A Study On The Influencing Factors Of Main Diseases Of Laterite Dams In Yunnan

The paper carried out test of red clay characteristics under dry-wet cycle to study the influence of water level fluctuation of reservoir on major disease of Yunnan red clay dam combining with theoretical analysis and finite element simulation.The indoor dry-wet cycle test studied the impact of red clay characteristics under different compaction on occurrence and development of red clay cracks.Establishing coupling model by theoretical analysis and simulating water level fluctuation of Yunnan red clay dam reservoir with finite elements,the paper researched the influence of seepage fieldstress field coupling on seepage and landslide.Changes in the internal seepage field of earth dams lead to changes in the stress field of earth dams,which is an important cause of instability in earth dams.Therefore,it is of practical engineering significance to study the factors influencing the main diseases of laterite dams under the rise and fall of reservoir water levels.A mathematical model of seepage field-stress field coupling is established through the analysis of the coupling effect of seepage field-stress field.The finite element software ABAQUS was combined,which allows the establishment of an earth dam model with constant initial material parameters and different slope conditions,to calculate the seepage field,stress field and displacement field of different earth dam models,and to analyse the main disease influencing factors of laterite dams in Yunnan under the conditions of cyclic rise and fall of reservoir water levels.The main conclusions are as follows.(1)Clarified the relationship between Yunnan red clay characteristics and cracks growth under different compaction in dry-wet cycle test.The more dry-wet cycles there were,the less shearing strength the soil body had.While the greater the compaction degree was,the more the initial water content approached the optimal,the slower the red clay characteristics parameters decreased,the less red clay deterioration and cracking phenomenon there was.(2)Based on the basic theory of seepage field,the author established a mathematical model of seepage field-stress field coupling and studied the influence of seepage field interacting with stress field.The reservoir water level rise driving the infiltration line rise was greater than the reservoir water level fall driving infiltration line fall,and the change of the infiltration line was lagging.The seepage point of the infiltration line and the intersection of the downstream dam slope and the tail-water surface were easy to have seepage under the impact of the seepage field.(3)The author applied ABAQUS to establish the earth dam model of three working conditions with slope ratios 1:1,1:1.5,and 1:2 under the condition of reservoir water level fluctuation.Comparing the seepage field and stress field of the earth dam under different working conditions,it's shown that when the reservoir water level rose and fell circularly,the shear stress of the earth dam increased and the shear strength declined.The earth dam with the largest slope ratio had a landslide when the ninth water level rising,while the other two the earth dams was stable overall in the later reservoir water level fluctuation.