干湿循环作用下砂岩蠕变损伤及本构模型  

Creep Damage and Constitutive Model of Sandstone Under Dry-wet Cycles

作　　者：霍树义 金坎辉 杨涛 周晴晴 张薇 崔建军 HUO Shu-yi;JIN Kan-hui;YANG Tao;ZHOU Qing-qing;ZHANG Wei;CUI Jian-jun(Logistics Management Office,Hebei University of Water Resources and Electric Engineering,Cangzhou 061001,China;Hebei South Canal River Management Office,Cangzhou 061001,China)

机构地区：[1]河北水利电力学院后勤管理处,河北沧州061001 [2]河北省南运河河务管理处,河北沧州061001

出　　处：《土木工程与管理学报》2020年第2期163-169,共7页Journal of Civil Engineering and Management

摘　　要：为了探究干湿循环次数对砂岩蠕变力学及损伤特性的影响,对砂岩进行了干湿循环0,5,10,15,20次下的常规单轴加载和蠕变试验,结果表明:经干湿循环过后,砂岩的强度、弹性模量等各项力学指标均较天然状态下有不同程度的降低;在低干湿循环次数下,砂岩的蠕变破坏应力值达到了短期峰值应力的80%,而在高循环次数下,蠕变破坏应力仅为短期峰值应力的60%;干湿循环次数越多,砂岩蠕变软化特征越明显,且砂岩的初始损伤越大,在同等时间内,蠕变损伤发展越迅速,蠕变破坏时间越短;长期强度与短期强度的比值随干湿循环次数的增加而递减;基于试验结果,建立了考虑干湿循环作用初始损伤以及蠕变时效损伤的分数阶非线性本构模型,该模型可以很好地模拟和预测不同干湿循环作用后岩石的蠕变损伤及变形发展情况。To investigate the effects of the number of dry-wet cycles on creep mechanics and damage characteristics of sandstone,the conventional uniaxial loading and creep tests were carried out for sandstone under 0,5,10,15 and 20 times of dry-wet cycles.The results show that the strength,modulus of elasticity and other mechanical indexes of sandstone are lower than those of natural state.The creep failure stress of sandstone reaches 80%of the short-term peak stress at low dry-wet cycles,while at high cycles,the creep failure stress is only 60%of the short-term peak stress.With the increase of dry-wet cycles,the creep softening characteristics become more obvious,the initial damage becomes larger,the creep damage develops more rapidly.The ratio of long-term strength to short-term strength decreases with the increase of the number of dry-wet cycles.Based on the test results,a fractional nonlinear constitutive model considering the initial damage and creep aging damage under dry-wet cycles is established.The model can well simulate and predict the creep damage and deformation development of sandstone after different dry-wet cycles.

关 键 词：干湿循环 砂岩 蠕变 长期强度 损伤 本构模型 

分 类 号：TU45[建筑科学—岩土工程]