高温-冷却-冲击循环下花岗岩物理损伤及力学劣化试验研究  

Experimental study on physical damage and mechanical degradation of granite subjected to high-temperature cooling impact cycling

作　　者：詹金武 周亚来 王雨 黄明[3] 江松 ZHAN Jin-wu;ZHOU Ya-lai;WANG Yu;HUANG Ming;JIANG Song(School of Civil Engineering,Fujian University of Technology,Fuzhou,Fujian 350118,China;School of Architecture and Civil Engineering,Liaocheng University,Liaocheng,Shandong 252059,China;College of Civil Engineering,Fuzhou University,Fuzhou,Fujian 350116,China)

机构地区：[1]福建理工大学土木工程学院,福建福州350118 [2]聊城大学建筑工程学院,山东聊城252059 [3]福州大学土木工程学院,福建福州350116

出　　处：《岩土力学》2024年第8期2362-2372,2386,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金青年基金(No.52008111);福建省自然科学基金(No.2022J05185)。

摘　　要：高温岩石经不同冷却方式冷却后的力学特性直接影响着深地岩土工程施工的安全性。以中风化花岗斑岩为研究对象,对400℃下循环自然冷却和遇水冷却试样展开单轴压缩试验和循环动态冲击试验,对比分析花岗岩力学性质的变化规律,并基于Logistic分布规律,引入受荷损伤变量和热循环损伤变量建立花岗岩统计损伤本构模型,确定了相应参数表达式,验证了本构模型的适用性与合理性,结果表明:在单轴压缩试验中,随着热循环次数的提高,花岗岩内部微裂隙开始扩展、贯通形成宏观裂纹,岩样质量和纵波波速开始衰减,静态应力-应变曲线中的弹性变形阶段逐渐缩短,出现明显的不稳定破坏阶段;冷却方式可以显著影响岩石强度的劣化速度,但对花岗岩的最终静态抗压强度无明显影响。在0.30 MPa冲击气压下,随着冲击次数的增加,自然冷却花岗岩的动态抗压强度先增大后减小,首次冲击可有助于提高自然冷却花岗岩的抗压强度,当热循环超过3次时,花岗岩的抗循环冲击能力开始下降。基于Logistic分布建立的动态损伤本构模型与试验曲线具有较好的一致性,且模型参数获取简单,物理意义明确,具有一定适用性。研究成果可为变温环境下岩体施工、修复及围岩稳定性分析提供参考。The mechanical properties of high-temperature rocks,after being cooled by various methods,significantly influence the safety of deep earth geotechnical engineering.The study primarily investigated medium-weathered granite porphyry.Uniaxial compression and cyclic dynamic impact tests were performed on specimens cooled naturally and via water immersion at 400℃.The aim was to compare and analyze the change in the mechanical properties of granite.Utilizing the Logistic distribution law,loading damage variables and thermal cycling damage variables were incorporated to develop a statistical damage constitutive model for granite.The corresponding parameters were determined,and the applicability and reasonableness of the model were verified.The results reveal that during uniaxial compression testing,the internal microcracks in granite expand and coalesce into macroscopic cracks as the number of thermal cycles increases.Furthermore,the mass of the rock samples and longitudinal wave velocity decrease,while the elastic deformation phase in the static stress-strain curve shortens,indicating a distinct unstable damage stage.The rate of deterioration of rock strength can be significantly affected by the cooling method,but the final static compressive strength of granite is not significantly affected.Under an air pressure impact of 0.30 MPa,the dynamic compressive strength of naturally cooled granite initially increases and then decreases with increasing impact cycles.The initial impact enhances the compressive strength of naturally cooled granite.However,when thermal cycling exceeds three cycles,granite's resistance to cyclic impacts diminishes.The dynamic damage model,formulated using the Logistic distribution,exhibits good alignment with the experimental curve.The model parameters are readily obtainable,possessing a clear physical interpretation and practical applicability.This research offers valuable references for the construction,repair,and stability analysis of rock masses in variable temperature environments.

关 键 词：高温岩石 自然冷却 遇水冷却 多次冲击 损伤程度 

分 类 号：TU45[建筑科学—岩土工程]