基于循环冲击荷载的机制砂喷射混凝土动力特性机理分析

Analysis of dynamic characteristics of machine-made sand shotcrete based on cyclic impact load

为探明轴压荷载作用对循环冲击荷载下机制砂喷射混凝土的动力特性的影响规律,借助大直径分离式霍普金森压杆试验仪器,开展了轴压荷载作用下的循环荷载冲击试验,进行了机制砂喷射混凝土的动力特性机理分析。试验结果表明:轴压荷载与荷载冲击速度主要影响机制砂喷射混凝土的峰值应力与应变、应变率和破坏形态等性能指标,增大轴压荷载可降低试件的变形;相同轴压荷载作用下,试样破坏的荷载冲击速度与冲击次数成反比;相同冲击速度作用下,轴压越大,试件破坏时的冲击次数越多;相同冲击速度与轴压荷载作用下,冲击次数越多,试件的峰值应变与应变率上升,峰值应力与动弹性模量下降。

In order to find out the influence of axial compression load on the dynamic characteristics of machine-made sand shotcrete under cyclic impact load,the cyclic load impact test under axial compression load was carried out with the help of large diameter split Hopkinson compression bar test instrument,and the dynamic characteristics and mechanism of machine-made sand shotcrete were analyzed.The test results show that the peak stress and strain,strain rate and failure mode of the manufactured sand shotcrete are mainly affected by the axial compression load and load impact velocity,and the deformation of the specimen can be reduced by increasing the axial compression load.Under the same axial compression load,the load impact speed of specimen failure is inversely proportional to the number of impacts.Under the same impact velocity,the greater the axial pressure is,the more impact times the specimen is damaged.Under the same impact speed and axial compression load,the peak strain and strain rate of the specimen increase,and the peak stress and dynamic elastic modulus decrease with the number of impacts.