Statistical analysis of causes and countermeasures to the accidents in coal mines

Statistics and analysis was made in causes, places and proportions about all kinds of disasters and accidents in coal mines of China in resent 50 years. The analysis indicates the emphasis reason that result in the accidents in coal mines are artificial cause explosion of mash gas and coal dust, water flood, fire hazard. The accidents mostly happened on stope which is more often than other places, following by the driving work face. This not only supplies the managers with basic reference about safe administration, but also suggests the countermeasures in reducing accidents： improve the disposition of person, perfect all kinds of rules and regulations, severely investigate, analyze and deal with the accidents.     

张峰水库大坝黏土心墙填筑碾压试验及施工参数确定

针对张峰水库大坝黏土心墙填筑设计标准,通过现场碾压试验,取得黏土填筑施工工艺及参数,为水库大坝黏土心墙填筑施工提供依据。     

汾河二库枢纽工程的质量控制

汾河二库枢纽工程拦河大坝为碾压砼重力坝，最大坝高８８ｍ，总库容１．３３亿ｍ３，电站装机容量９６００ｋＷ。按照监理合同，山西省水利水电工程建设监理公司汾河二库监理部承担全部枢纽范围的工程项目施工监理任务，对大坝工程、发电厂房工程和机电金属结构工程的建筑...     

逆断层附近非均匀应力场声发射测试与巷道稳定性数值分析

由于断层带附近应力集中和围岩破碎严重给巷道断面布设和维护带来巨大安全隐患,需及时掌握断层附近地应力分布和围岩破裂形式及其对周边巷道稳定性影响。选取淮南某矿逆断层上、下盘进行试验,利用MTS试验系统配合声发射测试初始地应力场和岩石破裂方式,经ANSYS对比分析不同应力条件下逆断层附近巷道稳定性。经岩石力学试验发现,砂岩破坏后尺度较小、AE事件数较多,泥岩破坏后尺度较大、AE事件数较少。由地应力实测可知,逆断层附近以构造应力为主,上盘岩层挤压使得下盘总体受力偏大。开挖后巷道周边次生应力在一定范围内出现了应力跌落区,跌落区范围和围岩裂隙发育范围接近。同时,伴随着应力跌落的范围扩大、初始应力减小,岩层开始移动剧烈和围岩破裂范围扩大。由围岩塑性分布和岩层移动可知,调整后主应力有助于提高巷道稳定性。以上研究结果,以期为复杂埋藏环境下矿山巷道的布设和支护问题,提供一定的施工技术依据。     

Synergistic Effect of Atmospheric Pressure Plasma Pre-Treatment on Alkaline Etching of Polyethylene Terephthalate Fabrics and Films

Dyeing of PET materials by traditional methods presents several problems.Plasma technology has received enormous attention as a solution for the environmental problems related with textile surface modifications,and there has been a rapid development and commercialization of plasma technology over the past decade.In this work,the synergistic effect of atmospheric pressure plasma on alkaline etching and deep coloring of dyeing properties on polyethylene terephthalate(PET)fabrics and films was investigated.The topographical changes of the PET surface were investigated by atomic force microscopy(AFM)images,which revealed a smooth surface morphology of the untreated sample whereas a high surface roughness for the plasma and/or alkaline treated samples.The effects of atmospheric pressure plasma on alkaline etching of the structure and properties of PET were investigated by means of differential scanning calorimetry(DSC),the main objective of performing DSC was to investigate the effect of the plasma pre-treatment on the T_g and T_m.Using a tensile strength tester YG065 H and following a standard procedure the maximum force and elongation at maximum force of PET materials was investigated.Oxygen and argon plasma pre-treatment was found to increase the PET fabric weight loss rate.The color strength of PET fabrics was increased by various plasma pre-treatment times.The penetration of plasma and alkaline reactive species deep into the PET structure results in better dyeability and leaves a significant effect on the K/S values of the plasma pre-treated PET.It indicated that plasma pre-treatment has a great synergistic effect with the alkaline treatment of PET.     

不同骨料混凝土屏蔽性能的MC法模拟研究

为研究不同骨料对混凝土的屏蔽性能的影响,利用MCNP5模拟~(137)Cs源放出能量为0.662MeV的γ射线穿过不同骨料的混凝土试块,得出出射能谱、线衰减系数、透射率及半衰减厚度,并利用γ射线屏蔽实验进行了验证。结果表明:MCNP5模拟计算的线衰减系数和实验测得的数据最大相对误差仅为3.17%,说明MC法模拟不同骨料混凝土屏蔽性能是可行的。结果为混凝土屏蔽性能的探索提供了模拟试验支持并对以后新型屏蔽混凝土骨料的研究具有重要指导意义。     

影响煤巷锚杆支护初锚力的主要技术因素分析

对锚杆支护初锚力的作用、工程中锚杆支护初锚力的状况和影响因素进行了详细分析,并基于分析和工程实例提出了提高锚杆初锚力的方法与原则,取得了较好的效果。     

UML活动图在物流业务流程分析中的应用

大多数物流企业的业务流都采用传统的数据流图方法,造成了物流企业资源分配上的不均匀,使用户 和管理人员难以相互沟通.在以建立我国商务车队的管理系统为最终目的的背景下,将北京市某物流企业作为 研究对象,在进行较为详尽的调查基础上,运用UML(unified modeling language)语言进行了业务流程分析,明析 物流企业的业务流程.为进一步建立商务车队管理软件奠定了基础.     

极坐标下圆形孔硐蝶形塑性区分布特征与扩展规律

针对埋深大、采掘工程和构造区附近的巷道或硐室围岩会形成蝶形塑性区的问题,采用理论计算和计算机编程的方法从极坐标下圆形孔洞围岩塑性区形成和发展的角度出发,阐述了圆形孔洞围岩塑性区形成的力学机制,分析了圆形孔洞围岩塑性区不同的几何形态和范围,重点研究了蝶形塑性区形成、发展及边界扩张的空间演化规律,并探讨了影响蝶形塑性区分布的关键因素和各因素之间的变化特征对蝶形塑性区的影响程度和工程危害。研究发现:孔洞围岩形成蝶形塑性区后,当埋深、孔半径,内摩擦角和黏聚力参数不变时,随着侧压系数从0.4减小至0.3,蝶形塑性区边界从1.43 m增加至3.22 m,随着侧压系数继续的微小变化从0.3减小至0.2,蝶形塑性区边界从3.22 m呈对角线成倍发展扩张至12.27 m,蝶叶扩张至无限大后消失,其中蝶叶扩展影响因素按程度从大到小依次划分为侧压系数、埋深、孔半径,内摩擦角和黏聚力。研究成果为矿山、水利水电、隧道、油气勘探等深部工程稳定性分析及其控制提供了理论依据。     

商品混凝土在施工中出现裂缝的成因及控制

我们在新疆康尔勒市××工程施工中,针对工程中出现的结构裂缝,及时处理,将裂缝基本消除,质量经验收合格,受到各方的好评。一、出现裂缝的原因1.混凝土裂缝的概念混凝土裂缝出现的原因较复杂,不便一概而论。首先要弄清,什么是裂缝,如何正确认识混凝土裂缝和处理裂缝。