石膏矿采空区稳定性主要影响因素正交试验研究

采用房柱法开采的石膏矿山,采空区稳定性的主要影响因素为矿柱和护顶层。基于Bieniawski矿柱强度公式和＂伏萨尔梁＂概念对矿柱的安全系数和护顶层抗压缩破坏安全系数进行了计算,并采用正交试验方法,对影响矿柱及护顶层稳定性的各因子进行了敏感度分析。结果表明：矿柱稳定性的主要影响因子为矿柱尺寸,其次为上覆岩层厚度;石膏护顶...     

矿柱破坏原因分析及加固方案设计

结合广东某铁矿矿柱破坏的实际情况,在现场调查的基础之上,采用有限元数值方法对矿柱破坏原因进行了分析。分析表明,矿柱自身地质条件较差(节理裂隙过多)、采场结构参数不合理等是导致矿柱破坏的重要因素。设计了喷射混凝土+锚杆的加固方案。加固方案在矿山实施后,解决了采场出矿难的问题,取得了较好的应用效果。     

空场采矿法间柱与顶柱回收方法应用

密云铁矿经多年开采,即将由露天转入地下开采。在露采转入地采的过程中,挂帮矿体采用了分段凿岩阶段空场法开采,回采结束后形成了体积约52 500 m3的空区,并留下了大量矿柱,总矿量达40多万t,随着时间延长,地压不断增加,矿柱已出现局部冒落破坏,随时会有冲击地压的产生,而以下矿体又改用无底柱分段崩落法,在崩落法正是回采前,需对采空区处理并回收矿柱遗存矿量。针对密云铁矿挂帮矿开采所留间柱与顶柱回收问题,从回收方法、爆破方案和回收顺序进行了分析探讨,并对全部遗留矿柱进行成功回收。     

间隔人工间柱留矿全面采矿法在倾斜中厚金矿体的应用

本文介绍间隔人工间柱留矿全面采矿法的特点及其在倾斜中厚金矿体的应用简况,并对该法进行评价.     

我国锰矿地压的基本问题与解决途径

以缓倾薄层锰矿床的地层特征，原岩应力等的基础，简述了锰矿床开采技术特征，采矿方法及相应地压活动规律与现状，针对花垣，遵义，鹤庆，斗南等锰矿山由房柱法开采年引起的地压隐患，提出了相应的原则与方法。     

黄土坡体上储煤仓保护煤柱的留设研究与实践

在黄土丘陵地区进行煤炭开采,常常会引起山体滑坡、崩塌等次生灾害,本文以位于黄土坡体顶部储煤仓保护煤柱留设的实践为例,针对储煤仓区域地形特征、煤炭开采条件,对坡体地表受煤炭开采影响的移动、变形特征进行了对比分析,提出了储煤仓保安煤柱加坡体防滑煤柱的联合防护方法,采用开采影响移动角法确定了防滑煤柱尺寸,开采实践证明受护坡体未产生滑坡且储煤仓保持了安全正常使用,留设坡体防滑煤柱的方法是有效的。     

Fracture toughness of single grains and polycrystalline Li7La3Zr2O12 electrolyte material based on a pillar splitting method

In the present study an advanced pillar splitting method is used to determine the fracture toughness of a garnet-type Li₇La₃Zr₂O₁₂ (LLZO) electrolyte. The obtained results are compared to data derived on the basis of conventional Vickers indentation. Furthermore, potential micro-pillar size effects are investigated. The estimated fracture toughness values for single grains and polycrystalline LLZO material obtained via both methods are in good agreement, yielding ∼ 1 MPa m^0.5, hence the data indicate that LLZO exhibits relatively low fracture toughness and has a brittle behavior.     

Pillar[n]arenes at the Chemistry-Biology Interface

Macrocyclic chemistry has provided chemists with a wealth of molecular ‘hosts’. Ever since resurgence in the field during the 1970s and 1980s these hosts’ similarities to natural structures, such the active sites of enzymes, have been noted. Latterly there has been great interest in the recently reported pillar[n]arenes. As if to underline the importance of these compounds, exciting applications are starting to emerge, from electrochemical sensors to antimicrobial agents. Novel uses appear destined to have an impact on clinical conditions from Alzheimer's disease to cancer treatment. In order to demonstrate the impact of pillar[n]arenes across the chemistry-biology interface this review will cover the current state of the art from biomimicry and analyte-specific detection to emerging clinical applications. Examples include pillar[n]arene-based ion channels, enzyme-responsive compounds, imaging agents, biofilm inhibiting derivatives, drug complexing and drug releasing systems.     

A review of energy associated with coal bursts

A coal burst is defined as a rapid expulsion of coal(and potentially gas) from the boundary of the roadway. Rock and coal fractures together with micro seismic vibration is a common occurrence during mining, however, it is very uncommon for coal and rock to be propelled into the roadway. Irrespective, such occurrences do occur and appear to require significantly more energy than is available from strain energy release during coal cutting. The sources of energy which can contribute to the propulsion of coal from the face or ribs are typically strain energy from the surrounding ground, seismic energy from a rapid rupture of the ground in the vicinity, or rapid expansion of gas from within the burst source area. The aim of this paper is to briefly review the bursts which may be related to strain energy, seismic energy and gas energy.     

清式硬山墀头的设计与施工技术

清式硬山建筑山墙在檐柱以外的部分现均叫做墀头。墀头分为上、中、下三个部分。本文通过介绍墀头尺寸的确定；盘头、戗檐的设计；墀头设计举例；盘头、戗檐的加工及砌筑；墀头内侧（腮帮）做法等，全面讲解了清式硬山墀头的设计与施工技术。