Optimizing support performances of bolt reaming and anchoring in a coal drift

In current practice of bolt reaming and anchoring of roadways in soft coal and rock mass,resin cartridges bend easily under the strong pushing and stirring of bolts,and the resin accumulates in the bolt-reamed area and does not participate in the stirring.As a result,bolts encounter high drilling resistance and cannot reach the bottom of drillholes.The effective anchorage length is far less than the actual anchorage length.Bolts are not centered,and the shear is misaligned at the joint surface in the reaming area,which leads to cracking of the whole anchoring solid and large shear deformation of bolts.This study systematically analyzes the characteristics of roadway bolt reaming and anchoring.The influences of resin stirring force,bolt pull-out force,and reamingeanchoring solid strength on reamingeanchoring performance were analyzed theoretically.The main purpose is to develop a device that enhances reaming and anchoring.The mechanism through which the device strengthens the reamingeanchoring solid was analyzed theoretically.Numerical simulation and experiments were carried out to verify the improved performance of the small-pore reaming and anchoring using the proposed technology.The results showed that the stirring migration rate of the resin cartridge is greatly improved by adding the device to bolts.The reaction rate of the anchoring mixture,stirring pressure,pull-out force of the reaming and anchoring system,bolt concentricity,and shear and compressive strengths of the anchoring solid are also enhanced in the reaming area.This ensures that the resin cartridge in the reaming area is completely stirred,which greatly improves the shear resistance of the reamingeanchoring solid.Meanwhile,the drilling performance,torsional force,and stirring efficiency of bolts are maximized and prevail over those of conventional bolts.

Cuttings transport: Back reaming analysis based on a coupled layering-sliding mesh method via CFD

Inadequate hole cleaning is one of the main reasons for inefficient operations in extended-reach drilling.The mechanism of cuttings transport under the back reaming operation,which is frequently adopted to remove the cuttings,has been investigated in this study.To this end,a coupled layering-sliding mesh method with the Eulerian-Granular approach has been established innovatively.The dynamic layering method has been employed to simulate the axial motion of the pipe,whereas the sliding mesh method has been used to simulate the pipe rotation.The back reaming operation of a connector-furnished pipe has been simulated,and the sensitive parameter analysis has been conducted.The results thus obtained demonstrate that the increase in the initial bed height,inclination,and the diameter and length of the connector causes a significant increase in the cuttings concentration.In addition,the cuttings concentration is observed to decrease significantly with the pipe rotation speed.Furthermore,two main factors contribute towards the cuttings accumulation around the connector,namely,the difference in the cross-sectional area and the pushing effect of the connector—like a“bulldozer”.The“bulldozer”effect of the connector dominates when the tripping velocity is significant compared to the velocity of the cuttings.Conversely,the effect of the difference in the cross-sectional area becomes the leading factor for cuttings accumulation.The“bulldozer”effect of the connector causes a more severe impact on hole cleaning.In both cases,increasing the tripping velocity only mildly affects the cuttings concentration.It is therefore suggested that the tripping velocity should be slower than that of the sand during the back reaming operation.Furthermore,increased fluid velocity might lead to a higher accumulated cuttings concentration around the connector when the cuttings bed has not entirely passed through the connector.A significant flow rate can be safely applied after the cuttings have passed through the connector furnished with a large diameter,such as the bottom hole assembly.This exploration serves as an essential guide to predicting and controlling tight spots while back reaming.

Experimental research on characteristics of hole reaming and side cutting of one-cone bits

The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than the bit diameter due to side force. However, the reaming effect was not very apparent, whether drilling with an offset or conventional one-cone bit. The side cutting displacement increased gradually with increasing depth of drilling and side force. The side cutting displacement of offset onecone bits was larger than that of conventional ones under the same conditions of weight-on-bit （WOB）, rotary speed, side force and borehole depth.

Vigorous Endosteal Reaming across Fracture Site to Aid Union in Atypical Femur Fractures

Background: Bisphosphonate abuse is associated with atypical femur fractures, which despite different fixation methods have increased non-union, delayed union, and re-operation rates. Therefore, there is a need for a surgical technique that may enhance union in such cases. Herein we are introducing a novel technique of sequential multiple vigorous reaming across the fracture site to introduce reaming debris/endosteal bone graft around the fracture site. Materials and Methods: We present a retrospective analysis of five prospectively treated patients with atypical diaphyseal femur fracture who presented to us from January 2015 to August 2019. All the patients were followed up at regular intervals and assessed both clinically and radiologically. Results: All 5 cases operated with our technique showed union at a mean follow-up of 16 weeks (12 - 20 weeks). There were no complications reported in our study at the last mean follow-up of 25 months (12 - 51 months). Conclusion: This technique of multiple vigorous reaming at and around the fracture site provides a new paradigm in the management of AFF. The autograft around the outer cortex promotes the formation of bridging callus and results in the early union.

髋臼一次磨锉成形在初次全髋关节置换中的应用

目的回顾性分析应用髋臼一次磨锉成形在初次全髋关节置换中的临床效果。方法2018年1月至2023年1月,江苏省泰州市中医院收治70例单侧髋关节行初次THA的患者。其中,35例采用髋臼一次磨锉成形,为一次磨锉成形组;另35例采用传统方法从最小号髋臼锉开始磨锉,直至软骨下骨出现均匀渗血,为传统磨锉方法组。两组髋臼磨锉结束后再将相应型号的髋臼假体按预定角度打入,股骨侧处理方法一致。记录两组的手术时间、术中出血量,术后髋臼假体前倾角、外展角及Harris髋关节功能评分。结果一次磨锉成形组的手术时间和术中出血量明显少于传统磨锉方法组,差异有统计学意义(P<0.05);两组的平均髋臼前倾角和外展角均在安全范围内,差异无统计学意义(P>0.05);术后2周Harris髋关节功能评分一次磨锉成形组优于传统磨锉方法组,但差异无统计学意义(P>0.05)。两组患者术后3个月门诊复诊均无异常情况。结论髋臼一次磨锉成形可以减少髋臼磨锉失误,缩短手术时间,减少术中出血量,加速患者康复。

股骨近端防旋髓内钉-Ⅱ治疗31-A3型股骨转子间骨折扩髓与否的有限元分析

背景:针对股骨转子间骨折是否需要扩髓的问题尚有争议,一些人认为不扩髓缩短手术时间、减少出血、降低高龄患者术中风险,但此举是否会降低髓内钉支撑效果,尚无依据。另一些人认为扩髓可选择直径更粗的髓内钉,获得更好的力学支撑,但基础研究显示此方法存在脂肪栓塞、破坏骨质(尤其高龄骨质疏松患者)等风险。目的:通过有限元分析股骨近端防旋髓内钉-Ⅱ治疗31-A3型股骨转子间骨折时扩髓与不扩髓的力学分布特点。方法:纳入一名健康志愿者,CT扫描其股骨获取DICOM格式文件,顺序导入Mimics、Geomagic Wrap、SolidWorks、Hypermesh、Ansys软件处理文件,得到A3.1型、A3.2型及A3.3型股骨转子间骨折模型,分别与9,11 mm直径、170 mm长度的股骨近端防旋髓内钉-Ⅱ进行装配,赋予材料属性,设定各接触面相互作用关系及定义载荷及边界条件,之后进行求解。观察不同模型中股骨应力分布、内固定应力分布、股骨位移及内固定位移情况。结果与结论:①各型骨折采用扩髓髓内钉固定时股骨应力均小于非扩髓髓内钉固定,A3.3型骨折股骨最大应力值大于A3.1型和A3.2型;②各型骨折采用扩髓髓内钉固定时内固定应力均大于非扩髓髓内钉固定,A3.3型骨折内固定最大应力值大于A3.1型;③扩髓与非扩髓对股骨及内固定位移影响较小,应力影响较大;④提示采用扩髓髓内钉固定可使股骨应力减小,内固定整体承担应力增大,远端锁钉承担应力减小;与非扩髓髓内钉固定相比,采用扩髓髓内钉固定可能会提供更好的治疗效果。

单级套管扩孔一次跟进钻孔技术在滑坡治理中的应用

河南某山地滑坡前后两次治理,效果欠佳,滑坡体未得到有效抑制。工程预应力锚索需穿越残积层与各风化层中成串孤石群及中风化岩层中发育的破碎带,成孔深度长、孔径大。解决成孔中塌孔、卡钻、埋钻等问题,确保成孔质量,成为本滑坡治理工程施工难点与重点。基于此,采用了单级套管扩孔一次跟进钻孔技术。本文详细介绍其基本原理和施工技术要点,并对其治理效果评价分析,结果表明,利用单级套管扩孔一次跟进钻孔技术不仅可较好地对滑坡体进行治理,且可缩短工期、减少施工成本。

机械扩孔煤体增透应力变化规律研究

机械扩孔作为一种新型煤层卸压增透强化措施,可广泛适用于低透气性瓦斯煤层。为了探究机械扩孔应力演化规律,通过理论分析,揭示机械扩孔应力分布特征,以车集煤矿2616煤层为研究背景,借助ABAQUS数值模拟软件分析扩孔过程中煤层应力演化规律。结果表明:机械扩孔后孔洞周围煤体应力场存在动态演化过程,由内向外呈圆环状分布,依次为破碎区、塑性区、弹性区和原始应力区;机械扩孔过程中造穴阶段应力扰动范围和应力集中情况都显著大于钻进阶段。

自张式膨胀管技术的研究与应用

孔内膨胀管钻探技术是保障复杂地层孔壁稳定的有效技术之一。本文针对易出现缩径、坍塌、掉块的强水敏性地层,提出了一种自张式膨胀管护壁方法,并根据该方法的护壁原理研制了相适配的新型扩孔钻具、膨胀管及膨胀管投送装置,在不改变钻孔结构的情况下,对复杂孔段进行局部扩孔,投送膨胀管借助自身张力自然弹开而固定在相应的扩孔段,实现钻进时护壁。通过室内及现场试验对机具进行了优化,最终取得了良好的应用效果。试验证明:该方法操作简单可靠、易于定位,相较于水泥浆护壁具有处理速度快、停待时间短、减少重复处理等优势,适用于岩心钻探领域多孔段复杂地层的固壁与护壁,有利于降低孔内事故处理的成本、提高钻进效率,具有较好的推广应用价值。

不同钻进参数下反井钻机扩孔钻进速率与岩渣特征试验研究

通过不同钻进参数下反井钻机扩孔钻进斜井的现场工程测试与室内岩渣筛分试验,分析了不同钻进参数下扩孔钻头破岩钻进速率及其岩渣特征。结果表明:在单轴平均抗压强度41.6 MPa的砂岩地层中,获得了斜井反井钻机扩孔钻压、转速、扭矩等钻进参数与钻进效率之间相关关系;在试验范围内随钻压增加,扩孔钻进速率不断提高;在钻压为14 MPa、转速为9 r/min时,获得的最大扩孔钻进速率为1.41 m/h;在相同转速条件下,随着钻压增加,扭矩也同步升高,而扭矩与钻进速率之间呈线性正相关关系;通过筛分岩渣分析,扩孔钻头破岩形成的岩渣形态分为<0.50 mm的粉末状、0.50~<5.00 mm的颗粒状、5.00~40.00 mm的薄片状和>40.00 mm的大块板状或肋条状4类,岩渣粒度在10.00~20.00 mm范围内占比相对较高。研究成果可为快速判识反井钻机扩孔钻进效果和围岩稳定状态提供理论支撑。

导向槽定向水力压裂煤层增透强化瓦斯抽采技术及应用

针对低透气性高瓦斯煤层预抽瓦斯困难问题,提出导向槽定向水力压裂煤层增透技术,通过理论推导计算煤层段扩孔后塑性区分布,分析穿层钻孔煤层段水压裂缝的起裂与扩展,揭示导向槽定向水力压裂煤层增透的力学机制,研发导向槽定向水力压裂煤层增透装备。在山西中兴煤矿进行现场应用,结果表明:利用水射流方法对穿层钻孔煤层段进行扩孔,使得煤中产生形似圆柱孔洞,穿层钻孔围岩塑性区半径与钻孔半径成正比,钻孔扩孔是增大塑性区范围的一种有效方法,裂隙扩展明显,瓦斯采出率提高。同时研发了一种导向槽定向水力压裂防突成套装备,主要部件有移动高压水力泵站、喷头、喷嘴、螺旋辅助排渣水射流高压钻杆、孔口防喷装置以及高压旋转接头,结合井下水力化作业远程监测和控制,现场监测结果表明,通过增透作业钻孔的方法,平均瓦斯浓度和瓦斯抽采混合量提高到常规孔的2.75倍和1.81倍,说明采取导向槽定向水力压裂措施的增透效果显著。

特厚煤层孤岛煤柱水力扩孔防冲卸压技术研究

砚北煤矿2502采区大巷保护煤柱两侧采空,为孤岛煤柱,应力集中程度高,由于煤层较厚,传统大直径钻孔卸压无法取得较好的防冲效果,针对该问题,提出了煤层水力扩孔卸压的技术。通过理论分析研究了水射流破煤和扩孔的卸压机理,水力扩孔通过增加钻孔孔径扩大了单孔的卸压范围;确定了砚北煤矿特厚煤层水力扩孔的主要技术参数,采用数值模拟分析了钻孔内分段扩孔的卸压模式;开发了相应的配套设备,采用双层高压钻杆实现煤体的“钻-割”一体化卸压,提高了卸压效率。通过砚北煤矿现场试验表明,煤层水力扩孔在水压40 MPa和高压喷嘴作用下,扩孔半径能够达到0.35~0.5 m,钻屑量在扩孔区域明显降低,表明水力扩孔能够显著降低煤体内应力集中,达到冲击地压防治的目的。

汽车车轮用高扩孔率热轧复相钢带的研制

设计了一种微合金化的汽车车轮用高扩孔率热轧复相钢,并对其进行了工业试制。采用金相检验、力学性能测试等方法研究了高扩孔率热轧复相钢的显微组织及力学性能。结果表明:试制产品的显微组织主要由贝氏体、铁素体构成,还分布有少量的马氏体、残余奥氏体以及弥散析出的第二相粒子,产品的屈服强度、抗拉强度、断后伸长率分别超过了520,610MPa和24%,屈强比为0.85~0.87,扩孔率达到83%以上,沿板宽方向的扩孔率在10%以内波动;增加Si元素含量能明显改善扩孔性能,同时会影响产品的表面质量,将Si元素的质量分数控制在0.20%左右较为合适;试制产品具有优异的局部成形性、良好的抗疲劳性和焊接性能,在疲劳试验承载力为1700 N·m的条件下,车轮弯曲疲劳寿命达到60万次以上。

扩孔参数对AF1410超高强度钢切屑微观形貌的影响

通过对AF1410钢扩孔加工试验探究主轴转速和进给速度对切屑微观形貌的影响,为改善切屑形貌提升AF1410超高强度钢的扩孔质量提供依据。对有典型形貌特征切屑的自由表面、后表面和上表面进行观测,结果表明,切屑自由表面均为锯齿状片层结构且锯齿片层的宽度随主轴转速和进给速度的增加而增加。切屑后表面整体较光滑,随着主轴转速的增加,后表面光滑程度增加,利于提升已加工表面质量,且在主轴转速为800r/min时,顶部出现撕裂锯齿状毛边,同时进给速度对后表面影响较小。切屑上表面均呈周期锯齿状,切屑厚度随主轴转速增加而减小,锯齿高度随着主轴转速和进给速度的增加而增加。

机械扩孔有效抽采半径数值模拟及现场应用

为研究掘进工作面机械扩孔的卸压增透效果,以扩孔后的抽采有效影响半径为考察指标,借助COMSOL-Multiphysics数值模拟软件建立机械扩孔模型,动态分析机械扩孔后的瓦斯流场,拟合得出扩孔有效影响半径与抽采时间的关系曲线;通过理论分析和现场考察试验,类比同等工况条件下机械扩孔与普通钻孔的预抽效果,定量探讨2种施工工艺条件下瓦斯流量衰减系数。研究表明,机械扩孔的瓦斯抽采流量平均值为0.0222 m^(3)/min,最低瓦斯抽采流量是初始抽采流量的56.9%,下降幅度为43.1%;而普通钻孔的瓦斯抽采流量平均值为0.006826 m^(3)/min,最低瓦斯抽采流量是初始抽采流量的22.6%,下降幅度达77.4%。机械扩孔抽采浓度由72%降到38%,降幅为47.2%,普通钻孔抽采浓度由39%降到17%,降幅达56.4%,说明机械扩孔卸压增透效果显著。

随钻选择性扩眼器锥直型水眼液力特性研究

在随钻扩眼技术中,扩眼器的射流效率决定了整个扩眼技术的效率,对整个扩眼技术应用极为重要。针对扩眼器和扩眼器刀翼水眼的液力特性,建立了其物理有限元模型。通过分析可知,射流可以起到清洗岩石切割和冷却刀翼的作用,扩眼器刀翼水眼的几何结构对射流性能有重要影响。为了优化扩眼器刀翼水眼射流性能,提出了将锥直型喷嘴应用于扩眼器刀翼水眼,对其进行了优化。该研究可为扩眼器刀翼水眼结构参数的优化设计提供理论指导,对提高侧钻完井质量、推广侧钻改造技术具有重要意义。

穿越深厚淤泥地层机械扩孔锚索施工方法的研究

根据工程需要制作扩径不同的机械扩大头,在外力作用下伞式扩大头打开进而达到扩孔作用。连杆机构上有喷嘴,旋转时切割土体并喷射浆体,浆体起到护壁作用。通过工程试验发现,在淤泥及淤泥质黏土地层中扩大头锚索其抗拔承载力明显高于常规锚索抗拔承载力,且后期蠕变小,其工艺技术大大提高了支护的安全性。

基于8D问题求解法解决汽车线束端子偶发失效问题

随着汽车行业的不断发展,汽车线束端子连接问题在汽车市场售后上也随之增多,基于当前8D问题求解法在汽车行业应用广泛,文章结合8D问题求解法分析市场上汽车线束端子连接偶发失效问题,并概述8D问题求解法的特点、应用范围及实施流程,有益于后续此类问题在生产厂商管控过程中及时发现,并为后续此类问题的解决提供思路。

煤矿超600 m垂直输料井快速钻井工艺及其关键技术

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