摘要
为了验证物探技术在岩溶塌陷调查中的应用效果，本文于广西来宾市吉利村开展了高密度电法和微动技术野外探测研究。结果表明：高密度对称四极电测深能直观地反映第四系覆盖层的厚度和低阻异常的深度，微动技术能定性地判定地下暗河和岩溶破碎带在地表的平面投影，将两种方法相结合能更加准确地圈出塌陷，以及引起塌陷的溶洞、地下河、断层破碎带及软土分布范围。地下暗河或岩溶破碎带在高密度联合剖面法上反映为低阻正交点异常，极距为45 m时正交点附近电阻率值约为250Ω＆#183;m；在微动 H/V比值谱上反映为 H/V极大值异常，极大值特征频率在2~6 Hz之间。依据2测线上的高密度电法和微动异常显示，圈出了两个易塌陷区，经对其中的一异常进行钻探验证，异常区覆盖层下42 m 厚的灰岩地层中钻遇溶洞8个，其中最大的高达5.7 m。
In order to verify the applicability of geophysical prospecting technology to the investigation of karst col-lapse,the field research was carried out employing high density resistivity and micro technology methods in Jili vil-lage,Laibin City,Guangxi.It showed that the high density symmetric quadrupole sounding method intuitively re-flected the thickness of the Quaternary overburden layer and the depth of the low resistivity section underground, while micro technology qualitatively analyzed the surface proj ection of the underground river and karst fracture zone. This would be more accurate in the case of circling collapse and unfavorable geologic bodies which caused collapse, such as caves,underground rivers,fault fracture zones and soft soil by combing two methods.It also showed that a low resistivity orthogonal point appeared in the high density profiling curve and its value was about 250Ω＆#183;m when the polar distance was 45 m while a great value anomaly appeared on the H/V spectrum and the maximum character-istic frequency was in the range of 2-6 Hz above the underground river or karst fracture zone.On the basis of anom-alies in the high density resistivity method and micro method of the line 2,the two sections circled were easy to col-lapse and one selected to be verified by drilling.Drilling revealed eight caves in limestone covered by a 42 m thick Quaternary overburden,of which the largest cave was up to 5 .7 m in height.
出处
《中国岩溶》
CAS
CSCD
2014年第1期118-122,共5页
Carsologica Sinica
基金
中国地质调查项目(1212011220193)
关键词
岩溶塌陷分区
高密度电法
低阻正交点
微动技术
特征频率
karst collapsed area
high density resistivity method
low resistivity orthogonal point
microtremor sur-vey method
characteristic frequency
