为解决下穿城区隧道爆破开挖振动大、进度慢、安全风险高等技术难题，基于重庆轨道交通10号线二期南湖站、万寿路站及区间隧道工程，开展施工方法比选和爆破方案设计及优化，按照“方案设计—爆破施工—振动监测—信息反馈—优化调整”的顺序进行爆破施工，对隧道开挖爆破过程中遇到的难题进行分析,并提出解决问题的具体方法。研究结果表明: 1）隧道开挖面设置上下2个爆破区，掏槽区设置在下半断面，通过优化调整掏槽眼结构形式及起爆顺序，在满足爆破振速≤2 cm/s的前提下，相对于常规爆破方法能提高最大单段起爆药量，增加循环进尺； 2）隧道开挖面按照先下后上分区间隔爆破，能实现开挖工序的快速衔接转换，相对于台阶法开挖，可便于大型机械设备作业，提高工效； 3）先下后上分区间隔爆破能及时完成全断面一次立拱喷浆支护，避免拱架拱脚悬空、成榀拱架损坏和支护不及时等问题，更有利于施工质量和安全。

The blasting excavation of tunnels crossing underneath urban areas has disadvantages such as large blasting disturbance, slow construction speed, and high risk. Therefore, a case study is conducted on Nanhu station-Wanshou Road station and a tunnel section of Phase Ⅱ of Chongqing metro line 10. Construction and blasting methods are compared and optimized. The blasting construction is mainly conducted according to the order of "scheme design, blasting construction, vibration monitoring, information feedback, optimization, and adjustment". Specific countermeasures are proposed for difficulties encountered during blasting excavation process. The research results indicate the following: (1) The blasting cross-section is divided into upper and lower parts, the lower part is set as cutting zone, and the cutting hole structure and blasting sequence are optimized. Under the premise of blasting vibration speed of no less than 2 cm/s, this blasting scheme increases the maximum amount of single stage detonating charge and cyclic advance compared to conventional blasting methods. (2) The blasting sequence of upper cross-section first and then lower cross-section rapidly connects each construction process, and it is more beneficial to large-scale mechanical operations and achieve high efficiency than bench-excavation method. (3) The blasting scheme of lower cross-section first and then upper cross-section provides condition for one-time shotcrete supporting, avoiding subsequent arch feet suspension, arch frame damage, and untimely support, which is more conducive to construction quality and safety.