摘要
高应力条件下膏泥岩动静态力学参数特征研究对分析地下深层或高应力地区膏泥岩力学状态、蠕变扩容约束因素、地下工程或容腔安全设计及地下空间应力场模拟等方面意义重大。通过对地下膏泥岩取样并开展力学试验,对其应力应变特征进行分析,结果表明:高应力条件下膏泥岩应力-应变曲线大致分为4个阶段,时间-应变曲线大致分为3个阶段;硬石膏含量增加能提高岩样的强度、模量及泊松比,同时延缓岩石的弱化,但在高应力系统下岩样具有较为明显的蠕变扩容特征;在45%和79%屈服水平下,屈服应力点之后塑性应变比例差异不大;有效围压50 MPa条件下,杨氏模量随着偏应力的增加而降低,泊松比随着偏应力的增加而增加;硬石膏体积分数>50%的样品内聚力和内摩擦角比硬石膏体积分数<50%的样品分别高35.7%和10.2%,表明虽然膏泥岩在高应力条件下易发生扩容蠕变,但硬石膏相对泥质而言能提高岩石抗剪切破坏的能力;根据动态资料计算的膏泥岩力学参数与静力学参数类似,高应力条件下硬石膏含量高的样品其动力学参数值也相对大一些,不同成分膏泥岩样品具有统一线性变化规律。
Based on the sampling of cream mudstone layer and mechanics experiment, this paper analyses the characteristics of stress and strain. The results show that the cream mudstone stress- strain curve is roughly divided into four phases under the condition of high stress and the time-strain curve is roughly divided into three stages. The anhydrite content can improve the strength, modulus, and Poisson＇s ratio, and delay the weakening of rock, but under the condition of high axial differentialstress, the rock sample has more obvious expansion and creep characteristics. Under the high effective confining pressure （50 MPa）, Young＇s modulus decreases with the increase of the deviator stress and Poisson＇s ratio increases with the increase of the deviator stress increases. The cohesion and internal friction angle of samples in which anhydrite content is 〉50% are 〉35.7% and 10.2% respectively than that of the anhydrite content 〈50% samples. This show that anhydrite can improve the ability of rock to resist the shear failure. The character of the cream mudstone static mechanical parameters is similar to that of the dynamic mechanical parameters. The study of the stress-strain characteristics of the cream mudstone under the condition of high stress has great implication for the deep analysis of the creep expansion characteristics of the engineering, and the simulation of the cream mudstone, the safe design of underground stress field of underground, etc.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第6期665-672,共8页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家"十二五"科技重大专项(2011ZX05014-006)
关键词
高应力
膏泥岩
应力
应变
偏应力
抗剪强度
力学参数
high stress
cream mudstone
stress
strain
deviatoric stress
shear strength
mechanical parameter
