Overview
The research project presented here includes the development and construction of a new robust and reliable long-time swelling testing device. The influence of external factors on the test as adjustment of loads, long-time accuracy of measurement, stiffness of the testing device or temperature should be eliminated or minimised. With this new testing apparatus and with samples from the Chienberg tunnel, i.e. dehydrated rock from the gypsum keuper, series of swelling tests under different axial loads should be performed. The duration of each test is estimated up to 10 years. The measurements should deliver information about the time development of the swelling process and in particular about the influence of pressure and on the long-term swelling strain.
The main aim of the project is to determine the relations between swelling pressure and strain of anhydrite rock.
Development and construction of a new experimental apparatus. Implementation of long-term swelling tests under clearly defined conditions until the completion of the swelling process.
Funding
Results
With the experimental results, the knowledge of the voltage dependence of the swelling behavior dehydrated rocks were improved. The new testing apparatus and the equipment display the correct behaviour and fulfill the requirements mentioned above. In some of the specimens, swelling strain can already be observed, but, as expected, it is too early for a more concrete evaluation of the results.
Technical Implications
With the experimental results, the knowledge of the voltage dependence of the swelling behavior dehydrated rocks were improved. The voltage dependence of the swelling behavior is of great importance for the structural concept of underground structures in Gipskeuper.