A drained triaxial compression test is conducted on quartz sand with initial void ratio of e. = 0.70, at a constant total cell pressure of o₃ = 350 kPa and a constant back pressure u₀ = 100 kPa. The test gave a peak deviator stress of qₚₑₐₖ = 785 kPa, and a maximum dilation rate of (-dev/deₐ)ₘₐₓ = 0.75. Maximum and minimum void ratios for this sand are eₘₐₓ= 0.91 and emin = 0.60. The ultimate friction angle, when shearing occurs at constant volume, is 'cv = 30°.
Draw a properly-scaled Mohr Circle diagram for the effective stress state at peak deviator stress. (σ'₁: = 1035 kPa; o₃ = 250 kPaₚₑₐₖ 37.7°)