查询词典 roof caving

Supporting type is suggested to be developed into 3-prop to improve adaptability besides 2-prop and 4-prop. The difference of caving difficulty degree of coal seam is the base of caving coal method at high, medium and low position. Caving with small step and open caving flashboard used widely not only cause serious mixture of coal and rock but also hinder the improvement of top coal recovery. So we suggest caving with large step or closing caving door. Four-bar-mechanism of hydraulic support restricts development of new style caving powered support. Stabilization framework of expansion link and all-shield caving tail beam at high, medium and low position are introduced here.

支架支护型式，除了两柱、四柱以外，建议开发三柱支架以改善适应性；煤层冒放性的差异，是高位、中位和低位放煤方法存在和使用的依据；目前广泛采用的小步距放煤和开放式放煤插板不仅造成严重混矸漏矸，也妨碍顶煤回收率的进一步提高，建议采用大步距放煤和可关闭放煤口；液压支架四连杆稳定机构，制约了新型放顶煤液压支架的开发，介绍了液压支架伸缩杆稳定机构及全掩护拖移高位、中位和低位放煤尾梁。

Aiming at bottom roof caving and support impact problems induced with abrupt large scale caving upper roof in face 21303 of Daliuta mine, this paper put forward the motion parameter at roof caving and calculation formula of roof shear breaking force with the help of theorem of momentum, theorem of moment of momentum and D' Alembert principle. Roof caving process was simulated by Ansys Ls-DYNA program, and maxim impact force was got. The theoretical research outcomes in the paper were applied in face 21303 of Daliuta mine, and were accordant with actual observing status of roof caving process.

针对神东煤炭公司大柳塔煤矿活井21303综采工作面，上层采空区顶板突然大规模垮落对下层顶板及支架的突然冲击问题，文章采用动量定理、动量矩定理、达朗伯原理推出了顶板垮落瞬间的运动量及顶板切顶垮落所需要的剪力值计算公式，用ANSYS LS-DYNA程序对顶板垮落过程进行了数值计算，得到了最大冲击力，在大柳塔煤矿活井21303综采工作面对顶板垮落特征进行了实际观测和理论成果验证。

The trial results show that with the disposal of induced caving roof by presplitting blasting and induced caving roof blasting, about 17.8 m in thickness of rock cushion is successfully formed in the inferior abandoned stope, which can bring down the harm of dashing blast of an explosion caused by roof collapse; apparent run-through flaws arise between presplitting blasting holes, and controllable caving is formed in the roof, abrupt collapse of large area roof is prevented, the productional safe surroundings of underground mining is improved; eventually, the resources' reclamation rate is improved from about 70% to 84.6%, and the dilution rate is abated from 25%40% to below 15%, so efficiently withdrawing is actualized.

试验结果表明：采用预裂爆破与诱导崩顶爆破的方法，通过对顶板的诱导崩落处理，成功地在下方采空区形成了厚度为17.8 m左右的岩石缓冲垫层，有效地降低顶板冒落带来的冲击气浪危害；在预裂孔间产生明显的贯通裂隙，从而在顶板上形成诱导可控崩落，防止顶板大面积的突然垮落，改善地下开采安全生产环境；最终资源的回收率由70%左右提高到84.6%，贫化率由25%~40%降低到15%以下，实现了资源的高效回收。

Through the comparison between at home and abroad, caving has developed on the stage of mature, organization and implementation of caving is perfect, the participants includes not only professional researchers but also a avocational lovers, the caving in our country is in its developing stage, and the caving technology and equipments are backward, caving security system is not complete, the participants are only the professional researchers and has not reach the stage which is popular.

通过对国内外洞穴探险发展的对比研究，指出洞穴探险在国外已经发展到了成熟阶段，洞穴探险的组织实施以及洞穴探险保障体系也发展地较为完善，参与洞穴探险的不仅仅是洞穴研究人员，更多的是业余的洞穴爱好者。

The text obtains some data that caving span of immediate roof is 30m, caving span of main roof at first weighting is 42m and caving span of main roof at periodic weighting is 14m. Mining influence range is determined about 40m through numerical modeling, namely about three advance pillars were in the range of mining influence.

利用数值模拟得出煤柱采场直接顶的垮落步距为30m，老顶的初次来压步距为42m，老顶的周期来压步距为14m；通过模拟超前支承压力，确定了采动影响范围约为40m，即采场超前的三个煤柱都在影响之内。

It is important to reduce the span of the hard roof to avoid its impact load on supports. However, at longwall top coal caving face, the periodical weight of roof is a main factor that crushes the top coal, which is beneficial to the top coal recovery. How to use the roof pressure safely is of crucial importance in top coal caving. Based on field monitoring, theoretical analysis of strata movement, the numerical model of compound structure of hard roof stepped cantilever and the top coal cantilever beam is built, and the parameters of the model are also determined. The elasto-plastic finite element method is used to analyze the effect of hard coal fracture under the abutment pressure of hard roof, and the cracking coefficient is defined according to the stress state of the element.

通过对岩层移动的现场观测，建立了&两硬&条件综放采场台阶悬臂—悬臂梁组合的煤岩组合结构力学模型，并以此煤岩结构为基础，建立&两硬&条件综放采场顶煤压裂的有限元数值模型，分析了坚硬顶板不同来压步距对坚硬顶煤的压裂效应，并确定了合理的支架阻力，从而对坚硬顶板进行有效的控制，消除坚硬项板对采场的冲击隐患，同时保证采场矿压对坚硬顶煤的有效压裂，达到提高顶煤回收率之目的，由此形成了坚硬顶煤、坚硬顶板条件下综放采场围岩控制的基本理论和方法。

A systematic study is made on the underground continuous mining of No.3 thick and low grade orebody of a nonferrous metal mine by a simulation test with similar material and by FLAC-3D method,including the study on the natural roof caving,the time-sequence system of artificially induced roof caving and the roof stress cha...

利用相似材料模拟试验和FLAC-3D研究方法，对某有色金属矿山厚大、低品位的3#矿体的地下连续开采进行了系统研究，包括矿体顶板自然崩落性、顶板人工诱导崩落时序系统以及开采过程中顶板应力变化规律的研究。

Common form of the roof surface: arch roof , shell-shaped roof of shoes, V-shaped hull roof , flat roof shell, wheel-shaped cable roof , saddle -shaped roof .

曲面屋顶常见形式有：拱屋顶、球鞋形网壳屋顶、V 形壳屋顶、扁壳屋顶、车轮形悬索屋顶、鞍形屋顶。

The cast-in-place reinforced concrete spatial core beamless roof is one kind of new beamless roof system, it is self-possessed lightly, the span is big, after is continues the belt capital of column the beamless roof, the plate beamless roof, the dense rib beamless roof, complies with the time to the beamless roof system request new beamless roof system, at present already entered the use in some engineering project upthrow, has obtained the good economic efficiency and the social efficiency.

现浇钢筋混凝土空心板无梁楼盖是一种新型的无梁楼盖体系，它自重轻，跨度大，是继带柱帽的无梁楼盖、平板无梁楼盖、密肋无梁楼盖之后，顺应了时代对无梁楼盖体系要求的新型无梁楼盖体系，目前已经在一些工程项目上投入使用，取得了良好的经济效益和社会效益。

On the practice basis of fully mechanized sublevel caving of hard and thick coal, a discrete element software was used to do simulation test and influence of crack in process of mining coal on the top-coal caving and the development process of the fracture were analyzed, which could be used to determine the top coal caving characteristics.

分析了倾斜厚煤层顶煤裂隙和顶煤可放性的影响因素，在硬、厚煤层综采放顶煤现场实践的基础上，运用离散元软件进行了模拟试验，分析了煤层在采动过程中形成的裂隙对顶煤冒落的影响以及裂隙的发育过程，据此判断顶煤的冒放性。

The network space is the typical form of abstract space when it comes to the digital stage.

网络空间是抽象空间数字化阶段的典型形式。

The Notarial System,as the system of judicial certification in our country,is both the constructor and the defender of social credit system,It has its special value and function in the social honesty.

公证制度作为我国司法证明制度，既是社会信用体系的建设者，同时也是社会信用的捍卫者，在诚信中有其特殊的价值和功能。