面波多道分析法精细探测浅部煤层采空区应用研究

为精细探测浅部煤层采空区分布范围，在相移法中引入低频聚焦因子，提出一种低频聚焦型相移法，其具有在短接收排列上提取低频频散能量的优势。模拟结果表明:该方法显著改善了频散能量在低频端的聚焦性，扩展了可拾取的频带范围，增大了探测深度，缩短了计算频散能量所需的排列长度，提高了面波多道分析方法(MASW)的横向分辨率。浅部煤层采空区实测试验结果表明:采用低频聚焦型相移法提取频散能量，通过MASW方法获得了高精度的横波速度水平切片，可以清晰识别出采空区范围、保安煤柱位置及其几何形态。证实了低频聚焦型相移法可提高MASW横向分辨率的有效性与精细探测浅层煤层采空区的可行性。

Fine detection of shallow coal mined-out areas by multichannel analysis of surface waves

In order to finely detect the distribution range of shallow coal mined-out areas, a low-frequency focused factor is introduced into the phase shift method, and a low-frequency focused phase shift method is proposed, which has the advantage of extracting low-frequency dispersion energy on a short receivor array.The synthetic test results show that the low-frequency focused phase shift method significantly improves the focus of the dispersion energy at the low frequency, extends the range of frequency bands that can be picked up, and increases the detection depth.Meanwhile, the method shortens the spread length required to calculate the dispersion energy, ensuring that the MASW method has a high lateral resolution.The real data in the shallow coal mined-out area shows that using the low-frequency focused phase shift method in the dispersion energy extraction, the MASW method obtains high-precision horizontal slices of the shear wave velocity and identifies the extent of the mined-out area, the location of the security pillar and its geometry.It confirms the effectiveness of the low-frequency focused phase shift method to improve the lateral resolution of MASW and the feasibility to detect the shallow coal mined-out area finely.