热-液耦合作用下花岗岩单轴力学特性的实验研究

Experimental Study on Uniaxial Mechanical Properties of Granite under Thermo-hydraulic Coupling

为研究热-液耦合花岗岩单轴力学性能及破坏方式,对花岗岩进行不同温度作用下的热-液耦合循环处理,采用单轴压缩试验分析其力学特征的变化规律。结果表明:①峰值强度随温度升高而增加,50~100℃下,降低11.51%,100~150℃下,降低1.77%;峰值应变与循环温度呈线性拟合关系,随温度升高,峰值应变降低;弹性模量随温度上升而先变大后减小,上升幅度较明显约123.21%。②峰值强度随循环次数增加出现不同变化,3次循环前均处于缓慢变化,后面变化明显,3~4次时,降低19.87%,4~5次时,上升22.70%;峰值应变与循环次数呈多项式拟合关系,3次循环时取得最大值;弹性模量与循环次数呈多项式拟合关系,3次循环时取得最小值。③峰值强度在等值线图中,50~100℃,以3次循环呈对称分布;峰值应变随循环温度升高和循环次数变多而降低;弹性模量等值线图中出现双峰模式,随着温度升高,循环次数变多,弹性模量增加。④应力-应变曲线大致经历压密、弹性、屈服、破坏4个阶段,发生脆性破坏。破坏分为劈裂、剪切。可见,热-液耦合作用对花岗岩的力学特性是有一定影响的。

In order to study the uniaxial mechanical properties and failure modes of thermo-liquid coupled granite,the thermo-liquid coupling cycle treatment of granite under different temperatures was carried out,and the variation of mechanical characteristics was analyzed by uniaxial compression test.The results show these as follows.①The peak intensity increases with increasing temperature.The peak intensity decreases by 11.51%when the temperature is in the range of 50~100℃,the peak intensity is reduced by 1.77%when temperature is in the range of 100~150℃;The peak strain is linearly related to the cycle temperature,it decreases as the temperature increases;The modulus of elasticity increases first and then decreases with increasing temperature,and the increase is about 123.21%.②As the number of cycles increases,there are different changes in peak intensity,it was slowly changed before 3 cycles,the peak intensity is reduced by 19.87% when the cycle is 3~4 times,the peak intensity is reduced by 22.70% when the cycle is 4~5 times;The peak strain has a polynomial fit with the number of cycles,the peak intensity is maximum when 3 cycles,the elastic modulus has a polynomial fit with the number of cycles,the elastic modulus is Minimum when 3 cycles.③In the contour plot,the peak intensity is symmetrically distributed in 3 cycles at a temperature interval of 50~100℃;The peak strain decreases as the cycle temperature increases and the number of cycles increases;In the contour map,the elastic modulus exhibits a bimodal mode,and the modulus of elasticity increases as the temperature increases and the number of cycles increases.④The stress-strain curve undergoes four stages of compaction,elasticity,yielding and failure,and brittle failure occurs.Destruction is divided into splitting and shearing.It is concluded that the thermo-liquid coupling has a certain influence on the mechanical properties of granite.