综合物探技术在武汉市江夏区大桥新区岩溶探测中的应用研究

Study on Application of Integrated Geophysical Prospecting for Karst in Daqiao New Area,Jiangxia Economic Development Zone,Wuhan City

武汉市主城区分布6条近东西向碳酸盐岩条带,各条带延伸至江夏区后都不同程度的加宽,致使江夏区碳酸盐岩近于全区分布。由于碳酸盐岩岩溶发育,近年来导致武汉市市政范围内发生十余起地面塌陷灾害。为查清武汉区岩溶分布,开展了岩溶探测技术方法研究。目前岩溶探测的方法较多,也有较多成功案例,但多以工程勘测为主,在城市范围内的岩溶探测实例较少。以武汉市江夏区大桥新区豹山还建小区为例,在分析该区岩溶发育地质特征的基础上,运用高密度电法、地质雷达法、超浅层瞬变电磁法、陆基声呐法、地震勘探法、井间CT等6种方法对岩溶发育地区进行了探测。通过对比不同技术方法探测岩溶效果发现:可控震源激发的横波探测效果较好,瞬变电磁技术对埋藏较浅的溶洞探测效果较准确,高密度电法对溶洞也有明显的反映。实例表明,在较复杂地质条件下采用多种技术方法综合探测,将会得到更准确的岩溶分布结果。

There are 6 near EW carbonate rock belts distributed in the main urban area Wuhan City, after extended into the Jiangxia Economic Development Zone they have broadened more or less, thus almost distributed in whole of the zone. The developed carbonate rock karst has caused ten more surface subsidence hazards within the administrative scope of Wuhan City in recent years. To find out karst distribution in the city has carried out study on karst prospecting technical methods. Since a great deal of karst prospecting methods at present with some rather successful cases, but they are mainly on project prospecting, while less on municipal scope karst prospecting cases. Taking the Baoshan rebuilding housing in the Daqiao new area of the zone as example, on the basis of area karst developed geological features analysis, through high density electric survey, ground penetrating radar, ultra-shallow TEM, land-based sonar, seismic prospecting and cross-well CT 6 methods carried out prospecting in karst developed area. Through comparison of different methods has found that the effect of vibroseis induced shear wave prospecting is rather good;TEM technology has rather high accuracy in shallow buried karst cave prospecting;and karst caves have clear reflection on high density electric survey results. The cases have shown that the integrated prospecting of multiple techniques under rather complex geological condition will acquire more accurate karst distribution result.