# Evaluation of Flow Liquefaction Susceptibility in Non-Plastic Silty Soils Using the Seismic Cone

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

_{0}/q

_{t}for classification and Ψ assessment. For non-plastic silty soils, drainage conditions during cone penetration must be accounted for and are used to allow soil classification and correct the cone tip resistance. An empirical formulation is proposed to correct q

_{t}for partial drainage measurements and predict Ψ for non-plastic silty soils. Mining tailings results of in situ and laboratory tests were used to validate the proposed methodology producing promising responses. The Ψ value estimated through the proposed methodology are in the range of those obtained from laboratory tests, indicating an adequate prediction of behavior for non-plastic silty soils.

## 1. Introduction

_{1}+ 2σ′

_{3})/3) space, the state parameter Ψ is defined as the difference between the current void ratio (e) and critical state void ratio (e

_{c}), at the same mean stress [15]. The degree of contractiveness or dilatancy of soils is characterized by positive or negative Ψ values, respectively. In practice, a state parameter equal to −0.05 is considered a minimum state limit to ensure satisfactory engineering performance against flow liquefaction [16].

_{0}/q

_{t}[20], or cone resistance to pressuremeter limit pressure, q

_{c}/p

_{L}[21].

_{0}/q

_{t}ratio to derive Ψ. Both the stiffness (G

_{0}) and the shear resistance (q

_{t}) are controlled (although differently) by void ratio, mean stresses, compressibility, and soil structure, and are therefore different functions of the same variables [22]. As a ratio, these two measurements can be useful in predicting the soil state [20,22,23,24].

_{0}value can be determined from in situ shear wave velocity measurements (V

_{s}), as in Equation (1):

_{0}/q

_{t}ratio is presented in Equation (2) [20]:

_{a}are the mean effective stress, and the standard atmospheric pressure, respectively, and q

_{c}= q

_{t}is for sands with full drainage.

_{0}/q

_{t}ratio (Equation (2)) from SCPTu test data. Recognizing the importance of the state parameter in assessing susceptibility to flow liquefaction in mining tailings and knowing that this material is silty grain-sized, this paper aims to present an adaptation of an early method introduced by Schnaid et al. [25] for application in non-plastic silty soils. The first stage of the methodology is a classification system that was expanded to consider partial drainage, a common condition observed during in situ tests in mining tailings. New zones are explored to include parameter combinations that characterize non-plastic highly sensitive soils. The second stage of the methodology consists of defining the state parameter from Equation (2). In this situation, an empirical correction of q

_{t}was proposed to consider the partial drainage conditions during cone penetration in silty grain-sized soils. Adopting the correction, q

_{t}values were obtained for a drained condition, and the Ψ values could be calculated using Equation (2), previously proposed for granular soils with drained behavior. The results from the SCPTu tests were used to validate the expansion of the method. Values of the Ψ estimates from field tests using the proposed correction of q

_{t}mostly fell within the range of values obtained through laboratory tests.

## 2. Drainage Conditions on CPTu Tests

^{−5}m/s < k < 10

^{−8}m/s), such as silty soils and mining tailings, there are no consensual guidelines for correct testing and data interpretation [26,27]. The results of a standard cone penetration test (CPTu) (v = 20 mm/s) are affected by partial drainage during the penetration [28], which, may induce errors in the prediction of soil parameters.

_{h}is the coefficient of horizontal consolidation. According to Randolph and Hope [29], fully undrained penetration occurs when V values are higher than a value around 30–100, and fully drained penetration occurs when V values are less than a value around 0.03–0.01.

_{q}can be helpful; B

_{q}greater than 0.5 is enough to characterize undrained conditions and lower values may indicate partial drainage [35].

## 3. Classification and Flow Liquefaction Evaluation for Non-Plastic Silty Soils Based on Seismic Cone Tests

#### 3.1. Laboratory Test Results Analysis

_{max}/G

_{0}) were plotted against the normalized maximum shear resistance (q

_{1}), obtained through Equation (4).

_{3}is the triaxial confining stress.

_{max}values increases the G

_{0}/q

_{max}ratio and decreases q

_{1}, positioning the combined data above and on the left in Figure 2, respectively.

_{max}values. Figure 1 illustrates the significant reduction in undrained shear resistance for mining tailing samples compared to sand samples. Similar results were found by Zhu et al. [44], who investigated the influence of the presence of fine particles in a granular matrix, verifying that there is a deleterious effect on the undrained shear strength with the increase of fine particles, in addition to facilitating the generation of excess pore pressures. Moreover, it is interesting to note that for drained conditions, the combination of results for both sands and mining tailings is quite similar in normalized maximum resistance (q

_{1}), with only the G

_{0}/q

_{t}ratio being lower in the case of tailings. This behavior supports the analysis of non-plastic silty soil behavior based on formulations employed to sands in drained conditions.

#### 3.2. Developed Expansion on the Classification System

_{0}/q

_{t}) expressed on the y-axis and the normalized cone resistance (Q

_{tn}) expressed on the x-axis. The expanded proposed method is shown in Figure 3. The auxiliary vertical lines, presented in the classification system, help define the type of material and drainage conditions during cone penetration. A vertical line for Q

_{tn}= 50 has already been recognized as a safe and conservative limit to separate sands from sand mixtures: soils above the A-A line with Q

_{tn}> 50 are granular, and cone penetration occurs in drained conditions [28]. At the same time, values of Q

_{tn}< 50 are representative of sand and silt mixtures where partial drainage may occur during cone penetration. The soils below line B-B, characterized by Q

_{tn}< 10, are typically clays, and cone penetration will occur in undrained conditions. Intermediate conditions are representative of mixtures of clays, silts, and sands, where cone penetration is likely to occur under partially drained conditions. In addition to the vertical lines of Q

_{tn}= 50 and Q

_{tn}= 10, a line was inserted to intermediate empirical Q

_{tn}= 20. This line presents a possible frontier between mixtures with a higher proportion of sand (on the right) and a higher proportion of silty fines (on the left).

_{tn}= 10 and continues through line B-B for values lower than Q

_{tn}= 10. The definition of this master line was carried out based on the results of field trials. Another notable factor observed is that the granulometry of the soils evaluated in the system tends to reduce from right to left and from top to bottom in the graph.

_{0}/q

_{t}ratio.

_{0}/q

_{t}versus Q

_{tn}, as illustrated in Figure 3.

#### 3.3. State Parameter Assessment for Non-Plastic Silty Soils and Flow Liquefaction Evaluation

_{0}/q

_{t}ratio, it is possible to estimate the Ψ value for sands. Therefore, for drained conditions, this correlation also can be used to estimate Ψ values for non-plastic silty soils, such as mining tailings. To allow this point of view, the cone tip resistance in Equation (2) must be a drained value and can be named as q

_{tD}, and Equation (2) can be rewritten as Equation (5):

_{tD}was obtained for these materials.

_{tD}) and undrained cone tip resistance (q

_{tUD}) is also a function of soil type.

_{m}= Q), the effective resistance parameters (c′ and ϕ′), the pore pressure parameter (B

_{q}), and the angle of plastification (β), (Equation (6)):

_{v}

_{0}and σ′

_{v}

_{0}are the total and effective vertical stresses, respectively.

_{q}, with c′ = 0 and β = 0.

_{t}. Therefore, Figure 5 allows us to estimate the drained (q

_{tD}) and undrained (q

_{tUD}) cone tip resistance for a specific friction angle value, which can be correlated to soil type. Drained conditions are associated with B

_{q}= 0, and undrained conditions are characterized by B

_{q}in the 0.6 to 1 interval [34,35].

_{tD}/q

_{tUD}) and effective friction angle (ϕ′). This correlation is shown in Figure 6, where the variation range of q

_{tD}/q

_{tUD}has been established by two curves obtained from Senesset et al. [45]. In addition, results from the literature plotted in Figure 6 demonstrate that the method can reasonably describe experimental measurements. Figure 6 demonstrates that the q

_{tD}/q

_{tUD}ratio varies from 3 (for effective friction angles around 20°) to about 10 (for effective friction angles around 38° and 40°).

_{tD}) and standard cone tip resistance (q

_{t}

_{20}), (Equation (7)):

_{tD}/q

_{t}

_{20}ratio for partial drainage conditions. The proposed empirical equation is dependent on the q

_{tD}/q

_{tUD}ratio (provided by Figure 6) and B

_{q}(Equation (8)):

_{tD}/q

_{tUD}assumes a fixed value, depending on the estimated soil friction angle (Figure 6), and α is a parameter dependent on the material stiffness, ranging from 0 to 1. An initial simplified evaluation adopts an average value of α = 0.5, although this parameter depends on soil type and should be calibrated. It should also be noted that the proposed empirical proposal (Equation (8)) was developed considering extreme values of B

_{q}, which could be calibrated in future work according to the behavior of each material. In general, the equation proposed in this study can be used to obtain q

_{tD}values in different types of non-plastic silty soils, in which cone tests at standard speed provide results under partial drainage conditions, which makes their adequate interpretation difficult.

_{tD}/q

_{tUD}ratios calculated from Equation (8). Once q

_{tD}values are estimated from the proposed correction, Equation (2) can be used to determine the Ψ values for non-plastic silty soils, which allows the flow liquefaction susceptibility evaluation.

_{tD}values obtained through empirical equations coincide or are very close to the q

_{t}values measured in the test. Therefore, we can conclude that the empirical equation provides a quick and simplified solution to obtain an estimation of q

_{tD}from which constitutive parameters can be assessed.

_{tD}can be utilized in the two-stage classification soil system based on seismic cone penetration measurements, presented previously in Figure 4.

#### 3.4. Validation and Calibration

_{s}records in the four verticals. Data from the SCPTu tests carried out in three different deposits were evaluated for bauxite mining tailings. For the bauxite mining tailings deposit “A”, seven verticals of seismic cone tests were evaluated, with an average depth of 14 m and a total of 41 V

_{s}. records in all verticals. Five vertical seismic cone tests were evaluated for the “B” bauxite mining tailings deposit, with an average depth of 8 m and a total of 23 V

_{s}records. For the bauxite mining tailings deposit “C”, 14 SCPTu test verticals were evaluated with an average depth of 12 m and a total of 57 V

_{s}records for all verticals. For zinc mining tailings, three vertical seismic cone tests were evaluated and carried out in the same deposit, with an average depth of 12 m for each vertical and a total of 21 V

_{s}records. Five vertical seismic tests were evaluated for iron mining tailings, carried out in the same deposit, with an average depth of 22 m each and a total of 131 V

_{s}records. Lastly, three SCPTu test verticals were evaluated for copper mining tailings, with an average depth of 30 m for each vertical and a total of 87 V

_{s}records.

_{t}

_{20}) into an equivalent drained one (q

_{tD}) is provided by results in gold, iron, and bauxite mining tailings (no or low plastic silts). This database was selected for evaluation of this stage, as drained and undrained triaxial tests, using bender elements, were available for these materials, which allowed comparison between the Ψ values estimated from the SCPTu tests and those measured in the laboratory.

_{q}values close to zero, and the proposed correction is marginal. The Ψ values calculated from the SCPTu are spread across a wide range, from −0.15 to about 0.2, whereas laboratory tests fall into a much narrower range (from +0.05 to +0.08) (Figure 10). This may indicate that the methods proposed originally by Schnaid and Yu [20] need to be more accurate or that field data is scattered due to the actual spatial variation of tailings. However, it is interesting to observe that laboratory and field data indicate that these tailings can flow liquefaction for the Fundão Dam.

_{q}values indicating partial drainage. The friction angle of the gold mining tailings measured by the laboratory tests is 32° [43]. The q

_{tD}/q

_{tUD}ratio was adopted as 7, considering the Senneset et al. [45] approach. This value is also very close to the response obtained when analyzing the poroelastic theory results [27]. A good fit between laboratory and field Ψ values prediction is obtained for α close to unity (Figure 11).

_{t}

_{20}values to the q

_{tD}values obtained by the proposed correction. The estimated Ψ values from q

_{t}

_{20}were verified. However, it was shown that the material presents contractive behavior and susceptibility to the flow liquefaction, generating high Ψ values compared to the range defined by laboratory test results. However, applying the tip resistance correction for drained conditions, the estimated Ψ values are very close to the range defined by the laboratory test results.

_{q}values for a partial drainage condition. In this case, the correction of q

_{t}

_{20}was already necessary for Ψ estimation. To apply the empirical equation to correct the q

_{t}

_{20}value for drained conditions, a q

_{tD}/q

_{tUD}ratio was adopted equal to 7. This value is defined in Figure 6 for a friction angle of 32.4°, which was obtained by triaxial tests. In this analysis, a good fit between laboratory and field Ψ values prediction is obtained for α close to 0.5 (Figure 12).

## 4. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- Nierwinski, H.P.; Schnaid, F.; Odebrecht, E. In-situ state parameter assessment of non-plastic silty soils using the seismic cone. In Proceedings of the 6th International Conference on Geotechnical and Geophysical Site Characterization, Online, 26–29 September 2021. [Google Scholar]
- Robertson, P.K.; Fear, C.E. Liquefaction of sands and its evaluation. In Proceedings of the IS-Tokyo ’95: The First International Conference on Earthquake Geotechnical Engineering, Tokyo, Japan, 14–16 November 1995; Ishihara, K., Ed.; Balkema: Rotterdam, The Netherlands, 1995; pp. 1253–1289. [Google Scholar]
- Seed, H.B. Soil liquefaction and cyclic mobility evaluation for level ground during earthquakes. J. Geotech. Eng. Div. ASCE
**1979**, 105, 201–255. [Google Scholar] [CrossRef] - Castro, G. Liquefaction and cyclic mobility of saturated sands. J. Geotech. Eng. Div. ASCE
**1975**, 101, 551–569. [Google Scholar] [CrossRef] - Finn, W.D.L. Liquefaction potential: Developments since 1976. In Proceedings of the 1st International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, St. Louis, MO, USA, 28 April 1981; Prakash, S., Ed.; University of Missouri-Rolla: Rolla, MO, USA, May 1981; Volume 2, pp. 655–681. [Google Scholar]
- Ishihara, K. Liquefaction and flow failure during earthquakes. Géotechnique
**1993**, 43, 351–415. [Google Scholar] [CrossRef] - Seed, H.B.; Idriss, I.M. Simplified procedure for evaluating soil liquefaction potential. J. Geotech. Eng. ASCE
**1971**, 97, 1249–1273. [Google Scholar] [CrossRef] - Robertson, P.K.; Wride, C.E. Evaluating cyclic liquefaction potential using the CPT. Can. Geotech. J.
**1998**, 35, 442–459. [Google Scholar] [CrossRef] - Davies, M.P.; McRoberts, E.C.; Martin, T.E. Static Liquefaction of Tailings–Fundamentals and Case Histories. In Proceedings Tailings Dams ASDSO/USCOLD; Association of State Dam Safett Official: Las Vegas, NV, USA, 2002. [Google Scholar]
- Jefferies, M.G.; Been, K. Soil Liquefaction: A Critical State Approach; CRC Press, Taylor & Francis: Boca Raton, FL, USA, 2016; 690p, ISBN 978-1-4822-1368-3. [Google Scholar]
- Morgenstern, N.R.; Vick, S.G.; Viotti, C.B.; Watts, B.D. Fundão Tailings Dam Review Panel. Report on the Immediate Causes of the Failure of the Fundão Dam. August 2016. Available online: https://www.resolutionmineeis.us/documents/fundao-2016 (accessed on 15 April 2022).
- Robertson, P.K. Evaluation of flow liquefaction and liquefied strength using the Cone Penetration Test. J. Geotech. Geoenviron. Eng.
**2010**, 136, 842–853. [Google Scholar] [CrossRef] - Yang, J.; Liang, L.B.; Chen, Y. Instability and liquefaction flow slide of granular soils: The role of initial shear stress. Acta Geotech.
**2022**, 17, 65–79. [Google Scholar] [CrossRef] - Zhu, Z.; Cheng, W. Parameter Evaluation of Exponential-Form Critical State Line of a State-Dependent Sand Constitutive Model. Appl. Sci.
**2020**, 10, 328. [Google Scholar] [CrossRef] - Been, K.; Jefferies, M.G. A state parameter for sands. Géotechnique
**1985**, 35, 99–112. [Google Scholar] [CrossRef] - Shuttle, D.A.; Cunning, J. Liquefaction potential of silts from CPTu. Can. Geotech. J.
**2007**, 44, 1–19. [Google Scholar] [CrossRef] - Ledesma, O.; Manzanal, D.; Sfriso, A. Formulation and numerical implementation of a state parameter-based generalized plasticity model for mine tailings. Comput. Geotech.
**2021**, 135, 104158. [Google Scholar] [CrossRef] - Robertson, P.K. Estimating in situ state parameter and friction angle in sandy soils from CPT. In Proceedings of the 2nd International Symposium on Cone Penetration Testing, Huntington Beach, CA, USA, 9–11 May 2010. [Google Scholar]
- Been, K.; Crooks, J.H.A.; Becker, D.E.; Jefferies, M.G. The cone penetration test in sands: Part I, State parameter interpretation. Géotechnique
**1986**, 36, 239–249. [Google Scholar] [CrossRef] - Schnaid, F.; Yu, H.S. Interpretation of the seismic cone test in granular soils. Géotechnique
**2007**, 57, 265–272. [Google Scholar] [CrossRef] - Yu, H.; Schnaid, F.; Collins, I. Analysis of Cone Pressuremeter Tests in Sands. J. Geotech. Eng.
**1996**, 122, 623–632. [Google Scholar] [CrossRef] - Schnaid, F. Geocharacterisation and properties of natural soils by in situ tests. In Proceedings of the International Conference on Soil Mechanics and Geotechnical Engineering; AA Balkema Publishers: Rotterdam, The Netherlands, 2005; Volume 16, p. 3. [Google Scholar]
- Schneider, J.A.; Moss, R.E.S. Linking cyclic stress and cyclic strain based methods for assessment of cyclic liquefaction triggering in sands. Géotechnique Lett.
**2011**, 1, 31–36. [Google Scholar] [CrossRef] - Robertson, P.K. Cone Penetration Test (CPT)-Based Soil Behaviour Type (SBT) Classification System–An Update. Can. Geotech. J.
**2016**, 53, 1910–1927. [Google Scholar] [CrossRef] - Schnaid, F.; Nierwinski, H.P.; Odebrecht, E. Classification and state parameter assessment of granular soils using the seismic cone. J. Geotech. Geoenviron. Eng. ASCE
**2020**, 146, 06020009. [Google Scholar] [CrossRef] - Holmsgaard, R.; Nielsen, B.N.; Ibsen, L.B. Interpretation of Cone Penetration Testing in Silty Soils Conducted under Partially Drained Conditions. J. Geotech. Geoenviron. Eng.
**2015**, 14, 204015064. [Google Scholar] [CrossRef] - Dienstmann, G.; Schnaid, F.; Maghous, S.; Dejong, J. Piezocone Penetration Rate Effects in Transient Gold Tailings. J. Geotech. Geoenviron. Eng.
**2018**, 144, 04017116. [Google Scholar] [CrossRef] - DeJong, J.T.; Randolph, M.F. Influence of partial consolidation during cone penetration on estimated soil behavior type and pore pressure dissipation measurements. J. Geotech. Geoenviron. Eng.
**2012**, 138, 777–788. [Google Scholar] [CrossRef] - Randolph, M.F.; Hope, S.N. Effect of cone velocity on cone resistance and excess pore pressure. In Proceedings of the IS Osaka–Engineering Practice and Performance of Soft Deposits; Yodogawa Kogisha Co. Ltd.: Osaka, Japan, 2004; pp. 147–152. [Google Scholar]
- Chung, S.F.; Randolph, M.F.; Schneider, J.A. Effect of penetration rate on penetrometer resistance in clay. J. Geotech. Geoenviron. Eng.
**2006**, 132, 1188–1196. [Google Scholar] [CrossRef] - Kim, K.; Prezzi, M.; Salgado, R.; Lee, W. Effect of penetration rate on cone penetration resistance in saturated clayey soils. J. Geotech. Geoenviron. Eng.
**2008**, 134, 1142–1153. [Google Scholar] [CrossRef] - Paniagua, P.; Carroll, R.; L’Heureux, J.-S.; Nordal, S. Monotonic and Dilatory Excess Pore Water Dissipations in Silt Following CPTU at Variable Penetration Rate. In Proceedings of the 5th Intern. Conf. on Geotechn. and Geophys. Site Characterisation, ISC’5, Queensland, Australia, 5–10 September 2016; pp. 509–514. [Google Scholar]
- Suzuki, Y.; Lehane, B.M. Rate dependence of qc in two clayey sands. In Proceedings of the 3rd International Symposium on Cone Penetration Testing, Madison, WI, USA, 13–14 May 2014; Volume 1. [Google Scholar]
- Schnaid, F. In Situ Testing in Geomechanics: The Main Tests; Taylor e Francis: London, UK, 2009; 329p. [Google Scholar]
- Hight, D.W.; Georgiannou, V.N.; Ford, C.J. Characterization of clayey sand. In Proceedings of the 7th International Conference on Behavior of Offshore Structures, Cambridge, MA, USA, 12–15 July 1994; Volume 1, pp. 321–340. [Google Scholar]
- Santos, J.A.; Gomes, R.C.; Lourenço, J.C.; Marquer, F.; Coelho, P.; Azeiteiro, R.; Santos, L.A.; Marques, V.; Viana da Fonsceca, A.; Soares, M.; et al. Coimbra Sand Round Robin Tests to Evaluate Liquefaction Resistance. In Proceedings of the 15th World Conference on Earthquake Engineering 15 WCEE, Lisbon, Portugal, 24–28 September 2012. [Google Scholar]
- Sharma, R.; Baxter, C.; Jander, M. Relationship between shear wave velocity and stresses at failure for weakly cemented sands during drained triaxial compression. Soils Found.
**2011**, 51, 761–771. [Google Scholar] [CrossRef] - Carraro, J.A.H.; Prezzi, M.; Salgado, R. Shear Strength and Stiffness of Sands Containing Plastic or Nonplastic Fines. J. Geotech. Geoenviron. Eng.
**2009**, 135, 1167–1178. [Google Scholar] [CrossRef] - Salgado, R.; Bandini, P.; Karim, A. Shear strength and stiffness of silty sand. J. Geotech. Geoenviron. Eng.
**2000**, 126, 451–462. [Google Scholar] [CrossRef] - Huang, Y.T.; Huang, A.B.; Kuo, Y.C.; Tsai, M.D. A laboratory study on the undrained strength of a silty sand from Central Western Taiwan. Soil Dyn. Earthq. Eng.
**2004**, 24, 733–743. [Google Scholar] [CrossRef] - Nyunt, T.T.; Leong, E.C.; Rahardjo, H. Strength and Small-Strain Stiffness Characteristics of Unsaturated Sand. Geotech. Test. J.
**2011**, 34, 551–561. [Google Scholar] - Prashant, A.; Bhattacharya, D.; Gundlapalli, S. Stress-state dependency of small-strain shear modulus in silty sand and sandy silt of Ganga. Géotechnique
**2018**, 69, 42–56. [Google Scholar] [CrossRef] - Bedin, J. Study of the Geomechanical Behavior of Tailings. Ph.D. Thesis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil, 2010. (In Portuguese). [Google Scholar]
- Zhu, Z.; Zhang, F.; Dupla, J.-C.; Canou, J.; Foerster, E. Investigation on the undrained shear strength of loose sand with added materials at various mean diameter ratios. Soil Dyn. Earthq. Eng.
**2020**, 137, 106276. [Google Scholar] [CrossRef] - Senneset, K.; Sandven, R.; Janbu, N. Evaluation of Soil Parameters from Piezocone Tests; Transportation Research Record 1235; Geotechnical Division, The Norwegian Institute of Technology: Trondheim, Norway, 1989. [Google Scholar]
- Sandven, R. Strength and Deformation Properties Obtained from Piezocone Tests. Ph.D. Thesis, Norwegian University of Science and Technology, Trondheim, Norway, 1990; 342p. [Google Scholar]
- Lehane, B.M.; O’Loughlin, C.D.; Gaudin, C.; Randolph, M.F. Rate effects on penetrometer resistance in kaolin. Geotechnique
**2009**, 59, 41–52. [Google Scholar] [CrossRef] - Ouyang, Z.; Mayne, P.W. Effective friction angle of clays and silts from piezocone penetration tests. Can. Geotech. J.
**2019**, 1, 1230–1247. [Google Scholar] [CrossRef]

**Figure 1.**The methodology proposed and explained by Schnaid et al. [25] for classifying (

**a**) and evaluating the state parameter value (

**b**) of sands using SCPTu tests.

**Figure 2.**Drainage effects on the stiffness and strength parameters obtained by triaxial tests conducted on sands and mining tailings. Data: Sands—Drained tests [36,37,38,39]; Sands—Undrained tests [40,41,42]; Gold mining tailings—Drained and Undrained tests [43]; Iron mining tailings—Drained and Undrained tests [11].

**Figure 3.**An expanded classification system based on CPTu tests data derived from the study by Schnaid et al. [25].

**Figure 4.**Expanded two-stage flow liquefaction chart evaluation based on CPTu tests data, derived from a study by Schnaid et al. [25].

**Figure 6.**Variation of q

_{tD}/q

_{tUD}ratio obtained from Senneset et al. [45] solution, and test results for different materials. Data from: Sennesset et al. [45], Dienstman et al. [27], Lehane et al. [47], Kim et al. [31], Chung et al. [30], Ouyang and Mayne [48], and Morgentern et al. [11]. (figure presented in Nierwinski et al. [1]).

**Figure 7.**A proposed empirical correlation for cone tip resistance correction for standard tests performed on intermediate drainage materials (α = 0.5) (presented in Nierwinski et al. [1]).

**Figure 8.**A proposed empirical correlation for cone tip resistance correction for standard tests performed on intermediate drainage materials (α = 0.5) (presented in Nierwinski et al. [1]).

**Figure 10.**Estimation of Ψ from SCPTu tests compared to laboratory range for iron mining tailings (presented in Nierwinski et al. [1]).

**Figure 11.**Estimation of Ψ from SCPTu tests, considering or not the correction of q

_{t}values, compared to laboratory range for gold mining tailings (presented in Nierwinski et al. [1]).

**Figure 12.**Estimation of Ψ from SCPTu tests, considering the correction of q

_{t}values, compared to laboratory range for bauxite mining tailings (presented in Nierwinski et al. [1]).

**Table 1.**Summary of the variation of the geotechnical physical characteristics of the evaluated mining tailings.

Mining Tailing | D_{50} (mm) | γ_{n} (kN/m³) | w_{nat} (%) | G | Liquid Limit (LL) | Plastc Index (IP) |
---|---|---|---|---|---|---|

Gold | 0.032 | 18.6–20.5 | 31–39 | 2.86–3.15 | - | NP |

Bauxite A | 0.0023 | 15.9–20.1 | 23–89 | 2.72–3.27 | 34–53 | 1–17.3 |

Bauxite B | 0.03 | 15.8–17.8 | 55–70 | 3.0–3.15 | 31–39 | 5–14 |

Bauxite C | 0.003 | 17.5–18.8 | 40–47 | 3.01–3.07 | 38 | 3 |

Zinc | 0.015 | 11.3–14.9 | 90–210 | 3.28–3.37 | 61–101 | 25–54 |

Iron | 0.075 | 15.7–19.0 | 6–15 | 2.92–3.06 | - | NP |

Copper | 0.075 | 14.2–16.5 | 50–63 | 2.82–2.85 | - | NP |

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Nierwinski, H.P.; Schnaid, F.; Odebrecht, E.
Evaluation of Flow Liquefaction Susceptibility in Non-Plastic Silty Soils Using the Seismic Cone. *Mining* **2024**, *4*, 21-36.
https://doi.org/10.3390/mining4010003

**AMA Style**

Nierwinski HP, Schnaid F, Odebrecht E.
Evaluation of Flow Liquefaction Susceptibility in Non-Plastic Silty Soils Using the Seismic Cone. *Mining*. 2024; 4(1):21-36.
https://doi.org/10.3390/mining4010003

**Chicago/Turabian Style**

Nierwinski, Helena Paula, Fernando Schnaid, and Edgar Odebrecht.
2024. "Evaluation of Flow Liquefaction Susceptibility in Non-Plastic Silty Soils Using the Seismic Cone" *Mining* 4, no. 1: 21-36.
https://doi.org/10.3390/mining4010003