Study On Cooperative Mining Of Strip Filling Zone And Stability Of Surrounding Rock In Alpine Valley

When the conventional room and pillar method is used to mine the mineral resources in the high mountain valley terrain,the large-scale goafs left behind are likely to induce geological disasters such as mountain collapse and river bed subsidence,and the pillars left in the stope are difficult to effectively recover,resulting in resource waste.In order to achieve the goal of safe,efficient and low-depletion mining resources under high mountain valley terrain,taking the Yichang Shaiqi River Phosphate Deposit as the research object,a strip-filling zone cooperative mining technology suitable for it was proposed.Through the method of proportion test,theoretical analysis,numerical simulation,and similar simulation of the filling body,the deformation and stability of the surrounding rock in the stope were systematically studied during the mining process.First,by carrying out the ratio test and uniaxial compression mechanics test of the cement-end sand filling body,the stress-strain curves of the different lime-sand ratio filling bodies at different ages were obtained,and the mechanical properties and the filling properties of the different lime-sand ratio filling bodies were explored.Changes with age.The analysis shows that the mechanical properties of the lime-sand ratio of 1:4 are significantly affected by age in the first 14 days,and the mechanical properties of other lime-sand ratios are less affected by age;the compressive strength and elasticity of all lime-sand ratios The modulus reached about 80%of the 28d strength at 14d.Carrying out the ratio test of the filling body laid the foundation for the later theoretical research and practical application on site.Secondly,according to the roof structure and non-uniformly loaded load characteristics during two-step mining,a one-step mechanical model of fixed beams with roof and two-step"roof-filling body"mechanical model is constructed to derive the two-step mining process The bending deformation deflection equation of the top plate.Taking the tensile strength of the roof of the mining area as the evaluation index,the critical conditions of roof stability were obtained.Different stope structural parameters and filling patterns were designed for the high and low stress mining areas.The theoretical results show that the strip width is 12m and the mining area span When the limestone-to-sand ratio of the filling body in the 72m high and low stress mining area is1:4 and 1:6,it can ensure the stability of the stope roof.Finally,the FLAC^3D numerical simulation method is used to study the bearing characteristics of the stope pillars.The analysis shows that there are three types of stress distributions in the high-altitude valley underground stope pillars:"asymmetric saddle shape","arch shape",and"oblique pointed shape".In the form,the surrounding rock ore pillar and the filling body are mainly shear failure.According to the pressure characteristics of the mining pillars,the zonal filling mode is optimized.Under the selected parameters of the stope structure and the optimized filling mode,the similar deformation test was used to study the stress and deformation characteristics of the surrounding rocks of the stope in the Shaiqi River mining area.The surrounding rock of the stope is relatively stable,further demonstrating the feasibility of cooperative mining in the zone filling zone of the high mountain valley.