摘要
陷落柱充填物的颗粒流失是诱发矿井突水事故的重要原因之一。为了研究陷落柱充填物在颗粒流失过程中初始级配与孔隙结构、粒度分布间的关系,利用变质量破碎岩体渗流试验系统,采用稳态渗流法得到分级加载条件下陷落柱充填物的颗粒演化规律和粒度分布特征,进而分析颗粒流失过程中的孔隙结构和水流突变规律。结果表明:①陷落柱充填物岩样普遍存在大量微观孔洞、裂缝和颗粒拼接等结构,颗粒流失在很大程度上取决于试样自身属性,外部荷载F和渗透压力P只起某种促进作用;②流失前后的充填物颗粒满足分形条件,具有分形特征,整个渗透流失过程中细小颗粒占比高达34.4%,试样颗粒的分形维数D随级配n值的增大而减小,流失颗粒中级配值n=0.3和n=0.9的试样更易于破坏,造成结构性失稳;③整个渗透历程中孔隙度存在2个骤减区段,其值分别出现在渗透历程的63 s和484 s左右,孔隙结构的调整与粒径级配有关,水流与试样间的往复作用会在进出水口形成稳定的导水通道,渗透后充填体内部存在孔洞、塌陷和空腔;④颗粒流失下的试样突水过程可分为初始渗流、灾变失稳和管流涌水3个阶段,各阶段下的流速和时间关系总体上趋近一致,突水过程一般会持续5~10 s。渗透过程中溃出物的质量m与Talbol幂指数n值可用指数函数拟合,溃出物的质量随Talbol幂指数n值的增大而增大,且充填体结构崩塌时会出现明显的水流喷溅、水位差浮动和压头掉落现象。
Particle loss of karst collapse column fillings is one of the major causes of water inrush accidents in mines.In order to investigate the relationship between initial grading,pore structure and particle size distribution of karst collapse column fillings during particle loss,the steady-state percolation method was used to obtain the particle evolution and particle size distribution of karst collapse column fillings under graded loading conditions using a variable-mass crushed rock percolation test system,and then to analyze the pore structure and water flow mutation during particle loss.The results show that①A large number of microscopic pores,cracks and particle splicing structures exist in the karst collapse column filler samples,and the particle loss depends largely on the properties of the specimen itself,with external load F and permeation pressure P only playing a facilitating role;②The filler particles before and after the loss meet the fractal conditions,with fractal characteristics,and the proportion of fine particles in the entire permeation loss process is as high as 34.4%.The fractal dimension D decreases with the increasing value of grading n,and the specimens with grading values of n=0.3 and n=0.9 in the lost particles are easier to destroy,resulting in a structural instability;③There are two abruptly decreasing porosity segments in the whole permeation course,the values of which appear in the 63 s and 484 s of the permeation course respectively,and the adjustment of the void structure is related to the particle size grading,and the reciprocal action between the water flow and the specimens will be more effective in the inlet and outlet.After infiltration,there are holes,collapses and cavities in the filling body;④Particle loss under the specimen bursting process can be divided into three stages,namely initial seepage,catastrophic destabilization and pipe water flow.The relationship between flow rate and time at each stage is generally consistent,and the bursting process will generally last 5-10 s.During infiltration,the col-lapse mass m and Talbol power exponent n can be modelled with available exponential function.The mass of collapse increases with the value of Talbol power exponent n,and the significant water spattering,floating water level difference,and head drop occur during the collapse of the fill structure.
作者
张天军
张秀锋
庞明坤
刘楠
张硕
高航标
ZHANG Tianjun;ZHANG Xiufeng;PANG Mingkun;LIU Nan;ZHANG Shuo;GAO Hangbiao(College of Safety Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;School of Science,Xi’an University of Science and Technology,Xi’an 710054,China;Cuijiagou Coal Mine,Shaanxi Province,Tongchuan 727101,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2021年第10期3245-3254,共10页
Journal of China Coal Society
基金
国家自然科学基金面上资助项目(51774234,51874234)
陕西省自然科学基金面上资助项目(2021JM-390)。
关键词
颗粒流失
陷落柱
孔隙结构
突水
分形特征
particle loss
karst column pillar
water inrush
pore structure
fractal characteristics
