【作者】 姚强岭；

【导师】 曹胜根； 李学华；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2011， 博士

【摘要】 当煤矿巷道顶板围岩含水时,在开挖和服务期间,巷道顶板岩石吸水或失水过程中将会导致其强度和完整性显著弱化,严重时发生围岩大变形、甚至冒顶,严重影响矿井的安全生产。因此,开展富水巷道顶板强度弱化机理及其控制研究,具有重要的科学与工程意义。论文在现场调查了富水巷道工程地质特征、变形破坏因素以及顶板强度弱化特征的基础上,提出了富水巷道的概念,并解释了其含义和特点。针对典型的富水巷道顶板条件,对富水巷道顶板的岩层矿物组分、微结构特征,及其软弱岩层的物理性质弱化规律、不同含水状态下含水砂岩强度损伤特征,以及含水砂岩的分类进行了系统研究,发现富水巷道顶板岩层富含粘土矿物且粒间孔隙较为发育、连通性好,遇水后强度降低,这是富水巷道顶板围岩强度弱化的内在影响因素。并根据含水砂岩不同含水状态下的声发射特征,提出了富水巷道顶板稳定性预测预报的技术原理。应用弹塑性理论的基本知识,对富水圆形巷道在无支护、锚杆支护下围岩塑性区半径和位移进行了理论研究,发现水作用下巷道塑性区半径及位移较无水状态下增大,并分析得到了富水巷道塑性区半径和位移与原岩应力、支护强度、原始渗透水压力、有效水压力系数以及内聚力之间的变化规律。现场钻孔探测与COMSOL3.5a多场耦合数值模拟相结合,详细研究了顶板强度弱化规律,发现水作用下富水巷道顶板裂隙在掘进稳定期间仍在扩展发育,且顶板下沉量随着岩石含水率增加而逐渐变大,从而揭示了富水巷道顶板强度弱化的基本原理和规律。以富水巷道顶板遇水前后物理力学性质特征、直接顶岩性以及顶板水赋存层位为依据,建立了富水巷道顶板不同顶板条件下的分阶段控制技术体系;现场实测和数值模拟发现富水巷道顶板水赋存层位岩石裂隙较为发育且顶板水具有可控性的特点,提出了有控疏水、合理保水技术以减少顶板水对岩石侵蚀弱化作用和提高围岩自身强度的基本思路;利用FLAC模拟研究得到了富水巷道顶板锚杆支护主要技术参数。更多还原

【Abstract】 When the surrounding rocks of roadway roof contain water in coal mine, the strength and integrality of roof rocks would be weaken significantly in process of wa-ter absorption and loss, large deformations of surrounding rocks even roof-fall acci-dent which have a strong impact on safety production of the mine will happen in se-vere case. Therefore, researches on strength weakening mechanism and control of water-enriched roofs in mine roadway will have an important science and engineering significance.Based on field investigation of engineering geological characteristics, deforma-tion destruction factors and roof strength weakening characteristics in water-enriched roadway, the concept of water-enriched roadway is put forward by this paper. In the meanwhile,this paper explains the meanings and features of water-enriched roadway.Aiming at the condition of roof in representative water-enriched roadway, the systematic researches about rock mineral components, microstructure characteristics, physical property and weakening rules of weak strata, the strength damage features of water-bearing sandstone under different water-bearing states and classification of wa-ter-bearing sandstone have been done in the laboratory. It is found that the roof strata in water-enriched roadway is rich in clay mineral with developmental intergranule pores and good connectivity, its lower strength after encountering water is the internal influence factor for strength weakening of roof. According to AE features of wa-ter-bearing sandstone under different water-bearing states, this paper presents a tech-nical principle of roof stability forecast in water-enriched roadway.Basic knowledge of elasto-plasticity theory is applied to research plastic zone ra-dius and displacement of surrounding rocks in water-enriched circular roadway under the condition of no support or anchor bolt support. It is found that plastic zone radius and displacement under the effect of water is bigger than the case without water. The change rules between plastic zone radius, displacement and in-situ stress, support strength, original seepage water pressure, effective water pressure coefficient, cohe-sion are analysed in water-enriched roadway. Roof strength weakening rules have been researched in detail by field hole detection combined with COMSOL3.5a mul-ti-field coupling numerical simulation software. Results indicate that roof fractures are still expanding and developing at stability period of excavating under the effect of water in water-enriched roadway and roof convergence increases gradually along with the augment of rock water ratio. Thus the basic principles and rules of roof strength weakening in water-enriched roadway are given by this paper.According to the roof physical mechanical properties of pre and post encounter-ing water, lithology of immediate roof and occurrence horizon of roof water, control technique system by roofs and by stages in different regions of water-enriched road-way is established by this paper. Results of field measurement and numerical simula-tion show that the rock fractures in occurrence position of water which has controlla-bility develop a lot, hereby the thinking of controlled drain and reasonable wa-ter-preserved technology is put forward to decrease the erosion weakening effect of rocks with water and increase own strength of surrounding rocks. FLAC simulation software is used to determine the main technological parameters of roof bolt support in water-enriched roadway. Field application shows that this coal mine gains fairly good technical and economic effect by the research achievements from this paper.更多还原