Tutorial video of ASTM D 30 80 Direct Shear Test of Soils Under Consolidated Drained Conditions.

This is just a quick step-by-step guide on how to conduct a Shearbox test.

[@kasibantejames4373]

Hello kindly help where I can get the shear box loading charts

[@frost2728]

when you have round or square shear boxes of 50; 60 and 100mm; which box should we choose or which parameter allows us to make a more suitable choice than another?

[@zagamer3373]

A larger size shearbox would generally be more preferable I'd time permits it, a larger sample would need to saturate longer. Also note the extra stress on the load cell so as to not overshoot and damage it.

[@frost2728]

@@zagamer3373 thank you

[@emilbu5118]

I have a similar machine. A better model. Doesnt it consolidate with the machine? Not just leave it soaked.

[@zagamer3373]

There is a small amount of consolidation happening, the load during soaking is less than 10N though, but yes since it is free draining some consolidation is happening. If you were to do a consolidation test beforehand you can determine the rate of consolidation and pore pressure dissipation rate. During a undrained test your rate of strain should be high enough to allow the buildup of pore pressure. Hope this answers your question.

[@thantthinzarmyint9929]

Can you tell me how to connect the machine with laptop 😢

[@zagamer3373]

You would connect the ldvs to the data acquisition system and from the data acquisition connect to a pc. The digishear itself does not connect with pc. Hope this helps

[@clyden073]

Hi, I want to ask about the test procedure. Is it necessary for the sample to go through consolidation procedure first before shearing phase? Or we can actually go straight to shearing phase right after we prepared the sample? I got a bit confused because the ASTM standard called it "consolidated". Thank you so much for this video

[@zagamer3373]

Luckily you dont have to go through consolidation first, after you have prepared the sample you just have to place it in the shearbox and have it saturate (6h-12h usually for sand and 12-24h for heavy clays.) after its nice and saturated you can start the shear at the correct rate. Its called a "consolidated" test due to the weights slowly consolidating the sample and drained as the excess pore pressure is being dissapated into the water.

[@clyden073]

@@zagamer3373 Thank you so much, your video really helps me :)

[@Tellie-iu4uv]

I just wanted to ask if for unconsolidated undrained and consolidated undrained, do I have to put water in the water chamber? or placing water is only necessary for consolidated undrained?

[@zagamer3373]

Yes water, the sample needs to be saturated.

[@kathleenarchivedo3904]

hi thank you for this video . please tell me how many kg total we are going to load until the test finish? description of sample : undisturbed material silty clay material and how can we get the optimum moisture content that we will used for the test.

[@zagamer3373]

The weight in kgs that will be used is based on the 3 forces for each test, generally I prefer 50kPa then 100kPa and finally 200kPa, for this test range the weights are as follows: 50kPa -> 1.75kg on the right and 0.75kg on the left. 100kPa -> 3.5kg on the right and 1.5kg on the left. 200kPa -> 7.25kg on the right and 0.75kg on the left. note that you can also do a force range of 100kpa then 200kpa and finally 400kpa. With Silty clays I personally have found better results on the higher forces. As for the optimum moisture content, generally you would take a accurate representation of your sample (usually 1/4 of the sample) and perform a Modified or AASHTO Proctor Test. Hope this answers some of your questions.

[@zagamer3373]

The load in kg will depend on the test range (ie. 50kPa -> 100kPa -> 200kPa etc.) The optimum moisture content is determend with a modified proctor test.

[@karllising5755]

Where did you get the shear box chart?

[@zagamer3373]

From a excel spreadsheat with the calculations. you can also get a unit converter to assist.

[@charinagacura5214]

can i request shear box chart for round sample? @@zagamer3373

[@fadhelfebriangafar3602]

Hai, may i ask you a some questions? 1. Why WF Brand have two arms for weight? because i see the other brand only have 1 arm. 2. As far as i know the arm of weight is to give the normal load (N). so why WF Brand makes 2 arms while 1 arms is already can do that. 3. At your video, i see the shearbox loading chart. is it given from WF or from ASTM ? 4. I see on Controls Group Video for AUTOSHEAR, they only put the weight on right arms.. Why ?? Thanks, i hope you read and reply my comment .

[@zagamer3373]

as far as I know the reason for the 2 arms are for finer control of the vertical load, the chart is just for excel with the basic calculation. I hope that answers some of your questions.