【摘要】 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。更多还原

【Abstract】 With the introduction of the equivalent hydraulic conductivity of pipe flow for the water inrush of confined karst cave,a nonlinear model of coupled seepage-pipe flows was established to simulate the entire process of water inrush.The model was combined with the strength reduction method and solid mechanics to study the change of flow state of water inrush of confined karst cave.The instability of water blocking rock pillar and the water inrush occurred at Qiyi mine in south China were discussed.The water discharge from the working front increased with the increasing of the reduction factor of the strength of the water block rock pillar before the rock pillar losing its stability.After the failure of the rock pillar,water burst out from the confined karst cave to form pipe flow.The amount of the water irrupted reached the peak value in a short time then decreased slowly according to the simulation.The turbulent flow at the initial stage was changed into the laminar pipe flow finally due to the limited water reserve of the karst cave.The safety factor of water blocking rock pillar was introduced and the relations of the safety factor,the water pressure in the karst cave and the thickness of the water blocking rock pillar were studied.The thickness of the water blocking rock pillar with the safety factor of 1.5 was proposed to be the calculated safety thickness.The safety thickness of the water blocking rock pillar was proposed to be equal to the sum of the depth of blasting hole,the depth of blasting disturbance and the calculated safety thickness.更多还原