Visual fatigue relief zone in an extra-long tunnel using virtual reality with wearable EEG-based devices

Long-time driving and monotonous visual environment increase the safety risk of driving in an extra-long tunnel. Driving fatigue can be effectively relieved by setting the visual fatigue relief zone in the tunnel. However, the setting form of visual fatigue relief zone, such as its length and location, is difficult to be designed and quantified. By integrating virtual reality(VR) apparatus with wearable electroencephalogram(EEG)-based devices, a hybrid method was proposed in this study to assist analyzers to formulate the layout of visual fatigue relief zone in the extra-long tunnel.The virtual environment of this study was based on an 11.5 km extra-long tunnel located in Yunnan Province in China.The results indicated that the use of natural landscape decoration inside the tunnel could improve driving fatigue with the growth rate of attention of the driver increased by more than 20%. The accumulation of driving fatigue had a negative effect on the fatigue relief. The results demonstrated that the optimal location of the fatigue relief zone was at the place where driving fatigue had just occurred rather than at the place where a certain amount of driving fatigue had accumulated.

Power allocation and mode selection methods for cooperative communication in the rectangular tunnel

For the multipath fading on electromagnetic waves of wireless communication in the confined areas,the rectangular tunnel cooperative communication system was established based on the multimode channel model and the channel capacity formula derivation was obtained.On the optimal criterion of the channel capacity,the power allocation methods of both amplifying and forwarding(AF) and decoding and forwarding(DF) cooperative communication systems were proposed in the limitation of the total power to maximize the channel capacity.The mode selection methods of single input single output(SISO) and single input multiple output(SIMO) models in the rectangular tunnel,through which the higher channel capacity can be obtained,were put forward as well.The theoretical analysis and simulation comparison show that,channel capacity of the wireless communication system in the rectangular tunnel can be effectively enhanced through the cooperative technology;channel capacity of the rectangular tunnel under complicated conditions is maximized through the proposed power allocation methods,and the optimal cooperative mode of the channel capacity can be chosen according to the cooperative mode selection methods given in the paper.

Excavation of Inlet Tunnels at Geheyan Power Station

The Geheyan Power Station on the Qingjiang river has four inlet tunnels, on the right bank, with its excavation diameter of 11.3 m to 12.5 m, after lining diameter of 9.5 m, axis to axis spacing of 24 m. The thickness of the pillar between tunnels should usually be more than two times of tunnel diameter to ensure the stability of surrounding rock during excavation. In this paper, the excavation methods of tunnels with the pillar thickness as small as the tunnel diameter, such as smooth surface blasting, shotcrete support protection, are emphatically discussed.

Upper Lillooet River Hydroelectric Project： The Challenges of Constructing a Power Tunnel for Run-of-River Hydro Projects in Mountainous British Columbia

The Upper Lillooet River Hydroelectric Project （ULHP） is a run-of-river power generation scheme located near Pemberton, British Columbia, Canada, consisting of two separate hydroelectric facilities （HEFs） with a combined capacity of 106.7 MW. These HEFs are owned by the Upper Lillooet River Power Limited Partnership and the Boulder Creek Power Limited Partnership, and civil and tunnel construction was completed by CRT-ebc. The Upper Lillooet River HEF includes the excavation ofa 6 m wide by 5.5 m high and approximately 2500 m long tunnel along the Upper Lillooet River Valley. The project is in a moun- tainous area; severe restrictions imposed by weather conditions and the presence of sensitive wildlife species constrained the site operations in order to limit environmental impacts. The site is adjacent to the Mount Meager Volcanic Complex, the most recently active volcano in Western Canada. Tunneling conditions were very challenging, including a section through deposits associated with the most recent eruption from Mount Meager Volcanic Complex （-2360 years before the present）. This tunnel section included welded breccia and unconsolidated deposits composed of loose pumice, organics （that represent an old forest floor）, and till, before entering the underlying tonalite bedrock. The construction of this section of the tunnel required cover grouting, umbrella support, and excavation with a combination of road header, hydraulic hammer, and drilling-and-blasting method. This paper provides an overview of the project, a summary of the key design and construction schedule challenges, and a description of the successful excavation of the tunnel through deposits associated with the recent volcanic activity.

Application of Distributed Intelligent Power Supply Technology in Expressway Tunnels

With the coordinated development of today's social economy with science and technology,various advanced technologies are being used in highway engineering,especially the distributed intelligent power supply technology in expressway tunnels,which has a very significant advantage.In order to realize the effective application of this technology and promote the power supply effect in expressway tunnel,this study analyzes the advantages of this technology and its application in expressway tunnel,hoping to provide scientific reference for the application of distributed intelligent power supply technology and the engineering development of expressway tunnels.

电力管廊通风规律及结构布局优化研究

为改善电力管廊的通风效果,依托北京新机场高速公路综合管廊工程,采用数值分析与现场试验的方法,对电力舱通风规律进行系统研究。在得到初步规律的基础上,通过改变通风方式、通风口位置和电缆布局,对比研究机械进风自然排风和自然进风机械排风、通风口设在管廊顶部和两侧、10 k V和110 k V电缆交换位置3类6种工况下的通风效果。结果表明:1)现有正常通风条件下,从进风口到排风口,进风口处气流组织混乱;同时,由于在进风口处气流2次改变运动方向导致能量损失很大,致使可用于驱动管廊内空气的能量减小,通风效果下降,造成能源浪费。2)将通风口(风机)布置在电力舱两侧时,因初始风速与通风方向一致,避免了能量损失,有效提高了通风效果。研究显示,管廊中间断面的平均风速提高了0.31 m/s,变幅达39.6%;温度降低了1.6℃,变幅达6.1%;压力损失降低了13.7 Pa,变幅达30.4%,极大地改善了电力舱通风效果。3)在通风口(风机)位于顶部的条件下,对电缆布局优化后,10 k V电缆表面温度降低3.21℃,110 k V电缆表面温度升高1.68℃,纵断面平均温度下降0.365℃,电缆布局调整有利于降低舱内温度,减少压力损失。

基于锥角控制的下风向风力机功率调节策略

针对中小型下风向风力机开展了功率调节策略研究.首先,对100 W下风向风力机进行了仿真计算和风洞实验,探究了下风向风力机的气动性能;然后,分析了风轮锥角对风力机输出功率和叶根载荷的影响机制,归纳出输出功率与锥角余弦值的三次方正相关,叶根载荷与锥角余弦值的平方正相关;最后,形成了一套基于锥角控制的下风向风力机功率主/被动调节策略.研究结果表明:采用主动调节策略可在超额定风速运行时有效控制风轮输出功率,并可使叶根载荷极值降低14.2%;较控制前,采用被动调节策略可使得在超额定风速运行时,输出功率与额定功率的平均偏差减小20.84 W.两种调节策略皆可实现超额定风速运行时下风向风力机输出功率的有效控制.

爆破振动下城市管架型热力管道响应与安全研究

以下穿热力隧道的北京冬奥支线区间隧道爆破为背景,建立热力管道三维动力有限元模型,利用锤击测试试验验证了数值模型的可靠性.在数值模型中输入实测的爆破振动波,研究爆破地震波作用下管架型热力管道动态响应.结果表明:爆破地震波作用下,管道结构的有效应力为45.89 MPa,有效应变仅为0.02%,与重力初始作用时结构应力应变分布保持一致,爆破振动对管道结构的作用效应较小;放大输入地震波5~100倍,管道结构的PPV随之等倍数增大,而最大等效应力和最大等效应变的增幅仅为4.5%左右;提取实测地震波低频成分并施加在管道结构上,并不会引起热力管道的应力和应变大幅度增加,管道材料的等效应力均在50 MPa以下.由此可见,地震波峰值和主频对管道应力应变分布影响均较小。具有波纹管膨胀节的架空管道结构受力均匀,变形协调性和抗震性能较好,因工程爆破振动造成破坏的可能性不大.

隧道牵引分区所雷击暂态特性及其二次设备电磁兼容研究

牵引供电系统遭受雷击会在分区所内产生过电压与过电流,对分区所开关柜中二次设备产生瞬态电磁干扰,影响其正常运行。文中针对电气化铁路隧道分区所,建立雷击暂态仿真模型,计算了接触网不同位置遭受雷击时分区所的过电压与过电流,建立了27.5 kV开关柜的电磁场有限元仿真模型,分析开关柜中不同区域的瞬态电场、磁场分布。结果表明:雷击接触网会在分区所内产生幅值较大、频率较高的过电压与过电流,在其作用下开关柜低压室瞬态电场可达147.2 V/m、瞬态磁场可达1.3 kA/m,断路器室前壁处瞬态电场可达822.9 kV/m、瞬态磁场可达15.85 kA/m,超过标准规定的幅值,二次设备需要考虑相应的电磁屏蔽措施。论文结果对牵引供电系统雷击过电压/电流防护以及二次设备电磁兼容设计具有参考价值。

接立面转弯隧洞的侧式出水口水力特性

对于接立面转弯隧洞的侧式出水口,立面转弯隧洞的转弯段将直接影响侧式出水口的水力特性。若立面转弯隧洞参数设计不合理,极易导致侧式出水口内部发生流动分离。选取RSM紊流模型,针对接立面转弯隧洞的侧式出水口进行数值模拟,探究立面转弯隧洞曲率半径R、弯道后直隧洞长度L及转弯角度α等参数对出水口水力特性的影响规律,并对隧洞内流动过程进行了讨论。增加立面转弯隧洞曲率半径R和弯道后直隧洞长度L能显著改善出水口的水力指标。当曲率半径R≥12 D(D为隧洞直径)、弯道后直隧洞长度L≥16 D时,侧式出水口内部无明显流动分离,拦污栅断面流速分布均匀且无反向流速区。研究成果将对抽水蓄能电站侧式进/出水口的设计提供指导。

公路隧道风光水储互补发电系统容量配置研究

为降低公路隧道的电力运营成本,探究可再生能源互补发电系统在公路隧道的应用前景,研究合适的容量配置求解方法。建立利用风、光、水和储能设备的互补发电系统为公路隧道提供电力资源。以特长公路隧道(总长7.1 km)为估算模型,采用改进后的粒子群优化算法,即离散型自适应粒子群优化算法,以全生命周期的建设成本和设备维护成本最小为目标函数,以缺电负荷率(LPSP)和储能电池的状态为约束,对风力发电设备、光伏发电设备、水力发电设备和储能设备的最优容量配置进行求解。结果表明:1)对比标准粒子群算法,离散型自适应粒子群优化算法的总投入成本更少,寻优能力更强;2)对比该隧道1年的用电成本,前期投入将在5年内回本;3)在风光水储互补发电系统的设备全生命使用周期的20年内,该隧道可节省1 920.39万元电费。

抽水蓄能电站无压泄洪洞台阶消能型式研究

基于甘肃某抽水蓄能电站泄洪洞洞内消能设计,探讨在流量及底坡恒定的条件下,台阶尺寸与消能率的相关关系,探寻台阶尺寸的初拟原则,采用现行NB/T 10867-2021《溢洪道设计规范》中跌落流上限及滑行流下限的经验公式(坡角范围为2.86°~59.53°)进行台阶消能流态的初步判别,通过Chanson半经验公式理论计算和CFD数值模拟水工隧洞底板布置不同台阶尺寸对应的消能特性。结果表明:在流量及坡度不变的情况下,台阶尺寸(台阶步长及高度)对消能率的影响有限;台阶尺寸越大,水力要素受流动边界条件影响和扰动越明显;初拟台阶尺寸时,应分析水流掺气点位置及出现掺气均匀流位置随台阶尺寸变化向上游移动的速率,同时结合实际边界条件、便于施工及后期运维等方面综合考虑,台阶高差宜控制在0.20~0.60 m。

电力隧道渗漏水成因分析及治理措施研究

电力隧道内电缆数量较多,电缆及其他电力设施对水非常敏感,如果积水淹没电缆(尤其是电缆接头部位),可能会造成事故和损失。文章详细分析了暗挖、盾构等结构形式隧道的渗漏水成因,对管片、环梁、沉降缝、墙体及管孔等部位渗漏水治理措施进行研究,提出了针对性的治理建议并进行了试点应用,为电力隧道渗漏水治理工作提供参考。

超长电力隧道通风设计运行参数计算方法

为有效排除电缆发热量,超长电力隧道通风能耗巨大。实际运行中电缆大多数时候处于非饱和运行状态,故实际所需的通风量明显小于通风设计工况,因此存在很大的通风节能潜力。但是,由于缺乏理论支持,该节能措施难以落实。为此,本文针对超长隧道内部温度场进行数值模拟研究,探讨通风量、电缆发热强度和通风区段长度的相关性,建立了基于隧道出口气温不高于40℃限制条件下的运行参数关联式,可快速准确地预测已建成隧道实时所需通风量,也可用于隧道设计阶段参数计算。

超长电力电缆隧道冬季温度分布特征及通风节能潜力

为了解冬季通风时隧道内的换热情况和节能潜力,对冬季室外气温为4~12℃时超长通风区间特高压电力隧道内的温度分布特征进行数值模拟研究。采用ANSYS Fluent 19.2软件,通过用户自定义程序完成电力隧道全长的模拟。对冬季隧道的传热特征和通风节能潜力进行分析,定义并给出了冬季能实现最大节能效果的临界通风量。结果表明:具有超长通风区间的电力隧道存在通过降低通风量从而实现节能的潜力;冬季电力隧道前段土壤放热、后段土壤吸热,土壤放热量占比受室外气温影响,而土壤吸热量占比受室外空气温度和通风量影响;冬季室外气温越低,临界通风量越小,通风节能潜力越大,当冬季室外气温为4~12℃时,最大可能节能率为91%。

大型抽水蓄能电站长直型隧洞风尘迁移规律研究

抽水蓄能电站地下洞室群施工存在通风难度大、风尘迁移变化规律无显著特征等难题,采用DPM气固两相流模型,针对地下洞室群中不同坡度的长直型隧洞进行数值试验研究,重点揭示了典型隧洞在不同施工条件下的风尘迁移规律及小粒径沉降粉尘分布特征。研究表明:不同区域粉尘质量浓度随风机风速的增大呈下降趋势,当风速增至21 m/s时开始升高;掌子面附近区域粉尘质量浓度随供风距离的增大呈上升趋势,当供风距离大于25 m时,风机风速不再满足隧洞内通风要求;掌子面附近区域粉尘质量浓度随隧洞坡度的增大呈显著上升趋势,通风管附近出现明显的粉尘空白带;小粒径沉降粉尘分布特征由通风管位置决定,沉降粉尘颗粒最多处位于通风管出口与掌子面之间,粒径分布较广,呈正态分布规律,在通风管出口正后方处急剧下降,并沿隧洞出口方向数量逐渐减少,平均粒径逐渐减小;流出洞外的粉尘颗粒平均粒径偏小。本研究可为抽水蓄能电站地下洞室群整体施工设计提供参考。

隧洞平行摄影测量立体影像尺度差估计及匹配优化

为提升平行摄影隧洞序列影像的同名点匹配率及精度,对成像规律及匹配方法展开研究。提出了一种窗口尺度自动改正的LK光流法,核心是利用物像空间关系构建尺度差模型,并采用可变窗口进行特征点光流跟踪。结果表明:隧洞序列影像像点尺度差呈对称性径向分布,差异值符合幂函数模型增长趋势;将该方法应用在多组尺度差立体像对的匹配实验中,均取得了优于0.3个像素精度的实验结果,较基本光流法至少提升34.3%,最大提升45.5%。研究成果可为顾及尺度差的匹配方法提供参考,也可为隧洞平行摄影立体影像匹配提供基础。

基于动态格栅的湍流风实验模拟方法研究

开发一种基于动态格栅的湍流风实验模拟方法和装置,并通过调节格栅运动参数和来流风速,实现对湍流风特征参数的定量调控。实验分别研究罗斯贝数Ro、格栅雷诺数Re_(M)、格栅运动角加速度α、格栅运动周期长度T对湍流参数的影响规律。结果表明,湍流参数仅对罗斯贝数敏感,平均风速与湍流度均随罗斯贝数增加而增大,而湍流积分尺度则呈现先减小后增大的趋势。综合实验工况参数,得到湍流强度可调节范围为0.05~0.39,湍流积分尺度可调节范围为0.15~1.56 m,适用于缩尺比1∶20~1∶1200范围的风电机组模型实验。

滨海核电厂址污染物扩散数值风洞模拟研究

为评估核电厂对周围环境的影响,集成CFD-数值风洞软件,采用Autocad进行前处理建模,采用Paraview软件进行后处理分析,以研究污染物在大气中的迁移扩散过程。利用2003年于俄克拉荷马州俄克拉荷马市进行的城市联合实地研究(IOP9)的观测数据对该数值风洞软件进行评估,比较了数值风洞与IOP9现场试验污染物释放点下风向轴线污染物体积分数和风场结果。比对结果显示,风场各性能统计指标F_(AC5)=F_(AC2)=1,F_(B)=-0.23,M_(G)=0.75,E_(NMS)=0.07,S_(AA)=11.9;污染物体积分数统计指标F_(AC5)=1,模拟结果与观测数据较吻合。以某滨海核电厂为对象,研究核电厂污染物在大气中扩散对周围环境的影响。数值模拟结果显示,垂直于来流风向污染物体积分数总体呈高斯分布,受地形影响在山脊等位置处体积分数会陡然下降。将数值模拟的体积分数和风洞试验结果进行比较,结果显示在各垂直剖面监测点的吻合因子为10,各水平剖面监测点的吻合因子为3.5。数值风洞模拟结果有一定的参考价值,与现场试验和风洞试验结合可为核电厂污染物扩散模拟研究提供便利。

防风网对大跨度煤棚风荷载特性的影响

为了研究防风网对大跨煤棚风荷载的影响,通过风洞刚性模型测压试验,对3种透孔率的防风网下煤棚表面风荷载进行研究,分析了风向角、有无防风网和防风网透孔率对典型测点和分区的体型系数以及测点的脉动风荷载的功率谱特性的影响。结果表明:不同风向角下,结构体型系数极值出现的位置和范围差别较大;防风网对减小煤棚风荷载有较好效果,放置防风网后煤棚表面呈现为绝对值较小的负压;大部分风向角下,20%的透孔率防风网对减小风荷载效果更好;不同位置测点受来流脉动影响情况不同,煤棚迎风侧角部测点脉动风荷载无量纲功率谱数值较大,且功率谱成分复杂,放置防风网后其峰值明显减小。