【作者】 王永强；

【导师】 宋选民；

【作者基本信息】 太原理工大学 ， 工程力学， 2010， 硕士

【摘要】 在我国的能源结构中,煤炭能源在可预见的时期内仍将占据主导地位。大采高超长工作面的研究和推广应用,不仅有利于工作面单产提高,而且能减少巷道掘进率和维护强度。在近年的快速推进高产高效工作面开采实践中,人们注意到工作面开采速度即时间因素对开采力学响应及破坏的影响问题,也即存在时间因素对地下工程围岩的变形及强度的影响作用。因此,研究采动影响下回采巷道围岩变形特点,对于正确认识综采条件下岩层的运动规律,深入研究巷道变形与回采速度之间的关系,促进安全生产,降低生产成本具有重要的现实意义。本文主要做了如下研究工作:(1)比较全面地介绍了流变力学的研究方向、研究内容、影响因素等,总结出岩石工程流变学的主要研究方向主要包括蠕变、应力松弛、长时强度、弹性后效和滞后效应等。对开尔文模型、麦克斯韦尔模型、鲍埃丁—汤姆逊模型、伯格斯模型、粘塑性模型、粘弹塑性模型等流变组合模型的蠕变、松弛等进行了理论分析。(2)分析了巷道围岩的流变特性和时效特性,总结出巷道围岩流变变形的主要影响因素包括岩石材料本身所具有的粘性性质、岩石材料受到的应力水平和加载方式、温度湿度和赋存环境等。在回采引起的巷道变形中,回采引起的支承压力是主要因素。回采速度对围岩应力场的影响主要体现为:回采速度的不同影响了围岩应力转移过程的完整程度;回采速度的不同造成了单位时间开采截深的变化,从而影响了围岩的截深加卸载过程以及加载速率的变化;回采速度的不同对岩石蠕变时间也有一定的影响,从而影响了岩石的变形及应力分布。(3)采用四元件伯格斯流变模型对上湾矿51101工作面回采巷道围岩变形进行了流变特性分析。(4)利用FLAC3D中提供的Burgers蠕变粘塑性模型进行数值模拟,得到不同回采速度情况下巷道围岩的变形—时间曲线。通过对数值模拟结果的分析得出回采速度越快,围岩变形量越小。在工作面支承压力影响范围以外巷道围岩的变形主要由是由岩石的蠕变起作用;当巷道开始受支承压力影响时,围岩变形急剧增加,此时围岩的变形主要因素为工作面的超前支承压力,岩石的蠕变因素退居到次要地位。在相同的条件下,回采速度越慢,巷道围岩应力作用时间越长,变形量越大。(5)通过上湾矿51101工作面实测位移—时间曲线与数值模拟结果对比分析得出巷道位移各观测点的位移—时间曲线与模拟情况基本相符,能够真实反映模拟对象。更多还原

【Abstract】 Coal energy will still play a leading role in energy structure of China in the foreseeable future. With the research and broad application of large mining height technology and super long coal face, not only the output can improved, but also the roadway drivage ratio and maintenance quantity can reduced. In recent years,with the practice of coal face of high-output and high-efficiency under the fast mining, it is noted that the deformation and the strength of underground works are affected by the time factor.Therefore, the study on surrounding rock deformation characteristics under the influence of mining can help to correctly understand the movement rule of roof terrane under fully-mechanized mining, further study the laws between the deformation of roadway and mining speed, promote safety production and reducing producti-on costs. The work involves:(1)This paper makes a comprehensive introduction to the research directions,contents and influencing factors about rheological mechanical theory,summarizes the major research directions which include creep, stress relaxation, long-term strength, elastic after effect and hysteresis effect, etc. The creep, relaxation about combined models which incloude Kelvin model, Maxwell model,Poynting-Thomson model,Burger model,viscous-plastic model, viscous-elastic-plastic model are given.(2)Through to analyze the rheological properties and aging characteristics of surrounding rocks,the main influencing factors are obtained which influence rheological deformation of roadway:viscous properties of the rock material itself, stress levels and loading conditions to the rock, the temperature and humidity, the occurrence environmen of the rock and so on. The deformation of mining roadway which caused by the mining is produced mainly by the abutment pressure. The influence to the stress field of surrounding rock which is caused by mining speed is mainly embodied in:the integrity degree of transfer process about surrounding rock stress under different mining speed; the changes of cutting depth unit time are caused by different mining speeds,which affected unloading and loading process and changes in loading rate about the surrounding rock; mining speed differences have a certain impact to the creep time on the rock, which affects the deformation and stress distribution.(3) According to analyze the rheological properties of roadway about the Shangwan Coal Mine 51101 Face, deformation formula which is effected by the vertical stress is derived by using the Burgers rheological model of four-ele- ments.(4) The surrounding rock deformation - time curves in different extraction rates are obtained by using Burgers creep viscoplastic model which provided by FLAC3D. Through to analyze the results of numerical simulation,conclusions are obtained: the faster mining speed, the smaller deformation rock;the deformation of surrounding rock is mainly caused by the creep outside Support pressure of the face;when the roadway is began to affecte by the support pressure of the face, deformation is caused by the support pressure of the face ;under the same condition, the slower mining speed, the greater deformation of surrounding rock which creeps longer.(5) By contrast with displacement - time curves on51101 face of Shangwan Coal Mine, the figures of numerical simulation can truly reflect the condition of simulated objects.更多还原