【作者】 李志国；

【导师】 李夕兵；

【作者基本信息】 中南大学 ， 采矿工程， 2010， 博士

【摘要】 发展矿业、修筑铁路、水电建设等都离不开巷(隧)道、涵洞等地下工程的大量掘进。这些工程的开挖,在相当长时期内仍将以钻爆法施工为主。因此,凿岩机具在矿山建设、隧道掘进等地下工程的施工装备中仍占有重要地位。回顾整个凿岩机具发展史,在很长一段时期内风动凿岩机曾占据主导地位,但受其能源、结构限制,风动凿岩机效率低,能耗高,噪声、粉尘污染严重等问题难以有效解决；近几十年,节能、高效的液压凿岩机得到了蓬勃发展,但诸如废油排放与环境污染、泄漏与清洁、易燃与安全、资源枯竭和成本等仍是其难以解决的问题。而近几年,倡导清洁生产及低碳经济,致使深部岩体工程对采掘作业安全、环保、节能、高效要求越来越高,发展安全、环保、节能、高效的水力凿岩机成为趋势。在深井采掘作业中,水力凿岩机可以直接利用采掘面与地面之间高度差产生的巨大水力落差势能,使整个矿山采掘作业的能源和采掘成本大为降低,且消除了废油排放与环境污染、泄漏、易燃等一系列液压凿岩机所无法避免的弊端,其安全、环保、节能、高效的优势更加明显。而到目前,所试制的水力凿岩机总体能量利用率低下问题,成为困扰其工业应用的关键问题所在。鉴于此,本文以国家高技术研究发展计划(863计划)——水势能直接驱动的深部金属矿采掘技术与装备项目为依托,以试制的SYYG65型导轨式水力凿岩机样机为主要研究对象,开展了如下工作：基于实验需求,自行开发建成了水力采掘实验系统,为水力凿岩机冲击凿岩效率实验研究提供了完备的实验平台。实验系统包括水压动力泵站、导轨及凿岩台架等机械部分、性能测试及数据采集处理系统等。可模拟深井高压水环境,直接对水力凿岩机及水力潜孔冲击器(DTH)等水力破岩机具开展性能测试和试验研究。从水力凿岩机凿岩工作原理出发,针对其能量的转化与传递,分析出凿岩机总体凿岩效率的高低,主要取决于凿岩机冲击机构及冲击凿入这两大系统的能量转化及传递效率。通过对水力凿岩机冲击机构工作原理的分析,阐述了其不同于一般液压机械的独有特点,指出这一特殊水力机械在数学模型的建立,冲击速度、瞬态流量等参数的测试等方面都面临棘手的问题；分析指出采用非线性数值模拟则是一种简单易行和动态、综合、比较符合客观实际的研究方法,并首次采用非线性仿真工具——SimHydraulics液压传动和控制系统构筑搭建了后控式水力凿岩机冲击系统流体/机械混合实物动力仿真模型,建模过程避免了对系统运行状态转换的考虑,简单有效地实现了活塞和阀芯在水压力作用下的耦合计算。编制完成了相应的数据后处理函数模块,实现了活塞行程及运动循环辨识、测试数据整理计算、结果输出、自动循环计算等一系列功能,并通过凿岩机运行实验验证了该模型的有效性。利用建成的水力采掘实验系统开展了凿岩机不同工作压力下的冲击性能实验、不同蓄能器参数下的冲击性能实验及冲击器前后腔压力和活塞位移测试三项实验,与相应的仿真结果相结合,针对该SYYG65型水力凿岩机,指出可以通过增大高压水进水口口径、增大前腔与配流阀的连接导水管径、改变信号孔位置、选取蓄能器合适的充气压力及有效容积等途径来提高系统的能量利用率。应用波动力学对凿岩机冲击凿入系统进行了简要分析,引入应力波的峰值系数及能量分布矩两个品质因数,用于衡量实测的活塞冲击应力波形。通过冲击实验发现,从应力波的能量分布矩及峰值系数来看,随着冲击压力的升高,均表现出波形偏离矩形波形,不利于能量向岩石传递；当冲击压力继续升高到一定范围后,两个品质因数均表现出了局部较优值,表明对于凿岩机来说冲击压力也会对应力波形产生影响,并存在最优冲击压力。利用水力采掘实验系统开展凿岩机凿岩实验测试,并采用通径分析方法对实验数据进行了分析研究,发现在冲击压力变化不大的情况下,要想获得理想的凿岩速度,必须同时保持较高推进压力和钎杆转速,而推进压力又会通过对钎杆转速反向作用于凿岩速度；总体来说,对凿岩速度的影响由大到小依次为：推进压力与钎杆转速的共同作用、钎杆转速直接作用及推进压力直接作用。在以上研究成果基础上,对水力凿岩机冲击器、蓄能器等相关结构参数做了相应调整,经对关键零部件重新选材加工后,装配成功SYYG65-B型导轨式水力凿岩机。经性能测试及凿岩实验,该机在冲击压力9.124MPa下单次冲击能≧85J,能量利用率≧20%,凿岩速度(?) 420mm/min,基本达到设计要求；在冲击压力9.61MPa时,同时保持较高推进压力(0.95MPa)和较高钎杆转速(157.4r/min)时,得到最大凿速449mm/min相比原SYYG65样机,能量利用率有近10%的提高,凿岩速度每分钟提高200多毫米,其冲击凿岩效率得到明显提高。更多还原

【Abstract】 Development of mining, construction of railways, and the hydropower construction etc. involve large-scale excavations of underground engineering such as tunnels, culverts etc. Drilling and blasting is still the main construction method for underground engineering in a long time. Therefore, the rock drilling equipments is still vital for mines, tunnels and other underground constructions. Reviewing the history of the rock drilling equipments, the pneumatic rock drill was mostly used; however, its usage is limited by its energy and structural problems, low efficiency, high energy consumption, serious noise, dust pollution and other disadvantages. Over the past several decades, highly effective and energy-saving hydraulic rock drill has been developing vigorously. But problems such as waste oil emission and pollution, leakage and clean, inflammability and security, resource exhaustion and cost are still hard to be solved. Especially in recent years, cleaner production and low-carbon economy was proposed, which causing high demand for safety of deep rock mass engineering, environmental protection, energy-saving and efficiency. Thus, the development of the water powered percussive rock drill was promoted.In deep mining operations, the enormous power source born in high fall between surface and underground can be utilized by the water powered percussive rock drill directly. So the cost for power source and excavations was largely decreased, and lots of defects such as waste oil emission, pollution, leakage, inflammability etc. which the hydraulic rock drill can not avoid were eliminated. Water powered percussive rock drill have obvious advantages such as safety, environmental protection, energy-saving, high efficiency, up to now, its key limitation for industrial application is low energy efficiency. Based on the above considerations, the track-type water powered percussive rock drill SYYG65 is researched funded by national high technology research and development program (namely 863 Program)—water directly powered excavation techniques and equipments in deep metal mine. The main researches contain the followings. The water powered excavation test set-up was developed, and a complete experimental platform was constructed for the research on percussive drilling efficiency of water powered percussive rock drill. The whole system contains hydraulic power section, guideway, drilling bench and other mechanical parts, test and data acquisition system etc. The experimental set-up can be used to simulate deep high-pressure hydraulic environment. And the performances of the water powered excavation implements such as water powered percussive rock drill and water powered down-the-hole hammer (DTH) etc. can be directly measured and studied by this experimental system.From the drilling principle of the water powered percussive rock drill, according to the energy transformation and transmission, the main factors affecting the efficiency of rock drill were found, namely the energy transformation and transmission of the impact system and percussive penetration system.From the working principle of the impact system of the water powered percussive rock drill, its characteristics which are different from the general hydraulic machinery were described. It is hard to establish mathematical model for this special waterpower machinery, and the impact velocity, instantaneous flow and other parameters were still hard to measure. Thus, it was proposed that nonlinear numerical simulation is a simple, dynamic, integrated, and reality accordant method for researching the impact system. And a dynamic simulation model of water-powered percussive rock drilling system was built by SimHydraulics toolbox, and then the fluid/mechanical hybrid simulation was realized. The simple and effective coupling calculation of piston and valve core under the water pressure was carried out by avoiding transition of the running state of the system. Some post-processing functions were compiled to realize the identification of the piston stroke and motion cycle, data record and calculation, result output, loop computing and some other functions, and the efficiency of SimHydraulics dynamical simulation on water-powered percussive rock drilling system was validated.Three experiments for water powered percussive rock drill were done on the water powered excavation test set-up, which are impact performance test under the different working pressure, tests of the impact properties about different accumulator, synchronous tests about the pressure of front and back cavity and the displacement of the piston. Combining with the corresponding simulation results, some measures for improving the energy efficiency of the impact system were pointed out for SYYG65, which are larger diameter of the high-pressure water inlet; larger aqueduct diameter connected the front cavity with the port valve; different place of the signal orifice; appropriate inflation pressure and effective volume for the accumulator.The percussive penetration system of the water powered percussive rock drill was analyzed with the wave mechanics. The stress peak coefficient and the moment of energy distribution were introduced to evaluate the measured stress waveform. From the impact experiment, some conclusions were found. The stress peak coefficient and the moment of energy distribution were increased with the increasing of impact pressure; and the waveform is deviated from the rectangular wave, which is unfavourable for the energy to transfer from drill to rock. However, as the impact pressure reaches to a certain range, the stress peak coefficient and the moment of energy distribution present a local extremum. Results show that impact pressure also has the effect on stress waveform, and has an optimal impact pressure.The drilling experiment was done on the water powered excavation testing set-up. Testing data was analyzed by the Path Coefficient Analysis. Result shows that the high propulsion pressure and the high rotational speed of the drill steel are both needed for an ideal drilling speed. But the propulsion pressure has an indirectly reverse influence on the drilling speed through the rotational speed of the drill steel. In general, the impact effects for drilling speed in turn are the interaction of propulsion pressure and rotational speed of the drill steel, the rotational speed of the drill steel, the propulsion pressure.Based on the results mentioned above, some structural parameters of water powered impacter and accumulator were improved. Some key parts of the rock drill were over-manufactured. And the track-type water powered percussive rock drill SYYG65-B was developed successfully. The performance test and the rock drilling test showed that some parameters can reach a certain value under 9.124 MPa water pressure, such as single impact energy (?)85J, energy efficiency(?)20%, drilling speed(?)420mm/min, which are basically consistent with the design requirements. When the impact pressure was 9.61 MPa, keeping the propulsion pressure at 0.95MPa and rotational speed of the drill steel at 157.4r/min at the same time, the drilling speed could reach the maximum value of 449mm/min. Compared with the SYYG65, the energy efficiency of the SYYG65-B is improved nearly 10%, it can drill 200mm longer per minute than the SYYG65, and the percussive drilling efficiency was improved obviously.更多还原