Details
| Original language | English |
|---|---|
| Article number | 012080 |
| Journal | IOP Conference Series: Earth and Environmental Science |
| Volume | 1124 |
| Issue number | 1 |
| Publication status | Published - 2023 |
| Event | Eurock 2022 - Rock and Fracture Mechanics in Rock Engineering and Mining - an ISRM Regional Symposium - Helsinki, Finland Duration: 12 Sept 2022 → 15 Sept 2022 |
Abstract
In order to widen the basis for the dimensioning of storage caverns in rock salt, some special attention must be paid to the temperature developments within the cavity during its operation. Passed numerical investigations have shown that a temperature change in the storage medium, such as natural gas or hydrogen, can cause stress differences of several MPa in the rock mass surrounding the cavern. If, as a result, the difference between horizontal and vertical stresses is increased, the rock being additionally loaded by a fluid pressure can fracture orthogonally to the lowest principal stress. The knowledge of temperature conditions and heat flows in the cavern surrounding salt rock are therefore of great importance. A wide variety of factors must be considered when investigating such mechanisms. The novel test facility at the Institute of Geotechnical Engineering of the Leibniz University Hannover is used to simulate the situation that occurs at the caverns edge when storage medium is withdrawn. This means, the cooling and the gas pressure inside the cavity are reconstructed on hollow cylindrical test samples made of rock salt from various locations to draw conclusions about the propagation of fractures and thus the safety of salt caverns under gas-loading. Before inducing any mechanical loads by means of a triaxial cell, a comprehensive investigation of the temperature field, resulting from the locally limited, artificially induced cooling of a sample is carried out with the new testing facility. While local temperatures in the sample drop by about 20 Kelvin, it is free to contract inwards, causing thermal stresses to decrease significantly. Therefore, the facility needs to be optimized and the testing scheme is changed. Instead of reducing stresses thermally, one of the mechanical loadings is diminished while the gas pressure inside the borehole is kept constant. As a result, the material visibly fractures while mechanical loadings are at a fully-compressive state.
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In: IOP Conference Series: Earth and Environmental Science, Vol. 1124, No. 1, 012080, 2023.
Research output: Contribution to journal › Conference article › Research › peer review
}
TY - JOUR
T1 - Numerical and laboratory investigations of thermally induced fractures in rock salt
AU - Körner, Feline
AU - Baumgärtel, Lukas
AU - Leuger, Bastian
N1 - The research project “LARISSA” is supported by the Federal Ministry for Economic Affairs and Energy (BMWi) of Germany within the framework of the 7th Energy Research Programme (FKZ: 03EI3028).
PY - 2023
Y1 - 2023
N2 - In order to widen the basis for the dimensioning of storage caverns in rock salt, some special attention must be paid to the temperature developments within the cavity during its operation. Passed numerical investigations have shown that a temperature change in the storage medium, such as natural gas or hydrogen, can cause stress differences of several MPa in the rock mass surrounding the cavern. If, as a result, the difference between horizontal and vertical stresses is increased, the rock being additionally loaded by a fluid pressure can fracture orthogonally to the lowest principal stress. The knowledge of temperature conditions and heat flows in the cavern surrounding salt rock are therefore of great importance. A wide variety of factors must be considered when investigating such mechanisms. The novel test facility at the Institute of Geotechnical Engineering of the Leibniz University Hannover is used to simulate the situation that occurs at the caverns edge when storage medium is withdrawn. This means, the cooling and the gas pressure inside the cavity are reconstructed on hollow cylindrical test samples made of rock salt from various locations to draw conclusions about the propagation of fractures and thus the safety of salt caverns under gas-loading. Before inducing any mechanical loads by means of a triaxial cell, a comprehensive investigation of the temperature field, resulting from the locally limited, artificially induced cooling of a sample is carried out with the new testing facility. While local temperatures in the sample drop by about 20 Kelvin, it is free to contract inwards, causing thermal stresses to decrease significantly. Therefore, the facility needs to be optimized and the testing scheme is changed. Instead of reducing stresses thermally, one of the mechanical loadings is diminished while the gas pressure inside the borehole is kept constant. As a result, the material visibly fractures while mechanical loadings are at a fully-compressive state.
AB - In order to widen the basis for the dimensioning of storage caverns in rock salt, some special attention must be paid to the temperature developments within the cavity during its operation. Passed numerical investigations have shown that a temperature change in the storage medium, such as natural gas or hydrogen, can cause stress differences of several MPa in the rock mass surrounding the cavern. If, as a result, the difference between horizontal and vertical stresses is increased, the rock being additionally loaded by a fluid pressure can fracture orthogonally to the lowest principal stress. The knowledge of temperature conditions and heat flows in the cavern surrounding salt rock are therefore of great importance. A wide variety of factors must be considered when investigating such mechanisms. The novel test facility at the Institute of Geotechnical Engineering of the Leibniz University Hannover is used to simulate the situation that occurs at the caverns edge when storage medium is withdrawn. This means, the cooling and the gas pressure inside the cavity are reconstructed on hollow cylindrical test samples made of rock salt from various locations to draw conclusions about the propagation of fractures and thus the safety of salt caverns under gas-loading. Before inducing any mechanical loads by means of a triaxial cell, a comprehensive investigation of the temperature field, resulting from the locally limited, artificially induced cooling of a sample is carried out with the new testing facility. While local temperatures in the sample drop by about 20 Kelvin, it is free to contract inwards, causing thermal stresses to decrease significantly. Therefore, the facility needs to be optimized and the testing scheme is changed. Instead of reducing stresses thermally, one of the mechanical loadings is diminished while the gas pressure inside the borehole is kept constant. As a result, the material visibly fractures while mechanical loadings are at a fully-compressive state.
UR - http://www.scopus.com/inward/record.url?scp=85146553932&partnerID=8YFLogxK
U2 - 10.1088/1755-1315/1124/1/012080
DO - 10.1088/1755-1315/1124/1/012080
M3 - Conference article
AN - SCOPUS:85146553932
VL - 1124
JO - IOP Conference Series: Earth and Environmental Science
JF - IOP Conference Series: Earth and Environmental Science
SN - 1755-1307
IS - 1
M1 - 012080
T2 - Eurock 2022 - Rock and Fracture Mechanics in Rock Engineering and Mining - an ISRM Regional Symposium
Y2 - 12 September 2022 through 15 September 2022
ER -