Hydrodynamic Characteristics of Undular Tidal Bores in the Qiantang River Based on Field Observations

Understanding the undular tidal bores in the Qiantang River is essential for effective river management and maintenance.While breaking tidal bores have been studied extensively, reports on undular tidal bores in the Qiantang Riverremain limited. Furthermore, observed data on undular tidal bores fulfilling the requirements of short measurementtime intervals, and spring, medium, and neap tide coverage, and providing detailed data for the global vertical stratificationof flow velocity are quite limited. Based on field observations at Qige in the Qiantang estuary, we analyzedthe characteristics of undular tidal bores. The results showed that the flooding amplitude (a) of the first wave isalways larger than its ebbing amplitude (b). Moreover, the vertical distribution of the maximum flood velocity exhibitesthree shapes, influenced by the tidal range, while that of the maximum ebb velocity exhibites a single shape. Duringthe initial phase of the flood tide in the spring and medium tides, the upper water body experiences multiple oscillatingchanges along the flow direction, corresponding to the alternating process of the crest and trough of the tide levelupon the arrival of the tidal bore. The tidal range is a crucial parameter in tidal bore hydrodynamics. By establishingthe relationship between hydrodynamic parameters and tidal range, other hydrodynamic parameters, such as the tidalbore height, maximum flood depth–averaged velocity, maximum flood stratified velocity at the measurement points,and duration of the flood tide current, can be effectively predicted, thereby providing an important reference for rivermanagement and maintenance.

Effects of data smoothing and recurrent neural network(RNN)algorithms for real-time forecasting of tunnel boring machine(TBM)performance

Tunnel boring machines(TBMs)have been widely utilised in tunnel construction due to their high efficiency and reliability.Accurately predicting TBM performance can improve project time management,cost control,and risk management.This study aims to use deep learning to develop real-time models for predicting the penetration rate(PR).The models are built using data from the Changsha metro project,and their performances are evaluated using unseen data from the Zhengzhou Metro project.In one-step forecast,the predicted penetration rate follows the trend of the measured penetration rate in both training and testing.The autoregressive integrated moving average(ARIMA)model is compared with the recurrent neural network(RNN)model.The results show that univariate models,which only consider historical penetration rate itself,perform better than multivariate models that take into account multiple geological and operational parameters(GEO and OP).Next,an RNN variant combining time series of penetration rate with the last-step geological and operational parameters is developed,and it performs better than other models.A sensitivity analysis shows that the penetration rate is the most important parameter,while other parameters have a smaller impact on time series forecasting.It is also found that smoothed data are easier to predict with high accuracy.Nevertheless,over-simplified data can lose real characteristics in time series.In conclusion,the RNN variant can accurately predict the next-step penetration rate,and data smoothing is crucial in time series forecasting.This study provides practical guidance for TBM performance forecasting in practical engineering.

Research and Application of Advanced Detection of Water Hazards in Coal Mine Bore-Hole

For many years, the “short excavation and short exploration” excavation mode has been mainly used in the underground tunnel excavation of coal mines, which is difficult to meet the needs of rapid tunnel excavation. For this reason, CCTEG Xi’an Research Institute has innovatively proposed a new working mode of “long excavation and long exploration” using directional long drilling and borehole geophysical exploration. This method utilizes directional long boreholes that have already been constructed, and uses transient electromagnetic technology in the borehole to detect the radial range of 30 meters and the depth exceeding 1000 meters of the borehole, ultimately forming a three-dimensional imaging of the entire spatial geological anomaly body, providing reliable technical support for the safety and long-term excavation of the tunnel. This paper introduces the application which is a long-distance advanced detection of 1026 m. .

Contribution of Electrical Resistivity Tomography and Boring Technique in the Realization of Ten (10) Large Boreholes in a Crystalline Basement Rocks in the Centre-West of Benin

In order to ensure access to drinking water for Benin populations by 2021, the Emergency Measure program for the reinforcement of the drinking water supply system of Savalou city was initiated in 2018. This program focuses on densification and extension of hydraulic infrastructures. Therefore, it is prominent to use rigorous approach for implementation and execution of drilling activities. The present work has the advantage of combining the use of electrical resistivity tomography and borehole technique to locate ten high flow drilling in Savalou city. The electrical resistivity tomography (ERT) panels were made based on the dipole-dipole arrays with 48 electrodes with 5 m inter-electrode spacing. The drilling was carried out over ten selected points and in two stages: confirmation test using piezometer and borehole diameter enlargement. Moreover, only piezometers with flow rate greater than 10 m3/h were enlarged. The tomography processing has identified 10 fractured zones that are defined by 250 - 1000 ohm.m resistivity values and a width between 15 - 55 m. The confirmation test carried out over ten piezometers exhibits high flow rates ranging from 9 to 35 m3/h with depths of 30 to 68 m. Nine over the ten boreholes with a flow rate equal or greater than 10 m3/h, have improved their flow rates by 50% to 100% after the boring technique. Thus, the cumulative flow rate has reached 252. 7 m3/h for Savalou city and his surrounding areas.

Tunnelling performance prediction of cantilever boring machine in sedimentary hard-rock tunnel using deep belief network

Evaluating the adaptability of cantilever boring machine(CBM) through in-depth excavation and analysis of tunnel excavation data and rock mass parameters is the premise of mechanical design and efficient excavation in the field of underground space engineering.This paper presented a case study of tunnelling performance prediction method of CBM in sedimentary hard-rock tunnel of Karst landform type by using tunneling data and surrounding rock parameters.The uniaxial compressive strength(UCS),rock integrity factor(Kv),basic quality index([BQ]),rock quality index RQD,brazilian tensile strength(BTS) and brittleness index(BI) were introduced to construct a performance prediction database based on the hard-rock tunnel of Guiyang Metro Line 1 and Line 3,and then established the performance prediction model of cantilever boring machine.Then the deep belief network(DBN) was introduced into the performance prediction model,and the reliability of performance prediction model was verified by combining with engineering data.The study showed that the influence degree of surrounding rock parameters on the tunneling performance of the cantilever boring machine is UCS > [BQ] > BTS >RQD > Kv > BI.The performance prediction model shows that the instantaneous cutting rate(ICR) has a good correlation with the surrounding rock parameters,and the predicting model accuracy is related to the reliability of construction data.The prediction of limestone and dolomite sections of Line 3 based on the DBN performance prediction model shows that the measured ICR and predicted ICR is consistent and the built performance prediction model is reliable.The research results have theoretical reference significance for the applicability analysis and mechanical selection of cantilever boring machine for hard rock tunnel.

Vibrations induced by tunnel boring machine in urban areas: In situ measurements and methodology of analysis

Excavation with tunnel boring machine(TBM)can generate vibrations,causing damages to neighbouring buildings and disturbing the residents or the equipment.This problem is particularly challenging in urban areas,where TBMs are increasingly large in diameter and shallow in depth.In response to this problem,four experimental campaigns were carried out in different geotechnical contexts in France.The vibration measurements were acquired on the surface and inside the TBMs.These measurements are also complemented by few data in the literature.An original methodology of signal processing is pro-posed to characterize the amplitude of the particle velocities,as well as the frequency content of the signals to highlight the most energetic bands.The levels of vibrations are also compared with the thresholds existing in various European regulations concerning the impact on neighbouring structures and the disturbance to local residents.

Flume Experiment Investigation on Propagation Characteristics of Tidal Bore in A Curved Channel

Tidal bore is a special and intensive form of flow movement induced by tidal effect in estuary areas, which has complex characteristics of profile, propagation and flow velocity. Although it has been widely studied for the generation mechanism, propagation features and influencing factors, the curved channel will complicate the characteristics of tidal bore propagation, which need further investigation compared with straight channel. In this study, the flume experiments for both undular and breaking bores’ propagation in curved channel are performed to measure the freesurface elevation and flow velocity by ultrasonic sensors and ADV respectively. The propagation characteristics,including tidal bore height, cross-section surface gradient, tidal bore propagation celerity, and flow velocity are obtained for both sides of the curved channel. And three bore intensities are set for each type of tidal bores. The freesurface gradients are consistently enlarged in high-curvature section for undular and breaking bores, but have distinct behaviors in low-curvature section. The spatial distributions of tidal bore propagation celerity and flow velocity are compared between concave and convex banks. This work will provide experimental reference for engineering design of beach and seawall protection, erosion reduction and siltation promotion in estuary areas with the existence of tidal bores.

Quality Control Measures of Bored Pile in Bridge Construction

In order to improve the quality of bored piles in bridge construction and ensure the overall quality of the bridge,we analyzed a series of problems in the construction process of bored piles,then propose corresponding quality control measures,in hopes of improving quality control of bored piles in bridge construction in our country.

强涌潮水流条件下直立圆柱体的涌潮作用力试验研究

为厘清强涌潮河口直立式圆柱体受到的涌潮作用力与涌潮水流条件、圆柱直径的关系,通过涌潮水槽模型试验研究了三种直径直立圆柱在不同潮前水深、涌潮高度条件下的涌潮作用力。结果表明,强涌潮的涌潮作用力为直立圆柱受到冲击力叠加该时刻的水流绕流阻力、圆柱前后水位压差力。通过数据回归分析,得到了一个无量纲涌潮作用力计算公式。该公式表明,涌潮作用力分析计算除了要考虑涌潮高度、圆柱直径外,潮前水深也是关键因素,且涌潮作用力与圆柱直径之间存在显著的非线性关系。

基于仿真数据驱动的激光钻进气体喷嘴结构优化

激光钻进采用气体作为循环介质进行清孔,合理的气体流动特性是高效清孔的保障,气体喷嘴是影响气体流动特性的直接因素,其结构设计不合理会严重影响激光钻进的效率。针对激光钻进实验平台中的气体喷嘴,构建喷嘴基本型态,对影响气体清孔效率的喷嘴结构尺寸进行分析,制定仿真方案,通过Fluent模拟气体流场,对清孔效果进行分析,采用神经网络分析喷嘴结构及仿真结果,训练神经网络模型,得出最佳清孔效率时的喷嘴结构参数并进行验证,为喷嘴结构设计提供参考。

10种杀虫剂对桃小食心虫防治效果评价

【目的】研究不同杀虫剂对桃小食心虫Carposina sasakii Matsmur的防治效果,筛选环境友好型农药和施药量,为有效控制桃小食心虫的发生与危害提供科学依据。【方法】选择10种新型杀虫剂2022年采用田间小区药效试验,比较不同杀虫剂的防治效果。【结果】10种处理药后7 d防效均较好,处理间无显著性差异(P>0.05),其中10%联苯·氟酰脲悬浮剂、1%苦参碱可溶液剂和12%甲维·虫螨腈悬浮剂,在药剂稀释倍数药后14 d,防效均能达到93.33%以上,1%苦参碱可溶液剂在药后21 d各所有处理区防治效果均在90.00%以上,不同药剂之间在药后14~21 d防治效果有一定波动。【结论】参试10种药剂各处理区药后7 d对桃小食心虫均具有显著的防治效果,其中1%苦参碱可溶液剂、10%联苯·氟酰脲悬浮剂和12%甲维·虫螨腈悬浮剂,施药后14 d防治效果表现优异,可在生产实践中使用。

HSP超前探测技术在煤矿TBM掘进巷道中的应用研究

随着全断面掘进机TBM(Tunnel Boring Machine)逐渐应用于煤矿岩巷掘进,对不良地质构造进行超前准确快速预测的需求日益迫切。通过对主动源地震波超前探测方法的特点和TBM破岩震源超前探测技术的适用性进行分析,结合煤矿巷道地质和生产条件,提出了适用于煤矿巷道TBM掘进的HSP超前探测方法。以河南平顶山首山一矿TBM掘进底板瓦斯治理巷道为工程背景,选用防爆硬件一体化设计的探测仪器在煤矿巷道中进行应用。构建了空间型观测方式对煤矿巷道近水平煤线进行探测,优化了双护盾TBM掘进巷道狭小空间检波器阵列式布置参数;基于时频分析、互相关干涉处理、反射与散射联合反演等方法处理原始信号并进行探测结果成像。研究表明:采用空间型观测方式可实现与巷道小角度斜交煤线的识别,设计震源与首检波器间距离为15 m时最优。通过时频分析提取有效信号,利用互相关干涉法获取虚拟震源道和反射特征曲线,并结合反射与散射联合反演成像得到探测区域地层反射能量分布图,能够较准确地推测得到围岩存在的不良地质构造。通过比较现场开挖揭露情况与探测结果发现两者吻合度较高,表明HSP超前探测方法可实现掘进工作面前方100 m范围内超前无损地质预测,有助于提高煤矿岩巷TBM掘进速度。

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。

甘肃省白银和张掖地区梨园梨小食心虫和桃小食心虫发生动态

在甘肃省白银和张掖地区梨园,利用三角形性诱捕器连续3年(2021年-2023年)监测了梨小食心虫Grapholita molesta(Busck)和桃小食心虫Carposina sasakii Matsumura种群动态。结果表明,该地区主要以梨小食心虫发生为主,一年发生3代和不完全4代;越冬代成虫约在4月上旬开始出现,第1代高峰期为5月中下旬至6月初,第2代高峰期为7月上中旬,第3代发生高峰期在8月底至9月中旬。不同地区不同年份年诱蛾总量差异较大,最高可达3835头/诱捕器,最低为412头/诱捕器。桃小食心虫在该地区1年发生2代,且发生量较少,全年诱虫总量在70头/诱捕器以下。通过对3个监测点3年数据的分析,初步掌握了梨小食心虫和桃小食心虫在甘肃省这两个地区的发生规律,为达到良好防控效果,应选择越冬代高峰期之前,即4月中旬进行第一次防治。

铁路隧道TBM施工物料运输方式对比分析

为便于选择TBM施工物料运输方式,以铁路隧道为工程背景,首先,简要总结有轨运输和无轨运输2种运输方式的特点及其工程应用情况;然后,根据施工实践拟定典型工况,研究典型工况下的运输方案及设备配置,并从设备配置和工期2个方面对有轨运输和无轨运输进行详细对比分析。研究结果表明:1)有轨运输和无轨运输在铁路隧道TBM施工中技术上都是可行的,总工期无明显差异。2)我国配合TBM施工的内燃机车质量明显不高且突破难度较大,应努力提升电动机车的工程适应性、可靠性、耐久性以及人性化设计;同时,需要规范有轨运输设备配置要求、轨道铺设和维护质量,以提升有轨运输的效率。3)需要研究适合TBM施工工况且成本低、通用性好的无轨运输设备。

镗杆切削力感知单元结构设计与优化

为满足测量镗杆切削力的需求,采用ANSYSWorkbench有限元分析软件对镗杆等效应力与等效应变分析,确定感知单元安装位置。提出两种镗杆感知单元结构,运用响应曲面优化法确定感知单元最佳优化方案,通过计算、分析相关参数,来确定最佳的优化方案,并与优化前的感知单元结构方案进行比较。结果表明:当未超过应变式微力传感器最大等效应变时,均布式感知单元结构中镗杆最大测量值为329N;以附加支撑感知单元最大测量值为1000N为设计目标,获得5种最优结构参数,在实际设计制造中,可根据实际情况从中进行选择。

集输小口径管道腐蚀弱磁检测定量评价

集输小口径管道在油气田分布广泛,但使用传统腐蚀检测方法难度大、费用高且必须开挖取样点后才能定量评价腐蚀程度。为了弥补这种不足,实现非开挖条件下进行定量评价:分析磁偶极子模型得到腐蚀缺陷附近产生的漏磁场的磁信号特点;通过有限元仿真模拟,得到了腐蚀缺陷深度及宽度与磁信号间的关系;将SY/T 6151-2009《钢制管道管体腐蚀损伤评价方法》中对腐蚀评价所需的缺陷宽度和深度参数,结合磁偶极子模型理论推导计算与磁信号特征参数的关系,得到了一种可应用于非开挖条件下的管道腐蚀弱磁检测定量评价方法,并在某油田管道进行了工程验证,为非开挖条件下管道腐蚀检测定量评价提供一定的理论依据。

黏性土中桩侧后注浆单桩抗压承载性能室内模型试验研究

后注浆技术的应用能有效减少桩周土体扰动和泥皮等造成的不利影响,从而提高钻孔灌注桩的承载力。目前有关后注浆技术的研究多集中于桩端后注浆,少有涉及桩侧后注浆,影响了桩侧后注浆技术进一步推广应用。根据桩侧后注浆工艺,开展单桩抗压室内试验,以研究桩侧后注浆量对单桩抗压承载性能的影响。结果表明:在荷载水平较大的工况下,相较于桩侧后注浆量为1 L的单桩,注浆量为2、3 L时单桩极限抗压承载力分别提高18.2%和66.0%,提高幅度与注浆量呈正相关,并且可以在很大程度上减小桩顶沉降量;桩侧后注浆桩桩身轴力在侧注浆点位附近减小较快,在整个加载过程中桩端附近处桩身轴力值均比较低,单桩受压表现为摩擦桩;水泥浆液同时存在上返和下劈扩散,在室内试验条件下,两者扩散高度均约为14倍桩径,在浆液扩散段桩侧摩阻力得到显著提高,且越靠近注浆点位提高程度越明显。

预切缝位置及深度对SBM滚刀破岩的影响

利用水射流对岩体进行预切缝是提高竖井全断面掘进机破岩效率、实现深部资源机械化开发的关键技术。针对预切缝位置及深度合理参数选取的难题,首先指出了锥面刀盘带动下滚刀破岩的工况特征,进而基于Cohesive单元方法,建立了预切缝条件下的滚刀破岩离散-连续耦合数值模型。以完整岩体为对照组,对比分析了不同预切缝距离和深度对滚刀破岩的受力特征和岩石破碎特征的影响规律。阐述了预切缝条件下,滚刀破岩时密实核形成、块状岩渣形成、Hertz裂纹扩展3个阶段性特征,指出了岩体的非对称破碎特性和不同区域岩渣的形成机制。最终从滚刀受力、破岩面积、破岩比能耗、岩渣破碎程度4个方面综合分析,确定了预切缝的最佳距离和深度取值范围。研究结果表明:预切缝可以显著减小竖井全断面掘进机滚刀破岩过程中的贯入力和侧向力。与完整岩体相比,贯入力峰值降低了44.0%~10.3%。侧向力峰值降低了35.2%~6.5%。预切缝间距及深度较小时,会限制滚刀破岩范围,同时使得破碎岩体块度更小,导致破岩比能耗增高。随着预切缝深度的增大,破岩体积先增大后趋于稳定,比能耗先减小后保持不变。最终,确定了切缝距离为70~90 mm,深度为60~80 mm时破岩效果最佳,破岩体积较无切缝时提高约1倍,破岩比能耗降低69.2%。研究结果为刀盘辅助破岩装备的设计及参数确定提供了参考。

精密镗床旋转轴几何误差完备性测量与辨识

针对四轴卧式镗床旋转轴需测几何误差的数目不统一与完备性缺失的问题,提出了基于形状创成函数的四轴卧式镗床旋转轴PIGEs形成机理分析方法与旋转轴完备几何误差测量辨识方法。基于形状创成机理构建了卧式镗床几何误差创成函数,确定了旋转轴可通过误差补偿进行调整的最少与位置无关的几何误差(Position-independent geometric error, PIGEs)数目。建立了卧式镗床旋转轴4项PIGEs、6项与位置有关的几何误差(Position-dependent geometric error, PDGEs)、6项安装误差(Setup error, SEs)与球杆仪(Double ball bar, DBB)测量轨迹半径之间的完备性函数模型,设计了基于DBB的四轴联动Viviani曲线测量轨迹,构建了旋转轴6项PDGEs的NURBS表征与PIGEs、SEs辨识方法。开展了误差补偿对比实验验证,结果表明,利用几何误差完备性测量与辨识结果进行误差补偿,较仅单一补偿6项PDGEs可提升圆轨迹测量精度40.69%。