本文關(guān)鍵詞： 混凝土重力壩 動態(tài)響應(yīng) 損傷機理 地震荷載 爆炸沖擊荷載 失效模式 損傷累積破壞　出處：《天津大學(xué)》2014年博士論文　論文類型：學(xué)位論文

【摘要】：隨著壩工技術(shù)的發(fā)展，一大批100m~300m級的高壩建設(shè)進入快速發(fā)展階段。在一般狀態(tài)下，大壩正常的安全運行可以得到保障。然而我國高壩建設(shè)主要位于西南強震區(qū)域，由于地震動的不確定性，超過設(shè)計地震的地震動是存在并可能發(fā)生，當(dāng)發(fā)生超設(shè)計地震時，大壩可能遭受破壞，抗震安全問題十分突出；同時高壩由于其顯著的政治經(jīng)濟效益，無疑成為局部戰(zhàn)爭和恐怖爆炸襲擊的重點攻擊對象，大壩一旦失事，后果不堪設(shè)想。因此，對突發(fā)極端荷載作用下的大壩動態(tài)響應(yīng)行為和損傷機理進行研究，評價高壩的抗震及抗爆安全性，是關(guān)系我國社會經(jīng)濟發(fā)展全局的防災(zāi)減災(zāi)重大工作中的重要內(nèi)容，也是我國水利工程建設(shè)中必須面對的前沿性關(guān)鍵技術(shù)問題和重要戰(zhàn)略課題。 由于失事后果嚴(yán)重，突發(fā)極端荷載下的高混凝土壩安全及防護問題值得關(guān)注。對于混凝土重力壩而言，可能引發(fā)大壩災(zāi)變的極端荷載主要包括：強地震荷載和爆炸荷載。為了揭示強震及突發(fā)性爆炸沖擊荷載下大壩的動態(tài)響應(yīng)行為和損傷破壞機理，本文（1）從強震作用下混凝土重力壩的動態(tài)響應(yīng)行為、斷裂破壞過程、潛在失效模式及極限抗震能力評價方法；初始裂縫、強震持時、主余震地震序列、近斷層地震動對大壩抗震性能的影響等方面，系統(tǒng)地研究了強震作用下混凝土重力壩的動態(tài)響應(yīng)及損傷機理；（2）并從炸藥在不同介質(zhì)的爆炸過程、沖擊波傳播特性、邊界效應(yīng)；水下和空中爆炸沖擊下的大壩毀傷特性；水下爆炸沖擊下的大壩破壞效應(yīng)、抗爆性能及損傷預(yù)測等方面，系統(tǒng)研究了爆炸沖擊荷載下混凝土重力壩的動力行為和毀傷機理。主要創(chuàng)新工作內(nèi)容如下： （1）探討了大壩強震斷裂破壞過程，概化出強震潛在失效模式 基于擴展有限元基本理論，研究了強震荷載作用下混凝土重力壩的動態(tài)響應(yīng)行為、漸進失效過程以及裂縫張開閉合行為，驗證了該方法在分析混凝土重力壩地震破壞過程的可行性，并討論了網(wǎng)格尺寸效應(yīng)；分析了混凝土重力壩在不同水平地震作用下的動力漸進破壞過程、破壞形態(tài)和開裂破壞位置，概化出強震作用下混凝土重力壩的潛在失效模式，得到了混凝土重力壩的抗震薄弱部位。 （2）建立了含初始裂縫的地震開裂模型，提出了極限抗震能力評價方法 建立了含初始裂縫的混凝土重力壩地震開裂模型，探討了初始裂縫對混凝土重力壩起裂時刻、開裂破壞過程、破壞模式、裂縫開展深度、及抗震性能的影響；從基于性能的抗震設(shè)防標(biāo)準(zhǔn)及理論出發(fā)，針對混凝土重力壩的結(jié)構(gòu)特點，提出了混凝土重力壩極限抗震能力評價方法，該方法首先基于性能的地震破壞評價模型，初步評估大壩的極限抗震能力，同時根據(jù)大壩開裂破壞模式、抗滑穩(wěn)定及壩基塑性區(qū)發(fā)展范圍等方面進一步綜合評價壩體-壩基系統(tǒng)的極限抗震能力。 （3）建立了損傷累積破壞指標(biāo)，系統(tǒng)討論了強震對大壩抗震性能的影響 利用能考慮混凝土軟化并可反映實際損傷耗散能的混凝土損傷塑性模型，根據(jù)混凝土重力壩損傷開裂發(fā)展特征，建立了大壩局部和整體損傷累積破壞指標(biāo)；基于能量持時的基本定義，對不同實測地震動的強震持時進行了預(yù)測，探討了強震持時對混凝土重力壩損傷累積破壞的影響；建立了主余震地震序列的構(gòu)造方法，通過將實測主震地震動和余震地震動前后連接起來形成了本文所采用的主余震地震序列，定量揭示余震作用對混凝土重力壩累積破壞的影響；采用Lagrangian算法建立了大壩-庫水-地基系統(tǒng)的動力耦合模型，對比分析了近斷層和遠(yuǎn)斷層地震動作用下的混凝土重力壩動力響應(yīng)行為和損傷累積破壞效應(yīng)。 （4）建立了水下爆炸氣穴模型，探討了不同邊界條件下的沖擊波傳播機制 建立了近邊界面水下爆炸氣穴效應(yīng)模型，并驗證了氣穴模型的有效性；研究了自由面、結(jié)構(gòu)面背水及結(jié)構(gòu)面背空氣對水下爆炸沖擊波傳播特性的影響；揭示了沖擊波與自由面反射的稀疏波相互作用以及沖擊波與結(jié)構(gòu)面的動態(tài)相互作用過程；分析了入射沖擊波與反射沖擊波的疊加效應(yīng)，以及由此導(dǎo)致的水面切斷效應(yīng)及氣穴現(xiàn)象；探討了沖擊波在不同介質(zhì)中的透射和反射機理，對比解析了沖擊波在結(jié)構(gòu)背水和背空氣下的傳播機制。 （5）提出了大壩抗爆高效數(shù)值計算方法，分析了爆炸沖擊下大壩毀傷特性 建立了基于Lagrangian和Eulerian耦合方法的爆炸沖擊荷載下混凝土重力壩全耦合模型，提出了適應(yīng)大規(guī)模和高度非線性問題的高效數(shù)值計算方法；考慮爆炸作用下混凝土的高應(yīng)變率效應(yīng)、沖擊波與結(jié)構(gòu)的動態(tài)相互作用以及結(jié)構(gòu)的動態(tài)響應(yīng)等復(fù)雜問題，通過與已有的試驗成果進行對比，，驗證耦合模型的可靠性；研究了起爆介質(zhì)對沖擊波壓力峰值、沖量、傳播速度的影響；對比分析了水下和空中爆炸下大壩動態(tài)響應(yīng)行為和毀傷特性。 （6）探討了大壩抗爆性能，首次提出了水下爆炸沖擊下大壩損傷預(yù)測模型 探討了水下爆炸沖擊荷載下混凝土重力壩的動態(tài)響應(yīng)行為和破壞效應(yīng)，分析了近大壩水下爆炸沖擊波的傳播特性；研究了起爆距離、炸藥量、起爆深度及庫前水位對混凝土重力壩破壞效應(yīng)和抗爆性能的影響，獲得了水下爆炸沖擊下混凝土重力壩的毀傷機理、破壞模式及抗爆薄弱部位，并得到了預(yù)警放水的有效人防措施；根據(jù)水下爆炸沖擊下混凝土重力壩的損傷破壞特征，建議了混凝土重力壩的損傷破壞等級分類，識別對重力壩破壞狀態(tài)最具影響的因子，首次提出了水下爆炸沖擊下混凝土重力壩損傷預(yù)測模型，劃分了相應(yīng)于不同破壞等級的重力壩損傷預(yù)測關(guān)鍵曲線，得到了水下爆炸沖擊荷載下的混凝土重力壩安全起爆距離。
[Abstract]:With the development of dam construction technology, a large number of 100m~300m grade high dam construction has entered a rapid development stage. In general condition, the normal operation of the dam safety can be guaranteed. However, the construction of high dam in China are mainly located in the southwest region of strong earthquake ground motion, because of the uncertainty over the design of the ground motion is present and may occur when when the earthquake occurred over the design, the dam may suffer damage, seismic safety problem is very prominent; at the same time the dam because of its significant political and economic benefits, will undoubtedly become the explosion of local wars and terrorist attacks as key attack on the dam, once the accident, the consequences be unbearable to contemplate. Therefore, research on dam dynamic sudden extreme loads and response behavior the damage mechanism, seismic evaluation and anti explosion safety of high dams, disaster prevention and mitigation in China is the relationship between the development of economy and society in the important work of major In the construction of water conservancy projects in China, it is also an important and important strategic issue which must be faced with in the construction of water conservancy projects in China.
Because of the serious consequences of accident, safety and protection problem of high concrete dam burst under extreme load of concern. For the concrete gravity dam, the extreme load may lead to dam disaster include: strong earthquake and explosion load. In order to reveal the behavior and damage mechanism of dynamic response under the load of Dam Earthquake and sudden explosion, this paper (1) from the dynamic response behavior of concrete gravity dam under strong earthquake, the fracture failure process, failure mode and ultimate seismic capacity evaluation method; initial crack, strong motion duration, major aftershock, influence of near fault ground motions on the seismic performance of the dam and other aspects, systematically studied the dynamic response and damage mechanism of concrete gravity dam under the action of strong earthquakes; (2) and from the explosion of explosives in different medium, shock wave propagation characteristics, boundary effect; underwater and air explosion The damage characteristics of the dam under impact and the damage effect, blast resistance and damage prediction under the impact of underwater explosion are systematically studied. The dynamic behavior and damage mechanism of the concrete gravity dam under blast loading are systematically studied.
(1) to investigate the dam strong earthquake rupture process, generalizes the earthquake potential failure mode
Expansion based on the theory of finite element, studied the dynamic response behavior of concrete gravity dam under strong loading conditions, progressive failure process and the crack opening closing behavior, the validation of the method in the feasibility analysis of earthquake damage process of concrete gravity dam, the effect of mesh size are discussed; dynamic analysis of concrete gravity dam under different earthquake hazard levels of progressive failure process failure mode and crack position, generalizes the concrete gravity dam under strong earthquake. The potential failure mode of the concrete gravity dam of the weak parts.
(2) an earthquake crack model with initial cracks is established, and the evaluation method of ultimate aseismic ability is proposed.
A gravity dam model with initial cracking of concrete cracks, discusses the initial cracking time of concrete gravity dam, failure process, failure mode, crack depth, effect and seismic performance; from the performance of anti-seismic standards and theory which based on the structure characteristics of the concrete gravity dam, put forward seismic performance evaluation concrete gravity limit method, the method based on the performance of the seismic damage assessment model, a preliminary assessment of seismic capacity limit of the dam, at the same time according to the dam cracking failure mode, anti seismic capacity limit sliding stability and development of dam foundation plastic range and further comprehensive evaluation of dam foundation system.
(3) the damage cumulative damage index is established, and the influence of strong earthquake on the seismic performance of the dam is systematically discussed.
By considering concrete softening and can reflect the concrete damage plasticity model actual damage dissipation, damage and cracking of concrete gravity dam according to the characteristics of development, establish local and global damage dam cumulative damage index; the basic definition of duration based on different measured ground motion duration of earthquake forecast, discusses the influence of strong shock when the damage cumulative damage of concrete gravity dam; establish the structural methods of major aftershock, the measured ground motion and mainshock aftershock and link up to form the main aftershock earthquake sequences are used in this paper, the quantitative effect of aftershocks reveal the impact of cumulative damage of concrete gravity dam is established; the dynamic coupling model of dam water - foundation system using Lagrangian algorithm, comparison and analysis of near fault and far fault ground motion of concrete gravity dam under the action of moving Force response behavior and damage cumulative damage effect.
(4) the cavitation model of underwater explosion is established, and the mechanism of shock wave propagation under different boundary conditions is discussed.
The cavitation effect model established near edge interface of underwater explosion, and verifies the validity of the cavitation model; on the free surface, affecting the structure surface water and surface structure of air blast wave propagation characteristics of underwater; reveals the sparse wave and free surface reflection shock interaction and interaction process the shock wave and the dynamic structure; analysis of the incident wave and the reflected shock wave superposition effect, and the resulting water cut effect and cavitation; discusses the shock wave in different media transmission and reflection mechanism, the contrastive analysis of the propagation mechanism of shock wave in the structure of water and air back back.
(5) a numerical calculation method for the high efficiency of the dam is put forward, and the damage characteristics of the dam under the explosion impact are analyzed.
The establishment of the concrete gravity dam full coupling model of blast load coupling and method of Lagrangian based on Eulerian, is proposed to meet the large-scale and highly efficient numerical calculation method considering nonlinear problems; high strain rate effect of concrete under explosion, shock wave and the dynamic interaction between the structure and the structural dynamic response and other complex issues, comparison through the test results and the reliability of the coupling model is verified; the initiation medium impulse pressure of shock wave peak, influence propagation velocity; comparative analysis of the dynamic response of the dam under explosion behavior and damage characteristics of water and air.
(6) the anti explosion performance of the dam is discussed, and the dam damage prediction model under underwater explosion shock is proposed for the first time.
To explore the underwater explosion shock load of concrete gravity dam under the dynamic response and damage effect, analysis of the propagation characteristics in the dam of the underwater explosion shock wave; study initiation distance, quantity of explosive, detonation depth and effect of water level on the library before the concrete gravity dam failure effect and anti explosion performance, the damage mechanism of concrete gravity dam water blast, failure modes and blast resistant weak parts, and the effective measures of water air defense warning; according to the failure characteristics of concrete gravity dam damage to underwater explosion, proposed concrete gravity dam damage classification, the most influential factor of dam damage identification, is proposed for the first time prediction model of underwater explosion under the impact of concrete gravity dam, corresponding to different damage level of the gravity dam damage prediction curve has been divided, underwater explosion The safety initiation distance of the concrete gravity dam under the blast impact load.

【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TV642.3

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