基于Hoke-Brown准则的瓦斯抽采钻孔稳定性分析及封孔技术  

Analysis of the stability of the gas extraction boreholes based on the HokeBrown criterion and their sealing-up methods

作　　者：李松涛[1] 孙玉宁[1] 王永龙[1] 刘春[2] 

机构地区：[1]河南理工大学能源科学与工程学院,河南焦作454000 [2]中国矿业大学物联网(感知矿山)研究中心,江苏徐州221008

出　　处：《安全与环境学报》2016年第3期135-139,共5页Journal of Safety and Environment

基　　金：国家科技支撑计划项目(2013BAA03B02);河南省高等学校重点科研项目(15A440002);河南省高校基本科研业务费专项(NSFRF140135)

摘　　要：针对煤层瓦斯抽采钻孔稳定性差、抽采率低等问题,结合广义Hoke-Brown强度准则、有效应力原理及非线性孔隙压力分布特征,推导了钻孔围岩弹塑性区半径和应力表达式,得到了钻孔周围塑性区半径随各影响因素的变化规律。基于理论分析,采用囊袋式注浆封孔技术,在山西某矿310207工作面回风巷进行了现场试验。结果表明:地质强度指标(GSI)和不均衡系数(λ)相比扰动性系数(D)对钻孔周围塑性区范围影响更大;当原始瓦斯压力点距离钻孔中心小于1 m时,塑性区半径受瓦斯压力影响开始显著上升。以瓦斯抽采体积分数大于30%作为衡量封孔效果的标尺,在3个月左右的观测时间内囊袋式注浆钻孔相比聚氨酯钻孔,瓦斯抽采有效时间可以延长约2个月,瓦斯平均体积分数提高约58.2%。In order to improve the stability of the gas extraction borehole and gas extraction efficiency,the paper intends to make a theoretical analysis of the stress of the surrounding rocks of the borehole and ways for positive precautions to prevent and control its collapse,so as to enhance and heighten the gas concentration extracted as well.For this purpose,given the nonlinear distribution of the pore pressure around the borehole rocks,the author of this paper would like to propose a general Hoke-Brown strength criterion,based on the principle of effective stress and the stress balance theory to make a survey of the stress and the radius of the elastic-plastic region nearby,for the borehole stability tends to be closely connected with the plastic scope of the surrounding rocks of the boreholes.It is just starting from what is said above,we have made careful and detailed exploration of the evolution of the radius of the plastic zone from the different points of view of the different influential factors concerned,such as the geologic strength index（GSI）,the imbalance coefficient（λ） and the gas pressure in the light of the established theoretical equation.Furthermore,we have adopted the capsule bag grouting method at the tailing gate of No.310207 panel,Shanxi,in accordance with the theoretical accounting and the geological conditions of the formation rock.The results of our study show that,with the increase of the GSI index,the low supporting force of the borehole wall can also display favorable sealing effects,for the elastic radius around the borehole tends simply to reach 0.102 3 m,that is,about 1.7times bigger than the radius of the borehole itself with its GSI being 55.In spite of this,the change of the disturbed factor（D）can only have a limited effect on the borehole stability,for the evolution of the radius of the plastic zone can likely be dramatically greater on the premise that the imbalance coefficient（λ） is over1.2.In addition,the gas pressure tends to produce remarkable impact gradually on

关 键 词：安全工程 钻孔稳定 瓦斯抽采 塑性区半径 封孔技术 囊袋式注浆 

分 类 号：X936[环境科学与工程—安全科学]