岩石吸水特性及水岩耦合力学特性试验

为了研究凝灰岩、泥炭质砂岩和泥质砂岩的吸水特性以及吸水引起的力学性能变化,利用X-射线衍射试验、SEM试验和压汞试验对3种岩样的矿物成分、微观结构和孔径分布特征进行了测试分析,在此基础上利用软岩水理作用试验系统对岩样的吸水特性进行了研究,并对吸水前后岩样的强度进行了测试。试验结果表明,3种岩石的吸水过程都可分为非线性吸水和线性吸水两个阶段,吸水特征曲线函数均为负指数函数,岩石的吸水量与其黏土矿物含量和其有效空隙数量之间为正相关；吸水后岩石强度的减小量和其吸水量与黏土矿物含量之间为负相关,较小的吸水量也会对岩石的力学特性产生较大的影响。

Experimental study on water absorption characteristics and water-rock coupling mechanical properties of rock

To better understand the water absorption (WA) characteristics and changes in mechanical properties caused by water absorption of tuff, carboniferous sandstone and argillaceous sandstone, this paper conducted the X-ray diffraction, Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry(MIP) tests to obtain their mineralogical composition, micro-structure feature and pore size distribution features. A soft-rock hydrophilic experiment system was used to study the WA characteristics of rock samples, and the strengths of rock samples before and after absorbing water were tested. The results show that the WA process of three rocks includes the non-linear stage and linear stage, and the functions of the WA characteristic curves are all negative exponential function. The WA value has positive correlation with the clay mineral content and the amount of the effective holes. The reduced strength of the rocks shows negative correlation with WA value and clay mineral content, moreover the little WA value can contribute bigger effect on the mechanical properties of rocks.