Mechanical properties and energy evolution of stratified cemented tailings backfill under triaxial compression
XU Wenbin
ZHANG Yalun
LI Tongxin
Abstract：In order to improve the stability and economy of the cemented tailings backfill during the high-stage subsequent stope filling process,layered cemented filling technology is com-monly adopted for the backfilling of stope.Layered cemented filling leads to a layered compos-ite structure of cemented tailings backfill composed of high-strength top and bottom layers,as well as a low-strength middle layer.To explore the mechanical properties,failure modes,en-ergy evolution and microstructure of stratified cemented tailings backfill with different struc-tural characteristics,the triaxial compressive tests and microstructural analysis of stratified ce-mented tailings backfill specimens with cement-to-tailings(c/t)ratio of 1∶20,1∶15 and 1∶9 were investigated under confining pressure of 0,50,100 and 200 kPa after curing for 3,7 and 28 d.The results show that the peak deviatoric stress and elastic modulus of stratified ce-mented tailings backfill specimens both increase with the improvement of the c/t ratio,the ex-tension of the curing age,and the increase of confining pressure.The cohesive of stratified ce-mented tailings backfill significantly increases with the increases of c/t ratio and curing age,but the internal friction angle shows a slight downward trend within a certain range.When there is a significant difference in the mechanical properties between layers,the sample under-goes initial elastoplastic deformation and then first fails in the low-strength area.Subsequent-ly,due to the redistribution of stress,the sample enters a secondary elastoplastic deformation stage,ultimately leading to the failure of the overall structure.The energy storage limit of stratified cemented filling increases with the increase of the middle layer c/t ratio and curing age.As the confining pressure increases,the failure modes of the stratified cemented backfill samples can be categorized into tensile failure of the middle layer,mixed tensile-shear failure of the middle layer,and overall shear failure.The tensile failure in the top or bottom layer can be induced by reducing the c/t ratio of the middle layer under low confining pressure.The num-ber of cracks on the surface of the stratified cemented backfill samples decreases with the in-crease of the c/t ratio,curing age,and confining pressure.The research results are of signifi-cant importance for the application of stratified cemented tailings backfill in subsequent back-filling of mines.
Keywords：stratified cemented tailings backfilltriaxial compressivemechanical propertiesenergy evolutionfailure modes
Publication Date：2025-03-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 343-354 )