Mechanical properties of structured high liquid limit clay under maximum drying stress conditions

Figures & data

Figure 1. The destruction site of the bengbu section of the mainstream of the Huaihe River (a) China map; (b) bengbu slope collapse behavior; (c) the destruction site.

Figure 2. The Particle size distribution of tested clay.

Table 1. Basic physical properties of the tested clay.

Properties	Value
Specific gravity, Gs	2.7
Liquid limit (%)	53.5
Plastic limit (%)	26.4
Plasticity index	27.1
Maximum dry density, $\rho$dmax (g/cm^3)	1.46
Optimum moisture content, wopt (%)	29.2
Classification of soil	CH

Table 2. Mineral composition of high liquid limit clay.

Mineral content (%)						Relative clay mineral content (%)
Qtz	Kfs	Ab	Cal	Py	Clays	I/S	It	Kao	Chl
21.9	2.2	7.1	25.7	0.5	42.6	33	34.5	14.4	17.9

Figure 3. Sample in different directions.

Table 3. Triaxial compression test of high liquid limit clay.

No.	Sample	Dry density (g/cm3)	Initial moisture content (%)	Cell pressure (kPa)	Testing item	D-W cycles
1	Reconstituted sample	1.39	31.2	50, 100, 200	CU	0
2	θ = 0° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	0
3	θ = 45° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	0
4	θ = 90° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	0

Table 4. Triaxial compression test of high liquid limit clay with 1 D-W cycle.

No.	Sample	Dry density (g/cm3)	Initial moisture content (%)	Cell pressure (kPa)	Testing item	D-W cycles
1	Reconstituted sample	1.39	31.2	50, 100, 200	CU	1
2	θ = 0° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	1
3	θ = 45° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	1
4	θ = 90° (undisturbed sample)	1.39	31.2	50, 100, 200	CU	1

Figure 4. TSZ-2 Automatic triaxial device.

Figure 5. SEM Tests (a) sample tray; (b) SBC-12 ion sputtering instrument; (c) sample chamber; (d) KYKY-EM6200 SEM.

Figure 6. Sample preparation equipment (a) sample trimmer; (b) dry oven; (c) soil sieve; (d) electronic scale; (e) mold and tamper; (f) saturation device.

Figure 7. Unconfined compression strength curve of high liquid limit clay.

Figure 8. 10.0kx SEM images of undisturbed and reconstituted samples of high liquid limit clay (a) undisturbed sample θ = 0°; (b) undisturbed sample θ = 45°; (c) undisturbed sample θ = 90°; (d) reconstituted sample.

Figure 9. Stress-strain and porewater pressure-strain curves of reconstituted and undisturbed samples (θ = 0°) of high liquid limit clay with 0 D-W cycles (a)reconstituted samples stress-strain curves; (b) reconstituted samples porewater pressure-strain curves; (c) undisturbed samples stress-strain curves; (d) undisturbed samples porewater pressure-strain curves.

Figure 10. Stress-strain curves for three undisturbed samples (θ = 0°, 45°, and 90°) with 0 D-W cycles, and stress-angle variation curves (a) 50 kPa; (b) 100 kPa; (c) 200 kPa; (d) stress-angle variation curves.

Figure 11. Stress-strain curves and porewater pressure-strain curves of reconstituted samples and undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay after 1 D-W cycle (a)reconstituted samples stress-strain curves; (b) reconstituted samples porewater pressure-strain curves; (c) undisturbed sample in 0° direction stress-strain curves; (d) undisturbed sample in 0° direction porewater pressure-strain curves; (e) undisturbed sample in 45° direction stress-strain curves; (f)undisturbed sample in 45° direction porewater pressure-strain curves; (g) undisturbed sample in 90° direction stress-strain curves; (h)undisturbed sample in 90° direction porewater pressure-strain curves.

Figure 12. Shear strength envelope for reconstituted and undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay with 0 D-W cycles.

Table 5. Shear strength parameters for reconstituted samples and undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay with 0 D-W cycles.

Sample	D-W cycles	Cohesion c/kPa	Friction angle ϕ/°
Reconstituted Sample	0	1.57	11.54
θ = 0° (Undisturbed sample)	0	13.73	10.51
θ = 45° (Undisturbed sample)	0	4.17	9.73
θ = 90° (Undisturbed sample)	0	7.92	10.33

Figure 13. Shear strength envelope for reconstituted samples and undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay after 1 D-W cycle.

Table 6. Shear strength parameters for reconstituted samples and undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay after 1 D-W cycle.

Sample	D-W cycles	Cohesion c/kPa	Friction angle ϕ/°
Reconstituted Sample	1	1.63	17.37
θ = 0° (Undisturbed sample)	1	12.21	18.82
θ = 45° (Undisturbed sample)	1	16.98	17.52
θ = 90° (Undisturbed sample)	1	11.13	20.42

Figure 14. Undisturbed high liquid limit clay samples (θ = 0°, 45°, and 90°) after 1 D-W cycle (a) θ = 0°; (b) θ = 45°; (c) θ = 90°.

Figure 15. Failure mode of undisturbed samples of high liquid limit clay (θ = 0°, 45°, and 90°) under 100 kPa cell pressure with 0 D-W cycles (a) θ = 0°; (b) θ = 45°; (c) θ = 90°.

Figure 16. General undrained shear behavior of sand under large deformation (Yoshimine and Ishihara 1998).

Figure 17. Effective mean principal stress paths of undisturbed samples of high liquid limit clay (θ = 0°, 45°, and 90°) with 0 D-W cycles.

Figure 18. Failure modes of undisturbed high liquid limit clay samples (θ = 0°, 45°, and 90°) under a 100 kPa cell pressure after 1 D-W cycle. (a) θ = 0°; (b) θ = 45°; (c) θ = 90°.

Figure 19. Effective mean principal stress paths of undisturbed samples of high liquid limit clay (θ = 0°, 45°, and 90°) after 1 D-W cycle.

Figure 20. Stress peak variation with cell pressure for undisturbed samples (θ = 0°, 45°, and 90°) of high liquid limit clay under 0 and 1 D-W cycle (a) high liquid limit clay with 0 cycles of D-W; (b) high liquid limit clay after 1 cycle of D-W.

Table 7. Variance of stress peak values for undisturbed samples (θ = 0°, 45°, and 90°) under 0 and 1 D-W cycle.

D-W cycles	Variance(s^2)
	50kPa	100kPa
0	47.08	320.50
1	8.16	94.88

Yoshimine M, Ishihara K. 1998. Flow potential of sand during liquefaction. Soils Found. 38(3):189–198. doi: 10.3208/sandf.38.3_189.

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Data availability statement

All data used during the study are available from the corresponding author by request.