Experimental study on the permeability and seepage characteristics of bimsoils

Figures & data

Table 1. Summary of research methods and factors of the permeability of bimsoils in latest literatures.

References	Research methods	Research factors
Zhou et al. (2017)	Laboratory test; theoretical analysis	Rock content; void ratio; particle shape
Ma et al. (2016)	Laboratory test	Particle size distribution
Wang et al. (2016b)	Laboratory test	Rock content; hydraulic gradient
Chen et al. (2019)	Numerical analysis	Rock content; rock size; rock shape; rock blocks' major axis direction
Zhang et al. (2021)	Laboratory test	Rock content
Wang et al. 2016a)	Laboratory test	Rock content; soil matrix
Luan et al. (2020)	Laboratory test	Rock content; hydraulic pressure
Jin et al. (2021)	Numerical analysis	Rock content; rock size; relative density
Xu and Shang (2006)	Mathematical statistics	Rock content；fine particle component
Xu et al. (2009)	Field test	Particle size distribution

Table 2. Mass percentage of sand particles in different particle sizes.

Talbot index	Mass percentage of different particle size (%)
	0–0.5 mm	0.5–2 mm
0.4	57	43
0.7	37	63
1.0	25	75

Figure 1. The raw materials of permeability experiments of bimsoils.

Figure 2. Laboratory apparatus for testing the permeability coefficient of bimsoils. (a) TS-70 constant-head permeameter (b) Permeameter for rock mass.

Figure 3. Process of sample preparation for permeability experiments.

Figure 4. Experimental apparatus for variable mass seepage of bimsoils. (a) Schematic layout of the experimental system (b) Seepage apparatus and lost materials collection system

Figure 5. The raw materials of variable mass seepage experiments of bimsoils.

Table 3. Factors and levels of orthogonal test.

Levels	Factors
	A (Talbot index)	B (Rock content) (%)	C (Rock size) (mm)	D (Cementation degree)
1	0.4	30	5–6	Non-cementation
2	0.7	45	6–8	Clay cement
3	1.0	60	8–10	Cement bond (PC32.5)

Table 4. Test schemes and results of orthogonal design.

Test number	Test condition	Average mass (g)	Average permeability coefficient (K20/cm·s^−1)
1-1	A1B1C1D1	3596.3	0.02186106
1-2	A1B2C2D2	3591	0.02256796
1-3	A1B3C3D3	304.3	0.11465366
1-4	A2B1C2D3	303	0.00491079
1-5	A2B2C3D1	3596.7	0.06469511
1-6	A2B3C1D2	3588.3	0.11054194
1-7	A3B1C3D2	3599.3	0.03374551
1-8	A3B2C1D3	301.67	0.00658828
1-9	A3B3C2D1	3587.67	0.15840192

Table 5. Interactive test schemes and results of rock content and cementation degree.

Test number	Clay cement		Average permeability coefficient (K20/cm·s^-1)	Test number	Cement bond		Average permeability coefficient (K20/cm·s^-1)
	Rock content	Cementation degree			Rock content	Cementation degree
2-0-1	30%	Non-cementation	0.05977974	3-0-1	30%	Non-cementation	0.04451235
2-1(1-7)		Clay (6%)	0.03374551	3-1(1-4)		Cement (6%)	0.00491079
2-2		Clay (8%)	0.043927056	3-2		Cement (8%)	0.003726848
2-3		Clay (10%)	0.01864209	3-3		Cement (10%)	0.002496646
2-0-2	45%	Non-cementation	0.071891067	3-0-2	45%	Non-cementation	0.055616192
2-4		Clay (6%)	0.044856837	3-4		Cement (6%)	0.016014632
2-5		Clay (8%)	0.060043878	3-5		Cement (8%)	0.014038148
2-6		Clay (10%)	0.025978453	3-6		Cement (10%)	0.011363306
2-0-3	60%	Non-cementation	0.168473127	3-0-3	60%	Non-cementation	0.055616192
2-7		Clay (6%)	0.141438897	3-7		Cement (6%)	0.11260422
2-8		Clay (8%)	0.176590872	3-8		Cement (8%)	0.072475439
2-9		Clay (10%)	0.084095267	3-9		Cement (10%)	0.021798521

Table 6. Test schemes of variable mass seepage of bimsoils.

Test number	Talbot index	Mass percentage particle 0–2 mm (%)	Mass percentage particle 2–3 mm (%)	Rock content	Rock size (mm)	Radius ratio	Total mass (g)
4-1	0.4	85	15	60%	8–12	4	13,326
4-2					12–16	5.3	13,233
4-3					16–20	6.6	12,974
4-4					20–24	8	13,020

Figure 6. Influence of various factors on permeability coefficient of bimsoils.

Table 7. Range analysis of the results of orthogonal test.

Index	Factors
	A (Talbot index)	B (Rock content)	C (Rock size)	D (Cementation degree)
Kj1	0.15908268	0.06051736	0.13899128	0.24495809
Kj2	0.1801484	0.09385135	0.18588067	0.16685541
Kj3	0.19873571	0.38359752	0.21309428	0.12615273
$\overline{K_{\mathrm{j}1}}$	0.05302756	0.020172453	0.046330427	0.081652697
$\overline{K_{\mathrm{j}2}}$	0.06004928	0.031283783	0.061960223	0.05561847
$\overline{K_{\mathrm{j}3}}$	0.066245237	0.12786584	0.071031427	0.04205091
Rj	0.013217677	0.107693387	0.024701	0.039601787
Optimal levels of reducing permeability	A1 (Talbot index, 0.4)	B1 (Rock content, 30%)	C1 (Rock size, 5–6 mm)	D3 (Cementation degree, Cement bond)
Important order	B (Rock content)>D (Cementation degree)>C (Rock size)>A (Talbot index)

Note: K_jm is the sum of the permeability coefficient corresponding to the factor m level in column j, the value of K_jm is able to judge the optimal level and optimal combination of factor j. $\overline{K_{\text{jm}}}$ is the average of K_jm. R_j is the range of column factor j, namely the difference between the maximum and minimum values of the average permeability coefficient at each level of column j factors, $R_{\mathrm{j}}=\max (\overline{K_{\mathrm{j}1}},\overline{K_{\mathrm{j}2}},\dots ,\overline{K_{\text{jm}}})-\min (\overline{K_{\mathrm{j}1}},\overline{K_{\mathrm{j}2}},\dots ,\overline{K_{\text{jm}}}).$

Table 8. Variance analysis of orthogonal test.

Variation	sum of deviation squares (SSj)		degrees of freedom (dfj)		F value		Significance
A (Error term e)	0.000262401		2		1
B	0.021049421		2		80.21839927		***
C	0.000936717		2		3.569785256		*
D	0.002430161		2		9.261235202		**
∑	0.0246787		8
Fα	F0.25(2, 2) = 3	F0.10(2, 2) = 9		F0.05(2, 2) = 19		F0.025(2, 2) = 39		F0.01(2, 2) = 99

Note: “*, **, ***” represents the influence degree of different factors. SS_j is sum of deviation squares, $S{S}_{\mathrm{j}}=\frac{\sum T_{\mathrm{j}}^2}{k_{\mathrm{j}}}-\frac{{({\sum }_{i=1}^n{y}_i)}^2}{n},$ where T_j is the sum of permeability coefficient at the same level of factor j, k_j is the level number of the factor j, y_i is the permeability coefficient of test and n is the total number of tests. df_j is degrees of freedom of factor j, $d{f}_{\mathrm{j}}=k_{\mathrm{j}}-1.$ F value is the index of significance test, $F_{\mathrm{j}}=\frac{S{S}_{\mathrm{j}}/d{f}_{\mathrm{j}}}{S{S}_{\mathrm{e}}/d{f}_{\mathrm{e}}}.$

Figure 7. Variation characteristics of permeability coefficient of bimsoils with clay cement.

Figure 8. Variation characteristics of permeability coefficient of bimsoils with cement bond.

Figure 9. The collections of lost material during the whole of seepage experiments (radius ratio of 5.3).

Figure 10. Time varying curve of component loss in bimsoils samples.

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Data availability statement

All data, models, and code generated or used during the study appear in the published article.