Effect of Water on Mechanical Properties of Coal Measures Mudstone Using Nanoindentation
Effect of Water on Mechanical Properties of Coal Measures Mudstone Using Nanoindentation
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DOI：
10.1155/2022/9032572
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发表时间：
2022-05
期刊：
影响因子：
1.7
通讯作者：
Wenshuai Li;Bang-you Jiang;Shitan Gu
中科院分区：
文献类型：
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作者：
Wenshuai Li;Bang-you Jiang;Shitan Gu
富含粘土矿物的泥岩表现出明显的水致弱化效应，泥岩力学性能受地下水影响显著。为了研究水对泥岩微观力学特性的影响，对不同含水率泥岩试样进行了单轴压缩和纳米压痕试验。利用Mori-Tanaka方法对微观尺度的测量进行了升级，以估计宏观尺度上相应的震级。结果表明，压痕模量变化明显，低至0.2 GPa，高至125 GPa，表明泥岩具有较强的非均质性。水对粘土矿物等水敏性矿物的微观力学性能有显著影响。水敏矿物在泥岩中所占比例最高，对泥岩的力学性质起重要作用。对于含水试样，用常规方法得到的弹性模量数据与均质化方法预测的值相近。研究结果表明，纳米压痕技术是评价岩石材料宏观力学性能的一种可行的实验技术。
Mudstone rich in clay minerals exhibits an obvious water-induced weakening effect, and the mechanical properties of mudstone are significantly affected by the groundwater. To investigate the effect of water on mechanical characteristics of mudstone at microscale, a series of uniaxial compression and nanoindentation tests were conducted on mudstone specimens at different moisture contents. Microscale measurements are upscaled to estimate the corresponding magnitudes at the macroscale using the Mori-Tanaka method. The results showed that the indentation modulus varied significantly, from as low as 0.2 GPa to a quite high value of 125 GPa, indicating a strongly heterogeneous distribution of mudstone. The water illustrated a significant effect on the microscale mechanical properties of water-sensitivity minerals like clay minerals. The water-sensitivity minerals occupied the highest proportion of the mudstone and were believed to play an important role in the mechanical properties of mudstone. For water-bearing specimens, the comparison with elastic modulus data obtained from common method indicated similar values as those predicted by homogenization method. The results of this study indicated that nanoindentation technique is a feasible experimental technique to assess the macroscale mechanical properties of rock materials.