软岩相似模型的蠕变特性及数值模拟试验研究

Experimental study on numerical simulation of creep characteristics for soft rock of similar model

为解决软岩工程相似模型试验中传统相似材料难以模拟深部软岩低强度、大变形和强流变等特性的问题,以砂子为骨料,石蜡为胶结剂,制作模拟页岩的相似材料试件,该试件取材方便,经济成本低,制作工艺简单,成型时间短,变形明显。对不同配比的试件进行了不同轴压下的蠕变试验,并运用ABAQUS软件对该类相似材料软岩巷道进行蠕变数值分析。研究结果表明:该相似材料试件的蠕变特性与典型的岩石蠕变特性基本一致;其稳态蠕变和轴向应变均与轴压成正比,与围压成反比;该相似材料软岩巷道较易发生顶板脱落和底鼓的现象,与工程实际情况一致,为采用相似材料模型方法研究深部软岩巷道的稳定性以及巷道的支护提供了一定的参考。

The practice of using traditional materials to simulate soft rocks in similar model tests is challenging because of their characteristics of low strength,large deformations,and strong rheology.In this study,the authors developed a new type of similar material which took sand as aggregate and paraffin as cementation to produce the similar material specimen of shale.The advantages of this method were that the materials were easy to obtain,the cost was low,the specimen was simple to manufacture,the forming process was short,and the deformation was easily recognized.The creep tests of specimens with different proportions of sand under different axial compressions were carried out.The numerical analysis of a soft rock roadway with this material was conducted in ABAQUS.The results showed that the creep characteristics of the specimens with this type of similar material were consistent with typical rocks.The steady creep and axial strain were both in proportion to the axial compression and inversely proportion to confining pressure.Roof shedding and floor heave were likely to occur in soft rock roadways built by this material,also the same for site-engineering conditions.This paper provides useful references for the study of stability of deep soft rock roadway and the support of the roadway using the similar material method.