温度梯度冻土压缩变形破坏特征及能量规律  

Deformation failure and energy properties for frozen soils with thermal gradients

作　　者：赵晓东[1] 周国庆[1] 商翔宇[1] 陈国舟[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008

出　　处：《岩土工程学报》2012年第12期2350-2354,共5页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB026103);国家高技术研究发展计划(863计划)项目(2012AA06A401);国家自然科学基金项目(50534040);中央高校基本科研业务费专项资金项目(2011QNA03);中国博士后基金项目(20110491489)

摘　　要：采用K0DCGF(K0固结—保持荷载冻结—形成温度梯度—再试验)方法,开展2种温度梯度冻结饱和黏土在3种固结压力下的恒围压加轴压剪切试验(CTC),研究温度梯度和固结应力对冻结饱和黏土变形破坏特征和能量规律的影响机制。结果表明:K0DCGF模式中温度梯度冻结饱和黏土呈脆性破坏特征,而均匀温度冻结饱和黏土呈塑性破坏特征;温度梯度冻结饱和黏土在CTC路径中的变形破坏过程可用3个阶段描述:弹性变形阶段,峰值应力前对应的微裂隙或微孔洞萌生阶段,峰值应力后对应的裂纹扩展贯通阶段;随温度梯度和固结应力增加冻土存储的可释放弹性应变能与外荷载所产生的总输入能量的比例逐渐增加,这与K0DCGF模式中冻结饱和黏土的脆性破坏特征与固结应力以及温度梯度之间关系基本对应。A series of triaxial compression tests on frozen clay are conducted under various thermal gradients and consolidation pressures by means of the KoDCGF （K0 consolidation, freezing with non-uniform temperature under loading） method. The deformation failure characteristics and compression energy are investigated. The test results indicate that the frozen saturated clay with thermal gradients has brittle characteristics. However, the frozen saturated clay with uniform temperature presents the plastic characteristics. The deformation process for frozen clay with thermal gradients can be divided into three stages： elastic deformation stage, micro-fissures （or micro-holes） developing stage before the axial stress reaches the peak value and the micro-fissures transfixion stage when the axial stress is greater than the peak value. The ratio of the elastic strain energy to the total input energy increases with the increase of the thermal gradients and consolidation pressures. This phenomenon is correspondent to the relationship between the brittle characteristics and the thermal gradients and consolidation pressures.

关 键 词：温度梯度 冻结饱和黏土 变形破坏 能量规律 脆性特征 

分 类 号：TU445[建筑科学—岩土工程]