天然与饱水状态下煤样动静力学特性

Dynamic and Static Mechanical Properties of Coal under Natural and Saturated Conditions

为了研究煤层中水含量对冲击震动波衰减及冲击能量的散射影响,采用霍普金森杆(SHPB)和伺服液压试验系统对自然状态和7 d饱水状态下煤样进行了力学特性试验。在静态单轴压缩和无围压SHPB试验下,7 d饱水煤样与天然状态煤样的强度软化系数最大值分别为0.69和0.59;在围压SHPB试验施加5 MPa的围压和8 MPa的轴压下,7 d饱水状态下煤样的动载强度比天然煤样高7.85%~18.44%;在三轴围压加载试验施加围压分别为3、6和9 MPa下,7d饱水状态下煤样的动强度比天然状态下动强度高7.85%~18.44%。天然状态下煤体试件从开始破坏到完全破坏的时间较长,破坏的颗粒较大,饱水状态下煤体破坏的时间较短,煤样破坏颗粒较小,三轴加载和动载围压作用加载前后煤样粒径没有明显差异。

To study the influence of water content in coal seam on the scattering of attenuation and shock energy of shock wave,we use SHPB and servo hydraulic test system totest coal samples.Under static uniaxial compression and one-dimensional dynamic load conditions,the maximum strength softening coefficients of 7-day saturated coal samples and natural coal samples are 0.69 and 0.59,respectively.In confining pressure SHPB test,when confining pressure is 5 MPa and axial pressure is 8 MPa,the dynamic load strength of coal sample is 7.85%~18.44%which is higher than that of natural coal sample under water saturated state for 7 days.In the triaxial confining pressure loading test,the confining pressures are 3 MPa,6 MPa and 9 MPa,respectively.The dynamic strength of coal samples in 7-day saturated state is 7.85%~18.44%which is higher than that in natural state.In natural state,the time from initial failure to complete failure of coal sample is longer,and the failure particles are larger.In water saturated state,the failure time of coal sample is shorter,and the failure particles of coal sample are smaller.