煤与瓦斯突出过程中煤体层裂演化特征实验研究

Experimental study on evolution characteristics of coal body spallation during coal and gas outburst

为了探究煤与瓦斯突出过程中煤体层裂演化特征,利用自主研制的煤与瓦斯突出实验模拟系统,研究突出过程中煤体层裂结构特征、煤体裂隙厚度演化特征和煤体质点运动演化特征。研究结果表明:在轴向应力0.9 MPa、瓦斯压力0.4 MPa时,煤体层裂发展时间持续85 ms,煤体共计出现11处裂隙。层裂从煤体后方的弱构面出现并向前方发展,其位置大多集中于突出腔体中后部,煤体层裂形式均为纵向贯通,在第9处出现最大纵向断裂裂隙。煤体裂隙总厚度约为75.6 mm、单处裂隙平均厚度约为8.4 mm,二者均呈现随时间递增的趋势。层裂过程中煤体单处裂隙厚度并不都是沿程递增的,部分煤体中部裂隙厚度呈现先增大后减小的特征。煤体的运动表现为靠近突出口端的运动速度更快、运动距离也更长。研究结果可为揭示煤与瓦斯突出层裂机制提供参考。

In order to explore the evolution characteristics of coal spallation in the process of coal and gas outburst,the self-developed experimental simulation system of coal and gas outburst was used to study the structural characteristics of coal spallation,the evolution characteristics of coal fracture thickness and the evolution characteristics of coal particles movement in the process of coal and gas outburst.The results showed that when the axial stress was 0.9 MPa and the gas pressure was 0.4 MPa,the development time of coal spallation lasted 85 ms,and the coal body had 11 fractures in total.The spallation occurred from the weak structural plane behind the coal body and developed toward the front,and the positions of most of them were concentrated in the middle and rear of the outburst cavity.The spallation form of the coal body was all the longitudinal penetration,and the largest longitudinal fracture appeared at the 9th place.The total thickness of coal fracture was about 75.6 mm,and the average thickness of single fracture was about 8.4 mm,both of which presented an increasing trend with time.In the process of spallation,the thickness of single fracture of coal body did not always increase along the way,and the thickness of partial fracture in the middle of coal body increased first and then decreased.The movement of coal body was characterized by faster movement speed and longer movement distance near the outburst outlet.The research results can provide reference for revealing the spallation mechanism of coal and gas outburst.