Please check code of practice

As far a I remember for soft rocks (UCS less than 30MPa) it is about 0.05%/min.

ASTM D2166 specifies a strain rate in the range of 0.5-2% per minute for the Unconfined compression test on cohesive soils.Strain rate in UU test is typically 1% per minute.

As recomended by Head, the shearing speed should be chosen so that the sample failure reached within 15 min.

Might better you should follow the standard for any test like that in ASTM or/and Joseph Bowled

It depends on your soil. There are some recommendation in the german standard DIN 18137-2. There is also an english version available.

Thank you all very much 

Following the german standard 18136 (unconfined compression test)  you have to use 1% of the initial specimen height (in mm) per minute for the deformation rate. For soils which are improved with a binder agent you should use 0,4% of the initial speciment height.

According to DIN18137-2 you use 1% of the initial specimen height per minute as deformation rate for the triax UU test.

Dear, 

It depends upon type of soil & not constant for all type of soil.

For sandy soils, a rate of strain 0.2 mm/ min may be suitable. For clayey soils, a rate of strain of 0.01mm/min or slower may be used.

For actual strain rate u may perform consolidation test and from that u may decide the strain rate.

Please use 

•  For the unconfined compression test 0.5% to 2% per minute on cohesive soils.
• For the UU test 1% per minute is good.
• Please note that these rates change when water content in the sample changes. For example. for unsaturated soils, you may need to use slower rates. 

The speed of the machine is totally depend of the sample conditions such as water content and % fine (clay and silt). 

Usually, the shearing rate of the Unconfined Compression test is 1 mm/min.

It depends on the type of geomaterial.

It may not effect the strength but can effect the Young's Modulus.

You conduct your tests according to some standard . The rate of speed is specified in this standard.

For assessing compressive strength qu, under seismic conditions what strain rate should we use Christian Ungewitter Boriana Tchakalova Mohsin Usman Qureshi Omar Hamdi Jasim . Is there any code provisions for sandy soil mixed with cement.

Samiul Islam These are very specific testing conditions. To my knowledge there is no such German standard or EN standard. Perhaps you can search in standards of the ASTM.

1mm/min

it depends on soil type. it is recommendable to use rate of strain within 0.5 to 1.5% of specimen height.