深井泥岩吸水特性试验研究

EXPERIMENTAL RESEARCH ON HYDROPHILIC CHARACTERISTICS OF MUDSTONE IN DEEP WELL

软岩吸水膨胀是深井软岩巷道产生大变形乃至坍塌的主要原因之一。采用自主开发研制的软岩水理作用测试仪,对深井泥岩进行吸水试验研究,同时进行SEM与X射线衍射试验,来揭示泥岩的吸水特性及其主要影响因素。经过对多个不同泥岩岩样的一系列试验及分析,建立泥岩吸水的过程函数,揭示吸水特性在时间序列上分为减速吸水和等速吸水两个阶段,吸水量与吸水时间双对数关系曲线呈上凸、下凹和直线3种类型。同时发现,孔隙率的大小、矿物含量与种类及黏土矿物的产状等,是泥岩吸水特性的主要影响因素。泥岩孔隙率与吸水量、吸水速率成正比关系,黏土矿物含量与吸水量、吸水速率成反比关系,且粒间孔隙中黏土矿物的分布形态不同,则特征曲线的形态也不同。

In order to grasp the hydrophilic characteristics of mudstone in deep well, a self-developed soft rock hydrophilic experiment system is used to analyze the main influential factors, as well as SEM and X-ray techniques are applied. Based on a series of test results of diverse mudstone samples, the hydrophilic characteristics can be divided into two stages in time series, i.e. decelerating suction phase and uniform speed suction phase. According to the lnQ-lnt curve, where Q is the soakage and t is the soaking time, there are three kinds of curves： convex, concave and linear curves. Porosity, content and sort of minerals as well as clay occurrence are the main factors influencing the hydrophilic characteristics of mudstone. The soaking velocity or soakage of mudstone is directly proportional to its porosity, but is inversely proportional to the clay mineral content. The characteristic curve is also affected by the occurrence of clay mineral obviously.