Study on Distribution Characteristics of Static and Dynamic Side Pressure of Borehole Wall in Main Ore-Pass Storage Section
In order to understand the side pressure distribution characteristics and differences of the ore-pass wall under the two conditions of ore storage and unloading,the No.2 main ore-pass of Shilu Iron Mine in Hainan was taken as the research object.Based on the Janssen formula,the relationship between the borehole wall pressure and the elevation was established.The dynamic and static pressure monitoring platform of the ore-pass was established simultaneously.The storage and drawing process of the ore storage section of the ore-pass was simulated,and the pressure variation characteristics were monitored.The distribution and difference of static and dynamic pressure were analyzed.The limitations and problems of the application of the Janssen formula were discussed,and the key suggestions were put forward based on the research results.The results show that with the increase of the measurement height,the static side pressure of the borehole wall gradually decreases,the dynamic pressure value is greater than the static pressure,and the dynamic side pressure of the borehole wall increases first and then decreases.When the height of the measuring point is 1.26 m,the peak value is 16.289 kPa,and the dynamic side pressure near the storage surface is the smallest,which is 3.073 kPa.The overpressure phenomenon causes a significant difference between the dynamic and static pressures.The Janssen formula can basically describe the relationship between the static side pressure of the borehole wall and the measurement elevation,but there are some limitations,which are derived from the impact compaction of ore unloading,the compaction of overlying ore rock,the bottom structure and the pressure of ore rock.These factors cause a small range of dynamic changes in the parameters such as the internal pressure and bulk density of the storage material,resulting in the calculation error of the Janssen formula model.In addition,when using the Janssen formula to calculate the dynamic pressure value,it should be noted that the overpressure coefficient is a dynamic value related to the height of the measuring point.In order to ensure the long-term stable operation of the storage section of No.2 main ore-pass,some engineering management suggestions have been put forward,such as using the inner sleeve steel plate concrete shaft lining repair method in the elevation range of 22-26 m,the storage height should be above 30 m,the ore rock fragmentation should be controlled,and the ore should be unloaded at an uniform speed.The research results have certain theoretical significance for the evaluation of ore-pass wall wear,and help to ensure the continuity of ore-pass transportation and improve the service life of ore-pass.
Ore-pass storage sectionSide pressure of borehole wallJanssen formulaPhysical test
万方数据
维普
