Post-construction settlement and creep law of waste dumps

The grain body creep of waste dumps including deceleration creep and constant creep was described by the Burgers model.Using the layered summation method,the vertical filling waste dump was sliced and the bottom part settled under the variable weight load of the overlaid part.The computational formulas of settlement in the waste dump filling dynamic process,post-construction settlement and cumulative settlement were derived from theoretical analysis though the steady and unsteady Burgers creep models.The monitoring data of Qidashan Iron Mine were used as a case of proofing.The results show that the correlation coefficients of fitting with both the unsteady and steady Burgers models are high,and the final settlement value of the former is 5.07 m,while the settlement curve of the latter is divergent,thus the unsteady Burgers model performs better in simulating the real working condition of mine subsidence.The waste dump was divided into ten layers and the settle rate of each layer was calculated by the creep simulation model in Flac3D.The post-construction settlement of the top layers is smaller than that of the middle layers and bottom layers,the settlement of the top layers decreases when getting closed to the upper surface of the waste dump.The settlement of the middle layers is larger than that of the bottom layers,and the fifth layer performs a largest settlement.