实时高温下加载速率对花岗岩力学特性影响的试验研究  

Experimental study of the effect of loading rates on mechanical properties of granite at real-time high temperature

作　　者：徐小丽[1,2] 高峰[2] 张志镇[2] 陈琳[3] 

机构地区：[1]南通大学建筑工程学院,江苏南通226019 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [3]南通大学理学院,江苏南通226019

出　　处：《岩土力学》2015年第8期2184-2192,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.11202108);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金(No.SKLGDUEK1204);南通大学前期预研科研项目(No.11ZY006)

摘　　要：为综合考虑温度、加载速率两个因素对花岗岩力学性质及破坏方式的影响,在实时高温（25~1 000℃）作用下利用MTS810电液伺服材料试验系统对岩样进行不同加载速率作用下的单轴压缩试验。研究结果表明：（1）各个温度点,岩样单轴压缩应力-应变曲线大致经历了压密、弹性、屈服、破坏4个阶段。岩样峰后曲线在加载速率为0.001~0.01 mm/s出现台阶型分段跌落状,在加载速率为0.01~0.1 mm/s呈现光滑、陡峭的连续曲线。（2）岩样峰值强度、弹性模量随温度的升高可分为4个阶段：25~200℃区间为缓慢上升段;200~600℃区间为快速下降段;600~800℃区间为缓慢上升段;800~1 000℃区间为平缓下降段。1 000℃时的峰值强度和弹性模量相对于25℃时分别降低了53.47%和64.34%。峰值应变与温度呈现三次多项式拟合关系。（3）岩样峰值强度、弹性模量与加载速率对数均呈现二次多项式增长关系,加载速率为0.1 mm/s时的峰值强度和弹性模量相对于0.001 mm/s时分别提高了38.82%和37.22%。岩样峰值应变与加载速率没有明显的对应关系。（4）单轴压缩状态下,随着温度的升高,花岗岩变形破坏形式由拉剪破裂向锥形破裂并伴随向碎性流动过渡,失稳型式由突发失稳向渐进破坏过渡。同一温度状态下,加载速率对岩样的破裂形式没有明显影响,但失稳型式发生了变化。To study the effect of temperature and loading rate on mechanical properties and failure modes of rock materials, experiments on granite were conducted under uniaxial compression at different loading rates and real-time high temperatures in the range of of 25-1 000 ℃ by the servo-controlled testing machine MTS810. The results show that： （1） Stress-strain curves of granite at real-time high temperature have the compaction, elasticity, yield and failure stages. Post-peak curves present stepped and segmented drop shape at loading rates from 0.001 to 0.01 mm/s, but present smooth and steeped continuous phenomena at loading rates from 0. 01 to 0.1mm/s. （2） The peak strength and elastic modulus are divided into four stages with increasing temperature, which is the slowly rising stage from 25 to 200 ℃, rapidly declining stage from 200 to 600 ℃, slowly rising stage from 600 to 800 ℃, and slowly declining stage from 800 to 1 000 ℃. The peak strength and elastic modulus at 1 000 ℃ decreases by 53.47% and 64.34% respectively, compared with that at 25℃. The peak strain presents cubic polynomial relationship with the temperature. （3） Both the peak strength and elastic modulus show a quadratic polynomial increased relationship with the logarithm of loading rates, the value of which increased by 38.82% and 37.22% respective at the loading rate of 0.1 mm/s to compare with that at 0.001 mm/s. The peak strain presents unobvious relationship with loading rates. （4） As the temperature increases under uniaxial compression state, the forms of deformation and failure of rock samples transfer from the tensile shear rupture to the cone fracture with fragmentation of liquidity;and the instability mode transfers from sudden instability to progressive failure. The fracture modes of rock sample are independent on the loading rate, but the instability patterns depends on loading rate.

关 键 词：花岗岩 温度 加载速率 力学性质 失稳型式 

分 类 号：TU452[建筑科学—岩土工程]