Theoretical Investigation on Vertical Additional Force on Shaft Lining in Special Stratum

The model of skaft lining under force is developed on the basis of the special stratum condition led to sbart cracking- The model is broken into 3 sub-questions to solve separately. According to the principle of superposition and strain compatibility, a second kind Fredholm integral equation is generated.A theoretical solution to vertical additional force on shaft lining is obtained by numerical method to the integral equation.

Prediction and safety analysis of additional vertical stress within a shaft wall in an extra-thick alluvium

An alluvium with a sandy aquifer at the bottom,but lacking an effective impermeable layer between the sandy aquifer and bedrock is referred to as a special alluvial stratum.Impacted by the drainage of the aquifer due to mining activities,a shaft wall in this special alluvial stratum will be subject to a downward load by an additional vertical force which must be taken into consideration in the design of the shaft wall.The complexity of interaction between shaft wall and the surrounding walls makes it extremely difficult to determine this additional vertical force.For a particular shaft wall in an extra-thick alluvium and assuming that the friction coefficient between shaft wall and stratum does not change with depth,an analysis of a numerical simulation of the stress within the shaft wall has been carried out.Growth and size of the additional vertical stress have been obtained,based on specific values of the friction coefficient,the modulus of elasticity of the drainage layer and the thickness of the drainage layer.Subsequently, the safety of shaft walls with different structural types was studied and a more suitable structural design,providing an important basis for the design of shaft walls,is promoted.

THE MINED NONLIEAR STUDY OF MEASURING METHOD AND CALCULATION ABOUT STRESS AND STRAIN IN THE VERTICAL SHAFT AND SURROUNDING ROCK

The damage of the overburden is a complex nonliear mechanical problem. To immediately master the stress state of the vertical shaft in process of the damage of overburden, and protect the shaft, in this paper, a series of new type of rock mass stress and strain compatible sensors are used. The vertical shaft wall mechanical parameter and surrounding mechanical parameter are calculated by the result of the measurement. A set of the calculation method of the vertical shaft and surrounding rock parameter are defined.

THE MEASUREMENT AND STUDY OF BLASTING VIBRATION AFFECTING IN SITU CAST CONCRETE LINING OF VERTICAL SHAFT

Vertical shaft is main form of drivage in deep mineral depoist. They also serve as the entrance into and the exit from the underground mine. The main problems in shaft and tunnel engineering is to solve the contradiction between drivage and lining. The measurement of blasting vibration affecting concrete lining strength of vertical shaft is carried out in experiment and theory in this paper.

Study on optimal design of vertical-shaft mechanical mixer based on numerical simulation of flow field

In the paper the three-dimensional flow fields are numerically simulated in the vertical-shaft mechanical mix tank of a water treatment plant by means of FLUENT software based on the method of Computational Fluid Dynamics (CFD). The influences of design parameters on flow fields and the mixing effect are analyzed. Firstly,the prediction capability of the turbulence model adopted in simulations is evaluated. And then,the mesh independence is checked up. Finally,the flow fields in various dimensionless blade diameters and dimensionless shaft spans are numerically simulated respectively. The results have shown that the numerical simulation method based on CFD is a feasible assistance for the optimal designs of mixers. Moreover,the optimal design of the blade diameter should take into account both the flow field and the power consumption. The optimization of the shaft span is to achieve a relatively even distribution of the flow field without any rupture. With the consideration of an optimal design,the dimensionless blade diameter and dimensionless shaft span should be 0.45 and 0.57 respectively in the case.

Numerical Simulation and Reinforcing Technology Research on Collapse of Weak Interlayer Shaft

The three-level shaft of the mixed pit shaft of Yixin Mine,built in 1983,failed continuously due to the influence of geological structure and the effect of water,which formed a collapsed space with a length of 18m,a depth of 12m,and a height of 12m at the level of-255m and to the southwest end.The 54m pit shaft below the-258m elevation of the pit shaft was filled with collapsed rocks forming a large loose body.The comprehensive processing plan for falling grouting and anchoring was proposed according to the geological conditions of the vertical shaft of the mixed pit shaft,adopting three-dimensional numerical simulation software as well as calculating the mechanical state of the vertical pit shaft surrounding rocks and using 3 to 5 parameters of Williams-Warnke failure criterion.

Hydraulic Fracturing Stress Measurements and Their Implication for the Design of the First Concrete Lined Pressure Shaft in Sri Lanka

The Urea Oya Multipurpose Development Project （UMDP） is a water transfer, hydropower and irrigation in the south-eastern part of the central highland region of Sri Lanka. During geotechnical site investigation program 42 hydraulic fracture tests and 42 impression packer tests were carried out in 3 boreholes to about 840 m depth. Based on the stress measurements the minimum and maximum horizontal stress ratios were calculated. In situ stress computations at all the tests were based on the assumption that the principal stress components were vertical （σv） and horizontal （σH and σh, the maximum and minimum, respectively）. The results of the measurements had a direct impact on the design of the major openings bearing a high overburden--the underground powerhouse and the transformer cavern--and revealed a significant optimization potential concerning the selection of the lining system of the pressure shaft.

城市浅埋隧道自然排烟竖井临界间距研究

竖井间距会改变竖井内外压差,当竖井内外压差为0时,隧道火灾烟气将无法排出,此时竖井对应位置为竖井临界间距。由竖井内外口压差理论分析,给出竖井临界间距理论模型,再采用FDS模拟进行仿真验证。结果表明:设置竖井可明显降低隧道温度,竖井间距为临界间距时,温度下降幅度接近150℃,人员疏散路径温度低于60℃,竖井排烟效率在55%~80%,可有效进行竖井排烟;当竖井间距大于竖井临界间距时,隧道内烟气压强小于竖井出口处风压,竖井排烟效率低于50%。

地下工程竖井定向连接四边形法最优图形分析

为了提高地下工程竖井定向精度,阐释了连接四边形法竖井定向方法,用一个角和一条边为参数确定对称四边形,构建了连接四边形严密平差模型,采用间接平差进行网形精度评估。编写程序遍历条件角和条件边计算定向边精度,绘制等值线,定量分析连接四边形法最优图形。该研究对于地下工程竖井定向具有实际应用价值。

黄金矿山深井开采研究进展与发展趋势

详细阐述了黄金矿山深井开采国内外研究现状及所面临的技术难题,围绕采动岩石力学理论、岩体结构识别与岩体质量分级、矿山三维工程灾害建模、深部采矿设计方法研究、深部采场爆破落矿技术、采动地压调控、采动地压监测、自承载主动释压支护技术、深部采动对地表岩移影响、通风降温技术、智能开采技术、超深竖井建设等展开了详细的讨论与分析;对于黄金矿山非爆采矿机器人研制、采动岩石力学、深部采动地压灾害防控、深井降温技术、超深竖井建设、基于采动地压均衡的深部连续智能化开采技术等方面的未来发展趋势提出了展望,为黄金矿山深井开采的系统研究提供参考依据。

考虑松动圈影响的公路隧道大直径竖井围岩压力计算方法

为研究公路隧道大直径竖井围岩压力计算方法,基于极限平衡法推导,并与官田竖井实测数据进行了对比验证,最后分析了竖井直径、侧压力系数、围岩等级对竖井围岩压力的影响规律。结果表明:①与实测数据对比结果显示,本文公式的平均误差度在12.85以内,相比其他公式的误差度在180以上,使相对误差减小了167.15以上,可指导工程人员进行竖井的施工设计;②竖井开挖直径越大,竖井井壁围岩压力越大,但是围岩压力的增长幅度随直径增大而逐渐减弱;③在未达到极限深度之前,侧压力系数越大,竖井井壁围岩压力越大;达到极限深度以后,不同侧压力系数下井壁的围岩压力一样大。侧压力系数越大,井壁围岩压力随竖井深度的增长越大,更快达到最大井壁围岩压力,即极限深度越小;④围岩等级越高,竖井的井壁围岩压力越小,在达到极限深度之后的围岩压力也越小。

超深基坑吊脚桩局部稳定性分析

目前基坑设计中对于吊脚桩预留岩肩的宽度和支护桩的嵌固深度取值大多从对上部支护结构内力及变形的影响角度出发,往往忽略了支护结构底部附近的局部稳定性问题。依托珠江三角洲水资源配置工程超深竖井项目,提出了外倾结构面下或破碎岩体吊脚桩基坑可能存在的3种破坏模式,采用极限平衡法分别给出了不同破坏模式下稳定安全系数的计算方法。同时针对不同破坏模式下,影响稳定安全系数的参数如岩层的埋深、结构面的倾角和力学参数、岩肩宽度、岩肩深度等进行了分析,结果表明外倾结构面倾角、结构面或岩体的力学参数对稳定安全系数影响较大。研究成果可为类似工程提供参考。

石油焦煅烧工艺冷却方式的对比与分析

对比分析回转窑和罐式炉不同的冷却方式,采用冷却效率高,并且对高温煅后焦热量可以余热利用的冷却技术正在成为新的发展方向。回转窑间接冷却不仅可以产生90℃的热水,而且还能解决直接喷淋冷却带来的焦粒粉化问题,是新建或者改造项目的优选工艺。罐式炉汽化冷却方式可以产生250~300kg/t-CPC的饱和蒸汽,经济性明显,是降低双碳排放的重要技术,但是产业化应用还需要解决水套材料、寿命方面的问题。

爆炸冲击波作用下立井防爆门及风机叶片动态响应特性

研究爆炸冲击波作用下立井防爆门及风机叶片动态响应特性,保证主要通风机连续、安全、可靠运转对保障矿井安全生产意义重大。根据相似理论设计搭建了小尺寸风井-风机-防爆门爆炸传播实验系统,开展了瓦斯爆炸冲击波传播实验,通过实验结果与数值模拟结果对比,验证了瓦斯爆炸冲击波传播数学模型的可靠性;利用分段接力模拟方法结合编写的描述防爆门运动过程udf代码,模拟了羊场湾矿Ⅱ020611回风巷掘进工作面发生瓦斯爆炸时冲击波传播过程,研究了冲击波作用下立井防爆门及风机叶片动态响应特性。研究表明:①冲击波作用下,初期防爆门上远风硐侧超压高于近风硐侧,而后出现高超压区由远风硐侧向近风硐侧移动现象,在超压未达到最大值之前防爆门上超压已分布均匀。②受冲击载荷作用,沿叶片径向方向出现不同的高压区,沿叶片的轴向方向,由叶片边缘向叶片中央超压逐渐增大。冲击波作用下叶片根部弯矩骤然增加至最高值又迅速降低,瓦斯爆炸当量越大,衰减越快。冲击波超压对叶片根部产生弯矩最大值与瓦斯爆炸当量呈对数关系。③对于叶片根部弯矩峰值,防爆门关闭时最大,防爆门被动开启次之,防爆门主动开启时最小。防爆门被动开启时,瓦斯爆炸当量越大,防爆门开启后泄压效果越差,配重对防爆门开启后泄压效果影响有限;相比于被动开启,防爆门主动提前开启可大幅度提高风机处的泄压效果,提高风机在灾变条件下的生存能力。

环境压力对隧道竖井排烟影响的数值模拟研究

通过FDS数值模拟,研究环境压力对隧道火灾的烟气蔓延规律、烟气分层特性和竖井排烟效果的影响。研究表明:低压环境下隧道顶棚的烟气具有更高的温度,火源-竖井和竖井下游区域顶棚温度的纵向衰减曲线均符合指数分布,温度衰减系数随着环境压力的增加而减小;火源-竖井区域的烟气运动由热浮力主导,层化曲线变化趋势不明显,竖井下游区域层化曲线受环境压力的影响较大,随着环境压力的降低,层化曲线出现顺时针旋转的趋势,层化强度降低,烟气层稳定性下降;低压环境中竖井的排烟效果要优于常压状态下的竖井,且竖井底部产生吸穿现象的临界高度也有所增加。因此,与一般海拔地区相比,海拔较高地区的隧道发生火灾时,较高竖井的排烟效果更好,吸穿临界高度更高,对下游烟气层稳定性的影响更小,更利于疏散排烟。

鹤壁九矿工作面开采对副井井筒采动影响分析

煤矿副井是地下开采活动的重要通道,肩负着矿井的人员提升、物料运输和通风等重要功能,在井筒保护煤柱开采中对井筒稳定性的研究至关重要。以鹤壁九矿新副井保护煤柱内工作面开采为研究对象,利用概率积分法计算井筒移动变形规律,并以此为基础,通过Drucker-Prager准则对井筒全段岩层的破坏情况进行判定,以此来评价开采方案对新副井的采动影响,可为煤矿的生产规划提供依据,为类似条件矿井井筒保护煤柱开采提供理论指导。

深井掘进技术在厚层高渗透性粉细砂层中适用性的数值模拟研究

科学合理高效开发深层地下空间是城市不断发展的必然趋势与重要难题。深井掘进技术(vertical shaft machine,VSM)是一种开挖超深竖井的新型工法,该技术施作的竖井结构形式简单、结构受力状态好、施工速度快、对周边环境扰动小、适用性广泛,可被广泛用于城市深层地下空间的点状开发。以中国首例使用VSM施工的南京市儿童医院沉井停车库项目为原型,建立在砂性土中开挖60 m竖井的数值模型,重点研究VSM竖井在厚层高渗透性的粉细砂层开挖过程的变形情况与开挖面的稳定性问题。数值模型结果表明:60 m竖井开挖过中地表变形量均控制在毫米数量级,且最大地表变形量不超过13 mm;在水位差1 m的水下施工过程中安全系数均较好控制在2.0以上。对于变形问题,分析不同开挖深度下的井底隆起变形和地表变形情况,表明在60 m开挖深度内,使用VSM开挖砂性土竖井在深度、安全性和对周边环境扰动上均具有明显优势。针对开挖面稳定性,计算分析与竖井内外水位差和竖井深度相关的开挖面安全系数,计算结果可用于指导实际施工,实现分段施工与精细化控制。

宽式防旋墩环形堰竖井水力特性分析

目前许多拟建抽蓄工程泄洪洞的环形堰竖井入口设置了新型宽式防旋墩,以消除喉口处由不可控漩流引起的呛水等不利流态,而宽式防旋墩环形堰竖井的水气特性与以往采用起旋墩和窄式防旋墩的竖井存在较大差异,业内对其认识尚不清晰。以石台抽水蓄能电站下水库泄洪洞的竖井作为研究对象,采用物理模型试验与数值模拟相结合的手段,分析了流态、流速、压力、消能率等水力指标。研究结果表明:宽式防旋墩引导水流平顺进入竖井形成脱壁流,其尾部可形成顺畅的进气通道,空气经此通道可充分进入竖井以保持井内流态与压力的稳定;新型竖井过流能力满足要求,各部位流速、压力分布正常,总消能率达85%以上;宽式防旋墩可消除不可控漩流导致的呛水现象并引导水流在竖井内形成脱壁流态,使竖井壁面免于空蚀破坏;墩尾通气量足够时,可取消通气管及环形堰与竖井结合部突扩体型,简化工程布置。相关经验可供类似抽蓄电站工程的泄洪洞竖井设计参考。

反井钻机施工大直径风井工程结构稳定性评价方法研究

针对大直径反井工程在扩孔期间的围岩稳定性问题,提出了一种考虑反井钻井法工艺特点的竖井结构稳定性评价方法,确定了围岩自稳能力是其关键因素,基于强度折减法,提出了以围岩稳定系数为核心的井帮围岩自稳能力定量评估方法,通过数值模拟手段确定了围岩极限自稳状态的强度折减系数k0,并以此作为围岩的稳定系数。为解决工程实际问题,提出了预防空帮失稳的工程处理措施,在扩孔阶段实施随钻临时支护作业,实现围岩的快速封闭。最后以李家壕煤矿回风暗立井工程作为研究对象,提出了局部失稳风险评估意见,并依托工程实践对评估准确性进行了验证,其结果表明评估结论与实际结果一致,验证了该井帮围岩稳定性定量评价方法及工程处理措施的有效性。

竖井巷道掘进超前地质探测研究进展与展望

以掘进机为代表的机械破岩是未来竖井巷道掘进技术发展的方向,为保障竖井巷道快速机械智能化掘进的安全,超前地质探测是不可或缺的工序。从探测范围、适用条件以及优势不足等方面对常规超前地质探测技术和随掘超前探测技术的发展现状与特点进行了分类总结,常规超前探测技术各有一定的适用范围,在钻爆法施工环境中得到了较好地应用。在面对掘进机复杂的施工环境时,常规超前探测技术难以适用。而随掘超前探测可以实现掘进与超前地质探测同步进行,实时预测工作面前方的不良地质,是井巷机械智能化掘进超前地质探测技术研究的重点。其中,竖井全断面掘进机是综合机械化凿井的发展方向和趋势,但其施工环境非常复杂,基于掘进机破岩震源地震波的超前地质探测是有效的预测方法。针对全断面竖井掘进机破岩震源超前探测方法的难点,即施工环境和破岩震源地震波场的双重复杂性,从多个方面提出了解决思路:针对震源先导信号,采用多种方法联合去噪,压制破岩震源干扰波;对于地震记录信号,采用以互相关为核心的地震记录重构方法恢复有效波场;开展竖井全空间三维立体探测和高精度成像的研究等。此外,开展多种随掘物探方法联合反演能够提高地质判识的可靠性和解释精度。研发竖井掘进机的掘探一体化装备是未来深入研究的方向。