| Because of the geological conditions,the spillway which located in Jinfo Mountain had to be built on the colluvial deposit foundation of the right bank.With the characteristics of loose structure and uneven physical and mechanical properties,the problems of uneven settlement and structure cracking had arisen when the colluvial deposit was used as foundation bearing layer,even threatened to the safety of the dam and the power station.Therefore,making the study of the rules between the behaviors of colluvial deposit and the overlying structure was particularly important on the engineering.In view of the spillway project of Jinfo Mountain,the stress-strain relationships of spillway under the natural foundation condition were studied,meanwhile,the rules between the spillway working behaviors and colluvial deposit layer thickness,the morphology of underlying bedrock,the parameters of the soil had been studied.The main contents and the results were as follows:(1)By conducting a series of tests,such as the natural density test,interior points test,compaction test,compression test,the triaxial test,and in-situ direct shear test,and in-situ modulus of deformation test,the physical and mechanical characteristics of colluvial soil horizon had been studied.Thus,the physical and mechanical parameters of the spillway colluvial deposit soil layer had obtained,and the parameters of Duncan-chang E-v model had been determined.(2)The problems of boundary,contact area,grid control and unit type selection were analyzed,and the three-dimensional finite element model of spillway was established;meanwhile,the simulations of water loads and hierarchical loads had been researched.(3)Through nonlinear elastic model of Duncan chang E~v,the finite element calculation of spillway in the conditions of cushion construction complete,structure construction and drainage operation had been carried out.Thereby,the working behaviors of spillway in the condition of natural foundation had been analyzed.(4)With changing the colluvial soil layer thickness,bedrock surface morphology and the soil parameters,the working behaviors of spillway under different conditions had been calculated,and the rules between the working behaviors of spillway and colluvial deposit features had been acquired.Combined with the calculation and analysis,the suggestions which were improving the working behaviors had been put forward. |
