Bottom Heave Treatment Technology Of Concrete Filled Steel Tubular Piles In Bottom-drawn Roadway Under Dynamic Pressure Disturbance

With the continuous consumption of coal resources,coal mining in the central and eastern part of China has entered the deep mining stage,the roadway surrounding rock stress has increased significantly,the strength of the rock body has been reduced,while the roadway support structure is still commonly used shallow support method,ignoring the management of the bottom slab surrounding rock,under the dual influence of mining disturbance,the roadway bottom drum phenomenon is becoming more and more serious,causing serious impact on the safe production of mines.In this thesis,based on the physical and mechanical properties of the surrounding rock and the distribution law of ground stress,we studied the deformation and damage mechanism of dynamic pressure roadway bottom slab and bottom drum control technology through theoretical analysis,numerical simulation and similar simulation test,revealed the deformation and damage mechanism of extruding fluidity floor heave,developed a steel pipe concrete pile bottom drum control scheme,analyzed the steel pipe Concrete pile deformation and damage characteristics and stress distribution law for different length,angle and row distance support,and determine the optimal support parameters.The main research conclusions are.（1）To study the deformation and damage of the surrounding rock of the roadway according to the mechanical properties of the surrounding rock and the distribution law of the ground stress,and to reveal the influence of the mining disturbance,the mechanical properties of the surrounding rock and the support structure on the bottom drum of the roadway,to analyze the mechanical analysis of the surrounding rock of the bottom plate of the dynamic pressure roadway based on the elastic-plasticity theory,and to calculate the depth of damage of the plastic zone of the surrounding rock of the bottom plate of the No.4 bottom extraction road in the north wing of the north one mining area of Chiyu mine,and to analyze the deformation and damage mechanism of the bottom drum of the extruded mobility in combination with the slip line field theory.（2）Develop a steel hybrid support structure to control the extruded liquidity bottom drum,assume the damage depth of the roadway bottom slab according to the plastic zone theory,establish a preliminary mechanical model of bottom drum management dominated by steel pipe concrete piles,analyze the force situation of the roadway surrounding rock under the influence of mining,analyze the support mechanism of anchor rods and anchor cables,the bearing characteristics and support effect of steel pipe concrete piles,reveal the control mechanism of extruded liquidity bottom drum and the interaction mechanism between steel pipe concrete piles and bottom slab surrounding rock by combining with the actual geological environment of No.4 bottom extraction road in the north wing of the north one mining area of Chiyu mine.（3）The numerical model of steel pipe concrete pile bottom drum control is established by FLAC^3D,and the effects of different support length,inclination angle and row distance of steel pipe concrete pile on the bottom drum control of the roadway under dynamic pressure disturbance are studied and analyzed,and the deformation and damage law,stress-strain evolution law and plastic zone distribution of the surrounding rock of the roadway under different support parameters of steel pipe concrete pile are compared and analyzed.The numerical simulation results show that the best effect of bottom drum control is achieved when the support length is 6m,the inclination angle is 40°and the row spacing is 1.4m.（4）Taking the No.4 bottom pumping lane in the north wing of the north one mining area of Chiyu mine as the engineering background,based on the numerical simulation results,a similar test model was established by two-way loading CM250/18 plane stress test bench to compare and analyze the deformation and damage of the bottom slab surrounding rock in the bottom pumping lane under the influence of mining disturbance after the original support and steel pipe concrete pile support,as well as the law of surrounding rock stress distribution,which further supports the effectiveness of steel pipe concrete pile on the management of extruded liquidity bottom drum through similar simulation tests,and provides a new idea for the research of the bottom drum management of the lane when the theoretical analysis and test results are consistent.