Abstract

The monitoring during one year of a gallery front of the Tournemire experimental station by optical metrology showed the presence of desiccation cracks sensitive to relative humidity variations in the gallery. The cracks are closed in summer, when RH is included between 90% and 98%, and open in winter when RH is lower. These cracks exhibit maximal aperture values ranging from 0.2 to 0.5 mm and different opening kinematics. One possible reason for these differences in surface opening could be the different crack length penetration within the rock mass, which the optical experimental method does not allow to measure. In order to highlight a possible relationship between the opening and the penetration of the desiccation cracks, we use a coupled hydro-mechanical numerical modelling taking explicitly into account the desaturation and resaturation of claystone. We focus on the aperture of three sub-horizontal cracks. The first results obtained remain quite qualitative, but the estimates of cracks penetration inferred by comparison between in situ measurements and numerical results are consistent with the results provided by geophysics.

摘要

通过光学计量学对 Tournemire 实验站的画廊正面进行的一年监测表明，画廊中存在对相对湿度变化敏感的干燥裂缝。当 RH 介于 90% 和 98% 之间时，裂缝在夏季关闭，而当 RH 较低时，裂缝在冬季打开。这些裂缝表现出从 0.2 到 0.5 毫米不等的最大孔径值和不同的开口运动学。这些表面开口差异的一个可能原因可能是岩体中不同的裂纹长度渗透，光学实验方法不允许测量。为了突出干燥裂缝的开口和渗透之间的可能关系，我们使用耦合流体力学数值模型，明确考虑了粘土岩的去饱和和再饱和。我们关注三个子水平裂缝的孔径。获得的第一个结果仍然是定性的，但通过比较推断的裂纹渗透估计现场测量和数值结果与地球物理学提供的结果一致。