【摘要】 以鄂尔多斯梅林庙矿500~600 m处红砂岩为研究对象,分别对不同冻结温度(10℃,-5℃,-10℃,-15℃)、不同围压(0,4,8,12 MPa)条件下饱水红砂岩进行三轴压缩试验。试验结果表明:(1)温度在10℃~-15℃变化时,饱水红砂岩的三轴抗压强度随温度的降低而增大,呈指数关系;弹性模量随温度的降低而增大,呈线性关系;黏聚力c随温度降低而减小;内摩擦角φ随温度降低而增大;(2)围压在0~12 MPa变化时,饱水红砂岩三轴抗压强度随围压的增加而增大,呈线性关系,仍然满足Mohr准则;弹性模量、峰值轴向应变、径向应变随围压的增大而增大,塑性增强;(3)试验条件下,泊松比受围压影响较小,但受温度影响显著,试验时应妥善考虑温度对泊松比的影响;弹性模量E受温度影响巨大,受围压影响显著,温度是弹性模量的主要影响因素,围压为次要影响因素。相对于泊松比而言,弹性模量的取值更易于受外界环境影响。(4)饱水红砂岩试件的破坏形态受温度和围压影响显著,但两者的破坏机制不同。温度降低导致岩石颗粒引力降低,孔隙冰增大了孔隙的摩擦面积,进而增大摩擦力;围压增大,则是由于岩石内部形成微裂隙,使黏聚力下降,同时也使得围压在垂直破裂面上的分力增加,进而增大摩擦力。更多还原

【Abstract】 Saturated red sandstones,as the research subjects from 500–600 meters deep of Meilinmiao mine in Ordos,in China,were tested respectively by triaxial compression in the condition of different temperatures(10 ℃,-5 ℃,-10 ℃,-15 ℃) and different confining pressures(0,4,8,12 MPa). Results show that:(1) When temperature range from 10 ℃–-15 ℃,the triaxial compressive strength of saturated red sandstones increase with the temperature dropping down,and present exponent relation. Elastic modulus increase and present linear relation;Friction angles increase while cohesive strengths c decrease,as temperature reduce.(2) When confining pressures change between 0–12 MPa,triaxial compressive strengths of saturated red sandstones increase with the confining pressures increasing,show the linear relation and still follow Mohr yield criterion. Elastic modulus,peak axial strain and peak radial strain increase with the increment of confining pressures.(3) Under the experimental conditions,the Poisson ratio are less affected by the confining pressure,but significantly affected by temperature,more attentions should be paid to the impact of temperature on Poisson ratio;The elastic modulus E is affected greatly by temperature and significantly by confining pressure. The temperature is the main factor affecting the elastic modulus and the confining pressure is the secondary consideration. Compared with Poisson ratio,the value of the elastic modulus is easily affected by external environment.(4) The failure modes of saturated red sandstone specimen are affected by temperature and confining pressure significantly. However,these are two different failure mechanism. Temperature decreases result in rock particles gravity reduction,and pore ice increases the pore friction area,then increases the friction;With the confining pressure increasing,it is due to the formation of micro-cracks inside the rock,that cohesive strength declines,at the same time,increases vertical component force,coming from rising confining pressure,on the fracture surface,thereby,increases the friction.更多还原