Transient coupled analysis of upstream tailings disposal facilities construction.

摘要

Extremely huge quantities of mined ore materials are processed annually to obtain the various types of minerals being the barebones of industry. Impounding the waste materials (tailings) of the mined minerals behind a raised embankment is the major and most common method used for the disposal of theses materials. Due to its execution simplicity and low cost, the upstream raising method has been the most common method used for retaining the disposed tailings in spite of being the most failure-vulnerable one. The sophisticated hydromechanocal behavior of the upstream tailings disposal facilities (UTDFs) during the staged construction makes the traditional approaches of consolidation, stability, and seepage analyses inefficient for producing accurate and, in many situations, correct design and evaluation of the UTDFs. The major objective of this thesis is to propose a thorough procedure for realistically evaluating the hydromechanical response of the UTDFs during their staged construction. The procedure incorporates a numerical model that reflects the combination of important realistic features of the UTDFs, namely (i) the partially saturated flow characteristics under the transient state dominating the facility throughout its operation/construction life; (ii) the two dimensional consolidation response of the facility components under both the partially and fully saturated cases considering (a) the full coupled response between the fluid and the solid phases and (b) the large deformation-nature of the tailings; as well as (iii) the appropriate mechanical behavior of the facility materials including a model that can detect the inception of liquefaction in the liquefaction-susceptible zones of the facility. The influences of a number of operational/construction measures that have been reportedly critical for the stability of the UTDFs are investigated in the light of the proposed model. Moreover, the inappropriateness of the traditional approaches for realistically evaluating the UTDF hydromechanical response during its staged construction is substantiated in the analyses carried out in this work.;The conclusions and recommendations drawn from this thesis are paramount not only for the feasibility, preliminary design and risk assessment studies of the UTDF during its operation/construction life but also for the on going analytical investigations and monitoring/instrumentations plans carried out throughout such life.