基于激波理论的新兴煤矿煤与瓦斯突出事故研究

通过分析新兴煤矿煤与瓦斯突出事故,发现在事故中由于煤与瓦斯突出事故诱发了激波的生成,瞬间产生的巨大超压,引起风流逆向,大量瓦斯随逆向风流从突出地点扩散传播至二水平,接触卸载巷电机车架空线所产生的电火花,从而引发瓦斯爆炸事故。提出了突出激波对事故的影响并分析了突出激波的形成及其破坏作用,研究了影响突出激波破坏作用的影响因素,得出参与突出的瓦斯量和瓦斯压力是影响激波强度的关键因素。有助于了解突出后的气流动力演化规律,并为煤与瓦斯突出事故的防灾、救灾措施的制定以及提高矿井的抗灾能力提供了参考。     

水平应力对半圆拱形巷道围岩应力分布及变形特征影响

水平应力是影响巷道围岩应力分布及变形破坏特征的重要因素,通过数值模拟方法研究了水平应力对直墙半圆拱形巷道围岩应力场、塑性区、位移场分布规律的影响,进而为确定巷道支护形式提供一定的理论依据。研究表明:影响巷道稳定性的关键因素是巷道周边的环向应力集中,随侧压力系数λ的增大,帮部围岩的竖向应力集中向顶、底板转移,从而引起塑性区向顶、底板转移,塑性区范围向顶、底板围岩内部扩展,巷道稳定性降低。当λ取值不同时,在巷道顶底板会产生相应的环向或径向拉应力区域,在拉伸作用下围岩整体性能降低,易发生压拉破坏。随λ增大,巷道帮部变形量逐渐增大,顶板下沉量先减小后增大最后减小,底鼓量先减小后增大。     

Rockburst hazard determination by using computed tomography technology in deep workface

The rockburst in mines results from the dynamic load coupled with static one in coal seams around workface zones, so it is essential to learn the stress distribution of the coal and surrounding rock for determination of rockburst risk areas. The relationship between the elastic wave velocity and stress applied on coal sample was investigated systematically by laboratory testing, theoretically analysis, as well as on-site observation, and a positive correlation between them under uniaxial compression was put forward. Furthermore, it is drawn that the anomaly of elastic wave velocity reflects the stress changes: the positive anomaly ascertains the stress concentration while the negative anomaly estimates the mining destress and weaken degree, and corresponding assessment criterions and parameters were established respectively. The hazard areas and degree of an island longwall face 16302C were forecasted before coal winning based on the elastic wave anomaly distribution rules using active tremor velocity inversion, monitoring results of mining shocks during exploitation indicate that the consistency between locations of big tremors and where forecasted by computed tomography (CT) exceed 80%. The successful application of this technology achieved remarkable economic and social benefits for disaster control in rockburst mines.     

考虑可靠性的矿井瓦斯传感器选址模型

针对依据现行煤矿安全规程及相关规范布置的瓦斯传感器有可能出现失效的情况,提出兼顾经济性和可靠性双目标的瓦斯传感器优化选址模型。借助图论和设施选址理论,以矿井通风网络节点为候选布置点,节点间的风流流经时间为监测等级,以煤矿相关规程规范硬性要求的布置点为必选点,建立瓦斯传感器多目标优化选址模型。然后,基于Pareto蚁群算法(PACA)阐述模型的求解过程。最后,结合某风网算例,给出模型与算法的具体应用。结果表明:模型的非劣解包含了传统的以最小化传感器成本为目标的选址模型最优解,并且可靠性越高所需的传感器就越多。     

Numerical and experimental study on flame spread over conveyor belts in a large-scale tunnel

Conveyor belt fires in an underground mine pose a serious life threat to the miners. This paper presents numerical and experimental results characterizing a conveyor belt fire in a large-scale tunnel. A computational fluid dynamics (CFD) model was developed to simulate the flame spread over the conveyor belt in a mine entry. Thermogravimetric analysis (TGA) tests were conducted for the conveyor belt and results were used to estimate the kinetic properties for modeling the pyrolysis process of the conveyor belt burning. The CFD model was calibrated using results from the large-scale conveyor belt fire experiments. The comparison between simulation and test results shows that the CFD model is able to capture the major features of the flame spread over the conveyor belt. The predicted maximum heat release rate, and maximum smoke temperature are in good agreement with the large-scale tunnel fire test results. The calibrated CFD model can be used to predict the flame spread over a conveyor belt in a mine entry under different physical conditions and ventilation parameters to aid in the design of improved fire detection and suppression systems, mine rescue, and mine emergency planning.     

非均质软基上桶形基础承载性能有限元分析

作为海洋平台的基础部分,桶形基础不仅承受海洋平台结构及自身重量等竖向荷载的长期作用,而且往往还遭受波浪等所产生的水平荷载及力矩等其它荷载分量的作用.因此,确定软基上桶形基础在竖向荷载(V)、水平荷载(H)和力矩(M)等共同作用下的承载特性,建立其在复合加载模式下的破坏包络面,并进而依此评价海洋平台基础及地基的稳定性,是...     

Y型通风下采空区瓦斯运移规律及治理研究

为了更好的研究Y型通风系统下的采空区的瓦斯流动和涌出规律,针对综放面Y型通风系统特点,建立了Y型通风采空区流场模拟的计算流体力学模型。通过数值模拟,系统研究了Y型通风采空区流场和瓦斯运移规律,对比分析了Y型通风和U型通风条件下的采空区流场及瓦斯运移特征,并将其应用于15120高瓦斯综采工作面的Y型通风系统中,根据现场的实际情况建立对应的CFD模型,得出Y型通风系统下采空区瓦斯流动及分布规律,数值模拟结果与现场大量观测数据相吻合,为瓦斯治理和通风系统优化提供理论依据。研究表明,采用Y型通风系统可消除采空区向上隅角的集中漏风,从而有效解决了U型通风上隅角瓦斯积聚和回风巷中的瓦斯。     

基于瓦斯涌出量预测的近距离煤层群开采顺序优化选择

随着中厚煤层资源的枯竭,近距离薄煤层群开采成为我国资源的重要补充。煤层群开采时合理的采掘部署是防止工作面瓦斯集中涌出的关键,本文通过分析近距离煤层群开采时各回采顺序下工作面瓦斯涌出量,建立了以工作面瓦斯涌出量预测为基础的近距离煤层群开采优化模型,利用计算机编程实现了模型的可视化操作。该模型通过对比分析全部种回采顺序方案,选择整个回采期间瓦斯涌出量最均衡的方案为最优方案。对翔升煤矿进行了实例分析,结果显示合理的回采方案可以使工作面最大瓦斯涌出量大大减小,使整个回采期间工作面瓦斯涌出量趋于均衡。为煤层群开采优化技术中的瓦斯环节提供了理论依据。     

基于性能化防火设计的建筑“准安全区”判定方法

为判定人员疏散过程中"准安全区"的安全性,采用基于性能化防火设计的方法对建筑"准安全区"的安全性进行判定。"准安全区"内烟气热辐射、烟气能见度及有毒气体等有害因素的指标必须达到"准安全区"规定的指标要求。发生火灾时,"准安全区"内距离地面2 m以下烟气层温度不应超过60℃,烟气层能见度不应小于10 m,烟气层CO浓度不应大于5×10-4mol/mol。工程应用中可根据"准安全区"各性能判定标准,通过火灾模拟软件模拟分析火灾场景下"准安全区"内各有害因素的性能参数分布,对"准安全区"的安全性进行定性、定量评估。     

HG减阻剂评价及现场试验研究

对HG减阻剂进行了元素分析、加入柴油中的指标评价及台架试验和行车试验。结果表明,在柴油中加入50 mg/L的减阻剂,对于车辆整体性能无明显规律和影响,对于车辆与国家相关标准的符合程度没有影响。在洛郑驻成品油管道进行了现场试验。加减阻剂10 mg/L,柴油输量可增加30%,作用效果优于原油管道。加减阻剂量8 mg/L,雷诺数为52 411、70 940和78 087时,对应的增输率分别为26.8%、30.2%和38.6%。