本文關(guān)鍵詞：高應(yīng)力巖體的動(dòng)態(tài)加卸荷擾動(dòng)特征與動(dòng)力學(xué)機(jī)理研究　出處：《中南大學(xué)》2013年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 高應(yīng)力巖體 波動(dòng)方程 層裂破壞 卸荷 LS-DYNA 非連續(xù)破壞

【摘要】：摘要：深部巖體由于其自重和地球構(gòu)造運(yùn)動(dòng)的影響,本身是應(yīng)力和能量的儲(chǔ)存體。開挖前,開挖面和周圍巖體之間處于準(zhǔn)靜態(tài)平衡(quasi-static)狀態(tài)。當(dāng)巖體開挖,原有的平衡狀態(tài)被打破,引起初始應(yīng)力和能量的重新分布、轉(zhuǎn)移和釋放,這將促使巖體內(nèi)部損傷演化的累積和發(fā)展,進(jìn)而可能產(chǎn)生宏觀的時(shí)效斷裂。由于開挖導(dǎo)致巖體初始應(yīng)力的轉(zhuǎn)移、釋放以及巖體的松弛變形嚴(yán)重影響地下工程開挖的穩(wěn)定性。如,深部開挖可能導(dǎo)致開挖面附近巖石的破壞甚至巖爆的發(fā)生,這使得深部巖體的破壞形式表現(xiàn)得非常復(fù)雜和特別。同時(shí),深部巷道開挖還常常會(huì)出現(xiàn)層裂等漸進(jìn)破壞模式。因此,由于開挖導(dǎo)致原巖應(yīng)力和能量的釋放不但影響開挖過程中的安全性,而且會(huì)嚴(yán)重改變巷道圍巖的支護(hù)要求和支護(hù)能力。 目前深部巖石力學(xué)問題的研究主要是從靜力學(xué)或準(zhǔn)靜力學(xué)及純動(dòng)力學(xué)的角度出發(fā),很少考慮高應(yīng)力巖體由于自身靜態(tài)初始應(yīng)力和外界動(dòng)力擾動(dòng)混合作用的行為特性。為此,本文圍繞初始應(yīng)力對(duì)彈性波傳播的影響,沖擊載荷作用下引起的層裂破壞,高應(yīng)力巖體加、卸荷作用下的破壞機(jī)理等展開了相關(guān)的理論、實(shí)驗(yàn)和數(shù)值模擬研究,旨在探討高應(yīng)力巖體破壞的巖石力學(xué)機(jī)理。主要內(nèi)容和結(jié)論性成果如下： (1)通過數(shù)學(xué)物理的方法求得了巖體加、卸荷過程中的定解問題。分析了初始應(yīng)力和初始應(yīng)力梯度對(duì)應(yīng)力波傳播過程的波動(dòng)方程、應(yīng)力波波速等的影響。設(shè)計(jì)了應(yīng)力波在有初始應(yīng)力的花崗巖試件中的傳播實(shí)驗(yàn),結(jié)果表明縱波和橫波波速都隨初始應(yīng)力的增加而增大,驗(yàn)證了理論推導(dǎo)的正確性。 (2)針對(duì)沖擊載荷作用下層裂破壞的多種表現(xiàn)形式,對(duì)一維桿件的層裂破壞特性、地下封閉爆炸的地表層裂特性、地下結(jié)構(gòu)的層裂特性進(jìn)行了理論分析。首次利用長(zhǎng)條形的花崗巖試件實(shí)現(xiàn)了一維應(yīng)力條件下的層裂破壞,并由試驗(yàn)結(jié)果推導(dǎo)出巖石層裂試驗(yàn)過程存在明顯的損傷破壞效應(yīng)。同時(shí),把初始應(yīng)力和初始應(yīng)力梯度引入到分析地下爆炸引起的地表層裂中,得出了新的層裂分析模型。進(jìn)一步,考慮到地下巖體存在初始應(yīng)力的特殊情況,通過將球面應(yīng)力展開成平面應(yīng)力的辦法實(shí)現(xiàn)了有圍壓情況下的花崗巖試件的層裂破壞,得到了有圍壓情況下的花崗巖層裂強(qiáng)度。 (3)針對(duì)開挖前的巖體本身是儲(chǔ)能體和處于準(zhǔn)靜態(tài)平衡狀態(tài)下的特點(diǎn),利用通用有限元程序LS-DYNA,運(yùn)用混合隱式-顯式(implicit-explicit)計(jì)算的方法成功模擬了高應(yīng)力巖體的應(yīng)力初始化-動(dòng)態(tài)卸荷過程。數(shù)值模擬的結(jié)果表明：在較高的初始應(yīng)力條件下,當(dāng)巖體的初始應(yīng)力快速卸除后,僅僅由于自身應(yīng)力的釋放就導(dǎo)致了巖石的破壞。針對(duì)不同的卸荷過程,創(chuàng)造性的提出了“等效應(yīng)力釋放率”和“等效應(yīng)變能密度率”的概念和計(jì)算方法,并通過數(shù)值模擬計(jì)算證明它們能很好的表征一維和多維高應(yīng)力巖體的不同卸荷過程。 (4)對(duì)深部硬巖巷道周邊的加載作用過程進(jìn)行了數(shù)值模擬。通過設(shè)置不同的初始應(yīng)力、不同的加載方式表明高應(yīng)力巖體的動(dòng)態(tài)加載過程有可能產(chǎn)生破裂區(qū)與非破裂區(qū)交替出現(xiàn)的現(xiàn)象。進(jìn)一步研究指出了動(dòng)態(tài)載荷作用在應(yīng)力梯度逐漸遞增的物體上除在作用面產(chǎn)生一個(gè)峰值區(qū)外,一定還會(huì)在離作用面一定距離的地方產(chǎn)生另一應(yīng)力峰值區(qū),并指出交替破壞現(xiàn)象能發(fā)生的主要原因是遞增的靜態(tài)應(yīng)力和遞減的動(dòng)態(tài)加載相互疊加的作用。
[Abstract]:Deep excavation can lead to the accumulation and development of initial stress and energy , which can lead to the accumulation and development of initial stress and energy , which can lead to the accumulation and development of initial stress and energy . At present , the study of deep rock mechanics is mainly from the angle of statics or quasi - static mechanics and pure dynamics . It is seldom considered the behavior characteristic of high - stress rock mass due to its static initial stress and external dynamic disturbance . For this reason , the paper studies the mechanics mechanism of rock mechanics , which is caused by the influence of initial stress on elastic wave propagation , the damage mechanism under the action of impact load , etc . The main contents and concluding results are as follows : ( 1 ) The problem of definite solution in the process of loading and unloading of rock mass is obtained by means of mathematical physics . The influence of initial stress and initial stress gradient on the wave equation , stress wave velocity and so on of stress wave propagation process is analyzed . The propagation experiment of stress wave in granite specimens with initial stress is designed . The results show that both the longitudinal wave and the shear wave velocity increase with the increase of the initial stress , and the correctness of the theoretical derivation is verified . ( 2 ) According to various forms of crack damage under the action of impact load , a theoretical analysis is carried out on the fracture characteristics of one - dimensional bar , the characteristics of ground surface crack in the underground closed explosion , and the layer crack characteristics of the underground structure . ( 3 ) The stress initialization - dynamic unloading process of high - stress rock mass is simulated successfully by using the general finite element program LS - DYNA for the rock mass before excavation itself . The numerical simulation results show that , under the condition of high initial stress , when the initial stress of rock mass is removed rapidly , the concept and calculation method of " equal effect force release rate " and " equal effect variable energy density ratio " are proposed , and the different unloading process of a multidimensional high - stress rock mass can be well characterized by numerical simulation . ( 4 ) Numerical simulation is carried out on the loading process of deep hard rock roadway . By setting different initial stress , different loading methods indicate that the dynamic loading process of high - stress rock mass can result in the alternation of rupture zone and non - rupture zone .

【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU452

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 李秀地;鄭穎人;徐干成;;爆炸荷載作用下地下結(jié)構(gòu)的局部層裂分析[J];地下空間與工程學(xué)報(bào);2005年06期

2 張艷霞;何暉;;巖石聲發(fā)射的Kaiser效應(yīng)研究進(jìn)展[J];地下空間與工程學(xué)報(bào);2007年06期

3 張世文;劉倉(cāng)理;李慶忠;劉喬;;預(yù)應(yīng)力對(duì)LY12鋁層裂強(qiáng)度的影響[J];爆炸與沖擊;2009年01期

4 嚴(yán)鵬;盧文波;李洪濤;陳明;周創(chuàng)兵;;地應(yīng)力對(duì)爆破過程中圍巖振動(dòng)能量分布的影響[J];爆炸與沖擊;2009年02期

5 鐘冬望;吳亮;余剛;;鄰近隧道掘進(jìn)爆破對(duì)既有隧道的影響[J];爆炸與沖擊;2010年05期

6 季鐘霖,李建林,熊舜華,魏勇作,彭希齡,賴仲康;含油巖石彈性特征及其與油氣的關(guān)系[J];地球物理學(xué)報(bào);1993年02期

7 陳俊達(dá),馬少鵬,劉善軍,金觀昌;應(yīng)用數(shù)字散斑相關(guān)方法實(shí)驗(yàn)研究雁列斷層變形破壞過程[J];地球物理學(xué)報(bào);2005年06期

8 沈聯(lián)蒂，，史

本文編號(hào)：1388046