Experimental Study on Physical-Mechanical Properties of Expansive Soil Improved by Multiple Admixtures

Table 10

Results of direct shear test.

Sample number	Fitting equation	Cohesive force c (kPa)	Internal friction angle φ (^o)	Shear strength τ(kPa) (the normal stress is 100 kPa)	Correlation coefficient r	Correlation index R^2
0	τ = 0.297σ + 81.75	81.75	16.5°	115.5	0.9931	0.9794
1	τ = 0.4136σ + 117.2	117.2	22.5°	164.5	0.9926	0.9779
2	τ = 0.5175σ + 124.95	124.95	27.4°	184.7	0.9919	0.9759
3	τ = 0.5571σ + 159.3	159.3	29.1°	204.0	0.9863	0.9593
4	τ = 0.5385σ + 129.25	129.25	28.3°	191.2	0.9910	0.9732
5	τ = 0.6906σ + 183.45	183.45	34.6°	247.5	0.9924	0.9774
6	τ = 0.5512σ + 135.25	135.25	28.9°	198.3	0.9894	0.9684
7	τ = 0.6058σ + 151.35	151.35	31.2°	215.8	0.9974	0.9923
8	τ = 0.5879σ + 126.55	126.55	30.5°	180.9	0.9944	0.9832
9	τ = 0.5935σ + 157.95	157.95	30.7°	216.1	0.9908	0.9725