Study On Measuring Geo-stress Using Annular Hole Relief Method And Geo-stress Field Back Analysis

High ground stress is one of the most significant features in underground engineering project.And high ground stress is also the main reason for rock bust collapse of roadways with fractured surrounding rock.It also the main reason for some other nature disasters.As a result,accurate test the underground stress including the original stress and the redistribute stress is very important.It is also meaningful for solving nature disaster and other problems.In this paper,the writer mainly use annual hole relief method to measure the underground stress and back analysis the geo-stress field.The main work is as follows:1.In the first step,do the lab test using granite items.Using a serious of granite items,dig different depth hole.The hole depth is ranging from 5mm to 50mm.and each hole is 5mm deeper.Then apply stress in one direction.By testing the strain of the hole in the middle of the hole,get the stress relief ratio.By the different depth holes,arrive the conclusion that the relationships between the hole depth and the stress relief ratio.2.Then using numerical simulation software for the indoor specimen is simulated,by numerical simulation for indoor test results of error correction,and also verify the validation of indoor test,indoor experiment and numerical simulation results are identical with each other.3.In Hongtoushan copper mine-707 level 21st stope near the tunnel do some a nnul hole measurement.Got with the drilling excavation,the release of stress curve is consistent with the laboratory test results,using this method to obtain the 21st produ ced mine roadway eight points stress value.4.By evolutionary neural network method for ground stress field inversion,by es tablishing the three-dimensional calculation model for simulation of the stope.first,the results of numerical simulation is used to obtain the training samples,training neural network model,and then the actual measurement of stress value input to the model,get the regional stress field inversion.The research achievements of this paper include,obtained the annular stress release rate of the relationship between the drilling depth and regularity.got the Hongtoushan copper mine the stress field in 21 mining,for the scene of the production has played a guiding significance.In addition,using the method of circular hole measured in-situ stress can be used as a method to determine the in-situ stress.