Digital monitoring of rotary-percussive drilling with down-the-hole hammer for profiling weathered granitic ground

Rock and geotechnical engineering investigations involve drilling holes in ground with or without retrieving soil and rock samples to construct the subsurface ground profile.On the basis of an actual soil nailing drilling for a slope stability project in Hong Kong,this paper further develops the drilling process monitoring(DPM)method for digitally profiling the subsurface geomaterials of weathered granitic rocks using a compressed airflow driven percussive-rotary drilling machine with down-the-hole(DTH)hammer.Seven transducers are installed on the drilling machine and record the chuck displacement,DTH rotational speed,and five pressures from five compressed airflows in real-time series.The mechanism and operations of the drilling machine are elaborated in detail,which is essential for understanding and evaluating the drilling data.A MATLAB program is developed to automatically filter the recorded drilling data in time series and classify them into different drilling processes in sub-time series.These processes include penetration,push-in with or without rod,pull-back with or without rod,rod-tightening and rod-untightening.The drilling data are further reconstructed to plot the curve of drill-bit depth versus the net drilling time along each of the six drillholes.Each curve is found to contain multiple linear segments with a constant penetration rate,which implies a zone of homogenous geomaterial with different weathering grades.The effect from fluctuation of the applied pressures is evaluated quantitatively.Detailed analyses are presented for accurately assess and verify the underground profiling and strength in weathered granitic rock,which provided the basis of using DPM method to confidently assess drilling measurements to interpret the subsurface profile in real time.

Performance of large-diameter pneumatic down-the-hole (DTH) hammers: A focus on influences of the hammer structure

Pneumatic down-the-hole (DTH) hammer has been extensively used in air drillings through hard and ultra-hard geological formations. Numerical modeling can offer close observation on the working behaviors by visualizing internal pressure status as well as provide reliable performance predictions for large-diameter DTH hammers to which conventional empirical and experimental approaches cannot be applied. In this study, CFD simulations coupled with dynamic meshing are utilized to simulate the air flow and piston movement inside the large-diameter DTH hammers. The numerical modeling scheme is verified against a theoretical model published in literature. Effects of structural parameters on hammer performance, including piston mass, piston upper-end diameter, piston groove diameter, and lengths of intake and exhaust stroke in both front and rear chambers, are analyzed in detail by virtue of sets of numerical simulations. The simulations suggest that changing the intake stroke of front chamber has a negligible influence on hammer performance while increasing the piston groove would lower all the four indicators of hammer performance, including impact energy, impact frequency, maximum stroke, and air consumption rate. Changing the other structural parameters demonstrates mixed effects on the performance indicators. Based on the numerical simulations, a large GQ-400 DTH hammer has been designed for reduced air consumption rate and tested in a field drilling practice. The air drilling test with the designed hammer provided a penetration rate 1.7 times faster than that of conventional mud drilling.

Analysis of effects of operating parameters on rate of penetration in drilling process with air down-the-hole hammer

Air down-the-hole(DTH)hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill,especially in some hard rocks such as granite,sandstone,limestone,dolomite,etc.with the same weight on bit(WOB)and rotations per minute(RPM).So,it has been widely used in many drilling fields including mineral resource exploration drilling,oil and gas drilling and geothermal drilling.In order to reduce drilling cost by selecting optimal drilling parameters,rate of penetration(ROP)should be estimated accurately and the effects of different factors on ROP should be analyzed.In this research,ANN model with several multi-layer perception back propagation(BP)networks for predicting ROP of air DTH hammer drilling was developed using controllable parameters such as impact energy,impact frequency,WOB,RPM and bit operating time for the formations with a certain drillability index of rock.Several BP neural networks with the different neurons in hidden layers were developed and compared for selecting optimal architecture of ANN.The effects of the drilling parameters such as impact energy,impacting frequency,WOB,RPM and bit operating time on the ROP of air DTH hammer drilling were investigated by trained ANN.From the analyses,the optimum range of drilling parameters for providing high ROP were determined and analyzed for a formation with a certain drillability index of rock.The methodology proposed in this study can be used in many mathematical problems for optimization of drilling process with air DTH hammer.

FGC-15D large-diameter DTH air hammer drilling system and its application in offshore rock-socketed pile hole drilling

In the past two decades, numerous large-diameter rock-socketed piles were constructed in China to support foundations of skyscrapers, great bridges or to retain soil in potential geological hazard areas. However, drilling large-diameter rock-socketed pile holes with conventional drilling method such as rotary drilling or cable tool drilling is time-consuming and the cost is usually very high. In order to drill large-diameter rocksocketed pile holes faster at relatively low cost, the FGC15A large-diameter DTH air hammer drilling system was developed in 1987 and was given the second-clasa award by Ministry of Geology and Mineral Resources in 1991. Since it was innovated the drilling system has been used in more than twenty important and tough pro- jects on land, and wonderful results were acquired. At the same time the large-diameter DTH air hammer drilling system was improved continuously. The FGC15D is the latest version of the technique.

Study on drilling mechanism and optimization of percussion-extruding DTH hammer bit

The authors tested the percussion-extruding Down-the-hole(DTH)hammer bit with five different structures and mainly analyzed the drilling mechanism between conical bit and stepped bit.In addition,aiming at "the pile effect" in combination with the advantage of stepped bit,we design a new cam spinning bit and test it outdoors.The result shows that using cam spinning bit can solve the problem of "the pile effect",which can also obtain higher drilling efficiency than using conical bit in high confining pressure strata.It is characterized by novel structure and high drilling speed as well as good guiding,and it is significant for improving efficiency in percussion-extruding drilling technique.

Reliability analysis of retractable drill bit with air reverse circulation used for drilling while casing

Casing-while-drilling(CWD)with down the hole(DTH)hammer drilling technology has been widely used in unconsolidated formations,due to its advantages in protecting the borehole wall,excellent rock cuttings capacity,and fast penetration rate in hard rock.As an important component of the CWD system,the structure of the retractable drill bit needs not only to ensure to form stronger reverse circulation,but also to be expandable or retractable as needed,otherwise the drill bit cannot be lift and put down smoothly in the casing,and may lead to drilling accidents.This paper developed a new type of reverse circulation DTH hammer drill bit used for CWD drilling technology.The retractable performance of this type of drill bit is studied using ADAMS software.The results show that it is smoothly expandable and retractable as designed under the conditions of the weight of the bit(WOB)of 0.5–2.0 t and the rotation speed of 30–60 r/min.To investigate the reverse circulation effect of the drill bit,Fluent software was used to simulate the flow characteristic inside it.The simulation results indicated that it can form strong reverse circulation,and the entrainment ratio h can reach 9.5%.

钻井利器的故事之“液动潜孔锤”

在各种钻探方法中,液动冲击回转钻进具有效率高、质量好、回次长、事故少、成本低等优点,而液动潜孔锤又是液动冲击回转钻进的技术核心。本文梳理了各种液动潜孔锤的结构特点及其与绳索取心钻具、孔底动力钻具相结合衍生的各种钻具,简要介绍了这一技术的典型应用案例,总结归纳了其下一步发展方向和技术难点,以期普及液动锤的应用,促进液动冲击回转钻进技术的进步。

单线隧道Ⅲ级围岩全断面不同爆破开挖工法对比

凿岩台车作为先进的隧道钻孔设备,钻孔速度快、施工安全和对环境友好,但是施工单位普遍使用积极性不高。依托秦岭太兴山长大高铁单线隧道爆破施工,综合对比分析研究了手风钻和凿岩台车2种钻爆施工方法的钻孔和装药效率、爆破超欠挖量、开挖成本、设备配件消耗费、折旧费、施工人员数量和安全性。结果表明:高铁单线隧道采用凿岩台车钻爆的施工效率低于手风钻,且凿岩台车爆破超挖量是手风钻的2倍以上,隧道爆破开挖总成本高于手风钻钻爆施工;但是凿岩台车施工安全性高,隧道掌子面施工环境友好,施工人员数量是手风钻的一半。最后指出凿岩台车钻爆是隧道爆破施工的趋势,给出了在人员培训和标准制定方面的一些建议。

潜孔冲击器钎头合金齿装配过盈量分析

潜孔冲击器钻进效率高成孔质量好广泛应用于各类成孔作业。冲击器工作过程中钎头受到活塞的高频次撞击和地层的反扭矩作用,钎头掉齿是主要失效问题。根据某石灰石矿场钎头的掉齿失效,分析了合金齿掉齿失效机理,基于厚壁圆筒理论、Tresca屈服条件和全增量理论等理论,分析并计算合金齿极限过盈量,确定过盈量合理范围。通过有限元仿真,模拟分析合金齿过盈装配过程。研究表明,过盈量不够导致固齿力小于脱齿力是发生掉齿的主因,通过分析对比理论计算与仿真模拟结果,得到合金齿装配优选过盈量为0.065 mm,能有效防止掉齿、脱齿现象发生。改进的钎头投入使用后,使用寿命较上一代有较大提升,对后续潜孔冲击器的设计与应用有一定的指导意义。

基于ABAQUS的气动潜孔锤球齿碎岩及布齿优化

为提高坚硬地层大直径潜孔锤的破岩效率与使用寿命,运用ABAQUS软件建立了球齿碎岩仿真模型,对比分析?18 mm球齿在不同钻进参数下冲击切削碎岩过程中的破碎比功、侵入深度、破碎范围与应力影响范围等曲线,优选钻进参数和布齿。分析结果表明:当钻压为1.2 kN、冲击功为30 J时,对岩石的破碎效率较高,球齿入岩的位移可达0.67 mm,并对岩石进行应力界限划分,得出应力影响范围为43.4 mm;通过双齿冲击切削模拟确定了较为优秀的圈距与间距:圈距取47.4 mm,间距取43.4~51.4 mm;考虑到球齿的磨损,利用圈距与间距对?711 mm大直径潜孔锤进行了优化布齿。

一种双臂露天钻机

介绍了一种新型双臂露天钻机的结构设计及工作原理,该机双钻臂同时运行的作业方式,大幅提高了工作效率,实现了可回转车身工作范围内的精准定位。该机器采用柴电双动力驱动,能耗低、污染小,且机动灵活。该机器配置多种位置传感器反馈控制以校准车身及钻杆,配合液压千斤顶固定支撑,大范围高效作业的同时兼具稳定性。

武汉长江Ⅰ级阶地原状土样获取技术研究

本文分析了原状土样获取的技术标准现状和行业现状,研究了钻进方式、取样工具选取的适宜性综合分析、土样的封装及运输。对比试验研究表明,在武汉长江Ⅰ级阶地粘土层段采用锤击钻进配合使用敞口薄壁取土器,在砂土层采用锤击和回转组合钻进配合使用内置环刀取土器,辅以胶盖自封和胶带密封,取得的原状样品在现场质量评测、室内样品制备性和试验性方面均有比较良好的表现,基于此套方法获取的原状样原始结构受扰动较小,土的原始结构力保持良好。

高能液动锤超硬岩快速钻进成套装备与技术

当煤矿井下瓦斯抽放孔钻孔施工中遇到f≥12的岩层时,采用PDC钻头的回转切削效率极低。为解决煤矿井下硬岩钻进的技术难题,提出了煤矿井下高能液动锤的成套配置方案。采用该技术方案开展了井下钻孔试验。试验结果表明,在石英砂岩(10≤f≤12)中,机械钻速18.63~32.84 m/h;在硅质泥岩(12≤f≤17)中,平均机械钻速21.91 m/h。为煤矿井下硬岩钻进提供了一种新技术,可提高煤矿硬岩钻进效率。

云南某铅锌矿区复杂地层钻探施工技术应用研究

云南某铅锌矿区地质条件复杂,岩石松散破碎,泥岩、页岩及煤系层发育,钻探施工中存在孔壁垮塌、缩径、卡钻、埋钻和成孔难度大、岩心采取率低等难题,施工进度慢,效率低。结合矿区复杂地层特点,通过采用金刚石底喷钻头、跟管钻进技术、高密度低失水泥浆等一系列钻探技术措施,应用绳索取心液动锤钻进技术,有效减少了孔内事故的发生,平均四次进尺提高22.97%,为项目的安全、高效和优质完提供了坚实的技术保障,为类似复杂地层的施工积累了经验。

矿山抢险救援钻孔施工工艺分析与优化——以笏山金矿抢险救援为例

快速、精准钻探是矿山事故抢险救援的重要手段之一。本文以笏山金矿抢险救援钻探施工为例,针对钻探地层、施工工艺、钻进流程等进行分析,合理搭配钻具组合,有效控制井斜,解决了快速钻进钻孔易偏斜、钻进效率低等问题,保证了钻孔的一次性成孔到位,达到了快速精准透巷、及时施救的目的,对于今后应急抢险救援钻探施工具有一定的参考价值。

基于ABAQUS仿真的水下液压破碎锤凿岩施工参数设计

针对液压破碎锤水下凿岩施工无法可视化、施工参数难确定的问题,采用ABAQUS仿真平台进行水下液压破碎锤凿岩模拟,对凿岩施工参数设计进行理论研究。不同型号破碎锤的冲击能大小对凿岩速度的影响很大,为获得理想的施工效率,需根据岩石参数选择破碎锤型号。研究发现3个自由面条件下凿岩产生2个方向的劈裂效果,随着凿岩布孔间距少量增大,凿入深度变化不大,但劈裂效果产生的深度变化较大。对于航道疏浚平整度要求高的情况下,选择凿入深度和产生劈裂效果深度相当的布孔参数,施工效率和施工质量均能达到理想的效果。

预应力混凝土管桩施工技术选择与应用

针对锦绣华庭项目复杂的地质条件,通过现场分别进行静压沉桩法与锤击沉桩法沉桩试验,总结分析两种不同沉桩方式的优缺点。通过考虑施工工艺的适用性和可改进性,以及工期、经济及社会效益等方面,最终选择更适合本项目施工的锤击沉桩法。但锤击沉桩法施工噪声和振动非常大,而项目位于古遗址、古文物区域及城区居民区,对施工振动、噪声控制等文明施工要求很严格。因此,对锤击沉桩施工方法进行了改进,以减少噪声和降低振动,同时达到了速沉桩、成桩率高的目的,并且克服了传统植桩法在复杂地基施工过程中遇到的难题,为以后相近条件的项目施工提供参考。

煤田地质单位地热资源勘查技术探析

地热资源是一种宝贵的可再生能源。地热资源中的热能、地热流体等是一种具有较高社会利用价值的热能。经过地质勘探,地热资源中可利用的主要是自然形成的温泉和浅层的地热能。分析了煤田地质单位在地热资源勘查中钻井方法薄弱、钻井效率低、施工周期长的现状,并预测了未来的发展趋势。通过概述中国地热资源的分布情况,分析和总结了地热资源复杂的地质特征和形成原因,列举了各种地质情况对钻井施工的主要影响,并给出了相关的技术措施。

双动力潜孔锤成孔灌注桩在建筑工程中的应用

在桩基施工中,钻孔灌注桩使用泥浆护壁施工,会对环境造成严重的污染,而夯击、挤压和振动的桩施工同样会对周围地层产生严重的扰动,对周边建筑物造成影响和损坏。为解决这些长期困扰桩工行业的难题,双动力多功能钻机应运而生。双动力多功能钻机与大直径潜孔锤的组合工法中,一次性入岩直径大、入岩效率高、无泥浆污染排放,可实现绿色环保施工,配置相应辅助装置及设备后,还可以进行中掘法压入预制桩、植入预制桩、深层搅拌软土改良加固处理、水泥混合土连续墙施工等。本文对双动力潜孔锤成孔灌注桩的施工方法在建筑工程中的应用进行了探讨和分析。

凿岩锤工艺在胶结砂施工中的工艺优化

胶结砂的工程性质与页岩和砂岩存在一定的差别,使用抓斗船组配置凿岩锤破碎、清渣作业时,需要根据胶结砂的分层情况、物理特性,调整施工工艺参数、优化设备、创造施工条件,以提高凿岩效率,从而提高施工效率,并保证施工安全。本文结合阿尔及利亚斯基克达油气港改扩建项目疏浚吹填工程施工,介绍了项目面临的胶结砂特点、采用的凿岩设备、抓斗配合凿岩棒的基本工艺等,从工程特点、施工机具调整、凿岩工艺阶段性调整等对凿岩工艺的优化思路和方向进行了阐述。