發(fā)布時(shí)間：2018-09-12 21:28

【摘要】：溢洪道自由射流或者汛期大壩漫流引起的高速水流,能夠?qū)哟矌r體造成嚴(yán)重沖刷,增大了壩基損壞的風(fēng)險(xiǎn)。國(guó)內(nèi)外對(duì)高速水流的特性和沖坑形成過(guò)程進(jìn)行了較多的研究,但對(duì)實(shí)際上廣泛存在的以基巖或破碎基巖為主的溢洪道巖石沖刷數(shù)值模擬研究很少。本文提出了一種模擬河床巖石沖刷破壞的數(shù)值模擬方法,結(jié)合流體動(dòng)力學(xué)和巖石力學(xué)理論,對(duì)溢洪道巖石沖刷進(jìn)行數(shù)值模擬研究。 主要研究?jī)?nèi)容及成果包括： (1)基于基巖沖刷理論和基巖的抗沖特性及分類,總結(jié)前人關(guān)于沖坑形成過(guò)程的概化模型。根據(jù)淹沒(méi)射流理論,結(jié)合挑流消能特點(diǎn),提出沖刷過(guò)程中基巖解體破壞的主要原因是：存在節(jié)理裂隙的河床巖體,經(jīng)過(guò)具有強(qiáng)烈脈動(dòng)的高速射流的直接沖擊和泄流引起的脈動(dòng)水壓力共同作用的結(jié)果。 (2)闡述離散單元法理論及其在巖土力學(xué)中的應(yīng)用,介紹離散單元法的基本思想和基本方程,探討離散單元法作為一種處理節(jié)理巖體的數(shù)值方法的優(yōu)越性。介紹通用離散單元法程序UDEC在巖石力學(xué)數(shù)值模擬中的應(yīng)用,分析UDEC的模擬方法和特點(diǎn),總結(jié)UDEC模擬基巖沖刷的可行性。 (3)基于流體動(dòng)力學(xué)和巖體力學(xué)理論,提出一種模擬河床巖石沖刷破壞的數(shù)值模擬方法,即將水流沖擊時(shí)均壓力和脈動(dòng)壓力與巖體力學(xué)模型耦合,實(shí)現(xiàn)河床基巖沖刷過(guò)程的數(shù)值模擬。 (4)建立河床巖體沖刷的力學(xué)模型,在通用離散元程序UDEC中建立節(jié)理巖體的二維模型,加載裂隙水壓力、挑射沖擊水流時(shí)均壓力和脈動(dòng)壓力,驗(yàn)證節(jié)理巖體在挑射水流作用下的解體破壞模型。模型中明顯可見巖體節(jié)理的失效、巖塊破碎及塊移動(dòng)等動(dòng)態(tài)響應(yīng)過(guò)程。 (5)研究動(dòng)力荷載的變化對(duì)沖刷的影響。通過(guò)改變加載的正弦應(yīng)力波的頻率和峰值應(yīng)力,研究巖石力學(xué)模型動(dòng)態(tài)響應(yīng)的區(qū)別。
[Abstract]:The free jet of spillway or the high speed flow caused by dam overflowing in flood season can cause serious scour to the rock mass of river bed and increase the risk of dam foundation damage. The characteristics of high velocity flow and the formation process of scour pits have been studied at home and abroad, but the numerical simulation of spillway rocks with bedrock or broken bedrock is seldom studied. In this paper, a numerical simulation method is proposed to simulate the erosion failure of rock in the river bed. Combined with the theory of fluid dynamics and rock mechanics, the numerical simulation of rock scour in spillway is carried out. The main research contents and results are as follows: (1) based on the theory of bedrock erosion and the characteristics and classification of bedrock scour resistance, the previous generalizable models of scour formation process are summarized. According to the theory of submerged jet and combined with the characteristics of energy dissipation, the main causes of bedrock disintegration and destruction during scouring are put forward as follows: the rock mass of river bed with joints and fissures exists. Through the direct impact of high speed jet with strong pulsation and the result of pulsating water pressure caused by discharge. (2) the theory of discrete element method and its application in geotechnical mechanics are expounded. This paper introduces the basic idea and equation of discrete element method, and discusses the superiority of discrete element method as a numerical method for dealing with jointed rock mass. The application of general discrete element method (UDEC) program in numerical simulation of rock mechanics is introduced. The simulation method and characteristics of UDEC are analyzed, and the feasibility of simulating erosion of bedrock by UDEC is summarized. (3) based on the theory of fluid dynamics and rock mechanics, In this paper, a numerical simulation method is proposed to simulate the erosion failure of riverbed rock, which is coupled with the rock mass mechanics model when the average pressure and pulsating pressure are affected by the water flow. Numerical simulation of the erosion process of riverbed bedrock is realized. (4) the mechanical model of riverbed rock mass erosion is established, and the two-dimensional model of jointed rock mass is established in the general discrete element program UDEC, and the fracture water pressure is loaded. The break-up failure model of jointed rock mass under the action of ejection flow is verified by the uniform pressure and pulsating pressure. Dynamic response processes such as failure of rock joints, fragmentation and movement of rock masses are obvious in the model. (5) the effect of dynamic load on erosion is studied. The difference of dynamic response of rock mechanics model is studied by changing the frequency and peak stress of the loaded sinusoidal stress wave.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV135;TV651.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 冬俊瑞,黃繼湯,徐一春,李永祥;三峽水利樞紐溢流壩挑流基巖沖刷研究[J];長(zhǎng)江科學(xué)院院報(bào);1991年02期

2 劉沛清，冬俊瑞，，余常昭;基巖的抗沖能力及其分類[J];長(zhǎng)江科學(xué)院院報(bào);1996年01期

3 焦愛萍;劉沛清;;挑射水流對(duì)巖石河床沖刷的研究進(jìn)展[J];水科學(xué)與工程技術(shù);2006年05期

4 張鵬,李玉柱,徐照明;基于人工神經(jīng)網(wǎng)絡(luò)的挑流沖刷預(yù)報(bào)[J];清華大學(xué)學(xué)報(bào)(自然科學(xué)版);2003年11期

5 龔振瀛,劉樹坤,高季章;寬尾墩和窄縫挑坎—收縮式消能工的應(yīng)用[J];水力發(fā)電學(xué)報(bào);1983年03期

6 余常昭;;射流沖刷作用及分散攙氣影響的研究[J];水利學(xué)報(bào);1962年02期

7 陳椿庭;;關(guān)于高壩挑流消能和局部沖刷深度的一個(gè)估算方法[J];水利學(xué)報(bào);1963年02期

8 章福儀;高壩深孔收縮式挑坎射流擴(kuò)散及沖刷特性的試驗(yàn)研究[J];水利學(xué)報(bào);1986年12期

9 鄧軍,許唯臨,曲景學(xué),楊永全;射流摻氣對(duì)沖刷的影響[J];水利學(xué)報(bào);2002年10期

10 劉沛清，冬俊瑞，余常昭;在巖縫中脈動(dòng)壓力傳播機(jī)理探討[J];水利學(xué)報(bào);1994年12期

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