查询词典 roof caving

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。

Analyses factors that affect cover caving ability of roof coal in sublevel caving mining method.

分析了放顶煤开采顶煤冒放性的影响因素。

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。

With the increasing of the bedrock thickness, pressurized pace was increased gradually, the roof caving and surface subsidence were gentled step by step. When the thickness of roof bedrock was larger than 60m, the bench subsidence was not occurred, and the value of surface subsidence was also small. The mining technology was proper and highly active, and the support programme was feasible. The roof was controlled effectively by the support system, and achieved safety mining.

随着基岩厚度的增加，顶板来压步距逐步增加，顶板垮落与地表下沉越来越缓和，基岩厚度大于60m时，顶板来压不再出现台阶下沉，地面下沉量较小；针对不同厚度基岩提出的采煤方法合理，高效，支护方案可行，能够有效控制顶板，实现安全生产。

Roof control ; Underground continuous mining ; Natural caving property ; Artificially induced caving ; Time sequence system

顶板控制；地下连续开采；自然崩落性；人工诱导崩落；时序系统

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。

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。

The top coal fracture is described distinctly under the condition of different roof span and mining technology parameters. Through orthogonal experiment of numerical simulation, the rational pretreatment span of hard roof is determined, and the rational working resistance of support is selected also. As a result: the hard roof is effectively controlled not only to protect the working face but also to promote the caving of hard top coal to increase the recovery ratio.

在有效控制坚硬顶板的基础上，利用数值模拟正交试验法，研究了采高、采放比、支架阻力、放煤步距等工艺参数对顶煤压裂效果的影响规律，从而对工作面工艺参数进行优化；并根据实验所得放煤方式对块体顶煤的适应性规律，选择&两硬&综放面的放煤工艺，从而形成了系统、完善的&两硬&条件综放工艺。

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。

In order to study basic roof's destruction movement that affects working face in horizontal section top coal caving in mining steep seams, this paper analyses tension of roof using elastic and thin board theory and concludes criterion of roof destruction based on long and narrow thin board.

摘要为研究急斜煤层水平分段放顶煤开采过程中基本顶破坏活动对工作面的影响，根据急斜煤层基本顶具有倾斜狭长板的特点，运用弹性薄板理论对基本顶岩层进行了拉应力分析，得出了顶板破断的判别准则，建立了基本顶初次破断后形成的&铰接结构&的力学模型。

It is also known as one of the most poisonous naturally occurring substances.

它也被称为一个最自然发生的有毒物质。

The greatest stress is found at the location on the cross section where V is the largest.

最大应力出现在横截面上V为最大的地方。