摘要
为探索循环动力扰动作用下冻融岩体的强度和变形特性及损伤机理,开展了两种冲击气压下冻融红砂岩的循环冲击试验,研究了循环冲击次数和冻融次数对应力波传播、动态应力-应变曲线、峰值应力和峰值应变的影响规律;基于Lemaitre应变等效原理,提出了能够综合考虑循环冲击和冻融影响的累积损伤因子的计算方法,分析了冻融和循环冲击作用后红砂岩的微观结构特征。结果表明:循环冲击荷载下不同冻融次数处理后的红砂岩试样均呈拉伸破坏模式;红砂岩试样可承受的循环冲击次数与冻融次数呈负相关,冻融75次后试样在首次冲击后即达到破坏状态;循环冲击次数主要影响透射波的起跳点、峰值点对应的横坐标和振幅以及反射波的振幅,而冻融循环次数对第一次冲击时透射波的起跳点、峰值点对应的横坐标和振幅影响较大;红砂岩试样累积损伤因子与动态峰值应力呈现较好的负相关变化规律;冻融和循环冲击复合作用后红砂岩内部裂纹沿颗粒边界扩展且与孔洞连接形成较为复杂的网络。
To study the strength,deformation characteristic and damage mechanism of freeze-thaw treated rock mass under the action of cyclic dynamic disturbance,the cyclic impact tests of freeze-thaw treated red sandstone under two kinds of impact pressure were carried out to investigate the effects of cyclic impact number and freeze-thaw number on stress wave propagation,dynamic stress-strain curve,peak stress,and peak strain.In addition,the calculation method of cumulative damage factor,which can comprehensive consider the effects of cyclic impact and freeze-thaw,is proposed based on the Lemaitre strain equivalence principle.Finally,the microstructure characteristics of red sandstone after freeze-thaw and cyclic impact are analyzed in detail.Results show that red sandstone specimens treated with different freeze-thaw number show tensile failure mode under cyclic impact load.The cyclic impact number that red sandstone specimen can withstand is negatively correlated with freeze-thaw cycle number,and red sandstone specimen after 75 freeze-thaw cycles treatments reaches the failure state after the first impact loading.Moreover,the cyclic impact number mainly affects the jump point,abscissa corresponding to peak point and amplitude of transmitted waves,and the amplitude of reflected waves.While the freeze-thaw number shows a great effect on the jump point,abscissa corresponding to peak point,and amplitude of transmitted waves during the first impact process.The cumulative damage factor of red sandstone specimen exhibits a good negative correlation with the dynamic peak stress.After the combination effects of freeze-thaw and cyclic impact,the cracks inside red sandstone spread along the grain boundary and connect with the pores to form a complex network.
作者
张蓉蓉
沈永辉
马冬冬
平琦
杨毅
ZHANG Rongrong;SHEN Yonghui;MA Dongdong;PING Qi;YANG Yi(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,Anhui,China;State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan 232001,Anhui,China)
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2024年第8期131-146,共16页
Explosion and Shock Waves
基金
国家自然科学基金(52074005)
安徽省博士后科学基金(2021B556)。
