本文選題：隧道 + 微差爆破　； 參考：《長沙理工大學》2014年碩士論文

【摘要】：微差爆破的效果與炮孔布置、圍巖和地質條件等因素有關,而微差時間的選取更是微差爆破設計的核心所在。多年來,在隧道微差爆破設計中,合理延遲間隔的研究較少,微差時間的設計現(xiàn)狀多是依靠工程經驗選取,在隧道掘進工程中,往往會出現(xiàn)爆破效果不理想的情況。因此,如何考慮段間微差時間具有重要的意義。本文以和新隧道Ⅲ級圍巖段爆破掘進工程為依托,綜合運用理論分析、數值模擬兩種方法進行研究。從巖石爆破破碎的作用機理出發(fā),根據爆破爆破漏斗的形成物理過程給出了掏槽眼與下一圈起爆眼間合理延遲間隔時間計算的數學模型。研究結果認為：隧道掘進巖體中炸藥起爆后物理過程主要包括爆轟階段、破碎階段、拋擲階段。其中爆轟時間決定于炸藥的爆速及裝藥長度；破碎階段所需時間決定于巖體中裂隙的發(fā)展過程；拋擲階段所需時間決定于破碎巖石的拋擲速度大小,而拋擲能的大小是決定拋擲速度的關鍵。最后計算得到適合本文工程的掏槽眼與下一圈起爆眼間合理微差時間為39.2ms-164ms。其次運用Midas/GTS數值模擬軟件對隧道爆破掘進的振動影響進行數值分析。建模時不體現(xiàn)炮孔形狀,采用將粉碎區(qū)邊界上的荷載等效后施加于隧道開挖輪廓面來模擬爆破振動。著重對比分析了掏槽眼與第一、第二圈輔助眼之間五種不同微差時間的爆破方案下,隧道爆破開挖對圍巖及隧道內結構物振速、應力的影響。計算結果表明：當微差時間選取75ms、100ms時,能有效降低圍巖質點振動速度和初支結構的受拉破壞影響范圍。
[Abstract]:The effect of millisecond blasting is related to the layout of blasting holes, surrounding rock and geological conditions, and the selection of millisecond time is the core of millisecond blasting design. In the design of tunnel millisecond blasting for many years, there is little research on reasonable delay interval. The present design situation of millisecond delay time is mostly based on engineering experience. In tunneling engineering, the blasting effect is often not satisfactory. Therefore, it is of great significance to consider the difference time between segments. In this paper, based on the blasting excavation project of the third grade surrounding rock section of the new tunnel, two methods of numerical simulation and theoretical analysis are used to carry out the research. Based on the mechanism of rock fragmentation and the physical process of blasting funnel formation, a mathematical model for calculating the reasonable delay interval between the cut hole and the next blasting hole is presented. The results show that the physical process of explosive detonation in tunneling rock mass mainly includes detonation stage, crushing stage and throwing stage. The detonation time is determined by the detonation velocity and charge length of the explosive, the time required in the crushing stage is determined by the development process of the cracks in the rock mass, and the time required in the throwing stage is determined by the throwing velocity of the broken rock. The magnitude of the throwing energy is the key to determining the throwing speed. Finally, the reasonable difference time between the cutting hole and the next ring detonation hole is 39.2 ms-164ms. Secondly, Midas/GTS numerical simulation software is used to analyze the vibration effect of blasting tunneling. The blasting vibration is simulated by applying the equivalent load on the boundary of the comminuted zone to the tunnel excavation contour. The effects of blasting excavation on the vibration velocity and stress of surrounding rock and structure in tunnel are analyzed in detail under five different millisecond time blasting schemes between cutting hole and first and second auxiliary hole. The calculated results show that the vibration velocity of surrounding rock particle and the range of tensile failure of the initial support structure can be effectively reduced when the differential time is 75 Ms or 100ms.
【學位授予單位】：長沙理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U455.6

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本文編號：1907902