The Integrated Optimization Of Soft Foundation Overflow Dam Based On The Fluid-solid Coupling

Because the engineering geological conditions of soft foundation overflow dam iscomplicated,so we not only to consider the profile of the dam,but also to control the seepageof the foundation in analysis.This paper summarizes the previous optimization method and itsshortcomings in the design application,use the fluid-solid coupling methods, analysis theprofile of the soft foundation overflow dam and the seepagecontrol measures of the foundation.Use the finite element software ANSYS as a platform,written the optimization command stream of the finite element calculation of the softfoundation overflow dam,and with an engineering example of its optimization analysis. Thispaper mainly do the following work:(1)Summarized the the present situation of the optimize research on soft foundationoverflow dam,state the coupled theory and methods of seepage field and stress field,provedthe feasibility of use the fluid-solid coupling method to optimize the soft foundation overflowdam from the overall.(2)Combined the dam optimization with seepage control measures,compare theoptimization results from the total cost.(3)Use the seepage control measures and geometric parameters of the dam as the designvariables, the seepage stability, the stress of dam, anti-sliding stability of dam and bearingcapacity of foundation and so on as the constraint condition, the total cost of the unit damsection as the objective function,to establish the optimization design mathematical model ofsoft foundation overflow dam.(4)Based on the similarity of temperature and seepage fields in themathematicalmodel,use the thermal analysis function of finite element calculation software ANSYS toanalyse the seepage of dam foundation, thus obtain the hydraulic head of dam foundation andthe seepage slope of seepage at the exit,and get the The state variables of the seepage. (5)Use fluid-solid coupling method of ANSYS,put the hydraulic pressure of nodes inseepage analysis as the "body load" applied to the back of the structure analysis.Consider weight of dam, hydrostatic pressure, uplift pressure (readingseepageanalysis results), calculate the structure stress and displacement of the dam, and get the statevariables of structure.(6)Use APDL to write the command stream file of ANSYS, loading the optimizedparameters of ANSYS automaticly, and establishing the optimization model of soft foundationoverflow dam automaticly.Take the qianwa power station of dulan county in Qinghai provinceas an example to execute the optimal design,and verify the correctness of this method. Theoptimization results show that this method is reasonable and reliable.(7)Study the impact of the seepage control measures of dam foundation onthe cross-sectional area of dam, the analysis results show that, when only have levelanti-seepage measures, the length of the blanket is3.8times of the dam upstream anddownstreamhead difference, the dam section area achieve to its optimal; when only havevertical anti-seepage measures, the depth of pile is1.4times of the dam upstream anddownstreamhead difference, the dam section area achieve to its optimal.