碎裂板岩不同含水状态下蠕变特性试验

Experiment of creep characteristics of cataclastic slate under different moisture state

为了认识不同含水状态下碎裂板岩的蠕变特性,利用Instron全数控电液伺服力学试验机对贵州黔东南地区隧道洞口的碎裂板岩进行单轴压缩蠕变试验,研究其自然风干、不完全饱和和饱和试样的蠕变特性。实验研究结果表明:(1)碎裂板岩蠕变过程主要包括衰减蠕变和稳态蠕变过程,超过一定应力后,在极短的时间内破坏,因此可由广义开尔文模型描述其蠕变过程;(2)自然风干试样蠕变破坏应力为66.2MPa,为自然风干试样瞬时单轴抗压强度的71.7%,不完全饱和试样蠕变破坏应力为56.1MPa,饱和试样蠕变破坏应力为38.2MPa;(3)不完全饱和试样的最大蠕变应变为自然风干试样的2.7倍,而饱和试样的最大蠕变应变值是自然风干试样的4.3倍。

Abstract：To understand the creep characteristics of the cataclastic slate with different moisture state, uniaxial com- pression creep experiments were done with the Instron electric-fluid servo-compression machine. The specimens were taken from the southeastern area of Guizhou province. Through the results of creep tests of the natural air dr- ying, unsaturated and saturated rock specimens, the law of how the moisture state affects the mechanical properties of rock creep was studied. The research results are as follows： （1） The cataclastie slate creep curve is composed by decay creep and steady-state creep stage, and when the stress reaches a certain value, the specimens are destroyed in a very short time, so it can be described by the generalized Kelvin model. （2） The compression creep failure stress of the natural air drying rock specimen is 66.2 MPa, which is 71.7 % of its ultimate compressive strength, when the compression creep failure stress of the unsaturated and saturated rock specimen is 56.1 MPa and 38.2 MPa respectively. （3） The maximum creep strain of the unsaturated and saturated rock specimen is 2.7 times and 4.3 times of the natural air drying specimen respectively.