| Hydropower is the most abundant renewable energy in China, and about70%~80%of the energy is concentrated in the western region, where these areas are moremountains and canyons, so it is appropriate to the construction of arch dams. Arch damshave advantages of strong overcapacity, high engineering safety, saving of engineeringmaterials, short period of construction, and less investment. At present, the types of archdams in China include arc arch, elliptical arch, parabolic arch, hyperbolic arch, andlogarithmic spiral arch, etc. Different arch dams are suitable for different geologicalconditions. The more types of dams, the more alternative opportunities in theengineering design. China has publicly announced to the world that non-fossil energyaccounts for about15%of primary energy in2020.Therefore, nowadays thedevelopment task of hydropower is still arduous, so the research of new type in archdams is still important and very necessary. Based on this, this article puts forward thatinvolute can be introduced into the design of arch dams, and runs analysis of it. Thisarticle focuses on the following work:Firstly this article introduces the finite element method, ANSYS software and APDL;then it mainly introduces unit type and describes the calculation principle of arch dams,lists the advantages of the finite element method used in analysis of arch dams anddescribes calculation principles of the finite element method.According to the different combination of S, β1, β2,144crown cantilever model is setup. Through the analysis of location and size of the model stress, the paper comes to theconclusion: when the β1and β2are fixed, the maximum tensile stress and maximumcompressive stress increase with the increasing of the overhang S, meanwhile, when Sand β2are fixed, the maximum compressive stress shows a decreasing trend with theincreasing of β1.Established the mathematical model of involute arch dam, and deduced central angleof the upstream arch ring curve, arc length integral formulas, the arch ring areacalculation formula and arch dam volume solution formula, compiled the C languageprogram, realized the formula of the automatic solution. After analysis and comparisonof their central angle, arc length, arch ring area, and arch size, it shows that as thestarting side parameter t0is fixed, base circle radius, upstream arch curve, curve arclength and radius of curvature of the curve arc length increase with increasing of elevation. When the starting side parameter t0increases, the volume of arch dam andcentral angle will increase. As a conclusion, to reduce the arch dam concrete castingparty quantity, the starting side parameter t0must be as low as possible.Several involute arch dam3D models have been built, calculation of displacementand stress is made under the condition of weight+downstream water pressure+sediment pressure+ascending temperature and the results of calculation are analyzed.The maximum displacement in the direction of river occurred nearby the crowncantilever of involute arch dam crest. The maximum displacement is about1cm. Theresults display that the first main stress is mostly pressure, which results from upstreamwater pressure and sediment pressure. And stress concentration occurred at dam heel inevery model, and the value of stress is large. This paper analyzes the reasons that resultin this phenomenon, and finds out the solution.The relationship between stressconcentration and t0is a similar parabolic curve. So this paper gets the conclusion thatwhen choosing involute as the type of the arch dam, the corresponding value of t0ischosen when the stress is as low as possible. |
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