High Step Dumping Stability And Failure Mode

This article is for the problem which a great of cracks, slipping in local area and influencingthe next cumulate or the safety of tailing pond at the Xiyuan Dump of Dexing Copper Mine. Wehave investigated the distribution of cracks. Angle of nature heaping have been measured. Theexperiment of sieving particle of size and physical and mechanical of geotechnical materialshave been conducted. And the distribution of seepage field and the position of saturation linewhich at210m water level have been investigated in profile V. On this basis, Bishop, Janbu andremaining thrust method would be used to analyse the stability against sliding of the dump. Theanalysis includes the following contents: analysis for the stability of the dump at present waterlevel and stack height, analysis for the stability when the water level raised to280m, analysis forthe stability with the progress of the soil accumulated to the design state, analysis for thestability of the dump influented by rain and calculation for safety platform width. In addition，the numerical calculation software FLAC3Dwas applied to analyse the deformation failure modeof dump in profile IV and profile V. This article got the following results：(1) At present water level and stack height, two positions in profile V and the position closeto the tailing pond in profile IV are in unstable state and slip failure may occurs in those positions;the other positions in other profiles are in stable or critical state.(2) The raising of tailing pond water level results in a larger safety factor of the dump, butthe dump is still in substable state; and the failure range enlarges with the raise of water level.(3) According to the progress of the soil accumulated, enhance the dump height to330m,360m and390m gradually in a certain range on300m platform, and then stack in the direction ofthe tailing pond keeping the3platforms in step-shape, the safety factor of the scheme is thehighest, which can meet the requirements of safety production.(4) The stability of the dump decreased with the influence of rain, the impeded drainage maycause slip failure of the dump, which results in full saturation of the dump.(5) The safety platform width should be more than40m, which can meet the safetyrequirements, and prevent the debris flow.(6) the main cause of the appearance of cracks at300m platform and413m platform is thatwith stacking, settling and compacting of the dump, displacement deformation or bulging occurs instress concentration area at toe of slope, bring along microcracks and creeps of the top of slopeand thus causing a great of cracks at the platforms.(7) Except for that the middle part in profile IV is slipping along the interface of the slip massand the bedrock, other positions are slipping in the dump interior.