地质雷达方法在武汉岩溶探测中的应用分析

Applied Analysis of Ground Penetrating Radar in Wuhan Karst Prospecting

武汉市域内自北向南有6条碳酸盐岩条带呈东西向分布,已发生数十起岩溶地面塌陷,因此对岩溶进行探测,已成为当前工程地质领域中的一个重要课题。以位于武汉市江夏区某还建小区为例,根据35m探测尝试的要求,对环境电导率、介电常数、发射频率等影响地质雷达探测效果的参数进行分析,确定了该区溶洞探测参数。施工采用二个型号地质雷达,其中LTD-2100型地质雷达采用的工作频率为100、40MHz,CAS-U25型地质雷达采用25MHz。依据探测数据,圈定了探测范围内溶洞的位置,经钻探验证与溶洞实际位置基本吻合。对比不同发射频率对异常的解释效果发现,100、40、25MHz对异常的分辨能力及探测精度依次降低。

Within the Wuhan City territory have 6 carbonate rock belts distributed from east to west. Tens of karst surface subsidences have been happened, thus the karst prospecting become an important topic in engineering geological field currently. Taking a residential area under construction in the Jiangxia District as example, according to requirements of 35m depth prospecting test, carried out analysis of environment electric conductivity, dielectric constant and emission frequency etc. parameters impacting ground penetrating radar prospecting effect, and worked out karst cave prospecting parameters. The operation has used 2 types of ground penetrating radar, the LTD-2100 radar has used operating frequency 100MHz and 40MHz;CAS-U25 type radar used 25MHz. Based on prospecting data have delineated karst cave positions within prospecting range, after drilling identification, prospecting results are basically tally with actual karst cave real positions. After comparing of different emission frequency effects from anomaly interpretation have found out that the resolving power and prospecting accuracy from frequencies 100, 40 and 25MHz lowering down successively.