摘要
在深部地下工程中,了解岩石的历史应力记忆能力,对确定岩体原位应力状况至关重要。为研究花岗岩在经历多期应力后所呈现的记忆能力,设置4组先期加载方案,并在先期加载结束后对试样进行单轴压缩试验,观察其声发射现象。结果表明:先期加载结束后立即进行单轴压缩试验,花岗岩Kaiser效应明显,在加载应力达到先期最大应力值时有剧烈声发射信号产生;花岗岩对多期应力具有一定记忆能力,当先期加载应力高于裂纹闭合应力(σ_(cc))时,即使其不为先期最大应力,在后续单轴压缩试验中,存在相对孤立且信号较强的声发射事件,花岗岩在该处呈现出低频高幅的声发射信号,反之若先期加载应力低于σ_(cc),花岗岩则难以记忆。
In the field of deep underground engineering,comprehending the historical stress memory capacity of rocks is essential for determining the in-situ stress conditions of rock formations.To investigate the memory capacity of granite subjected to multiple stress periods,an initial uniaxial compression test was conducted to derive the stress-strain curve of the granite.The threshold values for each stress level were determined using the strain response method.Subsequently,four distinct prior loading schemes were established to simulate the multiperiod stress conditions induced by various geological processes on granite.Following the completion of these prior loading schemes,uniaxial compression tests were performed on the specimens,and the Kaiser effect was evaluated.The acoustic emission parameters,including AE counts,cumulative AE counts,peak frequency,and amplitude,were identified and analyzed to assess the Kaiser effect after the uniaxial compression test on the preloaded specimens.The results indicate that when the uniaxial compression test is conducted immediately following the conclusion of preloading,the Kaiser effect in granite is pronounced.This is evidenced by significant acoustic emission signals occurring when the applied stress reaches the value of the previous maximum stress.Granite exhibits a capacity to retain memory of prior multi-period stresses,specifically,when the preloading stress exceeds the crack closure stress(σ_(cc)),even if it does not match the previous maximum stress,a distinct and strong signal is observed in the subsequent uniaxial compression test.During these acoustic emission events,granite generates low-frequency,high-amplitude signals.Conversely,if the preloading stress is below the crack closure stress(σ_(cc)),granite does not retain this memory.
作者
姜天乐
李夕兵
陈江湛
JIANG Tianle;LI Xibing;CHEN Jiangzhan(School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China)
出处
《黄金科学技术》
北大核心
2025年第4期829-845,共17页
Gold Science and Technology
基金
国家自然科学基金项目“深部多场耦合岩体致灾能量诱变试验系统”(编号:51927808)资助。
作者简介
姜天乐(2000-),男,江西南昌人,硕士研究生,从事岩石Kaiser效应影响因素研究工作。E-mail:225511060@csu.edu.cn;通信作者:陈江湛(1991-),男,湖南长沙人,讲师,从事深部岩石力学试验装备研究工作。E-mail:jiangzhanchen@csu.edu.cn。
