Study On The Mechanism Of Coupling Support Technology And The Parameter Optimization In Deep Soft Roadway

Support in the deep soft-rock roadway is a complex problem in underground engineering，for the large crustal stress and poor lithological characters it has to be the difficulties in roadwaysupport. In such roadway the single support method cannot obtain a good effect，and thecombined support also cannot do well in it，so always fall into the embarrassment that beforedigging after repairing repair while driving. The Single support failed because of the insufficientsupport strength，and the combined support failed on account of the non-coupling betweensupport system and surrounding rock mechanics characteristics. The traditional combinedsupport method is just a simple superposition of several support methods，without consideringthe supporting mechanism of the support system，the release of internal energy of surroundingrock and the work of surrounding rock self-supporting capacity，which cannot reach the couplingsupport in strength，stiffness and structure. The mechanism of coupling support technology andthe parameter optimization in soft-rock roadway are studied with the methods of theoreticalanalysis，numerical simulation and similarity model test and the main research achievements areas following：(1)The mechanical parameters of surrounding rock is obtained through field sampling andexperiments，and the law of surrounding rock internal energy release and self-supportingcapacity is analyzed by elastic-plastic theory，so the curve between support strength anddeformation can be got and the optimal supporting time is determined. By using the method ofnumerical simulation，the support mechanism of mesh-shotcreting support，bolt，cable，groutingand36U profile steel are studied and the coupling between supports and surrounding rock areanalyzed.(2)Through analysising the supporting effect with different bolt length and row spacing bynumerical simulation，different cable length and layout schemes，different grouting zone bynumerical simulation，the reasonable bolting，cabling and grouting parameters can be achieved.In consideration of the optimal supporting time，the continuous uniform deformation and stressof surrounding rock can be got，which means the coupling in stiffness.(3)Stress distribution of coal floor after the extraction is got by elastic theoretical analysis，and the stress distribution expression and The maximum stress concentration factor is obtained.The influence on below roadway caused by stress distribution of coal floor changes is analyzed，so the crustal stress around roadway can be determined after excavated. Through the numericalsimulation the feasibility of reinforcement scheme by using36U profile steel is verified.(4)Through similarity criterion analysis，the similarity ratio and similar constant aredetermined，the similar simulation experiment scheme is drew up.The Materials composion can be got through three factors quadratic orthogonal test. By analyzing the test results，the stress，deformation and supporting structure bearing size with four types of supporting schemes areobtained，which verify the feasibility of coupling support.