【摘要】 超小净距隧道钻爆法施工过程中,爆破产生的地震波不可避免地对先行隧道衬砌结构产生损伤,会危及其安全和稳定性。南京地铁隧道二号线工程实践,最小净距仅0.309 m,远小于隧道设计规范规定值,进行CRD工法的爆破全过程系统现场试验,分析先行洞衬砌在不同爆破方式作用下的振动波传播及分布规律,结果表明:上台阶爆破时先行洞迎爆侧衬砌产生的振速较大,但切向和水平相差不大,应将上台阶的爆破作为爆破控制的重点,选择合理的掏槽形式和掏槽位置,可以为后续爆破创造足够好的临空面;下台阶爆破对先行洞产生的振速较小,一般不会大于10 cm/s;上下台阶同时爆破作业产生的振速最大,超过爆破安全规程规定值20 cm/s,因此小净距隧道禁止上下台阶同时爆破。更多还原

【Abstract】 In the case of super-small-distance tunnels,due to the tunnel with small clear space,seismic wave generated must damage tunnel lining inevitably and influence its safety and stability.Combined with No 2 line of Nanjing metro with small clear space,its clear space is 0.309 m which is much less than the prescribed value of "Code for Design of Tunnel".The monitoring of blasting vibration was carried out systematically for the completed construction blasting process of CRD method.The in-situ monitoring of blasting vibration was carried out.The propagation and distribution of vibration waves were analyzed of existing tunnel lining with different blasting methods.The meaning conclusions were presented.It shows that lining vibration velocity of existing adjacent tunnel is higher when upper bench blasting method is adopted,but it is just about for tangential and horizontal level.So attention of monitored blasting is focused on upper bench.Rational cut-hole patterns and position are selected for better blasting face of subsequent blasting.Lining vibration velocity of existing adjacent tunnel decrease when lower bench blasting method is adopted,which is less than 10cm/s generally.Lining vibration velocity of existing adjacent tunnel is highest when upper and lower bench blasting synchronously method is adopted,which is more than 20 cm/s about the prescribed value of "Safety Regulations for Blasting",so upper and lower bench blasting synchronously is prohibited for closely-spaced running tunnels.更多还原