基于新型蠕变仪下的泥岩力学参数时效性研究

岩石在蠕变的过程中其基本力学参数变形模量E、内聚力c和内摩擦角是随时间和应力逐渐弱化的。本文对现行蠕变设备特点进行分析,研制了一套新型的五联单轴蠕变仪,此仪器能够在相同的应力条件下同时进行5个试件的蠕变试验。并且使用该仪器对宝鸡市秦源煤矿泥岩的力学参数E、c、在蠕变试验中的弱化规律进行了研究。提出了把粘塑性应变作为泥岩力学参数弱化的指标,得出了泥岩E、c、随粘塑性应变呈指数衰减的函数关系,并计算了该泥岩破坏时的E、c、。对该泥岩E、c、和粘塑性应变的函数关系式进行了分析,得到了岩石E、c、和应力(σ)以及时间(t)的耦合函数方程,为后续岩石非定常本构模型的研究奠定了基础。
力学参数〓时效性〓蠕变仪〓蠕变试验          
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EXPERIMENTAL STUDY ON TIME EFFECT OF MUDSTONE MECHANICAL PARAMETERS WITH NEW CREEP APPARATUS

The deformation modulus(E),cohesion(c)and internal friction angle(φ)are three basic mechanical parameters in the process of rock creep. They can gradually degrade with time and stress. This paper improves the present creep apparatus and develops a new man made five jointed uniaxial creep apparatus. The new apparatus can test five samples simultaneously under the different conditions for their mechanical parameters(E,c,and φ). The degrading regularities of above three parameters of mudstone collected from Qinyuan coal mine plant in Baoji Shanxi are investigated in the process of creep with this new creep apparatus. The results show that the dependent variable values of E,c, and φ are degraded exponentially with the viscoplastic strain, as the independent variable. The failure values of E,c and φ are calculated. The paper analyzes the relationship of E,c, and φ with the viscoplastic strain. Three coupling functional equations are obtained for indicating the influence of E,c, and φ on the stress(σ)and time(t), respectively. This paper lays a foundation for further establishment of unsteady mudstone constitutive model．