本文選題：右岸壩肩 + 拱壩承載力　； 參考：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：拱壩整體承載力及壩肩抗滑穩(wěn)定一直是拱壩工程所關(guān)注的重要問題。本文以某代表性拱壩為例,利用有限差分軟件FLAC3D,通過多種分析方法對該拱壩的整體承載力及壩肩抗滑穩(wěn)定進行了分析和評價,并對不同分析方法的適用性進行了探討。(1)利用超載法評價拱壩整體承載力。水容重超載法評價拱壩整體承載力,分別從超載過程中拱端推力的變化規(guī)律、壩體壩基變形及塑性區(qū)的發(fā)展、右岸壩肩的位移及塑性區(qū)變化特點等五方面進行了分析。(1)拱推力在建基面上的分布,隨著超載系數(shù)的增大,呈現(xiàn)出了向壩體中部高程位置轉(zhuǎn)移的特點。從法向與切向拱推力比值tanφ可看出超載對壩肩巖體的穩(wěn)定性不利。(2)斷層的錯動量曲線在超載系數(shù)為7.75時發(fā)生突變。(3)在水容重超載過程時,右岸壩肩巖體屈服區(qū)由低部高程逐漸向中高高程部位發(fā)展,并在超載系數(shù)為7.75時,屈服區(qū)貫通。(4)對前人提出評價拱壩整體承載力指標(biāo)K1、K2、K3、K4進行了探討,認(rèn)為K3不僅要考慮壩體特征點位移超載系數(shù)關(guān)系曲線拐點,還需綜合考慮壩肩變形與屈服規(guī)律。通過本拱壩水容重超載分析,得到K1=1.0,K2=1.75,K3=6.75,K4=8.75。庫水位超載法在超載過程中,拱推力變化規(guī)律與水容重超載法類似,超載系數(shù)為2.1時,斷層錯動量曲線出現(xiàn)拐點。但壩肩巖體塑性區(qū)分布遠(yuǎn)小于水容重超載法,且只在中高高程上有一定發(fā)展。水容重超載法得到的K1=1.0,K2=1.4,K3=2.1,K4=2.2。拱推力超載法由于沒考慮壩肩壩體之間的協(xié)調(diào)變形,分析拱壩整體承載力時,效果不理想,認(rèn)為不適合評價拱壩整體穩(wěn)定性。(2)強度折減法評價右岸壩肩整體穩(wěn)定性,得出的安全儲備系數(shù)為2.4。從失穩(wěn)模式來看,是壩肩邊坡自重情況下的穩(wěn)定性,而不能反映壩肩抗力體在拱推力作用下的抗滑穩(wěn)定問題,不能回答工程所關(guān)注壩肩抗力體特定失穩(wěn)模式的穩(wěn)定性,有一定的局限性。(3)為評價右岸壩肩關(guān)鍵塊體穩(wěn)定性采用了四種計算方法,方法I為折減關(guān)鍵塊體,方法II為折減形成關(guān)鍵塊體的結(jié)構(gòu)面,方法III為折減構(gòu)成關(guān)鍵塊體的結(jié)構(gòu)面及III巖體,方法IV為基于應(yīng)力變形的塊體極限平衡法等。(1)方法I時,右岸壩肩失穩(wěn)模式為淺層滑動。(2)方法II和方法III時,壩體拱推力影響范圍內(nèi)的巖體隨著折減系數(shù)的增大而不斷產(chǎn)生朝向坡外的變形,能較為客觀地體現(xiàn)關(guān)鍵塊體的失穩(wěn)趨勢。(3)方法IV物理意義明確,所得安全系數(shù)與剛體極限平衡法具有一致性,說明此種方法評價壩肩關(guān)鍵塊體穩(wěn)定性較為理想。
[Abstract]:The overall bearing capacity of arch dam and the stability of dam abutment against sliding stability have been an important issue in arch dam engineering. This paper, taking a representative arch dam as an example, uses a finite difference software FLAC3D to analyze and evaluate the overall bearing capacity of the arch dam and the stability of the dam abutment against sliding and the applicability of the different analysis methods. (1) to evaluate the overall bearing capacity of arch dam by overloading method. Water bulk density overload method is used to evaluate the overall bearing capacity of arch dam. The variation of arch end thrust in overloading process, the deformation of the dam foundation and the development of the plastic zone, the displacement of the right bank's abutment and the change of the plastic zone, etc. are analyzed. (1) the separation of the arch thrust on the building base. With the increase of overloading coefficient, it presents the characteristics of the position shift toward the middle elevation of the dam body. From the ratio of the normal to the tangent arch thrust, Tan Phi can be seen that the overloading is unfavorable to the stability of the abutment rock mass. (2) the fault momentum curve is abrupt when the overload coefficient is 7.75. (3) the yield area of the right bank abutment rock mass during the overloading process of the water bulk density From the low elevation to the middle and high elevation, the yield area penetrates through the overloading coefficient of 7.75. (4) the previous evaluation of the overall bearing capacity of the arch dam K1, K2, K3 and K4 has been discussed. It is considered that K3 should not only consider the overloading coefficient of the dam's displacement, but also consider the deformation and yield law of the abutment. In the overloading analysis of water bulk density of this arch dam, the variation of arch thrust in the process of overloading of water level of K1=1.0, K2=1.75, K3=6.75 and K4=8.75. is similar to that of water density overload method. When the overloading coefficient is 2.1, the fault momentum curve appears inflection point. But the plastic zone distribution of the abutment rock mass is far less than the water bulk overload method, and only one of the middle and high elevation is in the middle and high elevation. The K1=1.0, K2=1.4, K3=2.1, K4=2.2. arch thrust overloading method obtained by the method of water bulk density overload is not suitable for the overall stability of arch dam, because it does not consider the coordination deformation between the dam body and the overall bearing capacity of the dam, and thinks that it is not suitable for evaluating the overall stability of the arch dam. (2) the strength reduction method is used to evaluate the overall stability of the right bank abutment, and the safety reserve system is obtained. The number of 2.4. is the stability under the gravity condition of the abutment slope, but it can not reflect the stability of the dam abutment resistance body under the action of the arch thrust, and can not answer the stability of the specific instability mode of the abutment resistance body. (3) it is used to evaluate the stability of the key block body of the right bank abutment. The four method of calculation is that I is the key block to reduce the key block, and the method II is to reduce the structure surface of the key block. Method III is the structure surface of the key block and the III rock mass, and the method IV is the block limit equilibrium method based on the stress and deformation. (1) when I, the right bank abutment instability mode is shallow sliding. (2) II and method III, when II and method III The rock mass within the influence range of the thrust force increases with the increase of the reduction factor, which produces the deformation towards the slope outside. (3) the physical meaning of the method IV is clear, and the safety factor is consistent with the rigid body limit equilibrium method. It is said that the stability of the key block body of the abutment is better than that of the method. Ideal.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV223
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本文編號：2060154