深部开采动静载荷作用下复合动力灾害致灾机理研究

为研究深部开采动静载荷条件下冲击地压、突出两种灾害相互作用形成的复合动力灾害的发生条件与显现特征,利用重庆大学自主研发的"多功能真三轴流固耦合试验系统",以层状复合煤岩体为研究对象,进行了改变静应力组合、交变载荷频率和幅值、应变率及气体压力等试验条件的系列真三轴试验。试验结果表明:中间主应力、气体压力、交变频率和幅值、应变率等对复合动力灾害的显现特征均有较大的影响;真三轴试验条件下,层状复合煤岩体在临空面一侧多以劈裂成板、板曲折断的层裂形式破坏;基于荷载类型,可将复合动力灾害分为高静载型、扰动型、冲击型复合动力灾害3种类型,且在各类复合型动力灾害中,高压气体对复合动力灾害的孕育和发生具有积极的作用。

Disaster causing mechanism of compound dynamic disaster in deep mining under static and dynamic load conditions

In order to study the occurrence condition and behaviour characteristics of compound dynamic disaster of rock burst and coal gas outburst under static and dynamic loading conditions,a series of true triaxial tests under different static stress combinations,alternating frequency and amplitude,strain rate and gas pressure conditions of layered composite coal rock were conducted by using the self made “multi functional true triaxial fluid solid cou pling experiment system”.The research results show that the intermediate principal stress,gas pressure,alternating frequency and amplitude and strain rate have great influence on the behaviour of compound dynamic disaster.In general,the spalling failure is the main damage mode near the free face of layered composite coal rock under true triaxial test conditions.Besides,the compound dynamic disaster can be divided into three types by load types:high static load type,disturbance type and impact type,however,high pressure gas always plays a role of motive force and boosting power in either type of compound dynamic disaster,and both of its potential energy,seepage force and desorption expansion energy make positive contributions to the preparation and occurrence of compound dynamic disasters.