摘要
交通荷载、地震等引入的动态循环载荷对围岩剪切力学特性的劣化对隧道工程长期安全运行有重要影响。对复杂扰动载荷影响下的隧道围岩受力特征科学凝练,开展循环剪切载荷作用下砂岩的直接剪切试验,探究不同剪切静态预应力水平砂岩的强度劣化特征。研究结果表明:(1)幅值为20%τj的动态循环剪切载荷作用过程中,静态预应力水平较低砂岩并不会破坏。(2)动态循环剪切载荷引起的损伤与静态预应力水平成正比,动态循环剪切载荷作用后,剪切静态预应力水平为60%τj和70%τj的砂岩强度相较静态剪切对照组分别降低1.68%和6.91%。在隧道设计和长期稳定运行监测中,应该充分考虑到交通荷载、地震等引入的扰动应力波对围岩剪切强度的劣化。(3)动态循环剪切过程中失稳砂岩的剪胀效应显著,在隧道等岩体工程中,应特别注意动态剪应力导致的围岩剪胀对隧道衬砌等的影响。
The deterioration of shear mechanical properties of surrounding rock caused by dynamic cyclic load introduced by traffic load and earthquake has an important influence on the long-term safe operation of tunnel engineering.The mechanical characteristics of tunnel surrounding rock under the influence of complex disturbance load were scientifically condensed,and the direct shear test of sandstone under dynamic cyclic shear load was carried out to explore the strength degradation characteristics of sandstone with different shear static prestress levels.The results show that:(1)In the process of dynamic cyclic shear load with amplitude of 20%τj,the sandstone with low shear static prestress level will not be destroyed.(2)The damage caused by dynamic cyclic shear load is proportional to the static prestress level.After dynamic cyclic shear load,the strength of sandstone with shear static prestress levels of 60%τj and 70%τj is reduced by 1.68%and 6.91%respectively compared with the static shear control group.In tunnel design and long-term stable operation monitoring,the deterioration of surrounding rock shear strength caused by disturbance stress wave introduced by traffic load and earthquake should be fully considered.(3)The dilatancy effect of unstable sandstone is significant in the process of dynamic cyclic shear.In tunnel and other rock engineering,special attention should be paid to the influence of surrounding rock dilatancy caused by dynamic shear stress on tunnel lining.
作者
黄华
HUANG Hua(Shanxi Road&Bridge Intelligent Transportation Information Technology Co.,Ltd.,Jinzhong,Shanxi 045400,China)
出处
《黑龙江交通科技》
2024年第9期149-153,158,共6页
Communications Science and Technology Heilongjiang
关键词
动态循环剪切
静态剪切预应力水平
强度劣化
砂岩
dynamic cyclic shear
static shear static prestress levels
strength deterioration
sandstone
