摘要
南京地铁6号线万寿村站至燕尧路站区间深部主要为灰岩,盾构隧洞贯通后,深部岩体对隧洞维护起至关重要的作用,为了对该地铁深部稳定性提供理论指导,利用MTS815试验机对灰岩在经历干湿循环后进行了常规三轴压缩试验,研究了灰岩在不同次数干湿循环作用下和不同围压下的力学特性,结果表明:(1)受干湿循环作用前后试件的应力—应变曲线较为一致,均经历了较为明显的孔隙微裂隙压密阶段、较长的线弹性阶段、不太明显的屈服阶段和峰后阶段共4个阶段;(2)相同干湿循环次数后的灰岩试件,随着围压的增大,试件的峰值强度和弹性模量逐渐增大,弹性模量增幅不明显。在10次干湿循环后,试件的峰值强度的劣化最高达19.26%。干湿循环次数的增加会使灰岩的弹性模量减小,在10次干湿循环以内减幅较小;(3)围压为0时,试件的破裂模式为拉伸破坏,扩容现象明显;围压为2和4 MPa时,试件主要体现为剪切破坏。相同围压下,破裂模式属于剪切型破坏,随着干湿循环次数的增加,剪切破裂面倾斜度逐渐增大,剪切破坏愈加明显。
In order to study the mechanical properties of hard rock under different times of dry-wet cycles and different confining pressures,the MTS815 testing machine is used to perform conventional triaxial compression tests on limestone after dry-wet cycles.The results show that:(1)The stress-strain curves of the specimens before and after being subjected to the dry-wet cycle are relatively consistent,and they all have experienced four phases:a more obvious pore micro-crack compaction stage,a longer linear elastic stage,a less obvious yield stage and a post-peak stage.(2)For limestone specimens with the same number of dry-wet cycles,as the confining pressure increases,the peak strength and elastic modulus of the specimens gradually increase,but the increase in elastic modulus is not obvious.After 10 wet and dry cycles,the peak strength degradation of the specimen was up to 19.26%.The increase in the number of dry-wet cycles will reduce the elastic modulus of limestone,and the decrease will be smaller within 10 dry-wet cycles.(3)When the confining pressure is 0,the failure mode of the specimen is tensile failure,and the expansion phenomenon is obvious;when the confining pressure is 2 and 4 MPa,the specimen is mainly manifested as shear failure.Under the same confining pressure,the fracture mode is shear failure.With the increase of the number of wet and dry cycles,the inclination of the shear fracture surface gradually increases,and the shear failure becomes more obvious.
作者
樊德东
仇意
常乐
Fan Dedong;Qiu Yi;Chang Le(The Third Engineering Co Ltd of China Communications First Public Bureau,Beijing 101102,China;School of Resources Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《湖南文理学院学报（自然科学版）》
CAS
2021年第3期69-75,共7页
Journal of Hunan University of Arts and Science(Science and Technology)
关键词
岩石力学
三轴压缩
干湿循环
破裂模式
峰值强度
rock mechanics
triaxial compression
wetting-drying cycle
failure mode
peak strength
