非饱和白垩压缩变形依时特性的研究

A study on time－dependent behavior of the North Sea unsaturated chalk

工程实践和室内试验都表明，非饱和的油田白垩同一般岩土材料一样具有不可忽视的依时性态。为此，在试验和理论研究的基础上为非饱和白垩建立了一个修正剑桥模型，该模型可同时反映时间、应力和吸力对非饱和白垩强度及变形特性的影响，为进一步深入了解吸力对非饱和白垩依时性态的影响及其机理提供了一定的参考。

Engineering practices and laboratory tests display that the unsaturated chalk has time-dependent behaviours as other geomaterials. So based on the experimental and theoretical studies, a viscoplastic modified Cam-clay model is developed for simulating the time-dependent behaviour of unsaturated chalk. The combined effect of time, suction and stress is considered in this model, which can well depict the strength and deformation of the chalk. The achievement of the paper can give a better reference to time-dependent, behaviour of chalk.