Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak,cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laserscanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation quality assessment with the laser scanning technology can be reduced by 70%e90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

Construction Technology and Safety Risk Control Measures of Deep Foundation Pit Excavation

Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.

Application of Roadway Spray Material to Fire Prevention in Goaf Excavation

In order to reduce the risk of spontaneous combustion in goaf during goaf excavation process, polymer modified cement mortar spraying material was used to spray and seal the roadway surface. The experimental application was carried out in the upper channel 2304 of a mine in Henan Province. The test results showed that polymer modified cement mortar spraying material could effectively support the roadway and greatly reduce the deformation rate of the roadway. The best spraying thickness is 5 mm. Through the monitoring of tunnel air leakage, it is concluded that the polymer modified cement mortar spraying material can reduce the tunnel air leakage and play a better sealing effect.

Distribution characteristics and the evolution law of excavation damage zone in the large-span transition section of high-speed railway tunnel based on microseismic monitoring

Purpose–The microseismic monitoring technique has great advantages on identifying the location,extent and the mechanism of damage process occurring in rock mass.This study aims to analyze distribution characteristics and the evolution law of excavation damage zone of surrounding rock based on microseismic monitoring data.Design/methodology/approach–In situ test using microseismic monitoring technique is carried out in the large-span transition tunnel of Badaling Great Wall Station of Beijing-Zhangjiakou high-speed railway.An intelligent microseismic monitoring system is built with symmetry monitoring point layout both on the mountain surface and inside the tunnel to achieve three-dimensional and all-round monitoring results.Findings–Microseismic events can be divided into high density area,medium density area and low density area according to the density distribution of microseismic events.The positions where the cumulative distribution frequencies of microseismic events are 60 and 80%are identified as the boundaries between high and medium density areas and between medium and low density areas,respectively.The high density area of microseismic events is regarded as the high excavation damage zone of surrounding rock,which is affected by the grade of surrounding rock and the span of tunnel.The prediction formulas for the depth of high excavation damage zone of surrounding rock at different tunnel positions are given considering these two parameters.The scale of the average moment magnitude parameters of microseismic events is adopted to describe the damage degree of surrounding rock.The strong positive correlation and multistage characteristics between the depth of excavation damage zone and deformation of surrounding rock are revealed.Based on the depth of high excavation damage zone of surrounding rock,the prestressed anchor cable(rod)is designed,and the safety of anchor cable(rod)design parameters is verified by the deformation results of surrounding rock.Originality/value–The research provides a new method to predict the surrounding rock damage zone of large-span tunnel and also provides a reference basis for design parameters of prestressed anchor cable(rod).

Focal choroidal excavation complicated with choroidal neovascularization: a case report and review of the literature

Dear Editor,We write to report one case of focal choroidal excavation(FCE) complicated with choroidal neovascularization(CNV), and to review the literature on FCE. FCE is a newly recognized imaging finding with the development of optical coherence tomography(OCT) technology. FCE is defined as an area of macular choroidal excavation without evidence of posterior staphyloma or scleral ectasia[1].

Dynamic Reliability Assessment of Heavy Vehicle Crossing a Prototype Bridge Deck by Using Simulation Technology and Health Monitoring Data

Overloads of vehicle may cause damage to bridge structures,and how to assess the safety influence of heavy vehicles crossing the prototype bridge is one of the challenges.In this report,using a large amount of monitored data collected from the structural health monitoring system(SHMS)in service of the prototype bridge,of which the bridge type is large-span continuous rigid frame bridge,and adopting FEM simulation technique,we suggested a dynamic reliability assessment method in the report to assess the safety impact of heavy vehicles on the prototype bridge during operation.In the first place,by using the health monitored strain data,of which the selected monitored data time range is before the opening of traffic,the quasi dynamic reliability around the embedded sensor with no traffic load effects is obtained;then,with FEM technology,the FEM simulation model of one main span of the prototype bridge is built by using ANSYS software and then the dynamic reliability when the heavy vehicles crossing the prototype bridge corresponding to the middle-span web plate is comprehensively analyzed and discussed.At last,assuming that the main beam stress state change is in the stage of approximately linear elasticity under heavy vehicle loads impact,the authors got the impact level of heavy vehicles effects on the dynamic reliability of the prototype bridge.Based on a large number of field measured data,the dynamic reliability value calculated by our proposed methodology is more accurate.The method suggested in the paper can do good for not only the traffic management but also the damage analysis of bridges.

周边孔聚能装置间隔装药在光面爆破中的应用研究

隧道光面爆破工程的周边孔需要采用间隔装药方式,而大部分间隔装药方式采用“导爆索+雷管”联合起爆技术,此技术具有一定的局限性且经常发生拒爆现象。如何在保证隧道掘进效率的前提下提高光面爆破效果成为目前亟待解决的难题,从现场试验方面开展相关研究,提出“聚能装置+数码电子雷管”新型联合起爆技术,将其应用于高原某隧道,通过与原始的“导爆索+数码电子雷管”联合起爆技术的爆破后效果进行对比分析。实验结果表明:对比原始技术,新技术炸药单耗降低了0.2 kg/m^(3),半孔留痕率提高了5%,平均装药时间由原来的1.3 h降为1.0 h,稳定循环进尺的同时极大降低了耗材费用,提高了隧道光面爆破效果。

上海轨道交通车站暗挖技术应用与探索

[目的]上海的城市轨道交通经过多年发展,现已面临极其复杂和严苛的工程建设环境,地下车站大开挖导致的交通拥堵、房屋拆迁和管线搬迁等问题已逐渐成为社会舆论的焦点。针对地铁建设与周边环境的冲突与矛盾,上海轨道交通通过持续科技攻关和试验论证,提出了多项软土地层暗挖技术。[方法]介绍了暗挖技术的发展历史和应用现状;基于上海轨道交通建设的特点,介绍了上海轨道交通暗挖技术中顶管法、冻结法和管棚法的具体内涵及应用情况;探讨了大断面顶管法、超长特大断面管幕法、超浅埋大断面冻结法和束合管幕法等新型暗挖车站建造技术的研究和试点应用情况。[结果及结论]上海轨道交通暗挖技术主要包括盾构法、顶管法、冻结法、管棚法以及其他特殊暗挖工法,已广泛应用于地下区间工程、区间联络通道工程、车站附属结构工程以及车站局部改造工程等;新型暗挖车站建造技术能够有效应对新条件下上海轨道交通建设的特点和面临的挑战。

农用挖掘机卷筒虚拟装配规划设计与研究--基于CAM技术

首先,采用CAD软件对农用挖掘机卷筒结构进行了设计;然后,对结构的受力情况进行了分析;最后,基于CAM和VR技术实现了对农用挖掘机卷筒装配规划的设计与应用。仿真实验验证了此方法具有可行性,可对装配过程实现优化,大大提高设计效率。

《现代养猪技术》课程思政实践与评价

大思政背景下,课程思政是实现人才培养目标的“助推器”。该文从课程特点、思政元素挖掘、课堂呈现和实践效果的调查等方面详细的阐述了高职畜牧兽医专业群《现代养猪技术》课程思政改革与实践,以期为同类专业课的课程思政教学改革提供有益参考。

深基坑施工安全技术措施

本文主要阐述深基坑施工安全技术措施。首先分析深基坑施工安全技术措施的重要性,其次从深基坑施工前安全准备工作、基坑降排水、土方开挖、喷射混凝土及土钉施工、基坑防护、基坑监测等方面深入探讨加强深基坑施工安全的技术措施。本文旨在对深基坑施工安全措施进行分析,进一步提升深基坑施工安全技术水平,保障深基坑施工顺利进行。

硬梁包水电站方变圆大断面隧洞开挖技术

硬梁包水电站引水隧洞进口方变圆大断面洞室开挖通过先进行安全治理、锁口支护、超前预支护等措施后再进入洞段施工,先进行导洞开挖,再利用导洞开挖取得的技术参数和其所揭示的实际地质情况完成扩挖和分段分层开挖,施工时大量采用光爆和预裂爆破技术与工艺,抓住质量关键并严格过程控制,有效地保证了工程控制目标,效果明显,所取得的经验可为类似工程施工借鉴。

基于BIM技术深度策划的隧道掘进智能控制技术研究

为解决传统隧道铣挖法存在的截割作业工作环境恶劣、安全风险高、成隧质量差等问题,提出一种基于BIM和数字孪生技术深度策划的隧道掘进智能控制开挖方法。首先,通过地面综合物理探测构建隧道三维地质模型,导入隧道结构参数、设备模型、测量控制构件要素,生成基于BIM虚拟隧道掌子面场景;其次,运用BIM和数字孪生技术深度规划掘进机截割作业时截割部运动路径与轨迹,设计自动截割作业控制程序,并进行施工模拟碰撞,以提高模拟运算的准确性。结果表明,该方法解决了隧道铣挖法智能化、自动化施工水平低的问题,实现离机遥控操作自动截割作业;利用局域网和传感技术,解决高粉尘、低照度环境下掘进机截割部运动跟踪定位的难题,实现“人-机-环”全面感知;通过感知系统精确定位,跟踪测量掘进机和截割部的位姿,实现对掘进机的远程监测与控制;通过测控与传感器、计算机技术,能够精确地控制截割头位置,完成掘进断面截割自动成形;通过控制系统精确地控制,截割部运动控制精度达到±20 mm,从而有效提高隧道成形质量。

煤矿掘进机系统数字孪生技术研究

针对煤矿巷道掘进作业中,地质结构复杂、现场环境恶劣、掘进设备智能化程度低、安全事故频发等问题,提出了一种数字孪生解决方案。通过融合物联网、互联网、数字孪生和虚拟现实等技术,以PLC为硬件核心、MQTT协议和EMQX服务为基础、建立参数矩阵映射规则和故障原因分析表,实现了掘进作业数据采集与处理、设备与孪生模型间的数据映射、数据存储、作业过程仿真、远程遥控、智能故障检测与预警等功能,提升了煤矿掘进作业过程的数字化、智能化水平。研究结果表明,该方案在煤矿掘进作业过程中具备较强的可行性、可靠性和实用性,具有推广应用价值。

钢管锚锭板桩全回收基坑支护技术及模型试验研究

针对基坑工程中支护构件浪费、环境污染及高碳排放等问题,提出了一种钢管锚锭板桩全回收基坑支护技术并介绍了支护体系构成。实施了钢管锚锭板桩的大型缩尺模型试验,通过摄影测量技术(DIC和DPA)对模型板桩和管桩在开挖过程中的位移进行观测。试验结果表明:管桩的锚拉作用对结构位移具有显著限制,增加单位宽度的管桩数量可有效减小位移,管桩顶部的最大位移与开挖深度呈双曲线关系。模型地基的变形破坏形式与管桩至板桩的间距有关,随间距增加,破坏形态从管桩与板桩同时倾斜,到沿管桩位置滑裂,再到沿与板桩距离开挖深度约1.5倍的地表滑裂。开挖过程中管桩与板桩的桩顶变形基本协调一致。

煤矿采矿工程巷道掘进与支护技术策略探讨

巷道掘进与支护是煤矿采矿工程的关键性施工环节,其施工质量关乎于采矿工程建设运营过程的整体安全性。随着煤炭行业安全生产意识和要求的不断提高,人们愈发关注巷道掘进与支护环节的施工质量。基于此,本文在简要阐述采矿工程巷道施工特点的基础上,对掘进与支护施工的主要影响因素进行分析,并分别对掘进施工和支护施工的主要技术和实施要点进行探讨总结,以期为巷道掘进与支护技术的规范化、科学化实践运用提供参考和借鉴,促进煤矿采矿工程巷道掘进与支护施工质量性和安全性的进一步提升。

矿用硬岩巷道机械化掘进破岩形式研究现状及展望

硬岩巷道快速掘进是实现煤矿智能高效开采的重要环节,悬臂掘进机、TBM和底切割装备都在尝试解决这一难点,掘进技术和装备的发展直接影响采矿的安全生产和经济效益。首先,总结了悬臂掘进机在硬岩截割工况的适用范围和截齿消耗现状,分析截割破岩形式的现场试验,发现在较高的岩石强度条件下,截齿消耗量较正常磨损翻倍,掘进速度与开采速度的不匹配,严重制约了矿井生产。其次,分析了滚刀破岩形式和装备在矿山领域的应用和新产品现状,得出移动式矿用掘进设备采用滚刀挤压破岩,块状渣土少,粉末多,刀盘推力小,导致破岩能力不足。最后,分析了线性底切割破岩技术和非线性底切割技术的原理和装备研发现状。结果表明:随着振荡频率的提高,切削力显著降低,非线性底切割破岩单位体积消耗能量少,优势明显。但在硬岩条件下的掘进效率、设备稳定性等关键问题有待验证,非线性底切割技术有望突破未来矿山硬岩掘进的技术难题。

基于挖掘机匹配关键技术的履带式液压挖掘机实现高效率、低能耗研究与应用

对履带式液压挖掘机的动力系统与液压系统的现状分析和整机匹配关键技术的研究,给出提升整机生产作业效率和降低能耗的解决方案,并对履带式液压挖掘机进行常用工况下的整机性能测试,用测试数据验证匹配方案研究及改善的有效性,此研究方案为实际应用提供了理论上的依据。

煤矿井下巷道快速掘进技术的应用分析

为了解决煤矿井下巷道掘进效率低的问题,在对影响巷道掘进的因素进行分析的基础上,提出了一种新的煤矿井下巷道快速掘进体系,并对新的快速探测技术、快速支护方案和巷道掘进工艺等进行了研究。实际应用表明,采用新的快速掘进体系后,井下巷道掘进人员数量减少了18.8%,巷道掘进效率提升了57.1%。

煤矿巷道掘进技术与装备的现状及发展趋势

煤矿巷道掘进技术与装备直接影响开采环境的稳定性、安全性,同时决定着煤矿的生产效率,因此,有必要进一步分析、研究中国煤矿巷道掘进技术与装备的现状及未来的发展趋势,为煤炭行业进一步发展提供可靠性的参考。主要介绍了巷道掘进技术与装备的现状,探究了目前存在的问题,给出具有针对性的建议,同时简单分析了巷道掘进技术与装备未来的发展方向。