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- The longwall may relax some safety problems, but the other safety problems such as hard roof rock, the colliding and friction of the caved rock each other may be induced or intensified . 但是也可能诱发一些安全问题,如坚硬顶板对支架的冲击、采空区垮落岩石的撞击与摩擦诱发瓦斯事故等。
- Discussion on underground longwall mining method for extraction of Indian shallow thick coal seams under hard roof rocks 印度浅埋坚硬顶板厚煤层开采方法探讨
- Hard roof rocks 坚硬顶板
- In mining, if the hard roof is submitted to shear failure, the sidesteps might sink or even collapse. 摘要综放面开采过程中，坚硬顶板超前剪切破坏，会造成工作面台阶下沉，甚至工作面整体垮落。
- The roof rock was assumed in the elastic state,established the mechanical model of coal pillar and roof system. 假设顶板岩层处于弹性工作状态情况下,建立了煤柱-顶板系统的力学模型。
- The hardness and thickness of coal seam play a great role in the vertical distribution of stress in coal and the occurrence of rock bunt under the condition of hard roof and hard floor. 在“两硬”条件下，煤层厚度与硬度的变化对煤体中的应力分布有着很大的影响，从而对煤岩体系统中冲击矿压的发生有着很大的影响。
- The movement of hard roof in manless working face extraction has been simulated with three dimensional distinct element code for dividing into four stages. 分4个阶段模拟了无人工作面开采坚硬顶板采场顶板的运动规律。
- Forward support bolt combined with roop rock by bolting can play a roll of combined beam,which can prevent roof rock caving immediately after explosion. 超前支护锚杆锚固后与顶板岩石构成一体,这样使超前锚杆形成组合梁作用,放炮后,能够阻止顶板岩石冒落。
- Through changing the face support fashion,the hard roof is managed by cutter top supports to increased cutter top resistance in Qitaihe Tiexi Coal Mine. 七台河铁西煤矿通过改变工作面支护方式,使用切顶支架增大切顶阻力来管理坚硬顶板,使坚硬顶板得到了较好的控制,杜绝了顶板事故的发生。
- Hard-top convertibles have become increasingly popular because they offer the top-down fun of a convertible with the quietness and security of a hard roof when the top is up. 硬顶敞篷车开始越来越流行，因为他具备了敞篷车的乐趣和全顶车的安全。
- From whole to blocky and heavily fractured structure, the abutment stress ahead of working face reduces and the peak value of abutment stress migrates to inside of roof rock mass. 过断层后，顶板岩体中支承压力减小，比无断层存在的情况要低。由于顶板岩体中节理发育程度的不同，顶板岩体变形破坏规律和矿压分布各异。表现为由完整到块裂和碎裂结构，老顶的初次垮落步距、周期垮落步距和冒裂带高度均随着岩体破坏程度的增强而减小；顶板岩体中的支承压力亦由大到小变化，且支承压力峰值位置随着岩体破坏程度的增强向顶板岩体内部转移。
- One of the crucial elements influencing the rock burst is the structure of roof rock stratum, especially the flinty and thick sandstone roof over the coal seam. 顶板岩层结构,特别是煤层上方坚硬、厚层砂岩顶板是影响冲击矿压发生的主要因素之一。
- In view of the compound hard roof of Six picks the area,through carrying on the comprehensive servation and the mechanics analysis appeared to pressure appears of the working face production process. 针对复合型坚硬顶板的六采区,通过对工作面生产过程的矿压显现进行了全面观测和力学分析。
- We thus suspected that the collapsed roof rock from one of the two oldest Yellowstone supereruptions must have melted to form the bulk of the magma that was ejected during the younger Lava Creek catastrophe and smaller eruptions since. 我们因此猜测，较年轻的克里克熔岩凝灰岩以及之后的小型喷发，岩浆来源是黄石国家公园两个最古老的超级喷发之一，其崩陷的顶层岩熔成了后来喷发出的岩浆。
- The rock mass structure can be expressed by rock stratum effect thickness influence coefficient. It is more scientific then using roof rock and sand content in the study of coal seam gas preservation. 研究表明,煤层围岩岩体结构控制了煤层瓦斯的赋存,岩体结构可用岩层效应厚度影响系数来表示,应用这一参数研究煤层瓦斯赋存比用煤层顶板岩性及含砂率更科学。
- Gas drainage from roadway in roof rock is used in Yangquan Coal Mining Administration and comprehensive gas drainage based on gas source is used in Songzao Coal Mining Administration. 阳泉局采用顶板岩巷抽放法,松藻局采用针对瓦斯源的综合抽放方法。
- It is hard to sleep without a cooler in this room. 没有空气调节器，在这间屋里很难入睡。
- CONTROL DESIGN OF ROOF ROCKS FOR GOB-SIDE ENTRY 沿空留巷顶板岩层控制设计
- Lately they have been getting into hard rock. 近来他们一直热衷于演奏硬派摇滚。
- John felt it hard to rig out his family. 约翰感到难以为一家大小置备衣着。
