9 6.4. A series of saturated and unsaturated triaxial tests were conducted on a sand-clay mixture. Results are shown in Table 6.9. Assume that the co- hesion c' is zero and determine the internal friction angle ', effective stress parameter function, X versus u u, and capillary cohesion func- tion, c" versus ua u. Plot the effective stress parameter and capillary cohesion functions. - - 266 SHEAR STRENGTH TABLE 6.9 Triaxial Testing Results for Problem 6.4 Test (ua - Uw)s (kPa) 1 0 234 200 400 850 (σ₁ - ua)s (kPa) (kPa) 486 150 600 120 950 200 1300 260 6.5. Using Fig. 6.20, show mathematically that the relationship between suc-