Deformation And Stability Investigations Of The High Inner Dump Beneath A River

The deformation and stability of the high inner dump beneath a river are not only related to the safety of the open pit mine production,but also directly affect the safety of the river operation.Yingjin River traversed Yuanbaoshan open pit mine.In order to continue the mine project,it is necessary to divert the Yingjin River overlying the inner dump.Excessive deformation or instability of the inner dump,as the basement of the river,will cause the river to burst its Banks and flood the mining area,leading to serious mine accidents and ecological disasters.To ensure the implementation of the river diversion on the inner dump and the continuous development of the open pit mine,it is important to further study the post-construction deformation and the stability of the rolling and non-rolling compaction composite slope in the high inner dump with irregular basements,as well as the effects on the stability of the overlying river.Taking into account the safety of the river and the investment of the diversion,it is determined that part of the Yingjin River bed after the diversion is located on the surface of the south side of the stope and part of the bed is placed on the inner dump.Moreover,the construction design scheme was proposed that the high inner dump based on the irregular slope under the river bed was divided into two parts:rolling compaction area and non-rolling compaction area.The grain composition,volumetric weight,porosity ratio,compression modulus,permeability coefficient,shear strength and creep property of sand gravel and fine grained sandy soil were obtained by laboratory tests.Combined with field monitoring and laboratory rheological test results,the creep parameters of Burgers model in the rolling compaction area and non-rolling compaction area were determined by numerical simulation inversion.Based on the creep parameters obtained by numerical inversion,the Burgers creep numerical model was established to simulate post-construction of the high inner dump beneath a river in Yuanbaoshan open pit mine.The three-stage deformation evolution law of the rolling and non-rolling compaction composite slope in the high inner dump with irregular basements was obtained.Consequently,the influences of the slope morphology,advance position,groundwater,operation time on the post-construction deformation law and stability of the river bed were revealed.Combined with the limit equilibrium theory,the position and form for the developing of the inner dump project were determined,which satisfied the safety of the diversion.A practical creep theoretical model for predicting post-construction settlement of the high inner dump was selected.The key parameters are determined by numerical simulation and field monitoring results.In addition,the model was verified by comparing with numerical simulation and field monitoring results.This model provides a theoretical basis for stability analysis and dynamic control of the high inner dump.In order to speed up the construction of the inner dump,the concept of parallel construction inside and outside the inner dump rolling compaction area,as well as the development scheme of the inner dump dynamic construction with considering the slope stability and deformation control,were put forward in combination with the on-site production conditions.The location and time of the initial inner dump construction were determined.The slope morphology of the key engineering nodes during the construction and development processes of the inner dump was determined as well.Moreover,the annual plan for the construction and development of the inner dump was established,which provides a reference for the smooth construction of the inner dump that meets the requirements of the diversion.This paper includes 87 figures,42 tables and 148 references.