We developed a coupled hydro-mechanical (HM) model based on a semi-logarithmic swelling law to reproduce the outcomes of swelling tests of a clay-sulfate rock specimen collected from the Freudenstein tunnel, which was constructed in Triassic Grabfeld Formation (formerly Gipskeuper = “Gypsum Keuper”) in Southwest Germany in the period of 1987–1991. The swelling tests were conducted using an oedometer apparatus under constrained (no strain) or constant load conditions. We used the strain–time data obtained from the laboratory testing to calibrate the HM model. We then ran a sensitivity analysis to reveal the importance of influential parameters, namely the maximum swelling pressure \({\sigma }_{max}^{sw}\), swelling parameter \(k\), and diffusion coefficient \(D\) on the long-term swelling behaviour of clay-sulfate rocks under the oedometer conditions. The HM model is capable of predicting long-term swelling deformations, i.e., model results were found to agree reasonably well with the experimental data. The results also show that using only 12 months experimental strain–time data to calibrate the HM model leads to an underestimation of swelling strains at the equilibrium condition. The findings show that at least 24 months experimental data is required for the model calibration.

我们开发了一个基于半对数膨胀定律的耦合流体力学 (HM) 模型，以重现从 Freudenstein 隧道收集的粘土-硫酸盐岩石样本的膨胀测试结果，该隧道建于三叠纪 Grabfeld 地层（以前称为 Gipskeuper = “Gypsum Keuper”）在 1987 年至 1991 年期间在德国西南部。在约束（无应变）或恒定负载条件下使用固结仪装置进行溶胀测试。我们使用从实验室测试中获得的应变时间数据来校准 HM 模型。然后，我们进行了敏感性分析以揭示影响参数的重要性，即最大膨胀压力\({\sigma }_{max}^{sw}\)、膨胀参数\(k\)和扩散系数\(D \)在固结仪条件下粘土-硫酸盐岩石的长期膨胀行为。HM 模型能够预测长期膨胀变形，即模型结果与实验数据相当吻合。结果还表明，仅使用 12 个月的实验应变-时间数据来校准 HM 模型会导致低估平衡条件下的溶胀应变。研究结果表明，模型校准至少需要 24 个月的实验数据。