30 000 J多功能落锤冲击试验机研制及应用

Development and application of 30 000 J multi-function drop hammer impact tester

  • 摘要: 为深入研究冲击地压巷道锚杆支护材料的抗冲击力学性能,自主研制了30 000 J多功能落锤冲击试验机。该试验机由主机框架、抓脱锤装置、提升装置、锤体组件、液压缓冲装置、安全防护装置及电气装置等部分组成,可实现锚杆、锚索、托板及金属网等多种支护材料全尺寸动态力学性能测试和锚固岩体相似模型的冲击试验。选取了冲击地压煤矿常用的锚杆支护材料,初步开展了支护材料动态力学性能测试,测试结果表明:动载下锚杆颈缩不明显,表现出明显的脆性。随着冲击能量的增加,锚杆的冲击力峰值逐步增加,而延伸率大幅度降低;锚索受动载后钢丝易散开,外侧的钢丝更容易出现破断,破断位置通常位于夹具区域。动载作用下锚索的强度略有提高,而延伸率却大幅度降低,锚索的断后伸长率约为其静载的1/2;动载下拱形托板冲击力曲线具有明显的平稳震荡阶段,托板的冲击力峰值要明显大于其静载,变形量与静载基本相同,拱部结构在动载下能平稳变形吸能;随着冲击能量的增加,菱形网的冲击力峰值逐步增加,而变形量先增加后减小,菱形网具有很好的缓冲性能。多功能落锤试验机的研制为冲击地压巷道支护材料的动态力学性能测试提供了手段,为不同冲击危险性巷道的锚杆支护材料选取和支护设计奠定了基础。

     

    Abstract: In order to further study the anti-impact mechanical properties of different roof support materials in rock burst roadway, a 30 000 J multi-function drop hammer impact testing machine was independently developed. The testing machine is composed of host frame, grab hammer device, lifting device, hammer assembly, hydraulic buffer device, safety protection device, electrical device and other parts. It can realize a full scale dynamic mechanical property testing on various support materials such as anchor rod, anchor cable, supporting plate and metal mesh, and the impact testing of similar model of anchored rock mass. The commonly used rock bolt supporting materials in coal mines with rock burst are selected, and the dynamic mechanical properties of the supporting materials are preliminarily tested. The test results show that the rock bolt necking is not obvious under dynamic load, and it shows obvious brittleness. With the increase of impact energy, the peak value of impact force of bolt increases gradually, the dynamic breaking load is slightly greater than its static breaking load, and the elongation decreases significantly. Under the influence of dynamic load, the steel wire of anchor cable is easy to disperse, and the breaking position is usually located in the clamp area. Under the action of dynamic load, the strength of anchor cable is slightly increased, but the elongation is greatly reduced, and the elongation after breaking of anchor cable is only 1/2 of its static load. The impact force curve of arch supporting plate under dynamic load has an obvious stable vibration stage. The peak impact force of supporting plate is obviously greater than its static load, and the deformation is basically the same as the static load. The arch structure can stably deform and absorb energy under dynamic load. With the increase of impact energy, the peak impact force of the diamond mesh gradually increases, while the deformation first increases and then decreases. The diamond mesh has good cushioning performance. The development of multi-function drop hammer testing machine provides a means for testing the dynamic mechanical properties of the supporting materials of rock burst roadway, and lays a foundation for the selection and design of bolt supporting materials for roadways with different impact hazards.

     

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