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引入承压溶洞突水的管道流折算渗透系数,构建耦合非线性渗流–管道流于一体的承压溶洞突水全过程分析模型,在此基础上建立巷道前伏溶洞突水过程的流固耦合–强度折减法联动分析方法,研究承压溶洞突水全过程的流态转换机制。以七一煤矿石坝井承压溶洞突水事故为例,探讨防水岩柱的力学失稳机制和突水演化过程。研究表明:防水岩柱失稳前岩溶水非线性渗流,随着岩柱折减系数的增加,工作面渗水量增大,防水岩柱失稳后,溶洞水体突出,涌入巷道形成管道流。采用管道流模拟得到突水量在较短时间内达到峰值,由于溶洞水体储量供给约束,突水量逐渐减少,由突水初期的粗糙紊流最终变为管道层流。引入防水岩柱安全系数的概念,研究防水岩柱安全系数与溶洞内压、岩柱厚度的关系,将安全系数为1.5的岩柱厚度作为防水岩柱的计算安全厚度,提出防水岩柱工程留设厚度等于炮眼深度、爆破扰动深度和防水岩柱计算安全厚度之和的设计方法。将岩体流–固耦合理论、流态转换理论和强度折减法结合起来研究承压溶洞突水的非线性力学响应,为研究承压溶洞突水全过程提供了一种新的研究方法。
By introducing the permeability coefficient of the pipeline flow in the caverns under water pressure, the analysis model of water inrush of pressure caverns integrated with non-linear seepage-pipe flow is established. On this basis, the fluid-solid coupling - Intensity reduction method of linkage analysis method to study the whole process of water influx in confined caverns. Taking the caverns inrush caused by pressure caverns in the well of Qiyi coal mine as an example, the mechanic instability mechanism and water inrush evolution of the water-proof pillars are discussed. The results show that the seepage of karst water before instability of waterproof rock columns is nonlinear. With the increase of reduction coefficient of rock columns, the water seepage of working face increases. After the waterproof rock columns instability, the water of karst cave protrudes and flows into tunnel to form pipeline flow. The result of pipe flow simulation shows that the water inrush peak reaches a peak in a relatively short period of time. Due to the constraint of reservoir water supply, the amount of water inrush gradually decreases and the rough turbulence in the initial stage of water inrush eventually becomes the laminar flow. The concept of waterproof rock pillar safety factor was introduced to study the relationship between the safety coefficient of waterproof rock pillar and the internal pressure of cave and the thickness of rock pillar. Taking the thickness of rock pillar with safety factor of 1.5 as the calculated safe thickness of waterproof rock pillar, Design thickness is equal to the depth of blasthole, blasting disturbance depth and the calculation of the safety of waterproof rock pillars and design methods. The combination of fluid-solid coupling theory, fluid-state transition theory and strength reduction method is used to study the nonlinear mechanical response of water inrush pressure-bearing caverns, which provides a new research method for studying the whole process of water inrush in pressure caverns.