## 3 Testing Results and Analysis
### Triaxial UU Test  
[PERSON] and [PERSON] [34] proposed the use of the parameters of triaxial UU tests for simulating clay stability analysis and calculating bearing capacity when a construction load is high. To prepare remolded specimens, the present study used static triaxial UU tests. A discussion of mudstone and mudstone-cement specimens follows. Similar test  
Figure 12: Mohr circle and shear strength parameters of the testing samples for triaxial Consolidated Undrained tests: (**a**) CU-0%; (**b**) CU-4%; (**c**) CU-8%. Figure 13: Cohesion values and internal friction angles of the samples for triaxial Consolidated Undrained tests: (**a**) mudstone; (**b**) mudstone-cement. methods were used and the specimens did not achieve saturation. [PERSON] [48] and [PERSON] and [PERSON] [49] indicated that the curved envelope is sometimes approximated as a straight line as Equation (1) in unsaturated soils for design purposes. Care should be taken to not exceed the limits to which the envelope is applicable. Figure 14 indicates that when the specimens had a \(\gamma_{\text{d}}\) of 19.5 kN/m\({}^{3}\) and were cured for 28 days with C = 0%, 4%, and 8%, the c values were 70 kPa, 154 kPa, and 256 kPa, respectively, and the \(\phi\) angles were 27.26\({}^{\circ}\), 42.72\({}^{\circ}\), and 43.13\({}^{\circ}\), respectively. Cohesion and the internal friction angle increased with the amount of cement paste added. Clods with grains that passed through the #4 and #4-3/4\" sieves did not exhibit considerable differences. Specimens retained by the 3/4\" sieve exhibited greater clad grain sizes. After the completion of compaction, a large number of grains with varying sizes still existed in the specimens, preventing the complete compactness of the soil specimens. Therefore, specimens that were subjected to shearing forces tended to present dislocated grains and have reduced friction angles. Figure 15 presents the comparison diagrams for cement content, friction angle, and cohesion force. When the amount of cement paste added was increased, friction angle and cohesion force increased. Figure 14: Mohr circle and shear strength parameters of the soil samples for triaxial Unsaturated Unconsolidated Undrain tests: (**a**) UU-0%; (**b**) UU-4%; (**c**) UU-8%. Unconfined compression strength measures the strength of specimens under unconfined conditions, with soil generally subjected to overburden pressure under the ground surface. Therefore, shear strength can be represented using Equation (1); that is, shear strength is calculated using the c value and \(\phi\) angle parameters. The data presented in Figures 12 and 14 are organized in Table 1. For the parameter \(\sigma\), a shallow overburden pressure of 40 kPa was applied. The triaxial CU test specimens were set as saturated and the triaxial UU test specimens were set as unsaturated. The mudstone specimens had a C of 0%, whereas the mudstone-cement specimens had a C of 4% and 8%. After 28 days of curing, the shear strength \(\tau_{\text{f}}\) of saturated samples was 104.33 kPa, 186.13 kPa, and 206.10 kPa, while that of unsaturated samples was 90.61 kPa, 190.94 kPa, and 293.47 kPa. The relevant data are plotted in Figure 16, which indicates that unsaturated samples exhibited higher strength. The soaked samples generate negative pore water pressure because of compaction and the addition of cement under low strain conditions; thus, the specimen strength was not low. In Figure 8, the unconfined compression strength q\({}_{\text{u}}\) of specimens with C values of 0%, 4%, and 8% after 28 days of curing was 151, 1207, and 1488 kPa, respectively. However, real geoengineering foundations are confined. Thus, the adoption of \(\tau_{\text{f}}\) is more suitable for engineering applications.