多因素耦合效应对层状千枚岩动力特性的影响

Influence of Multi-factor Coupling Effect on Dynamic Characteristics of Layered Phyllite

为了研究不同长径比和倾角下应变率对层状千枚岩动力特性的影响,选用4种倾角(α=0°,30°,60°,90°)两种长度(L=25,50 mm)的层状千枚岩为研究对象,采用分离式霍普金森压杆(SHPB)装置进行不同冲击气压(p=0.150,0.175,0.200,0.225和0.250 MPa)的动态压缩试验.研究了两种长径比层状千枚岩不同应变率下动力特性的影响,分析了层状千枚岩层理倾角、长径比和应变率之间的耦合效应对层状千枚岩强度特征的影响关系.结果表明:动态压缩下两种不同长径比层状千枚岩动态抗压强度随层理倾角增加呈现先减小后增大趋势,动态峰值强度和峰值应变均随应变率增大而增大,层状千枚岩动态抗压强度与应变率呈幂函数关系;动态峰值强度关于倾角α和长径比L/D呈二元函数关系,在α=60°时,层状千枚岩动态抗压强度的长径比效应最为显著,在L/D=1时,倾角效应最为显著;不同倾角下,峰值应变在0°倾角下长径比效应最为显著,在90°倾角下长径比效应最弱;动态冲击下层状千枚岩动态抗压强度和峰值应变的应变率效应均强于长径比效应.

In order to study the effect of strain rate on the dynamic characteristics of phyllite under different length‑diameter ratio and dip angle,the samples with four dip angles(α=0°,30°,60°and 90°)and two lengths(L=25,50 mm)were selected as research objects.The dynamic compression tests under different impact pressures(p=0.150,0.175,0.200,0.225 and 0.250 MPa)were carried out by using the split Hopkinson pressure bar(SHPB)system.The dynamic characteristics of phyllite with two aspect ratios at different strain rates were studied,and the influence of the coupling effect between the bedding dip angle,aspect ratio and strain rate on the strength characteristics of phyllite was analyzed.The results show that under dynamic compression,the dynamic compressive strength of phyllite with two different aspect ratios decreases first and then increases with the increase of bedding angle,and the dynamic peak strength and peak strain increase with the increase of strain rate.The relationship between dynamic compressive strength of phyllite and strain rate follows a power function.The relationship between peak strength and bedding angleαand L/D is binary function.Whenα=60°,the aspect ratio effect on the dynamic compressive strength of phyllite is the most significant,and when L/D=2,the dip angle effect is the most significant.Under different bedding dip angles,the aspect ratio effect of peak strain is the most significant at 0°dip angle,and the weakest at 90°dip angle.The strain rate effect on dynamic compressive strength and peak strain of phyllite under dynamic impact is stronger than that of aspect ratio effect.