【摘要】：刀破巖效果的好壞直接關(guān)系到TBM施工的掘進(jìn)效率、工程進(jìn)展以及經(jīng)濟(jì)效益。研究盤形滾刀破巖機(jī)理,分析滾刀與圍巖的相互作用形式,對于改進(jìn)刀具設(shè)計(jì)、提高破巖掘進(jìn)效率都具有十分重要的理論和現(xiàn)實(shí)意義。基于上述背景,本文對盤形滾刀與巖石相互作用形式進(jìn)行了深入研究,以期進(jìn)一步揭示滾刀破巖機(jī)理及裂紋擴(kuò)展規(guī)律。本文的主要內(nèi)容和研究成果有： (1)基于巖石切削擴(kuò)展模型,運(yùn)用斷裂力學(xué)理論研究了滾刀作用下裂紋擴(kuò)展問題,得到了圍壓的增長抑制了中間裂紋擴(kuò)展并使得側(cè)向裂紋斷裂角增大的結(jié)論,從理論角度揭示了圍壓與滾刀作用下裂紋擴(kuò)展的關(guān)系。 (2)自主設(shè)計(jì)改裝了TBM沖擊破巖試驗(yàn)平臺,采用花崗巖與水泥砂漿材料制備了完整試件與多種類型的節(jié)理試件,運(yùn)用試驗(yàn)平臺開展了多圍壓水平下的滾刀破巖試驗(yàn)。分析了滾刀作用下巖體破碎特征,發(fā)現(xiàn)拉應(yīng)力在滾刀破巖過程中起主導(dǎo)作用。研究了巖體破碎模式以及破巖載荷、巖石破碎面積與圍壓的關(guān)系,探討了巖石節(jié)理特征對滾刀破巖的影響。 (3)運(yùn)用顆粒流數(shù)值模擬軟件PFC構(gòu)建了盤形滾刀破巖模型,從細(xì)觀角度分析了滾刀作用下巖石的破碎過程以及裂紋擴(kuò)展規(guī)律,對不同工況下滾刀載荷、裂紋分布形式、裂紋擴(kuò)展路徑以及裂紋數(shù)量等進(jìn)行了深入研究,模擬結(jié)果表明,圍壓較低時(shí),巖石呈現(xiàn)以張拉破壞為主的拉剪綜合失效模式,圍壓的增長使得巖石破壞模式逐漸過渡為以剪切破壞為主的拉剪綜合失效模式。分析了不同圍壓及刀間距下的破巖比能耗,得到了最優(yōu)刀間距隨圍壓的變化趨勢。
[Abstract]:The effect of cutting rock is directly related to the tunneling efficiency, engineering progress and economic benefit of TBM construction. It is of great theoretical and practical significance to study the rock breaking mechanism of disc hob and analyze the interaction between hob and surrounding rock, which is very important for improving the tool design and improving the driving efficiency of rock breaking. Based on the above background, the interaction between disc hob and rock is studied in this paper in order to reveal the mechanism of rock breaking and the law of crack propagation. The main contents and results of this paper are as follows: (1) based on the rock cutting growth model, the crack propagation problem under the action of hob is studied by using fracture mechanics theory. It is concluded that the increase of confining pressure inhibits the growth of intermediate crack and increases the fracture angle of lateral crack. The relationship between confining pressure and crack propagation under the action of hob is revealed theoretically. (2) TBM impact rock breaking test platform has been designed and modified independently, and complete specimens and various types of joint specimens have been prepared by using granite and cement mortar materials. The rock piercing test of hob at multi confining pressure level was carried out on the test platform. The fracture characteristics of rock mass under the action of hob are analyzed, and it is found that tensile stress plays a leading role in the rock breaking process of hob. The fracture model of rock mass and the relationship between rock breaking load, rock fracture area and confining pressure are studied, and the influence of rock joint characteristics on rock breaking with hob is discussed. (3) using the numerical simulation software PFC of particle flow, a rock breaking model with disc hob is constructed. In this paper, the fracture process and crack propagation law of rock under the action of hob are analyzed from a mesoscopic point of view. The load of hob, the distribution of crack, the path of crack propagation and the number of cracks under different working conditions are studied in depth. The simulation results show that, When the confining pressure is low, the comprehensive failure mode of tension and shear is the main failure mode of rock, and the increase of confining pressure makes the failure mode of rock gradually transition to the comprehensive failure mode of tension and shear which is dominated by shear failure. The energy consumption of rock breaking under different confining pressure and tool spacing is analyzed, and the variation trend of optimal tool spacing with confining pressure is obtained.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U455.3

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