Nos)
  • Plain Grid plates (2Nos)
  • Perforated grid plates (2Nos)
  • Loading pad with steel ball
  • Digital weighing machine
  • Loading frame with loading yoke
  • Proving ring
  • Dial gauges (2 Nos)
  • Weights
  • Tampering Rod
  • Spatula
  • Rammer
  • Sampler

direct_shear_apparatus_motorised

Fig 1: Direct Shear Test Apparatus

Test Procedure of Direct Shear Test

Test Procedure of Direct shear test contains following steps:

  1. Collect the soil specimen which is either undisturbed or remolded. The sample should be taken using sampler and Rammer. If cohesionless soil is taking then sampler and rammer are not required.
  2. The inner dimensions of sampler should be 60 mm x 60 mm in plan which are also the inner dimensions of shear box. The Thickness of box is about 50 mm while the thickness of sample should be 25mm.Fig 2: Shear Box,Porous Stones, Grid Plates, Loading pad Shear box and Arrangement of Plates
  3. Now attach the two halves of the shear box with locking pins and place the base plate at the bottom.
  4. Above the bottom plate, Place the porous stone and above it place the grid plate. Plain grid plates are used for undrained conditions while perforated grid plates are used for drained conditions.
  5. Now we have baseplate, porous stone and grid plate in the shear box. Weigh the box at this stage and note down.
  6. After that place the soil specimen above the grid plate. Undisturbed sample is directly transferred to shear box. If sandy soil is using, place it layers wise and tamper the each layer to get the required density.
  7. Note down the weight of shear box with soil specimen.
  8. Above the soil specimen, place the upper grid plate, porous stone and loading pad one above the other.Fig 3: Different Layers Positions in Shear Box
  9. Now the whole box is placed in a container and mounted on the loading frame.
  10. Proving ring is arranged in such a way that it should contact the upper half of the shear box.
  11. Loading yoke is placed on the steel ball of loading pad of shear box.
  12. Two dial gauges are fitted one to the container for measuring shear displacement and other one is to the loading yoke for measuring vertical displacement.
  13. Now locking pins are removed from the shear box and spacing screws are placed in their respective positions of the box.Fig 4: Applying Load on Specimen Loading on Shear Box
  14. The upper half of the box is raised slightly with the help of spacing screws. The spacing is decided depending upon the maximum size of particle.
  15. Now apply the normal stress which is generally 25 kN/m2. Also apply the shear load at a constant rate of strain.
  16. Now the box starts reacting to loads applied and for every 30 seconds note down the readings of proving ring and dial gauges.
  17. If the proving ring reaches maximum and suddenly drops it, means the specimen is failed. Note down the maximum value which is nothing but failure stress.
  18. For some soils, failure point is taken at 20% of shear strain.
  19. Finally remove the box and measure the water content of the specimen.
  20. Repeat the same procedure for different normal stresses of 50, 100, 150,200,250,300,400 kN/m2

Observations and Calculations for Direct Shear Test

Calculations are to be done using the observations taken from the test as follows:

  • Size of the box =
  • Area of the box =
  • Thickness of specimen =
  • Mass of specimen =
  • Volume of specimen =
  • Bulk Density of soil =
  • Dry density of soil =
  • Void ratio =
  • Mass of box + base plate + porous stone + grid plate =
  • Mass of box + base plate + porous stone + grid plate + Soil specimen =

Calculate the shear stress using below tabulated observations:

S.No Elapsed time Horizontal dial gauge reading Horizontal displacement Vertical dial gauge reading Vertical displacement Proving ring reading Shear force Shear stress

Now determine the shear stress at failure for different normal stress values:

Test no. Normal stress(kN/m2) Shear Stress at Failure (kN/m2) Shear Displacement at Failure Initial Water Content Final Water Content

Now plot a graph between normal stress and shear stress by taking normal stress on abscissa and shear stress at failure on ordinate. The graph looks like as shown below. Failure Envelope from Direct Shear Test

Fig 5: Graph plotted between Normal Stress and Shear stress

From the graph cohesion intercept (c’) and angle of shearing resistance () can be known and shear strength (s) can be calculated from the formula.

Result of Direct Shear Test

Shear strength of the given soil sample is = ______________ kN/m2.

Get Instant Quote

Our Hot Selling Instrument's

Servo Fully Automatic Compression Testing Machine

Servo Fully Automatic Compression Testing Machine

One of the key advantages of the SERVO CONTROLLED FULLY AUTOMATIC COMPRESSION TESTING MACHINE is its ability to deliver highly accurate results. This precision ensures that your materials meet the required standards, reducing the risk of costly errors and rework. Moreover, by producing consistent and reliable outcomes, you build a reputation for quality in your industry.

Automatic Compression Testing Machine

Automatic Compression Testing Machine

Manufactured as per International design, Plate model for highest mechanical stability, accurate centering of load and excellent repeatability. Fully Automatic pace rate control, auto stop and auto release on failure of test specimen, can be attached with flexural load frame or 500 KN load frame.

Semi Automatic Compression Testing Machine

Semi Automatic Compression Testing Machine

Pace rate is achieved manually by controlling the flow control knob and the adjustment can be made by observing the error on the display and the system is released manually after the peak load is achieved.

Rock Core Cutting & Grinding Machine

Rock Core Cutting & Grinding Machine

Rock Cutting Machine can be used to cut cores of varied sizes of concrete, stones, other building materials and metallic specimens.

NEW SERVO CONTROLLED COMPRESSION TESTING MACHINE