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.

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.

基于弹丸膛内运动参数和压力测试的火炮膛内燃气温度估算方法

为了解决火炮膛内测试环境恶劣而导致发射药燃气温度测试难度大的问题,基于微波干涉仪、压力测试系统,结合发射药配方性能计算理论、装药内弹道性能计算模型等理论,建立了一种基于实测参数的火炮膛内燃气温度估算方法,并开展了试验研究。结果表明:火炮膛内燃气温度的最高值约为2631.8 K,随着弹丸运动迅速降低,弹丸出炮口时膛内燃气温度降低到约1858.4 K;建立的火炮膛内发射药燃气温度估算方法可以有效地获得火炮整个内弹道过程中火药燃气温度随时间的变化规律,为低烧蚀发射药及装药的研制提供了一种新的研究手段。

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. .

Experimental study and numerical analysis on bearing behaviors of super-long rock-socketed bored pile groups

A centrifuge modeling test and a three-dimensional finite element analysis（FEA）of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypical materials are simulated using different indicators in the centrifuge model.The silver sand,the shaft and the pile cap are simulated according to the natural density,the compressive stiffness and the bending stiffness,respectively.The finite element method（FEM）is implemented and analyzed in ANSYS,in which the stress field during the undisturbed soil stage,the boring stage,the concrete-casting stage and the curing stage are discussed in detail.Comparisons in terms of load-settlement,shaft axial force distribution and lateral friction between the numerical results and the test data are carried out to investigate the bearing behaviors of super-long rock-socketed bored pile groups under loading and unloading conditions.Results show that there is a good agreement between the centrifuge modeling tests and the FEM.In addition,the load distribution at the pile top is complicated,which is related to the stiffness of the cap,the corresponding assumptions and the analysis method.The shaft axial force first increases slightly with depth then decreases sharply,and the rate of decrease in rock is greater than that in sand and soil.

三维适形放疗Philips Big Bore CT配合高压注射器的模拟定位技术的应用

目的:探讨Philips Big Bore CT模拟定位机配合强化扫描技术在三维适形放疗中的应用价值。方法:115例患者应用Philips Big Bore CT模拟定位机和安科公司ASA-200高压注射器,使用非离子造影剂进行强化扫描,全程由主管医生陪护。结果:115例患者顺利完成CT模拟定位强化扫描,与CT平扫相比良好地显示了肿瘤区(GTV),满足三维适形放疗或三维适形调强放疗精确勾画靶区的要求。结论:三维适形放疗时应用Philips Big Bore CT模拟定位机是完成各种复杂被动体位及同步固定模具扫描的基本保证,同时配合使用高压注射器强化扫描技术是精确勾画肿瘤区(GTV)、提高肿瘤放疗治愈率的有效措施之一。

全脉冲反射超深钻孔灌注桩浇筑界面检测方法研究

超深钻孔灌注桩的浇筑施工阶段质量控制是工程质量控制的重点和难点,文章针对传统混凝土浇筑界面检测方法在测试效率与稳定性方面存在的技术不足,提出一种基于超声波全脉冲反射的超深钻孔灌注桩混凝土界面检测方法。首先,通过构建能够解决灌注桩混凝土界面实时检测的超声波全脉冲反射技术体系,来实现技术方法的仪器设备研制与理论模型分析;随后,结合全脉冲信号的声学特征,提出目标信号识别方法,来精准定位斜面与标定反射回波的信号前缘时刻;最后,通过形成目标回波信号校验准则,来有效区分具有复杂性和动态性特征的钻孔内介质声学特征;同时,本文结合实地测试数据,来验证本文方法的可行性和正确性。通过本文方法研究,说明本文方法能够实现考虑浮浆层的超深钻孔灌注桩混凝土浇筑界面检测,有助于提高测试效率与稳定性,具有广阔的应用前景。

IMPROVEMENT OF MACHINING ACCURACY OF CANTILEVER BORING BAR SYSTEM USING PIEZOELECTRIC ACTUATOR

This paper is concerned with the work involved in improving the machining accuracy of a cantilever boring bar by on line compensation with a piezoelectric actuator. A boring bar is made into lever structure, with strain gauges attached to the bar for measuring its force induced deflections. The piezoelectric actuator is employed to compensate the deflections of the boring bar for accuracy improvement. Due to the mechanical advantage of the structure, the boring bar can be made into smaller size. The diameter of the bar implemented is 10 mm and the ratio of length to diameter (L/D) is larger than 8. It is found that the machining accuracy is improved considerably by using the piezoelectric actuator compensation system.

Research on the Dynamic Model of Spindle Rotation Induced Error Compensation System of Boring and its Simulation

In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.

预切缝辅助TBM滚刀破岩贯入荷载演化规律

基于全断面隧道掘进机(Tunnel Boring Machine,TBM)滚刀贯入室内模型试验,研究了3种不同破岩模式(完整岩样破岩、同轨迹破岩和异轨迹破岩)在不同围压条件下高强度花岗岩样贯入荷载演化特征,重点揭示贯入荷载-贯入度特征曲线、峰值荷载、最大跌落幅值变化规律,获取不同破岩模式在不同围压条件下TBM滚刀受力特性。结果表明:1)高围压组贯入荷载-贯入度特征曲线较低围压组先跌落,跌落幅度较小,但其对应的贯入荷载并非峰值荷载,而低围压组初次跌落荷载为峰值荷载,且跌落幅值较大;2)在中高围压10~15 MPa时,峰值荷载及贯入荷载最大跌落幅值均最小,表明此围压范围较利于TBM的掘进;3)低围压条件下选用异轨迹破岩模式较同轨迹破岩模式能更有效地降低TBM滚刀贯入荷载,但同轨迹破岩模式的岩样发生楔裂破坏,其最大跌落幅值最小,更能减少刀具所受冲击荷载,减少刀具磨损。

TK6926重型落地镗铣床静态、模态、热态性能仿真分析与实验测试

以TK6926重型落地镗铣床为对象,采用仿真分析和实验测试相结合的方法研究了其静态、模态、热态性能。建立了TK6926重型落地镗铣床的三维实体模型,添加边界条件后仿真得到了机床的静刚度、固有频率、模态振型、温度场和热变形;搭建了实验系统,测量得到了机床的静态、模态、热态性能参数,并与仿真结果进行了对比。结果表明,机床3个方向静刚度的仿真误差不超过14%,前3阶固有频率的仿真误差不超过15%,关键温度点和3个方向热变形的仿真误差都不超过20%。对大型机床整机静态、模态、热态性能仿真分析与实验测试具有指导意义。

顶管诱发条形基础沉降特征分析

顶管开挖将引起地表扰动,影响地面构筑物的安全。为了研究顶管施工对条形基础沉降的影响,依托合肥市顶管涵洞下穿既有建筑工程,采用有限元软件仿真计算顶管下穿过程,研究施工过程中条形基础的沉降特征,分析土仓压力、注浆压力、顶管直径和埋深对条形基础沉降的影响规律。研究表明,土仓压力增大会减小基础中心的沉降;注浆压力提高会使基础的初始隆起和其后沉降加剧;管径增加会减少基础边缘的沉降,当管径为3 m时基础中心沉降最大,为5.59 mm;随着埋深的增加,土仓压力和注浆压力对基础的影响减弱,但顶管沿轴向扰动范围扩大,5 m埋深时沉降量最大,为5.49 mm;顶管施工时,应考虑建筑基础在顶进扰动过程中的局部倾斜值是否满足要求,建议使用较小注浆压力和较大埋深,并选用合适管径。

航空燃油系统方孔滤网过滤机制及影响因素研究

方孔滤网是航空燃油系统典型的污染控制元件,易出现堵塞等问题,严重影响滤网及系统可靠性。运用流体仿真软件建立了方孔滤网简化模型,采用CFD-DEM耦合的方法,研究方孔滤网元件过滤过程,分析油液清洁度、滤网精度对过滤效率的影响。结果表明:滤网过滤初期主要是表面介质过滤,小于网孔颗粒群卡滞网孔是滤网过滤中期拦截的关键。颗粒浓度和滤网精度对滤网过滤效率有重要影响。颗粒浓度越高,颗粒过滤效率越低;相同颗粒在通过不同规格滤网时的过滤效率存在较大差异,其中滤网规格越小,通过的过滤速度越低,过滤效率越高,拦截颗粒越多。在保证过滤性能情况下,滤网规格选用精度可提高一级。

Philips公司Brilliance CT Big Bore大孔径4DCT常见故障及处理方法

以实例方式介绍Philips公司Brilliance CT Big Bore大孔径4DCT扫描时几类常见的故障现象及其处理方法。

钻孔灌注桩施工对地层及既有管沟振动影响规律研究

[目的]钻孔灌注桩旋挖成孔过程中会对地下既有建构筑物造成振动影响,因此需对旋挖成孔过程中引起的地层和建构筑物振动响应进行研究。[方法]以济南地铁4号线的车站基坑开挖工程为背景,通过现场测试及基于三维有限元模型的数值模拟方法,针对振源距离、埋深、开挖深度、电力管沟不同位置、同时施工桩数等因素对旋挖施工引起的土层和电力管沟振动影响规律进行了分析。[结果及结论]距离振源越近处的土体和既有管沟受到的振动影响越大,距离振源超过6 m之后的土体和既有管沟受到的振动影响可忽略;随着埋深的增加,土体受到的振动影响呈现减小趋势;开挖深度至12 m后,对浅层埋深管沟的振动影响可忽略不计;测点与振源处于同一深度时,测点处振动影响最大;随着同时施工的两桩净距减小,振动速度峰值呈现升高趋势,当同时施工的两桩净距10 m时可忽略振动耦合效应。

灌注桩后注浆施工技术在建设工程施工中的应用

传统钻孔灌注桩容易出现泥皮、沉渣等问题,影响灌注桩的成桩质量。为提升钻孔灌注桩的承载力与整体质量,灌注桩后注浆施工技术得到了广泛应用。文章首先阐述了灌注桩后注浆施工技术的原理;然后分析了灌注桩后注浆技术的参数设定方法;最后选取某建设工程为研究对象,研究了灌注桩后注浆施工的工艺流程及施工要点,同时提出了施工质量控制措施,为后续类似工程建设提供了借鉴。

复杂地质环境下桥梁钻孔灌注桩施工关键技术研究

钻孔灌注桩作为桥梁工程的基础,由于受复杂地质环境影响较大,其施工工序复杂,施工质量并不可控,从而导致工程事故频发。本研究以新疆某公路桥梁的桩基础工程为背景,计算了其钻孔灌注桩成桩质量的合理性,并通过COMSOL有限元数值模拟软件,计算了单根钻孔灌注桩在不同荷载条件下的应力分布和沉降变形情况。研究结果表明,数值模拟方法能够较好地模拟灌注桩的荷载–沉降变形过程,辅助实际监测结果确定桩的极限承载力,在一定程度上加快施工进程,降低工程风险。

Design Theory of Full Face Rock Tunnel Boring Machine Transition Cutter Edge Angle and Its Application

At present, the inner cutters of a full face rock tunnel boring machine (TBM) and transition cutter edge angles are designed on the basis of indentation test or linear grooving test. The inner and outer edge angles of disc cutters are characterized as symmetric to each other with respect to the cutter edge plane. This design has some practical defects, such as severe eccentric wear and tipping, etc. In this paper, the current design theory of disc cutter edge angle is analyzed, and the characteristics of the rock-breaking movement of disc cutters are studied. The researching results show that the rotational motion of disc cutters with the cutterhead gives rise to the difference between the interactions of inner rock and outer rock with the contact area of disc cutters, with shearing and extrusion on the inner rock and attrition on the outer rock. The wear of disc cutters at the contact area is unbalanced, among which the wear in the largest normal stress area is most apparent. Therefore, a three-dimensional model theory of rock breaking and an edge angle design theory of transition disc cutter are proposed to overcome the flaws of the currently used TBM cutter heads, such as short life span, camber wearing, tipping. And a corresponding equation is established. With reference to a specific construction case, the edge angle of the transition disc cutter has been designed based on the theory. The application of TBM in some practical project proves that the theory has obvious advantages in enhancing disc cutter life, decreasing replacement frequency, and making economic benefits. The proposed research provides a theoretical basis for the design of TBM three-dimensional disc cutters whose rock-breaking operation time can be effectively increased.

TBM在煤矿岩巷掘进中的应用研究

文章针对煤矿岩巷掘进复杂多变的地质条件和施工需求,阐述了全断面隧道掘进机(tunnel boring machine,TBM)的工作原理、结构组成和工艺特点,并通过实际案例,分析其在煤矿岩巷掘进中的应用效果。研究发现,TBM在掘进速度、施工安全性、企业效益等方面均表现出显著的应用优势。同时,由于TBM在使用中面临地质条件复杂、设备维护成本高、对操作人员技术水平要求高等问题,提出了相应的解决方案和优化建议,旨在进一步推动TBM在煤矿岩巷掘进中的广泛应用,为类似工程提供参考。