对不同岩性的岩石构建近红外光谱含水量反演模型过程中, 其特征集是否会因岩性不同而变化, 是建模时必须面对的关键问题。 针对该问题, 首先利用深部软岩水理作用智能测试系统进行了岩石吸水室内实验, 分别采集了砾岩、 粉砂岩、 夯土不同时刻3种不同岩性的含水岩石的近红外光谱各为51条、 106条和149条; 然后, 采用一阶导数法对原始光谱进行预处理, 消除环境干扰等对光谱的影响; 接着, 采用几何特征法提取光谱特征, 进行归一化处理, 消除量纲和变化幅度不同带来的影响; 分析了初始特征变量之间以及初始特征变量与含水量之间的相关程度, 并通过抑制阈值大小, 剔除冗余特征, 得到了两个强相关谱段处的特征变量; 最后利用最大信息系数（MIC）值作为度量标准, 对比分析了不同岩性的含水岩石近红外光谱的特征选择结果, 以期评价岩性对含水岩石光谱特征的影响。 结果表明: （1）砾岩、 粉砂岩、 夯土三种含水岩石的近红外光谱在1 400和1 900 nm附近都有着明显的吸收峰, 且随着含水量的变化, 吸收强度越来越强, 与含水量大小有明显的相关性; （2）对比砾岩、 粉砂岩、 夯土近红外光谱特征变量与其含水量的最大相关系数MIC值, 表明夯土的近红外光谱与含水量之间的相关性最强; （3）不同岩性的近红外光谱各个特征值与含水量的相关程度不同, 具体表现为在1 400 nm附近峰高、 右肩宽与含水量都具有较高相关系数, 只是相关性大小会因岩性不同而不同, 1 900 nm附近的右肩宽和峰面积与含水量都具有较高相关系数, 且右肩宽的相关程度高于峰面积; （4）不同岩性的含水岩石介质近红外光谱的特征变量与含水量相关性具有相似规律: 峰高、 右肩宽、 峰面积是相关程度最高的三个特性。

During the process of building inversion model of water content based on NIR spectrum, it is the key issue to figure out whether the feature set of rock will change along with the differences of lithology or not. Aiming at this problem, firstly conducting a laboratory experiment on water absorbability of rock by intelligent test system of hydrologic action on deep soft rock, this paper measures near infrared spectrum of water-bearing rock in three different lithology at different times. For conglomerate, siltite and rammed soil, we collect 51 pieces, 106 pieces and 149 pieces correspondingly. Afterwards, first-order derivative method is adopted in dealing with pretreatment of original spectrum, avoiding the influence of environmental interference on the spectrum. Next, the geometric feature method is used to extract the spectral features and normalize it to eliminate the influence caused by different dimensions and change amplitudes. Then, the correlation degree between initial characteristic variables and that between initial characteristic variables and water content are analyzed, and the characteristic variables at two strong correlation bands are obtained by referring suppression threshold size and eliminating redundant features. At last, Maximal Information Coefficient （MIC）is used as a metric to compare and analyze the feature selection results on near infrared spectrum of water-bearing rock with different lithology, in order to evaluate the influence of lithology on the spectral characteristics of water-bearing rocks. The results are as shown below: （1）The near infrared spectra of conglomerate, siltstone and rammed soil have obvious absorption peaks near 1 400 and 1 900 nm, and with the change of water content, the absorption intensity becomes much more stronger, which shows a significant correlation with the size of the water content. （2）The maximum correlation coefficient between the characteristic variables of near infrared spectra of conglomerate, siltstone and rammed soil and their water content value shows that the correlation between the near infrared spectrum of rammed soil and water content is the strongest. （3）Each characteristic value of near infrared spectrum of different lithology has different correlation degree with water content, which shows that the peak height near 1400nm, the right shoulder width and the water content all have high correlation. However, the correlation will vary because of different lithology, with the right shoulder width and peak area in the vicinity of 1900nm having higher correlation coefficient with water content, and the correlation degree of right shoulder width being higher than that of peak area. （4）The characteristic variables of near infrared spectrum of water-bearing rock with different lithology are similar to the correlation of water content—peak height, right shoulder width and peak area are the three characteristics with the highest correlation degree.