摘要
利用摆锤冲击加载SHPB试验装置，通过改变摆锤锤头的形状和控制锤头的冲击速度，以获得较为理想的加载波形，进行岩石动态压缩试验和动态巴西盘试验，测试砂岩试样的动态抗压强度和抗拉强度，并分析砂岩试样的抗压和抗拉强度随摆锤锤头冲击速度的变化规律。动态抗压强度试验过程中岩样破裂时的应变率为100～102/s，这是人们通常认为的中应变率范围，动态巴西盘试验时试样中心拉应力所对应的加载速率为100～400 GPa/s。测得砂岩试样的动态抗压和抗拉强度都随着摆锤冲击速度的增大而增大，表现出一定的应变率相关性。巴西盘试样最终沿着加载直径方向破坏成两半，但是试样和入射杆、透射杆接触面处的“V”字型破坏区随着冲击速度的增大而趋于明显。摆锤冲击加载的优势在于能够直接获得岩石分离式霍普金森压杆（SHPB）试验所需的理想的入射波形，该装置为测试中应变率条件下岩石的强度和破裂过程提供了一种试验手段。
By using the pendulum hammer driven SHPB apparatus,the ideal incident waveform is generated by changing the shape and by controlling the impact velocity of the pendulum hammer. The compressive test and Brazilian test of sandstone specimens were conducted using the pendulum hammer driven split Hopkinson pressure bar（SHPB） apparatus,and the variation of dynamic compressive strength and dynamic tensile strength under different impact velocity of the pendulum hammer is examined. The strain rate ranging from 100/s to 102/s, which is generally considered as intermediate strain rate,is measured during the dynamic compression test,and the loading rate corresponding to the tensile stress at center of rock disc,ranging from 100 GPa/s to 400 GPa/s, are generated during the dynamic Brazilian test. The dynamic compressive strength and dynamic tensile strength of the sandstone samples increase with the impact velocity,showing an obvious strain-rate dependency. During the dynamic Brazilian test the sandstone samples were finally separated into two halves along the loading diameter. The V-shaped failure zone at the contact area between the incident and transmitted bars and the rock specimen becomes larger with the increasing impact velocity. The advantage of the pendulum hammer driven SHPB apparatus is that the ideal incident stress waveform can be excited by the pendulum hammer,and it can supply a feasible experimental method to measure the dynamic strength and failure process of the rock under the intermediate strain rate.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2014年第12期2443-2450,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51222401
51374049)
中国–南非联合研究计划项目(2012DFG71060)
