为满足城市环境下隐伏岩溶非开挖、快速布设及精细化探测的需求，研究不同DAS光缆耦合方式对主动源信号及频散特征的影响，提出一套适用于城市道路的背景噪声成像方案。对比土埋法、石膏固定法、点胶固定法、胶带固定法和沙袋压覆法等多种光缆与地面的耦合方式，分析不同耦合条件下主动源信号的信噪比和频散曲线特征； 考虑施工便捷性和快速部署的需求，提出适用于城市道路条件的石膏固定耦合布设方法。采用背景噪声成像技术，在南京上元门地区开展城市岩溶探测方法的试验研究。利用金属铠装振动传感光缆作为传感阵列，连续采集多天的背景噪声数据，通过频率-贝塞尔变换方法得到80 m排列长度的面波频散谱，提取5~40 Hz频段的基阶频散曲线，采用竞争粒子群优化算法反演获得地下40 m以浅的地层横波速度结构。结果表明： 1）基于DAS的背景噪声成像方法得到的浅层横波速度剖面准确反映了浅地表地层结构，与邻近的钻孔资料具有很好的对应关系，验证了该方法的有效性； 2）沿光缆长度在70~120 m等处发现了明显的低速异常区，根据邻近钻孔低速异常区岩芯存在溶蚀现象，可以推测该区域为岩溶发育区。

To fulfill the requirements of trenchless excavation, rapid deployment, and high-resolution imaging of urban hidden karsts, the influence of various cable-ground coupling mechanisms on distributed acoustic sensing (DAS) signals is examined and an optimized ambient noise imaging scheme is proposed. Initially, five coupling methods including soil burial, gypsum fixation, glue bonding, tape attachment, and sandbag coverage are evaluated by analyzing the signal-to-noise ratio and dispersion characteristics of active-source signals. Balancing construction efficiency with signal fidelity in urban road environments, the gypsum-fixation method is identified as the optimal deployment strategy. Subsequently, a field validation is conducted in the Shangyuanmen area in Nanjing, China. Using a metal-armored sensing cable as a linear array, continuous ambient noise data are recorded over several days. Surface-wave dispersion spectra are generated via the frequency-Bessel transform for an 80 m array, and fundamental-mode dispersion curves are extracted within the 5－40 Hz range. The shear-wave velocity structure of the upper 40 m is then reconstructed using a competitive particle swarm optimization algorithm. The results indicate that: (1) The DAS-based ambient noise imaging method produces shallow velocity profiles that accurately characterize the near-surface stratigraphy, showing high correlation with local borehole logs. (2) Distinct low-velocity anomalies are detected at distances of 70－120 m along the array. Integrated analysis with borehole cores—which reveal significant dissolution features—confirms that these anomalies correspond to active karst development zones.