冲击和突出耦合致灾过程连续-非连续方法研究及应用

The new status of dynamic disasters in deep high-gas coal mines becomes increasingly intense. For examples,rockbursts usually have characteristics of gas outbursts,and gas outbursts are usually induced by rockbursts.Two kinds of dynamic disasters take place simultaneously. They interact and are induced mutually,leading to a coupling disaster-causing process.This gives a huge challengefor their prediction and prevention.Understanding the spatiotemporal distributionof fields of solid stress,fracture and gas pressure under mining is fundamental to predict and prevent dynamic disasters.Thus,the effective numerical methods must be developed.Using the present seepage model for fractured mediums,the actual interaction between gas and fractured coal and rock cannot be modeledIt is especially important to realize the positive feedback process that the cracking and swelling of coal lead to desorption and emission of gas and then desorption and emission of gas lead to further cracking and swelling of coal.The breakthrough stems from modeling of initiation and development of the gas concentration region.In this proposal,a continuum-discontinuum method considering a solid/gas couple will be developed.Using the method, the deformation-cracking-motion of coal and rock and the desorption-emission-concentration-outburst of gas will be modeled accurately and efficiently under mining.In addition,necessary optical measurements of processes of deformation and failure of coal with gas will be conducted by use of a pressure chamber with transparent windows,which will be designed in this proposal. Using the continuum-discontinuum method,the spatiotemporaldistribution of three fields mentioned aboveand the interactions between development of the gas concentration region and hard roof or floor rockbursts will be obtained numerically to guideline the safety mining in deep high-gas coal mines.

深部高瓦斯煤矿动力灾害表现出了愈演愈烈的新态势：冲击地压（冲击）往往兼具煤与瓦斯突出（突出）的特征，突出往往受冲击诱发；两种动力灾害相伴而生，相互影响，互为诱因，耦合致灾，这给动力灾害预防带来了巨大挑战。掌握采动应力场、裂隙场和瓦斯压力场（三场）的时空演化过程是动力灾害预防的根本，亟待发展行之有效的数值方法。现有的渗流模型难以模拟瓦斯与开裂煤、岩体真正相互作用等问题。认识到煤体的开裂、膨胀→瓦斯的解吸、散出→煤体的进一步开裂、膨胀这一正反馈过程尤为重要。瓦斯积聚区的形成和发展是问题研究的突破口。本申请项目拟发展一种适于模拟采动诱发煤、岩体变形-开裂-运动和瓦斯解吸-散出-积聚-涌出的高效、准确的固-气耦合连续-非连续方法。通过研制带透明视窗的压力室开展必要的含瓦斯煤体破坏过程光学观测。利用上述方法获得三场的时空演化过程、瓦斯积聚区的发展和坚硬顶板或底板冲击的相互影响规律，指导安全生产。

本项目围绕煤矿冲击和突出等灾害问题，采用自主开发的先进力学方法（例如，拉格朗日元与离散元耦合连续-非连续方法和非均匀变形场精细光学测量方法），开展了特色鲜明、创新性较强的算法研究、数值计算研究和实验研究，取得了预期的研究成果。针对冲击问题，在自主开发的拉格朗日元与离散元耦合连续-非连续方法的基础上，考虑了动力学效应，采用朱−王−唐本构模型取代了广义胡克定律，发展了考虑动力本构的连续−非连续方法。针对流-固耦合问题，在拉格朗日元与离散元耦合连续-非连续方法的基础上，考虑了裂隙渗流，发展了一种流-固耦合方法。提出了一种连续-非连续与光滑粒子流体动力学耦合方法。利用拉格朗日元与离散元耦合连续-非连续方法模拟了不同冲击条件下巷道围岩变形-开裂-运动过程。加载条件包括不同冲击速度条件下位移控制加载及周期冲击加载等。阐明了应力波反射和叠加导致洞室顶板开裂机理，解释了洞室两帮拉、剪裂相伴现象的原因。模拟了采动条件下采场岩层变形-开裂-运动过程。模拟结果很好地呈现了煤矿开采中一系列复杂现象，例如，采场上覆岩层的弯曲变形、下沉、开裂、离层和层间错动、直接顶的周期垮落和采空区局部闭合。模拟了断层的应力阻隔效应及滑动过程，定性探讨了开采速度快慢与断层阻隔效应强弱的关系。模拟了切顶卸压自成巷过程，并考虑了锚杆原始支护、锚索补强支护和液压支柱临时支护。利用考虑裂隙渗流的连续-非连续方法，模拟了含单孔洞圆盘水力压裂过程，研究了孔洞直径对水力压裂过程中裂缝扩展的影响。采用一种简化模型，模拟了红菱煤矿石门揭煤时煤与瓦斯突出过程，煤体破裂区近似呈半圆状，瓦斯和煤体射入巷道。为了提高数字图像相关方法对于相似模拟试验过程观测的适用性，提出了基于图像特征匹配算法的可靠子区数字图像相关方法。利用开发的数字图像相关方法，研究了平面应变含孔洞土样（受内压和侧压作用）变形破坏过程；研究了采动诱发断层滑移过程。