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通过对经历400℃~1 000℃高温后的粗砂岩进行常规三轴压缩试验,分析试样变形、强度和破坏特征与温度、围压的关系。结果表明:经历400℃高温后的试样围压高于20 MPa时,试样峰值强度附近出现明显屈服平台,经历超过600℃以上高温的试样均具有明显峰值点,随温度升高试样的塑性减弱脆性增强;400℃以内高温对试样的变形参数影响不大,经历超过400℃以上高温的试样的弹性模量、变形模量和极限应变随围压增加单调增加呈正相关性;试样的弹性模量和变形模量随温度升高单调降低,而峰值应变随温度升高单调增加。高温后试样峰值强度随围压增大而单调增加,符合Coulomb强度准则,综合围压影响系数为6.541;800℃以内高温对试样黏聚力、内摩擦角影响不明显,经历1 000℃高温后的试样黏聚力急剧降低,内摩擦角稍有增加;800℃以内高温对粗砂岩具有强化作用,扣除围压影响后试样材料强度与温度呈正相关,超过800℃以上高温使试样强度有所弱化,试样材料强度与温度呈负相关性;高温后试样的试验破坏角和理论破坏角基本一致,高温对试样破坏角影响较小,试验破坏角随围压增加而单调减小,围压对试样破坏角的影响大于温度的影响。
Through the conventional triaxial compression tests of coarse sandstone which experienced high temperature from 400 ℃ to 1 000 ℃, the relationship between deformation, strength and failure characteristics and temperature and confining pressure was analyzed. The results show that when the confining pressure is higher than 20 MPa after 400 ℃ high temperature, obvious yielding platform appears near the peak intensity of the sample, and the samples with the temperature exceeding 600 ℃ have obvious peak points. With the increase of temperature, The plastic deformation weakening brittleness enhanced; 400 ℃ within the high temperature on the deformation parameters of the sample has little effect, experienced more than 400 ℃ high temperature specimen elastic modulus, modulus of deformation and ultimate strain increases with the confining pressure increased monotonically increased; The elastic modulus and deformation modulus decrease monotonically with the increase of temperature, while the peak strain increases monotonically with the increase of temperature. After the high temperature, the peak intensity of the sample increases monotonically with the increase of the confining pressure, which accords with the Coulomb strength criterion and the influence coefficient of the confining pressure is 6.541. The influence of the high temperature within 800 ℃ to the cohesion and internal friction angle is insignificant, Cohesion of the sample after high temperature sharply decreased, the internal friction angle increased slightly; high temperature within 800 ℃ on the coarse sandstone has a strengthening effect, deducting the effect of confining pressure material strength and temperature was positively correlated, over 800 ℃ high temperature test The strength of specimen is weakened, and the strength of specimen is negatively correlated with temperature. The failure angle of specimen after high temperature is basically the same as the theoretical failure angle, while the impact of high temperature on specimen failure angle is small. Monotonically decreasing, confining pressure on the impact angle of the sample is greater than the impact of temperature.