【摘要】：我國目前水電裝機剛超過2億千瓦,規(guī)劃裝機到2050年將超過5億千瓦；大型水利水電工程建設(shè)主要有三種壩型可以選擇：堆石壩、常態(tài)混凝土壩、碾壓混凝土壩。碾壓混凝土壩發(fā)展最快。相比于常態(tài)混凝土壩,碾壓混凝土壩優(yōu)勢主要在于：(1)工程造價低；(2)建壩周期短；(3)環(huán)保適應(yīng)性強。然而,薄層碾壓的施工工藝使得碾壓混凝土壩與常態(tài)混凝土壩相比具有獨特的成層結(jié)構(gòu)力學(xué)特性。尤其是在地震作用下,容易形成表面裂縫和貫穿型裂縫,繼而出現(xiàn)滑動,最終影響大壩的整體穩(wěn)定性。因此,有必要研究在地震作用下碾壓混凝土壩成層特性對其抗滑穩(wěn)定性的影響�；诖�,本文展開了一系列研究,具體內(nèi)容如下： (1)采用有限元法分析了某碾壓混凝土重力壩典型壩段在地震作用下沿碾壓層面、建基面的抗滑穩(wěn)定性,確定了壩段的主要薄弱部位以及比較薄弱的層面。通過地震動超載分析計算壩體非線性模型各計算層面的最小抗滑穩(wěn)定系數(shù),并得到層面的抗滑穩(wěn)定系數(shù)與地震動超載倍數(shù)k的關(guān)系曲線,得到了碾壓混凝土重力壩超載潛力。運用強度折減法計算壩體非線性模型各計算層面的最小抗滑穩(wěn)定系數(shù),并得到層面的抗滑穩(wěn)定系數(shù)與強度折減系數(shù)k的關(guān)系曲線,得到了碾壓混凝土壩的強度儲備系數(shù)。 (2)碾壓混凝土采用層鋪施工,會導(dǎo)致壩體存在許多水平層面。如果層面結(jié)合能力比較差,層面的抗剪斷參數(shù)和壩體本身的抗剪斷參數(shù)存在較大差異,這種差異會直接影響壩體的整體穩(wěn)定性。本文將線彈性有限元時程分析與模擬退火算法結(jié)合起來,基于應(yīng)力場定義抗滑穩(wěn)定安全系數(shù),應(yīng)用模擬退火算法搜索碾壓重力壩在地震作用下最脆弱滑動面及相應(yīng)的安全系數(shù),進而得到不同層面抗剪斷參數(shù)對碾壓混凝土壩滑動面形狀及抗滑穩(wěn)定安全系數(shù)的影響,并與常態(tài)混凝土壩進行了對比。 (3)碾壓混凝土壩在強震作用下不可能一直處于線彈性工作狀態(tài),壩體混凝土?xí)霈F(xiàn)一定的損傷。本文采用塑性損傷模型,對碾壓混凝土壩進行了時程分析,提取了應(yīng)力場,繼而研究了層面抗剪斷參數(shù)對碾壓混凝土壩滑動面及抗滑穩(wěn)定安全系數(shù)的影響,并與線彈性模型得到的結(jié)果做了對比。
[Abstract]:At present, the hydropower installation in China is only more than 200 million kilowatts, and the planned installation will exceed 500 million kilowatts by 2050. There are three main dam types for large-scale water conservancy and hydropower projects: rockfill dam, normal concrete dam and roller compacted concrete dam. Roller compacted concrete dam develops fastest. Compared with normal concrete dam, RCC dam has the following advantages: (1) low project cost; (2) short construction period; (3) strong environmental protection adaptability. However, the construction technology of thin layer compaction makes RCC dam have unique mechanical properties of stratified structure compared with normal concrete dam. Especially in the earthquake, surface cracks and penetrating cracks are easily formed, and then sliding, which ultimately affects the overall stability of the dam. Therefore, it is necessary to study the influence of stratification characteristics of RCC dams on the stability of RCC dams under earthquake. Based on this, a series of studies are carried out in this paper. The main contents are as follows: (1) the stability of a typical section of a RCC gravity dam under seismic action along the roller compacted plane is analyzed by using finite element method (FEM). The main weak position and relatively weak layer of dam section are determined. Through the analysis of ground motion overload, the minimum anti-slip stability coefficient of each layer of nonlinear model of dam body is calculated, and the relation curve between the anti-slide stability factor and the overload multiple k of ground motion is obtained, and the overload potential of roller compacted concrete gravity dam is obtained. Using the strength reduction method to calculate the minimum anti-slide stability coefficient of each layer of nonlinear model of dam body, the relationship curve between the stability coefficient and the strength reduction coefficient k is obtained, and the strength reserve coefficient of the roller compacted concrete dam is obtained. (2) there are many horizontal layers in the dam body. If the layer binding capacity is poor, there is a great difference between the shear parameters of the plane and the shear parameters of the dam itself, which will directly affect the overall stability of the dam. In this paper, the linear elastic finite element time-history analysis is combined with simulated annealing algorithm. Based on the definition of anti-slip stability safety factor in stress field, simulated annealing algorithm is used to search the most vulnerable sliding surface and the corresponding safety factor of roller compacted gravity dam under earthquake action. The influence of different shear failure parameters on the shape of sliding surface and the safety factor of sliding stability of RCC dam is obtained and compared with that of normal concrete dam. (3) it is impossible for RCC dam to be in linear elastic working state under strong earthquake, and the concrete of RCC dam will be damaged to some extent. In this paper, the plastic damage model is used to analyze the time history of RCC dam, the stress field is extracted, and the influence of shear failure parameters on the sliding surface and safety factor of RCC dam is studied. The results obtained by the linear elastic model are compared with those obtained by the linear elastic model.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV642.2

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