Research On Gravity In The Whole Space Of Tunne

Tunnel gravity is a gravity prospecting method measured in underground tunnel.Compared with the gravity survey on the earth’s surface,the surface gravity anomalies are caused by the source body under the observing plane.For the tunnel gravity survey,the source bodies of the upper or lower or the surrounding of the tunnel can cause anomaly that is the total-space gravity anomalies.When the gravity survey is carried out in the tunnel,we can be more close to the ore body and the related structure,and observe stronger gravity anomalies than the surface gravity survey.It has better detectivity.Tunnels electromagnetic methods are difficult to achieve effective results,because of electromagnetic interference of the production facilities and electric power facilities,while the tunnel gravity survey is not affected.Based on the project of China Geological Survey—Northeast yunnan ore concentration area prospecting prediction,we carry out the tunnel gravity survey in the tunnel of HuiZe QiLinChang lead-zinc mine,and use the tunnel gravity to detecte the lead-zinc ore.From the tunnel gravity principle,the forward modeling,the tunnel correction,inference and interpretation,the practical application,through the research on the theory,method and application of gravity in tunnel.the following results are obtained:The theory of tunnel gravity is summarized,and the integral expansion formula of the three direction gradient anomaly is deduced.Through the forward modeling of high density vertical cuboid and inclined cuboid model,the spatial distributions of four parameters,including the gravity anomaly and the three directions gradient of gravity anomaly,are obtained.The interference factors,influencing rules and correction methods of tunnel gravity are summarized.According to the gravity anomalies forward simulation of high density vertical cuboid model,the positive and negative combinations of 4 parameters of gravity anomaly and the three direction gradient anomaly are obtained in the different spatial position.The method of qualitative prediction of vertical cuboid orebody’s location is established;On the basis of previous studies,the theory and method are further deepened.According to the gravity anomalies forward simulation of high density inclined cuboid model,the positive and negative combinations of 4 parameters,containning gravity anomaly and the three direction gradient anomaly,are obtained in the different spatial position.The new method of qualitative prediction of inclined cuboid orebody’s location is established.The problem of spatial qualitative interpretation of inclined orebody is solved.The forward modeling method is used to quantitatively explain the ore body,and the parameters such as the size and depth of ore body can be estimated by quantitative interpretation.Tunnel gravity survey is carried out in HuiZe QiLinChang lead-zinc diggings.Based on the above research results,this paper explains the reasons why the ore has not been seen in the borehole of tunnel,and predicts the approximate position,direction and depth of the ore body in the tunnel,and points out the next prospecting directions.