Coupled thermo-hydro-mechanical modeling of frost heave and water migration during artificial freezing of soils for mineshaft sinking

Artificial freezing of water-bearing soil layers composing a sedimentary deposit can induce frost heave and water migration that affect the natural stress-strain state of the soil layers and freezing process.In the present paper,a thermo-hydro-mechanical(THM)model for freezing of water-saturated soil is proposed to study the effects of frost heave and water migration in frozen soils on the formation of a frozen wall and subsequent excavation activity for sinking a vertical shaft.The governing equations of the model are formulated relative to porosity,temperature,and displacement which are considered as primary variables.The relationship between temperature,pore water,and ice pressure in frozen soil is established by the Clausius-Clapeyron equation,whereas the interaction between the stress-strain behavior and changes in porosity and pore pressure is described with the poromechanics theory.Moreover,constitutive relations for additional mechanical deformation are incorporated to describe volumetric expansion of soil during freezing as well as creep strain of soil in the frozen state.The ability of the proposed model to capture the frost heave of frozen soil is demonstrated by a comparison between numerical results and experimental data given by a one-sided freezing test.Also to validate the model in other freezing conditions,a radial freezing experiment is performed.After the validation procedure,the model is applied to numerical simulation of artificial freezing of silt and sand layers for shaft sinking at Petrikov potash mine in Belarus.Comparison of calculated temperature with thermal monitoring data during active freezing stage is presented.Numerical analysis of deformation of unsupported sidewall of a shaft inside the frozen wall is conducted to account for the change in natural stress-strain state of soil layers induced by artificial freezing.

钻井法凿井气-液-固耦合排渣流场及刀盘吸渣口优化

针对西部地区侏罗系地层煤矿立井钻井法施工中出现的气举反循环洗井排渣与钻进效率低下问题,以陕西可可盖煤矿中央回风立井ϕ4.2 m超前钻井为工程背景,基于CFD-DEM(计算流体力学和离散单元法耦合)研究方法,建立了气-液-固多相耦合排渣数值模型,揭示了排渣管内、井底流场的速度及压力分布规律,并基于自研的气举反循环排渣试验装置,采用PIV(粒子图像测速法)测试技术对流场分布的正确性进行验证;提出了优化刀盘吸渣口评判指标和方法,对吸渣口的数量、长径比、面积比、总面积占比进行优化,得到了超前钻头刀盘吸渣口布置的最佳方式和相关参数;讨论了钻头转速、注气量、风管没入比和泥浆黏度等主要因素对排渣流场的影响。研究结果表明:(1)排渣管内流体的运移以轴向流动为主,且途经注气端时,流速发生跳跃式剧增;井底流体的运移主要以水平流动为主,流体的垂直上返仅存在于吸渣口附近;井底流体的水平流动以切向流动为主,径向流动仅在吸渣口两侧较为明显,且远离吸渣口处,径流速度较小易产生岩屑沉积;(2)当刀盘吸渣口数量为2,长径比为0.4,面积比为1,总面积占比为1.94%时,吸渣口的布置方式最佳,且清渣率较现行吸渣口布置方式提高66%;(3)增大钻头转速可显著增强吸渣口的吸附作用,注气量、风管没入比与井底和排渣管内流体的轴向速度均呈正相关关系,低黏、低密度的泥浆易获取高流速,但携岩能力较差。研究结果可为破解侏罗系地层深大立井钻井法洗井排渣与钻进效率低下技术难题,提供有益的理论参考。

信湖煤矿主井钻-注平行作业施工技术

信湖煤矿主井深1 009.5m,净直径6m,采用钻-注平行作业方式施工,S孔地面预注浆完全不占用建井工期。S孔地面布置避开钻井施工地面设施,在基岩段进入设计注浆范围,进行基岩段注浆。该井筒共注入浆液27 007.5m3,剩余涌水量3.5m3/h,实现了打干井。

Research on Stress and Strength of High Strength Reinforced Concrete Drilling Shaft Lining in Thick Top Soils

High strength reinforced concrete drilling shaft linings have been adopted to solve the difficult problem of supporting coal drilling shafts penetrating through thick top soils. Through model experiments the stress and strength of such shaft linings are studied. The test results indicate that the load beating capacity of the shaft lining is very high and that the main factors affecting the load bearing capacity are the concrete strength, the ratio of lining thickness to inner radius and the reinforcement ratio. Based on the limit equilibrium conditions and the strength theory of concrete under multi-axial compressive stressed state, a formula for calculating the load-beating capacity of a high strength reinforced concrete shaft lining was obtained. Because the concrete in a shaft lining is in a multi-axial compressive stress state the compressive strength increases to a great extent compared to uni-axial loading. Based on experiment a formula for the gain factor in compressive strength was obtained： it can be used in the structural design of the shaft lining. These results have provided a basis for sound engineering practice when designing this kind of shaft lining structure.

Review and prospect of the effects of freeze-thaw on soil geotechnical properties

Freeze-thaw hazard is one of the main problems in cold regions engineering and artificial ground freezing engineering.To mitigate freeze-thaw hazards,it is essential to investigate the effects of freeze-thaw on soils engineering properties.This paper summarizes the effects of freeze-thaw on the physical and mechanical properties of soils reported in recent studies.The differences of freeze-thaw conditions between freezing shaft sinking and cold regions engineering are discussed.Based on the technological characteristics of freezing shaft sinking in deep alluvium,we further attempt to identify key research needs regarding the freeze-thaw effects on the engineering properties of deep soils.

255MW燃气-蒸汽联合循环机组轴封间隙测量及故障处理

针对某电厂2台255MW燃气-蒸汽机组的2号汽轮机出现轴封间隙过小的现象,经标高测试后分析发现该机组轴承座存在基础下沉和沉降不均的问题,提出了适当增大低压缸轴封上部间隙预留量的调整措施,为新机组安装提供了参考依据。

Relationship between Beating and Setting-on Place

In this paper,what causes the setting-on place of woven fabrics without adopting tension compensation is explained by means of experimental methods.Owing to that the main shaft speed and the beating speed of reed can not attain the normal values at setting-on,the warp tension and the beating force of the reed can neither reach the normal level.Therefore,the relative slippage movement of the weft against the warp during beating will be less,while the common movement of the weft together with the warp will be bigger than those at nor-mal running.As a result,the setting-on place is

冻结立井井筒机械化掘进现状及发展趋势

针对我国“富煤贫油少气”的能源赋存结构及煤炭未来一段时间将长期占据能源消耗主导地位的特点,回顾了我国煤炭井工开采领域冻结立井井筒机械化掘进发展历程。钻爆法凿井作为我国立井井筒施工的主要工法,炸药的应用大幅提高了冻结井筒的掘进效率,配套的伞钻打孔、抓岩机装岩、大型井架及设备提升、大模板砌壁等大型机械化设备的应用,大幅提高了井筒成井速度;竖井钻机、反井钻机及竖井掘进机作为特殊地层条件下立井井筒特殊凿井方式,也有各自应用范围。面对我国西部富水弱胶结地层特点及智慧矿山发展趋势,采用冻结+钻爆法施工难以满足千米级弱胶结岩层立井井筒智能化无人化的建设需求,而采用冻结+竖井掘进机钻井是未来超深立井井筒技术发展方向之一。结合国外冻结+竖井掘进机凿井工程案例,针对我国西部富水弱胶结岩层立井井筒建设,提出了冻结+竖井掘进机凿井在冻结壁厚度和强度设计理论、双层钢筋混凝土井壁永久支护、低温环境下竖井掘进机掘进破岩形式以及分级上排渣方式等冻-掘-支-运协同作业方面提出了合理化建议;明确了井壁结构与弱胶结围岩相互作用机理,优化双层井壁结构方法,构建竖井掘进机掘-支-运同步作业模式等,提升井筒建设综合效率,提高信息化水平,推动立井井筒向机械化、绿色化和智能化发展。

调谐质量阻尼器和非线性能量阱抑制内燃机闭环轴系扭转振动的比较研究

传统线性减振器在抑制内燃机轴系的扭转振动方面有着长期的应用,但较窄的减振带宽限制了其性能的发挥.考虑到内燃机闭环轴系的周期性激振力随转速的变化而变化,其在相对较宽的频率域内实现高效的减振十分必要.为了探究非线性能量阱(nonlinear energy sink,NES)替代调谐质量阻尼器(tuned mass damper,TMD)抑制曲轴扭转振动的可行性,文章将建立曲轴的多惯量非线性闭环自激耦合振荡模型,在此基础上,研究TMD和NES对闭环曲轴扭振减振的影响规律.分析过程综合考虑了轴系不同轴段位置的瞬态和稳态扭转振动.除此之外,定义了振动密度,性能领先效率和波动率3种函数综合考虑不同动力吸振器(dynamic vibration absorber,DVA)的性能优劣.讨论了NES和TMD在不同的设计参数下(变刚度、变阻尼和变位置排布)的减振效率和鲁棒性.结果表明,NES和TMD控制曲轴扭振时具有不同的刚度及阻尼失效区间.随着设计参数的变化,NES和TMD的减振性能交替领先,NES的综合性能领先了24.5%,TMD的综合性能领先了3.3%.同时,NES具有较高的阻尼依赖性(13.6%),TMD具有较高的刚度(3.6%)及位置依赖性(25.6%).

下沉式竖井掘进工法在软土地区的应用研究

城市地区的深层地下管网建设产生了大量超深竖井建设需要,而传统施工技术难以同时满足超深竖井施工低影响、高效且节约的需求。为此,本文介绍了一种新型施工技术——下沉式竖井掘进工法(VSM),与沉井工法、地下连续墙围护开挖工法等传统施工方法相比,该工法具有施工速度快、环境友好、工程造价低等优点。通过对VSM工法特点的总结,探讨了基于该工法的超深竖井设计要点。该工法应用于软土地区时,应注意需要满足土体抗隆起稳定性及地基承载力要求。最后,介绍了上海软土地区首个采用VSM工法的超深竖井工程。对该竖井施工过程的监测结果表明,VSM工法在上海软土地区有较好的适用性,竖井开挖施工对周边环境的影响可满足上海地区环境保护等级为一级的基坑变形控制要求。

沉井建造VSM工艺与成套装备及其工程应用

传统的沉井施工技术通常采用人工取土或小型机械取土,靠结构自重下沉,现场浇筑混凝土井壁的方式。然而传统方式存在施工效率慢,作业人员多且施工风险高,停沉突沉和倾斜现象多,对周围环境影响大等弊端。随着技术的发展,沉井施工技术也正在向装配式、机械化、数字智能化和绿色建造的趋势靠拢。针对目前前沿的沉井掘进技术-VSM工法极其国内外装备研制,总结了其工程应用情况,为沉井领域的机械化建造提供技术方案和设备选型参考。

Evaluation of excavation damaged zones(EDZs)in Horonobe Underground Research Laboratory(URL)

Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.

磷矿通风井反井施工技术研究及应用

贵州福麟矿业有限公司新桥磷矿山二号井回风竖井工程采用了反井钻机钻井法施工,反井钻机一次扩孔成井直径为3.5 m。通过对矿方提供的地质检查孔岩心资料进行分析,研究计算了在该地层条件下反井钻机扩孔拉力和扭矩等工作参数,并最终选择了TSJ-2000型水源钻机与BMC400型反井钻机结合的技术方案来进行导孔和一次扩孔成井。在施工过程中克服了缺乏类似项目经验以及缺少岩层发育资料等实际困难,确保顺利完成了井筒贯通,使得井筒偏斜率控制在0.3%以内。实践证明,在该磷矿回风竖井工程中采用反井钻机施工大直径竖井开挖是可行的,并为此类大直径竖井开挖项目提供了宝贵经验。

“科技乙方”商业服务模式创新及应用

基于矿山特殊施工高科技企业专业和核心技术优势,研究提出了“科技乙方”商业服务模式,通过提供科技含量更高的产品和服务,有效释放新质生产力的科技效能,该模式成功解决特殊凿井领域中大量“卡脖子”技术难题,并引领我国地下工程特殊施工技术的发展。“科技乙方”以技术力量实现价值创造,主要服务产品包括冻结技术、注浆技术、钻井技术及装备、智能化建井设计及建设、国家重大引调水技术服务。“科技乙方”是“技术+装备+工程”整体解决方案的提供商,在实施过程中对新出现的技术难题即时研究解决能力更加突出,已经在山西省中部引黄工程地面定向钻孔预灌浆工程和涌水应急抢险堵水工程中得到了实践检验。

台格庙矿区钻井法凿井钻进工艺可行性研究

神华新街台格庙矿区一井东部风井井筒设计成井深度857.5 m,设计净直径7.0 m,设计井壁厚度850 mm,以此为工程背景,从地质特征、工程条件、装备能力、钻井分级工艺等方面,分析了采用竖井钻机钻井法凿井钻进工艺的可行性。研究了拟建井筒穿越的地层及其岩石力学特性,基岩厚度将达到870 m,基岩占比达到99.3%;基于地质条件、井筒功能和井筒设计参数,计算得出钻井深度将达875 m、钻井直径为10.2 m,并梳理了全岩地层深大直径井筒机械破岩钻进面临的难题;对比分析了东部深厚冲积地层和西部厚基岩地层钻进分级工艺,分析确定了“一扩成井”钻进工艺具有可行性,超前钻孔直径范围为6.5~7 m,扩孔钻进直径为10.2 m。

大型竖井凿井大临工程快速施工实践与探讨

在山东黄金集团焦家金矿朱郭李家副井井筒凿井大临工程施工中,采用整体钢结构组合模板进行井架基础施工,利用砖砌墙支撑设备整体浇筑和凿井井架整体吊装。通过合理地布置施工顺序、优化基础施工方法和科学管理等措施,在工期、质量和安全等方面取得了非常好的效果,实现了立井大临工程快速优质施工的目标。

矿山标准凿井井架极限适用深度分析与构件优化设计

凿井井架是矿山竖井挖掘阶段的主要地上设施,现有标准图编制于1986年。采矿行业经过三十余年的发展,现行规范、常用工艺工法已与标准图多有不同。本文依托山东烟台某金矿1300 m凿井项目,梳理了井架所受各荷载间的联动-互斥关系。根据现行规范,分析了标准凿井井架的最大适用深度,分别计算了提升荷载和断绳荷载下的杆件应力,得出了最大适用深度增加的主要原因,并根据生产单位的诉求,采用空间结构模型计算方法,对标准井架构件进行了优化。

超深厚表土层特殊凿井技术探究

为了开发超深厚土层下的固体矿物资源,以2000m深厚表土层建井为工程背景,通过总结深厚土层中井筒建设成果,并参考深土层井筒施工经验与理论研究,对冻结法、钻井法及混凝土帷幕法等特殊凿井法进行了可行性分析。研究表明:在本工程背景下,使用单一的冻结法或使用单一的钻井法作为建井技术尚不成熟且实现难度较大;而采用冻结-帷幕凿井工艺具有一定的可行性。由于深井建设面临“高地应力、高地温、高水压”问题,为确保工程安全性,提出了冻结-帷幕凿井法,为后续超深厚土层凿井方法的选取提供了方向性的参考。

基于超大超深立井的凿井井架结构选型与设计

立井凿井井架是立井井筒施工期间进行提升和悬吊施工设备而设立的特殊钢结构体。近年来,随着我国矿产资源开发建设的不断发展,矿井的开采深度超过2000 m、井筒直径超过10 m时,现有的凿井井架无法满足施工的需要。研究设计了超深凿井井架,能够满足凿井井筒净直径11 m、凿井深度2500 m的施工要求。为进一步完善超大超深井凿井井架的设计理论,提升深井凿井技术装备水平,利用互联网技术对凿井井架工作状态下杆件的应变进行实测,既可以进一步提升立井井筒施工的信息化水平,也确保了超深立井凿井施工的安全。

基于BIM技术的煤矿井巷工程成本精准估计研究

为了提升煤矿井巷工程成本估计精度,提出了基于BIM(建筑信息模型)技术的煤矿井巷工程成本精准估计方法。以某项工程为依托,基于BIM技术的网格生成方法和三角剖分方法建立煤矿井巷工程的地质模型,投影主井、副井、风井空间数据,综合构建出煤矿井巷工程的演进模型。对影响工程成本的影响因子进行分析,将分析所得的影响因子数据代入到演进模型中,得出不同施工阶段的过程成本估计数据。研究结果表明,该方法的估计成本与实际成本一致度达到99.9%,估计结果较为精准,满足煤矿井巷工程施工的现实需求。