为了模拟钻杆在煤矿井下瓦斯抽采钻孔过程中的真实受力情况，满足实物钻杆的疲劳试验需求。

设计了一种矿用全尺寸钻杆动态加载系统，整个系统由钻杆加载平台、功率回收型液压泵站和测控系统3大部分组成，能够对不同规格的钻杆进行动态扭矩、轴向力和径向位移的复合加载。扭矩加载采用液压功率回收方式，由两个完全相同的液压马达和钻杆进行机械连接，主动马达带动钻杆和加载马达旋转，两者互为负载，加载马达将输出的流量反馈给主动马达，从而实现扭矩加载和功率回收，该闭环系统的能量损失由两个液压补偿泵进行弥补；轴向力和径向位移加载采用电液比例控制方式，由传感器采集各变量参数，可编辑逻辑控制器(programmable logic controller，PLC)对加载油缸的力和位移进行闭环调节，从而实现精确控制；试验过程中的各项运行参数和功率回收效率由测控系统进行数据采集并实时显示在上位机中。最后，采用ø127 mm×3 000 mm型外圆钻杆对系统的加载能力进行了试验验证。

结果表明：(1)加载系统的扭矩和转速可通过改变液压补偿泵的流量或压力，主动马达与加载马达的排量关系，变速箱档位等多种方式进行调节，能满足各种不同的试验工况。(2)当主动马达和加载马达的排量一致时，功率回收效率取得理论最大值77%。(3)在低速大扭矩工况下，实测的钻杆扭矩加载最大值为35 080 N∙m，对应的转速为28 r/min，电机功率为50.7 kW，功率回收效率为66.2%，有效降低了加载系统的装机功率。研制的钻杆动态加载系统成功解决了现有矿用钻杆疲劳试验装置加载能力不足及耗能大的问题，为钻杆的测试研究工作提供了有力的设备支撑，具有显著的应用价值。

This study aims to simulate the actual forces applied to drill rods during the borehole drilling for gas drainage from underground coal mines to satisfy the requirements of drill rods’ fatigue tests.

This study designed a dynamic loading system for full-size drill rods in coal mines. This system consists of a drill rod loading platform, a hydraulic pump unit with power recovery, and a measurement and control system, allowing for the composite loading of dynamic torque, axial force, and radial displacement on drill rods of different specifications. In this system, torque is loaded to drill rods using the hydraulic power recovery method. Specifically, two identical hydraulic motors, acting as loads mutually, are mechanically connected to the tested drill rod. The active motor drives the drill rod and the loading motor to rotate, while the loading motor returns the output flow to the active motor, thus achieving torque loading and power recovery. The energy loss of the closed-loop system is compensated by two hydraulic compensating pumps. The loading of axial force and radial displacement is controlled based on the electro-hydraulic proportion. Based on various variables collected by sensors, the programmable logic controller (PLC) performs closed-loop adjustment of the force and displacement of the loading cylinder to achieve precise control. During tests, various operating parameters and power recovery efficiency are acquired using the measurement and control system and then displayed in the upper computer in real time. The loading capacity of the dynamic loading system was verified using a round drill rod measuring ø127 mm×3 000 mm.

The results indicate that the torque and rotational speed of the dynamic loading system can be adjusted by changing the flow or pressure of hydraulic compensating pumps, the displacement relationship between the active and loading motors, and the gearbox gear, thereby meeting various operation conditions of the tests. In the case of the same displacement between the active and loading motors, the power recovery efficiency can reach the theoretical maximum (77%). Under the operating condition of a low rotational speed combined with a high torque, the measured torque loaded to the drill rod reached the maximum (35080 N∙m), corresponding to a rotational speed of 28 r/min, motor power of 50.7 kW, and power recovery efficiency of 66.2%. This suggests an effective reduction of the installed power of the dynamic loading system. Overall, the proposed dynamic loading system for drill rods in coal mines overcomes the limitations of existing devices for fatigue tests, such as insufficient loading capacity and high energy consumption, providing strong equipment support for drill rod tests and being of great application value.