含油泥岩各向异性蠕变研究

Creep of Anisotropic Oil Shale

以软岩非线性蠕变理论为基础,对含油泥岩的弹性模量、泊松比、蠕变变形速率进行了测试和研究,通过分级加载三轴蠕变试验发现:含油泥岩的侧向蠕变具有明显地各向异性,横向蠕变有明显的加速,并且比轴向加速蠕变阶段出现提前,在加速蠕变阶段,轴向蠕变的则不明显.随着应力水平以及层理面与样品端面夹角的增加,瞬时弹性模量也增大,有明显的各向异性;瞬时泊松比的变化显著,最大瞬时泊松比为常规三轴实验所测泊松比的2.5倍;横向形变的瞬时弹性模量随应变的增大而减少,两者呈非线性关系;同时,泊松比与蠕变呈非线性关系.根据含油泥岩蠕变力学参数,推导出横向各向异性非线性蠕变方程,为海下开采条件下的巷道支护提供了理论依据.

Based on the nonlinear creep theory for soft rock, three mechanics parameters of the Young＇s modulus, creep strain rate, and Poisson＇s ratio for oil shale have been measured and analyzed by triaxial stepwise loading creep test. The results show that the lateral creep is of obvious anisotropy and the lateral creep accelerates more obviously and earlier than that of axial creep. In the meantime, the Poisson＇s ratio has a nonlinear relationship with creep. With the increase of 0, the instant elastic modulus increases and the isotropy becomes obvious; The instant Poisson＇s ratio changes significantly, with the maximum value being 2.5 times as great as the value by conventional test. According to the creep mechanics test parameters, we have constructed a nonlinear creep formula, which provides a theory basis for roadway support in coal mining under the sea.