Study On Structural Characteristics Of Earth-rockfill Dam With Geomembranes

Earth dam developed at top speed during the past several decades, showed that it is a type of dam which has competitive power. Low earth-rockfill dams used a large number of impervious geomembranes, profited from that geomebranes is a kind of high-quality and economic impermeable material.Hydraulic permeability, leakage, stability and thickness studies of impervious geomembranes in embankment have been done according as test data supports, qualitative understandings or quasi-quantitative formulas while studies of the geomembranous structural problems(such as defect damages, stress damages and combined permeability, etc)are still in incipient stages. The impervious problem and arch effect in clay core are the problems which can't be fenced with all the times during the developing process of high earth dams.This article bases on the achievements of predecessors, integrates case study partially, mostly studies geomembranous structures, and uses FLAC3D a finite difference software to do numerical simulations of dam face geomembranes, clay core and geomembrane combined impervious systems. The primary coverage of the simulations is as follows.Firstly, analyses the structural stresses of dam face geomembranes. Mostly studies the cramp effect at anchorage zones and whether different anchoring ways that can influence the cramp effect. As a result, the article gets that wrapping anchoring ways can eliminate the cramp effect evidently.Secondly, take the simplified Pubugou project model as an example, analyses the mechanics and seepage flow of the impervious system with the clay core and geomembrane, then gets three conclusions as follows.Conclusion one, the arch effect has been ameliorated to some extent when there is geomembranes in front of the core.Conclusion two, the defect geomembranes can display its impervious character, reducing the risk of osmolar stability of the clay core wall which has the impervious flaw.Conclusion three, the geomembranes before core wall subsists the cramp effects.Thirdly, during simulation process, the calculation was done using self developing FLAC3D model (Duncan-Chang model) and Mohr model in FLAC3D respectively. The two results are similar. This self model supplies a program block for FLAC3D to use Duncan-Chang parameters in materials.