水对岩石亚临界裂纹扩展及门槛值的影响研究  

Study of subcritical crack growth of rocks and threshold values in different environments

作　　者：万琳辉[1] 曹平[1] 黄永恒[1] 汪亦显[1] 

机构地区：[1]中南大学资源与安全工程学院,长沙410083

出　　处：《岩土力学》2010年第9期2737-2742,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50774093);中南大学学位创新课题(No.2009bsxt061);湖南省安监局资助项目(2009)

摘　　要：亚临界裂纹扩展是岩体工程时间相依性的主要原因之一。采用常位移松弛法,对饱水和干燥两种状态下的大理岩、花岗岩双扭试件进行了亚临界裂纹扩展试验研究,获得了两种岩石在两种状态下的亚临界裂纹扩展速率V与应力强度因子KΙ的关系,分析了两种岩石在两种状态下亚临界裂纹扩展的规律,并确定了两种岩石在两种状态下的门槛值(干燥状态):大理岩0K为1.365,花岗岩0K为2.305;(饱水状态):大理岩0K为1.118,花岗岩0K为1.490。研究表明,两种岩石的IlgK与lgV关系有较好的线性规律,但由于岩石本身矿物成分等的不均匀性,同种岩石的IlgK与lgV关系离散性较大,饱水状态下离散性更大;水能加速岩石亚临界裂纹的扩展,且对不同的岩石,其影响程度也不一样;水可以使岩石亚临界裂纹扩展的门槛值有较大幅度降低,不同岩石其降低的程度也不一样。Subcritical crack growth is one of the main causes of time-dependent behavior in rocks.Applied the constant displacement relaxation method,subcritical crack growth in specimens made of marble and granite which were in dry and water-saturated environments was studied in double torsion test.The relations of the stress intensity factor K Ιversus the subcritical crack growth velocity V were obtained under the two different environments.The behavior of subcritical crack growth was analyzed.The threshold values of subcritical crack growth in rocks were obtained under the two different environments——dry environment：marble 0 K=1.365,granite 0 K=2.305;water-saturated environment：marble 0 K=1.118,granite 0 K=1.490.The results showed：the relations between I lg K and lgV accorded with linear rules;but it were discrete because of inhomogenous mineral composition,etc,it was more discrete under water-saturated environment;water can accelerate the subcritical crack growth;the effect degree was different in different rocks;the threshold values were reduced by water;the reduction was different in different rocks.

关 键 词：常位移松弛 双扭试件 亚临界裂纹扩展 水影响 IgKl与lgV关系 门槛值 

分 类 号：TU443[建筑科学—岩土工程]