重力垂直梯度测量探测能力的正演

Underground Vacancy Detection Based on Vertical Gravity Gradient Measurements

重力垂直梯度测量是一种探测地质构造、小地质体位置的技术,但利用该技术对地下空洞的探测还没有深入地研究。通过假定地下空洞的位置和体积,采用正演方法对重力垂直梯度测量探测地下空洞的能力进行研究,分析不同埋深及体积的人造空洞对地面重力及重力垂直梯度的影响;并利用CG-5重力仪进行了初步实验。实验表明:重力垂直梯度对浅层地下空洞具有很好的探测能力;通过正演计算表明:在埋深超过200 m时,地下空洞对重力垂直梯度的影响近似与体积成正比,在埋深超过400 m时,地下空洞的埋深对重力垂直梯度的影响近似成线性下降。

Vertical gravity gradient measurement is a technique that can be used for detecting geologic structure and small anomaly mass.However,for some reasons,the technique has not been carefully studied for detecting special object,like underground vacancy（manmade structure）.Its detecting ability was studied by the direct calculation method,and with different position and volume,gravity anomaly and vertical gradient on the floor caused by vacancy were analyzed.At the same time an experiment was carried out with the CG-5 gravimeter.With the theory calculation and experiment results,it showed that vertical gravity gradient had an advantage over gravity anomaly for detecting underground vacancy;under the depth of 200 m,vertical gravity gradient caused by vacancy had a distinct proportion with its volume;within the depth of 400 m,vertical gradient decreased linearly with the depth of vacancy.