Selection of Soil Shear Strength Parameters Based on Integrated In Situ Tests, Lab Tests and Numerical Calibration Approach

Selection of Soil Shear Strength Parameters Based on Integrated In Situ Tests, Lab Tests and Numerical Calibration Approach

Authors: Zhenhe Song, Robert Truby and Jim (Shunqin) Luo
Conference:  Mine Waste and Tailings Conference 2023
Date: July 13-14, 2023

ABSTRACT

Site investigations were conducted to obtain soil parameters for stability and deformation assessment for an upstream tailings storage facility. Three material types that control the tailings dam stability were identified during the site investigations, comprising coarse-grained silty/sandy tailings, fine-grained silty/clayey tailings and residual soil. Advanced in situ tests, including Seismic Cone Penetrometer Tests (SCPT) and Vane Shear Tests (VST) were conducted. A comprehensive laboratory testing program was undertaken, which included direct simple shear (DSS) tests and triaxial tests to assess the Critical State Line (CSL).

An integrated approach was adopted to determine soil parameters, takings advantage of both in situ and laboratory test results. The peak undrained shear strengths ratios (su/σ’v) of the fine-grained silty/clayey tailings were determined from the DSS test results. The CPT cone factor (Nkt) was calibrated using in situ su/σ’v strengths of the materials in relatively thin layers. Subsequently, the in situ strengths of all other layers were calculated using the Nkt factor. Due to partial drainage in the coarse-grained tailings, its peak and residual undrained shear strengths were assessed using triaxial and non-standard VST test results.

The yield stress of the residual soil was determined using laboratory tests, Self-boring Pressuremeter (PMT) and FLACTM numerical modelling results. The undrained shear strength of the residual soil was based on the calculated yield stress, PMT undrained shear strength and DSS test results.

 

Download the full paper.

Download

Recent Insights

June 2023
Leveraging Knowledge and Experience of a Well-Formed Independent Tailings Review Board to Enhance Tailings Facility Safety
May 2023
Is the Implementation of Dry Stacking for Tailings Storage Increasing? A Southern African Perspective
February 2023
Canadian Consulting Engineer's Lifetime Achievement Awards: Jeremy Haile
February 2023
Geotechnical Characterization of Collapsible Salty Sands Subjected to Monotonic and Cyclic Loadings – A Case Study for Areas with High Seismicity
November 2022
Application of the 3D Limit Equilibrium Method in Tailings Dam Breach Analysis
November 2022
Evaluation of Tailings Behaviour for Dam Breach Assessments
November 2022
Tailings Improvement by Stress-Densification from Waste Rock Capping
November 2022
Transforming Tailings Management Systems toward Alignment with the GISTM: A Case History
October 2022
Managing Excessive Pit Wall Deformation of Weak Rock Mass
October 2022
State-of-the-art Method for Estimating Long-term Hydroclimatic Conditions for Tailing Dam Water Management and Dam Safety Planning
August 2022
Observed Subsidence Progression at New Afton Mine in Response to Lift 1 Mining
June 2022
Hydrometric Monitoring and Effluent Discharge Mixing in Challenging Natural Conditions
May 2022
Inundation Modelling of Non-Newtonian Tailings Dam Breach Outflows
May 2022
Video: Tailings Management Compliancy Picks Up Momentum
May 2022
A Catch up with...Richard Elmer
February 2022
Engineer of Record Services for Tailings Facilities
November 2021
Knight Piésold's Projects Commended at Prestigious Awards
November 2021
Advances in Ensuring Tailings Dam Safety
November 2021
Gearing Up for Growth in Zambia