本文選題：巖爆 + 巖石力學��； 參考：《昆明理工大學》2014年碩士論文

【摘要】：巖爆發(fā)生在高地應(yīng)力條件下隧道或礦山等地下工程開挖過程中,是一種非常嚴重的動力災(zāi)害,受到國內(nèi)外學者越來越多的重視。為了從本質(zhì)上了解巖爆的特性,以預(yù)防巖爆的發(fā)生,必須從巖石受載的力學響應(yīng)著手進行研究。為此,本文采用霍普金森桿試驗系統(tǒng)(SHPB),對灰?guī)r進行一維動靜組合載荷試驗,在實驗基礎(chǔ)上,通過Flac3D軟件對該試驗過程進行數(shù)值模擬分析,綜合采用試驗和數(shù)值模擬結(jié)合的方法來研究巖石受到動力沖擊作用時的力學特性,以模擬深部巖體“高應(yīng)力+動力擾動”的受力模式,為研究巖爆的發(fā)生機理和力學本質(zhì)提供一定的參考。 試驗研究表明：1)當灰?guī)r受到?jīng)_擊載荷作用沒有嚴重破壞時,其應(yīng)力-應(yīng)變曲線在應(yīng)力峰值后期一般會呈現(xiàn)出特有的“應(yīng)變回彈”現(xiàn)象；當巖石破壞嚴重時,應(yīng)力峰值后期則不會出現(xiàn)“應(yīng)變回彈”現(xiàn)象,而是表現(xiàn)出和靜載實驗相類似的曲線走勢。2)在應(yīng)變率相近的條件下,隨著軸壓的增加,灰?guī)r動態(tài)強度會先增大后減小,當軸壓超過某一限值(巖石靜載強度的56%-71%之間)時,巖體的承載能力開始下降；在軸壓一定的條件下,隨著應(yīng)變率的增加,巖體動靜組合強度逐漸增大。3)在無軸壓條件下,灰?guī)r受沖擊后全部表現(xiàn)為吸能狀態(tài),而在有軸壓條件下部分巖樣則呈現(xiàn)釋能狀態(tài)；隨著軸壓的增加,巖石吸收的能量逐漸減小,直至最后開始表現(xiàn)為釋放能量。 數(shù)值模擬表明：1)隨著軸壓的增大,動載荷在巖體內(nèi)部所形成的軸向應(yīng)力逐漸減小位移逐漸增大；隨著動載幅值的增加,動載荷在巖體內(nèi)部所形成的軸向應(yīng)力逐漸增大,位移也逐漸增大；隨著動載頻率的增加,動載荷在巖體內(nèi)部所形成的軸向應(yīng)力變化不大,但位移逐漸減小。2)軸向靜壓和動載幅值決定了巖體內(nèi)部的軸向應(yīng)力分布情況,動載頻率對其影響不大；而動載荷幅值和動載頻率則是巖體內(nèi)部位移的主要影響因素,軸向靜壓對其影響不大。3)動載幅值和動載頻率的增大,都會導(dǎo)致巖體受沖擊的平均應(yīng)變率增加,軸向靜壓與應(yīng)變率的相關(guān)性不大。4)通過對巖體內(nèi)各位置的實時監(jiān)測發(fā)現(xiàn),巖體內(nèi)各點的軸向位移到達峰值后均出現(xiàn)位移減小的現(xiàn)象,這與試驗中的“應(yīng)變回彈”現(xiàn)象是一致的。 本文采用室內(nèi)動靜組合加載實驗和數(shù)值模擬相結(jié)合方法,對巖體一維動靜組合加載力學特性進行分析,研究結(jié)果可為深部礦山巖爆機理和預(yù)測預(yù)報提供實驗依據(jù)和參考。
[Abstract]:Rock burst occurs in the excavation process of underground projects such as tunnels or mines under high ground stress. It is a very serious dynamic disaster and has been paid more and more attention by scholars at home and abroad.In order to understand the nature of rock burst and prevent the occurrence of rock burst, it is necessary to study the mechanical response of rock load.In this paper, the Hopkinson bar test system is used to carry out the one-dimensional dynamic and static loading test of limestone. On the basis of the experiment, the numerical simulation analysis of the test process is carried out by Flac3D software.In order to simulate the "high stress dynamic disturbance" of deep rock mass, the mechanical properties of rock subjected to dynamic impact are studied by means of the combination of test and numerical simulation.It provides a certain reference for studying the mechanism and mechanical nature of rock burst.The experimental results show that when limestone is not seriously damaged by impact load, the stress-strain curve usually presents a special "strain rebound" phenomenon at the later stage of the stress peak, and when the rock is seriously damaged, the stress-strain curve usually presents a unique "strain springback" phenomenon at the later stage of the stress peak.In the later stage of the stress peak, the phenomenon of "strain rebound" will not appear, but the curve trend .2similar to that of the static load experiment.) under the condition of similar strain rate, with the increase of axial compression, the dynamic strength of limestone will first increase and then decrease.When axial compression exceeds a certain limit (between 56% and 71% of the static load strength of rock), the bearing capacity of rock mass begins to decrease, and under certain axial compression conditions, the strength of rock mass dynamic and static assemblage increases gradually with the increase of strain rate. 3) under the condition of no axial compression,The limestone exhibits energy absorption state after impact, while some rock samples show energy release state under axial pressure. With the increase of axial pressure, the energy absorbed by the rock gradually decreases, until the last performance is energy release.The numerical simulation shows that with the increase of axial compression, the axial stress formed by the dynamic load in the rock body gradually decreases and the displacement increases, and with the increase of the amplitude of the dynamic load, the axial stress formed by the dynamic load in the rock body increases gradually.With the increasing of dynamic load frequency, the axial stress formed by dynamic load in rock mass changed little, but the displacement gradually decreased. 2) Axial static pressure and dynamic load amplitude determined the axial stress distribution in rock mass.The amplitude of dynamic load and frequency of dynamic load are the main influencing factors of internal displacement of rock mass, but axial static pressure has little effect on the amplitude of dynamic load and frequency of dynamic load.The correlation between axial static pressure and strain rate is not significant. Through the real-time monitoring of each position of rock mass, it is found that the axial displacement of each point in rock mass decreases after reaching the peak value.This is consistent with the "strain rebound" phenomenon in the experiment.In this paper, the mechanical characteristics of one-dimensional dynamic and static combined loading of rock mass are analyzed by the combination of indoor dynamic and static loading experiments and numerical simulation. The results can provide experimental basis and reference for the mechanism of rock burst and prediction and prediction of rock burst in deep mines.
【學位授予單位】：昆明理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU45

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