中文摘要：

采用不会造成较大附加损伤的近似无损低应力水平加、卸载的方法,开展了考虑时间效应的冻融循环作用试验。在试验成本受限的情况下大幅度地降低了试验所需的岩样数。较常规试验方法,在试验岩样数不变的前提下,无需因岩样的离散性而进行主观地筛选数据,从而使得有效数据增多。随着冻融循环周期数增加,岩样表面孔隙及微裂隙不断扩大并出现软化层,裂纹加深,颗粒脱落程度加剧,发生片落、剥蚀,水分向岩石内部迁移,冻融损伤程度由内向外逐渐加深,并研发滴定技术定量标定了这种层进式损伤。进一步分析不同冻融循环周期数下岩样在不同上限应力循环作用下的动力响应变化规律。研究显示,阻尼比、阻尼系数及动泊松比均与冻融循环周期数呈线性递增的关系,动弹性模量与冻融循环周期数呈线性递减的关系;阻尼比、动泊松比均与幅值应力呈线性递减的关系,动弹性模量与幅值应力呈线性递增的关系。给出了阻尼比、动泊松比、阻尼系数、动弹性模量相互之间的定量关系,可通过一种参数的变化规律,预测另一种参数的变化趋势。在有限的试验条件、试验次数下,可有效地精简试验所需检测的参数。幅值应力越大,加、卸载转换时岩样弹性变形响应越迅速,不可逆变形越小,在同一幅值应力的情况下所吸收的能量减少。随着冻融循环周期数的增加,循环加、卸载前岩样的斜坡加载段逐渐变长,应力-应变曲线斜率逐渐变小;循环加、卸载后,不同加、卸载幅值应力下的每个周期中首次达到应力上限时岩样的轴向应变与冻融周期数呈线性关系,说明在冻融循环作用下,岩样孔隙率逐渐变大,密实程度降低,岩样有逐步软化的趋势。当幅值应力较大时,岩样的塑性累积量与冻融周期数呈指数型关系加速递增;当幅值应力较小时,岩样的塑性累积量与冻融周?

英文摘要：

By using the method of loading and unloading at the relative lossless low-stress level without causing a large additional damage,freeze-thaw cycle tests were conducted by considering the time effect.In the case of limited experimental cost,the number of rock samples required can be drastically reduced.Compared with the conventional test method,this novel procedure can obtain more efficient data from the limited data of certain rock samples without subjectively screening testing data due to the discreteness of samples.With the increase of the number of freeze-thaw cycles,the pore and micro-cracks on the surface of rock specimen are expanded and a softening layer is formed.The crack is deepened and the degree of particle shedding is aggravated.The occurrence of erosion makes moisture moving to the inside of rock specimen,and the degree of freezing and thawing damage gradually deepens from inside to outside.The development of titration technology calibrates the gradual damage.We further analyzed the dynamic response of rock samples under different upper limit stress cycles with different freezing and thawing cycles.The results show that the damping ratio,the damping coefficient and the dynamic Poisson＇s ratio are linearly increasing with the number of the freeze-thaw cycles.The dynamic elastic modulus decreases linearly with the number of the freeze-thaw cycle,but increases linearly with the amplitude stress.However,the damping ratio and dynamic Poisson＇s ratio decrease linearly with the amplitude stress.The quantitative relationships are established between the damping ratio,the dynamic Poisson＇s ratio,the damping coefficient and the dynamic elastic modulus.One known parameter can be used to predict the changing pattern of other parameters.Under the limited testing conditions and times,the numbers of parameters to be tested can be effectively reduced.If the amplitude stress is greater,the response of elastic deformation is more rapid,the irreversible deformation is smaller,and the energy absorbed is less.With