Parameter analysis of anchor bolt support for large-span and jointed rock mass

In order to obtain the optimal parameters of anchor bolt supporting system for large-span and jointed rock mass in Kaiyang Phosphor Mine, it is expensive and unavailable with the method of in-situ experiments. This paper describes a numerical modeling with discrete element method for the supporting effects of different type of anchor bolts. The anchor bolts with variant length of 0.5m, 0.8m, 1.0m, diameter of 10mm, 15mm, 20mm, setting spacing of 3.0m, 2.5m, 2.0m, and setting angle of 10°, 20°, 30°, are simulated respectively. The results show that there exist optimal parameters of anchor bolt support for large-span and jointed rock mass. For the bolt support of the concerning, the optimal length is 2.53.5m, the diameter is 2535mm, the spacing is 0.50.6m, and the setting angle is 105°.

Applied on bolting-cable anchor support of full-seam roadway in weaker thick coal seam

The designing method and the supporting mechanism of both bolt and small cable anchor for full seam roadway in the weaker thick coal seam are systematically analyzed, and the construction technology and the supporting results are briefly summarized.

Anchoring mechanism and application of hydraulic expansion bolts used in soft rock roadway floor heave control

Comparing with the resin bolt, the hydraulic expansion bolt has different anchoring mechanism and application advantage. According to the working mechanism of the hydraulic expansion bolt, its anchoring force is expressed in four forms including support anchoring force, tension anchoring force, expansion anchoring force and tangent anchoring force, and their values can be obtained on the basis of each calculation formula. Among them, the expansion anchoring force, which is the unique anchoring force of the hydraulic expansion bolt, can provide confining pressure to increase the strength of rock. Aiming at solving the problem of stability control in the soft rock roadway in Jinbaotun Coal Mine which has a double layer of 40 U-type sheds and cannot provide enough resistance support to control floor heave, the study reveals the mechanism of floor heave in the soft rock roadway, and designs the reasonable support parameters of the hydraulic expansion bolts. The observed results of floor convergence indicate that the hydraulic expansion bolts can prevent the development and flow of the plastic zone in the floor rock to control floor heave. Research results enrich the control technology in the soft rock roadway.

An experimental study of a yielding support for roadways constructed in deep broken soft rock under high stress

A rationally designed support for deep roadways excavated in broken soft rock under high stress was investigated. The deformation and failure characteristics and the mechanism of ''yielding support'' was studied for anchor bolts and cables. The rail roadway of the 2-501 working face in the Liyazhuang Mine of the Huozhou coal area located in Shanxi province was used for field trials. The geological conditions used there were used during the design phase. The new ''highly resistant, yielding'' support system has a core of high strength, yielding bolts and anchor cables. The field tests show that this support system adapts well to the deformation and pressure in the deep broken soft rock. The support system effectively controls damage to the roadway and ensures the long term stability of the wall rock and safe production in the coal mine. This provides a remarkable economic and social benefit and has broad prospects for fur- ther application.

High-resistance controlled yielding supporting technique in deep-well oil shale roadways

In order to avoid the deep-well oil shale roadway being deformed, damaged, or difficult to maintain after excavating and supporting in Haishiwan coal mine, this paper has analyzed the characteristics of the deformed roadway and revealed its failure mechanism by taking comprehensively the methods of field geological investigation, displacement monitoring of surrounding rock, rock properties and hydration properties experiments and field application tests. Based on this work, the high-resistance controlled yielding supporting principle is proposed, which is： to ＂resist＂ by high pre-tightening force and high stiff- ness in the early stage, to ＂yield＂ by making use of the controlled deformation of a yielding tube in the middle stage, and to ＂fix＂ by applying total-section Gunite in the later stage. A high-resistance controlled yielding supporting technique of ＂high pre-tightening force yielding anchor bolt ＋ small-bore pre-tight- ening force anchor cable ＋ rebar ladder beam ＋ rhombic metal mesh ＋ lagging gunite＂ has been estab- lished, and industrial on site testing implemented. The practical results show that the high-resistance controlled yielding supporting technique can effectively control the large deformation and long-time rheology of deep-well oil shale roadways and can provide beneficial references for the maintenance of other con-generic roadways.Deep-well Oil shale

既有隧道不同扩挖宽度下锚杆参数的优化

以黄山洞隧道工程为依托,通过对现场数据的监测和利用有限元分析软件Midas GTS NX进行数值模拟,分析了不同扩挖宽度下隧道拱顶沉降值、周边收敛值和围岩有效应力变化的规律,并改变锚杆的长度和锚杆间距,分析在不同锚杆长度下围岩有效应力、衬砌应力以及锚杆应力的变化规律,确定了不同扩挖宽度下最优的锚杆长度和锚杆间距.研究结果表明:随着扩挖宽度的增加,围岩有效应力由大至小依次为拱脚处压应力、拱腰处压应力、拱顶处压应力和仰拱处拉应力;拱顶处压应力随扩挖宽度的增大而减小,拱腰处压应力随扩挖宽度的增大而增大,但增大趋势不明显;受单侧扩挖方式的影响,扩挖侧的应力大于非扩挖侧;拱脚处受到应力集中的影响,其压应力随着扩挖宽度的增大而增大;扩挖宽度为1.5~2.5 m时的最优锚杆长度和间距分别为2.5 m和1.7 m,扩挖宽度为3.5~4.5 m时二者分别为3.0 m和1.2 m.

基于黏聚力模型的螺纹钢锚杆拉拔数值模拟

为研究螺纹钢锚杆锚固结构变形破坏机理,采用ABAQUS软件建立锚固结构轴对称数值模型,基于黏聚力模型,开展数值试验,获得锚固结构拉拔过程中锚杆变形、荷载以及锚固体位移场分布演化规律。试验结果表明:在相同的拉拔位移下,小肋间距锚杆也能够承受更高的拉拔荷载,表明小肋间距锚杆对巷道围岩变形的承载能力更强;在锚杆拉拔过程中,随着拉拔位移的增加,岩体破坏和离层区域呈倒碗形向岩体深部扩散,当拉拔位移增加至9.06 mm后,岩体锚固段末端处位移增速加大,岩体的最大位移为4.79 mm,出现在锚固段端口处,最终导致锚固段基体破坏;锚杆轴力与锚杆肋间距呈负相关,锚杆的轴力随着肋间距的减小而增加。

BFRP锚杆在岩土锚固中的研究现状与展望

随着新型纤维增强聚合物材料(Fiber Reinforced Polymer, FRP)的飞速兴起,轻质高强且具有优异耐腐蚀性能的玄武岩增强聚合物(Basalt Fiber Reinforced Polymer, BFRP)锚杆逐渐被应用于岩土工程以及锚杆加固的工程实践当中。基于BFRP锚杆的研究成果,阐述了BFRP锚杆的工作原理、锚固性能,总结了BFRP锚杆的力学性能试验和数值模拟研究进展,说明了在工程应用中使用BFRP锚杆取代传统钢筋锚杆的可行性与先进性,并对BFRP锚杆研究领域存在的不足进行了分析,为BFRP锚杆在岩土锚固领域的未来研究方向提出了合理化建议。

富水砂层深基坑支护结构模拟分析与优化

基于北京市通州区某深基坑工程,依据降水开挖及支护方案,使用midas GTS NX软件建模研究了在土钉墙-桩锚联合支护下,不同锚杆条件对富水砂层深基坑开挖变形特征的影响,并基于实际施工方案进行支护结构优化。结果表明,桩锚支护中预应力锚杆能够有效加固深层土体,约束其水平位移,显著改善基坑稳定性,相较于无锚杆情况,坡顶和桩顶的水平位移最大值分别减少了60.9%和75.4%;桩锚支护情况下,桩身侧移随桩直径的增大先减小后增大,存在最优桩直径范围,且该范围受到锚杆预应力大小的影响。

高延伸率锚索动态力学特性及工程应用

传统锚索延伸率低、抗冲击能力差,在强冲击载荷作用下易出现脆性破断失效,导致巷道出现冒顶、冲击地压事故等问题。基于此,自主开发了具有高强度、高延伸率及高抗冲击等特性的锚索,采用实验室试验、理论分析及现场试验等综合手段,分析了高延伸率锚索的静、动载力学性能,研究了高延伸率锚索化学成分、金相组织和夹杂物与普通锚索的差异,提出了高延伸率锚索支护吸能原理,并将高延伸率锚索在现场进行了应用。研究结果表明:静载作用下,高延伸率锚索抗拉强度为1790 MPa,最大力总延伸率8.1%,是普通锚索的1.61~2.25倍;动载作用下,高延伸率锚索钢丝不易散开,破断载荷与普通锚索基本相同,断后伸长率分别是锚索A、B、C的1.82倍、1.68倍和1.52倍,单位长度吸能量分别是锚索A、B、C的2.54倍、1.99倍和1.70倍,高延伸率锚索塑性变形能力更强,吸能能力更高。高延伸率锚索通过在冶炼和轧制工艺过程中控制有害化学元素和有益化学元素含量、细化金相组织及减少夹杂物尺寸和数量等方式提高了钢丝的塑性变形能力,进而提高锚索整体的抗冲击性能。高延伸率锚索在现场应用过程中经受了多次大能量冲击后,巷道支护效果良好,高延伸率锚索未出现破断,有效控制了巷道冲击破坏。

小断面TBM全长锚固锚杆受力特性研究及参数优化

为探究小断面TBM隧洞锚杆支护在地层围岩中的受力特性及支护参数的合理性,依托安徽桐城抽水蓄能电站自流排水洞工程,分别采用岩体力学法和数值模拟法计算得到隧洞Ⅲ类围岩工况下的锚杆内力和围岩位移,并在洞内TBM掘进段紧随TBM选取3个监测断面,分别采用锚杆应力计和多点位移计监测得到实际工况下的锚杆内力和围岩位移。对3种方法得到的结果进行对比分析后得出:1)数值模拟法和岩土力学法计算得到的轴力值变化趋势相近,均在锚杆中间部位出现轴力最大值,与中性点理论相符,最大轴力值为4.78 k N;2)3种方法得到的围岩位移值变化趋势相似,均在隧洞围岩表面出现位移最大值,在岩层内部围岩位移最小,最大位移为2.03 mm。进一步,与已有关于较大断面隧洞结构受力研究成果对比发现:小断面TBM隧洞的锚杆轴力及围岩变形均较小,锚杆支护作用未得到充分利用,据此提出了延迟、减少或取消小断面TBM隧洞锚杆支护的优化建议。

循环动载冲击下加锚裂隙煤体力学响应试验研究

为了解循环动载下加锚裂隙煤体的力学响应及破坏特征,采用分离式霍普金森压杆试验系统开展了循环冲击动载作用下加锚裂隙煤体动载冲击试验;分析了循环动载次数、动载冲击强度等因素对加锚裂隙煤体应力-应变曲线、锚杆轴力及宏观破坏的影响规律。研究结果表明:随着动载应变率的增加,锚固体试件强度增加,但随着动载冲击次数的增加,锚固体强度反而降低;冲击输入能量一定时,随着冲击次数的增加,煤体内部裂隙逐步扩展甚至破坏,锚杆对煤体扩展限制力降低;高能量冲击时,锚杆无法阻碍加锚裂隙煤体内部裂隙起裂与扩展,易发生加锚煤体整体瞬时破坏。

可调高式无砟轨道结构研究

针对无砟轨道基础变形适应能力小的难题,提出一种可调高式无砟轨道结构,由“扣件+垫板”组成,能够灵活调节轨道结构高度,主动适应轨下基础变形。建立可调高式无砟轨道结构整体受力分析有限元模型,分析轨道结构合理尺寸;建立轨道局部受力计算模型,分析垫板厚度变化的影响及锚固螺栓受力状态。结果表明:轨枕块高度为200 mm,埋深为140 mm时,各部件受力较小;通过更换不同厚度的垫板能够实现轨道结构0~60 mm的垂向调整量;锚固螺栓能够正常工作,满足强度设计要求。

煤矿双巷连掘工作面智能化锚杆钻车研究与应用

基于现有四臂顶锚杆钻车、六臂帮锚杆顶锚索钻车,对其进行智能化升级改造,研制智能化四臂顶锚杆钻车、智能化六臂帮锚杆顶锚索钻车,并在双巷连掘示范工作面开展试验应用。结果表明:2种钻车实现了顶/帮锚杆、顶锚索支护钻孔施工的电液智能化控制,在局部少量人工辅助下完成顶/帮锚杆支护钻孔、锚固全流程自动化施工,起到了减员、提效作用,为煤炭行业智能化转型提供技术支撑和有益参考。

软岩硐室锚网(索)喷联合支护工艺研究与应用

软岩条件一直是影响矿山巷道稳定的主要因素,对于软岩条件下施工的井下大型硐室,其支护稳定问题尤为重要。针对烂泥沟金矿井下软岩岩体稳固性差、支护体稳定性差、巷道变形大、返修率高的问题,依据软岩围岩变形特征和支护原理分析,结合烂泥沟金矿井下围岩条件变化特征,进行了锚网索喷联合支护工艺的研究与实践。研究实践发现,烂泥沟金矿软岩围岩暴露后及时地进行喷浆封闭处理,能够有效阻止岩块的位移,随后锚网支护加强岩体荷载承受力,待围岩充分释放变形能后,采取加强支护手段可有效控制围岩变形。监测结果表明,该支护方案取得了良好的支护效果,有效地将两帮及顶板岩移控制在允许范围。

软弱岩体锚杆物理锚固装置参数优化分析及试验研究

对于软弱岩体的锚杆支护,传统锚固剂锚固往往不能发挥理想的锚固效果。针对软弱岩体锚固性能差、锚固力易衰减的技术难题,提出一种物理锚固装置对软岩进行锚固,增强锚杆对软弱岩体的支护效果,确保锚固能力的持续稳定。采用数值模拟及室内试验相结合的方法开展系统研究。数值模拟结果表明:在设计参数范围内,锚固装置上倒齿的高度越大,锚固力越大;倒齿的角度越小,锚固力越小;倒齿的排数越多,锚固力越大,而倒齿间距对锚固力影响不显著。在数值模拟的基础上,选取锚固装置倒齿的最优参数并进行拉拔试验。试验结果表明:物理锚固装置能保证锚固力长时间不衰减,并且3排倒齿的锚固装置能提供的锚固力高于传统锚固剂锚固。本研究有助于解决软岩条件下锚杆锚固性能差的核心问题,为确保软弱岩体的锚杆支护效果提供了重要参考。

巷道中锚网索联合支护方案的应用分析

锚网索联合支护作为1种新型支护技术,具有支撑力度大、可防止巷道变形等优点,被广泛应用于煤矿巷道支护中。首先介绍了锚网索联合支护技术的基本原理和适用范围;然后,针对具体工程情况,在巷道形态、围岩情况和上覆厚度等因素影响下设计了1套支护方案,并进行了实践;最后,对施工过程和支护效果展开了详细分析,针对存在的问题提出了解决措施。

煤柱下方巷道变形失稳规律分析及控制

为解决煤柱下方回采巷道在实际开采中变形严重以及围岩破坏的问题,在对现场条件及支护现状分析的基础上,对当前支护状态下回采巷道的失稳特征进行综合;提出了对回采巷道补强加固支护的方案,并对方案进行详细设计;最后,通过实践生产验证了补强加固卸压方案应用后对围岩的控制效果。

煤矿回采巷道快速掘进技术的应用

为探索回采巷道所适用的快速掘进技术,以挖金湾煤业山4^(#)层一盘区2111巷为例,针对其掘进速度和进度缓慢的现状,提出快速掘进技术及支护参数优化思路。结果表明,快速掘进技术和支护技术应用后,回采巷道掘进速度、掘进效率均显著提高,支护作业时间缩短,巷道围岩变形也得到较好控制。

基于TRIZ的锚固剂装填设备创新研究

针对当前人工装填锚固剂存在危险系数大、劳动强度高等问题,应用TRIZ理论的因果分析得出相应问题模型,分别采用技术矛盾和物-场模型对锚固剂装填自动化的关键技术进行分析。根据施工场所具备条件的不同,形成了2个创新设计方案,通过试验样机验证,均能实现自动化装填锚固剂。采用TRIZ理论对锚固剂装填自动化的研究,为推进矿山领域锚杆(索)支护的自动化、智能化创新发展开拓了思路。