小净距隧道爆破施工安全性及其控制机理研究

Interlaid rock wall between neighborhood tunnels is 5m in the study. The interlaid rock wall between neighborhood tunnels and the rock mass of new neighborhood and the existing tunnel are damaged while new neighborhood tunnel is built by blasting method. When the damage grow to some degree, accident of safety will happen. Field test, field survey, theoretical study and Numerical computation are carried out in the study.Now,the blasting vibration rule found on the data gained from area beyond 5m of blasting source is not applied to the construction of new neighborhood tunnel with blasting method,so the blasting is not aright carried out. Blasting vibration velocity in the area within 5m of new neighborhood tunnel blasting source is surveyed, a theory controlling blasting vibration of rock mass near to tunnel blasting source is brought forwad.The damage range of new neighborhood tunnel rock mass is surveyed, damage mechanism of the rock mass of new neighborhood tunnel at dynamic and static stress is analysed and studied, and relationship between damage degree and safety of the rock mass of new neighborhood tunnel is studied, a theory insuring safety of the rock mass of new neighborhood tunnel is put forward.The blasting vibration velocity and damage range and internal displacement of interlaid rock wall are surveyed, the damage mechanism of interlaid rock wall at dynamic and static stress is analysed and studied, and relationship between damage degree and safety of interlaid rock wall is studied, a theory controlling the safe of interlaid rock wall is put forward. The blasting vibration velocity of existing tunnel is surveyed, damage mechanism of existing tunnel is studied, a criteria controlling safety of existing tunnel is put forward. At last, theories controlling neighborhood tunnels is put forwad.

本研究中，小净距隧道是指隧道之间岩墙厚度为5m的隧道，隧道爆破近区是指距爆源5m范围内的区域。针对新建小净距隧道爆破施工对中间岩墙和既有隧道产生的安全问题，采用现场试验、测试、理论分析研究和数值计算相结合的方法，进行如下试验研究：测试新建隧道爆破近区围岩振动速度，揭示隧道爆破近区围岩振动规律；测试新建小净距隧道围岩的损伤破坏范围，研究隧道围岩在爆炸应力和围岩静应力相互作用下的损伤破坏机理；测试中间岩墙的爆破振动速度、损伤破坏范围和内部位移，研究隧道爆破次数和隧道爆破部位对中间岩墙的累计损伤效应，进而研究在爆炸应力和围岩静应力相互作用下的损伤破坏机理；研究中间岩墙和新建小净距隧道围岩的损伤破坏范围、程度与其安全性的关系；测试既有隧道结构的爆破振动速度，研究其振速与隧道爆破近区振动规律的关系，进而研究其产生裂缝或掉块的临界条件。最后，提出保证新建隧道围岩、中间岩墙和既有隧道结构安全的控制理论。

随着交通设施的快速发展，由于受地形条件的限制，出现大量小净距隧道，研究小净距隧道爆破施工安全性及其控制机理具有重要的实用性和理论价值。结合隧道施工，测试了隧道爆破近区质点振动速度，研究近区爆破振动衰减规律；根据爆破振动衰减规律，研究降低爆破振动的机理，形成隧道爆破减振技术；通过模态试验，研究隧道爆破近区楼房自身特性，研究爆破对楼房损伤机理，形成爆破减振技术；研究隧道围岩及支护的爆破振动损伤机理，形成控制隧道爆破施工时围岩稳定控制标准及技术。最终形成小净距隧道爆破振动衰减规律及周围环境影响机理和控制措施，研究成果应用于重庆高铁交通枢纽、广深港高铁隧道、京张高铁八达岭地下车站及隧道和大连等市区隧道的建设中，取得了良好的社会和经济效益。