【作者】 饶增；

【导师】 傅洪贤；

【作者基本信息】 北京交通大学 ， 岩土工程， 2010， 硕士

【摘要】 随着铁路工程建设的迅猛发展,钻眼爆破法将会越来越多地被应用于铁路隧道的开挖。因此,研究爆破振动对初期支护的影响及其控制标准具有十分重要的现实意义。本文以贵州至广州铁路棋盘山隧道的钻爆施工为依托,结合“铁道部童大课题子课题：钻爆施工对围岩及支护的影响及控制标准的研究”,在已有的研究成果的基础之上进行了系统的研究。本文介绍了棋盘山隧道爆破振动监测试验情况,利用爆破振动实测数据进行回归分析,得出了近区和远区的爆破振动衰减规律。对比分析不同作用炮孔引起的振动,得出最大振速主要由掏槽眼爆破引起的结论,分析其原因主要有两个方面：(1)在所有不同作用炮孔之中,掏槽眼单段药量最大；(2)掏槽眼爆破的临空面条件较差,受到了较大的夹制作用,导致爆炸波能向岩体内部传播,从而引起了较大的爆破振动强度。利用实测的全断面爆破振动数据,对隧道拱顶、拱腰和边墙三者的质点振动速度的关系进行了初步的分析。在回归分析爆破振动衰减规律的基础之上,分别对远区和近区的爆破振动特性进行了分析,并阐述了爆破振动对喷射混凝土的影响特点。同时,对比近区、远区的爆破振动衰减规律,得出隧道爆破振动衰减规律具有区域性特点的结论,并参考已有的研究成果,结合本次爆破振动监测试验获取的数据,对棋盘山隧道爆破振动作用分区进行了初步的划分。利用应力波理论,通过分析应力波在不同介质中的反射、透射过程,研究爆破振动对喷射混凝土的作用机理,认为在爆破应力对喷射混凝土的作用过程中,最先是应力波产生的拉应力大于喷射混凝土的抗拉强度,然后是反射拉伸波所产生的拉应力大于混凝土与围岩的粘结强度。因此,在爆破应力波的作用下,喷射混凝土支护的破坏主要由喷射混凝土的抗拉强度所控制。通过计算,给出了喷射混凝土所允许的质点最大振速。同时,通过分析网喷混凝土的作用机理,给出网喷混凝土在爆破振动荷载作用下最大安全振速的建议值。总结了爆破振动对水泥砂浆锚杆的研究现状,通过分析应力波在围岩、砂浆、锚杆之间的反射和透射过程来研究隧道爆破振动对水泥砂浆锚杆的影响机理,得出了水泥砂浆锚杆在爆破振动荷载作用下的破坏主要是由水泥砂浆的抗拉强度所控制的结论,并在此基础之上通过计算给出了水泥砂浆锚杆所允许的最大安全振速的建议值。在本次试验研究成果的基础之上,提出了几条降低爆破振动对初期支护影响的具体措施。更多还原

【Abstract】 With the rapid development of railway engineering construction, drilling and blasting method will be widely used to excavation of railway tunneling. Therefore, it is of vital importance to study impacts and control standard of blasting vibration on primary support. This paper is supported by the drilling and blasting method of Qipanshan tunnel, combining the branch project of Ministry of Railway ("The study of impacts and control standard of drilling and blasting method on primary support"), and makes a systemic research based on the existing research results.In this paper, we introduced the blasting vibration monitoring test in Qipanshan tunnel, and used the measured blasting vibration data to do a regression analysis, concluding the attenuation law of the blasting vibration velocity in the near-field and far-field of the blasting. We compared the vibration velocities produced by the different blastholes, and found that the maximum vibration velocity was mainly caused by the blasting of the cutting hole. Two reasons are placed to explain this result:(1) The single explosive charge of the cutting hole is the maximum among all the different blastholes. (2) As the freeing surface condition of the cutting hole is poor, the freeing surface is exposed to larger press effects, which lead the blasting wave energy to spread into the internal part of the rock mass, and cause a larger blasting vibration intensity.In addition, we used the blasting vibration measured data of the whole section to analyze the relationship of the particle vibration velocities in vault, hance, and side wall.Based on the regression analysis of the attenuation law of the blasting vibration velocity, we also analyzed the characteristics of the blasting vibration of the far-field and the near-field, and stated the influence characteristics of the blasting vibration on shotcrete. Meanwhile, with the comparison of the attenuation law of the blasting vibration in the near-field and the far-field, we concluded that the attenuation law of the tunnel blasting vibration has a regional characteristic. Further, with the reference to the existing research results and the combination of the data obtained from this blast vibration monitoring test, we divided the area of the blasting vibration in Qipanshan tunnel initially.Besides, we used the stress wave theory to analyze the reflection progress and the transmission progress of the stress wave in different medium, and study the mechanism of the blasting vibration to the shotcrete. As a result, we concluded that in the progress of the impacts of the blasting vibration on the shotcrete, first, the tensile stress produced by the stress wave was larger than the tensile stress of the shotcrete; next, the tensile stress produced by the reflected tension shock wave was larger than the bond strength of the concrete and rock; at last, the compressive stress of the compression wave was larger than the compressive strength of the shotcrete. Therefore, under the effects of the blasting stress wave the tensile strength of the shotcrete controls the destructions of the shotcrete. Through calculation, we obtained the allowable maximum vibration velocity of the shotcrete. And, through analyzing the mechanism of the wire mesh concrete, we gave the advice of the maximum safe vibrating velocity under the effects of vibration loading on the wire mesh concrete.Furthermore, we summarized the present situation of the research of the blasting vibration to cement mortar bolt. Through analyzing the reflection progress and the transmission progress of the stress wave in the surrounding rock, mortar, and bolt, we studied the impacts of tunnel blasting vibration on the cement mortar bolt, and indicated that the destruction of the cement mortar bolt under the vibration loading influences was mainly controlled by the tensile strength of the cement mortar. Based on this result, we gave the advised value of the allowable maximum blasting vibration velocity of the cement mortar bolt through calculation.Based on the research result of this test, we pointed out some specific measures, which reduced the impacts of blasting vibration velocity on the primary support.更多还原