摘要
为了揭示分布于北天山中西部的志留系上统紫红色粉砂质泥岩的蠕变特性,为拟建于此的某深埋越岭特长隧洞的设计、施工,以及长期稳定问题评价提供依据,通过钻孔取样进行了三轴蠕变试验研究。试验在5台岩石三轴蠕变试验机上进行,围压分别为0、5、102、03、0 MPa。试验取得以下主要成果:1)揭示了这类黏土岩的蠕变特性可用西原模型加以描述,并由此建立了蠕变本构方程;2)采用曲线求参法求解了各流变参数;3)采用叠加原理与等时曲线法获得了岩石的长期强度;4)各蠕变参数随围压的升高而增大,长期强度较瞬时强度降低的幅度亦随围压升高而增大,单轴条件下降低25%,30MPa围压时降低52%;5)抗剪断长期强度较瞬时强度降低了60%(内聚力)和36%(内摩擦角)。这些成果为工程建设提供了科学依据,试验方法与成果整理方法可供同类工程参考。同时,还通过常规试验获得了该类岩石的主要物理力学性能,这将有助于蠕变试验成果在其他工程中类比使用。
Tri-axial creep test was carried out on borehole sampling basis in order to reveal the creep characteristics of purple silty mudstone in the Upper Silurian in the center and west of North Tianshan,and provide the basis for the designing,construction and long-term stability evaluation of the proposed deep and long tunnel.Test was performed on five rock tri-axial creep test machines with the confining pressure of 0,5,10,20 and 30 MPa,respectively.Through the study,the following resulted were achieved.Rock creep characteristics was proved to be describable by the Xiyuan Model and a creep constitutive equation was establish for this kind of mudstone.The creep parameters were gained by calculating them based on creep curves.Long-term rock strength was obtained by superposition theorem and isochronous curve method,and the confining pressure effect was revealed on the long-term strength.The creep parameters increased with the increase of confining pressure,and the difference between long-term rock strength and instant rock strength increased by 25% under uni-axial pressure and 52% under tri-axial pressure of 30 MPa as the confining pressure increased.The long-term shearing strength decreased by 60%（cohesion） and 36%（internal friction angle） compared with the instant shearing strength.These results provided a scientific basis for the engineering construction,and the test and result collation methods were available for other similar construction and research.Meanwhile,physical and mechanical property of silty mudstone was also obtained through routine tests,which helps to apply creep test result to other similar projects.
出处
《四川大学学报（工程科学版）》
EI
CAS
CSCD
北大核心
2012年第1期69-74,共6页
Journal of Sichuan University (Engineering Science Edition)
基金
国家自然科学基金资助项目(50620130440)
国际科技合作资助项目(2007DFB60100)
国家重点基础研究发展规划"973"资助项目(2010CB226802)
关键词
粉砂质泥岩
三轴蠕变试验
西原模型
流变参数
长期强度
silty mudstone
triaxial creep test
Xiyuan model
rheological parameters
long-term strength
