Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear
It is important to determine the volumetric change properties of hydrate reservoirs in the process of exploitation. The Skempton pore pressure coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A<...
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MDPI AG
2022-04-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/10/4/509 |
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| author | Ruchun Wei Chao Jia Lele Liu Nengyou Wu |
| author_facet | Ruchun Wei Chao Jia Lele Liu Nengyou Wu |
| author_sort | Ruchun Wei |
| collection | DOAJ |
| description | It is important to determine the volumetric change properties of hydrate reservoirs in the process of exploitation. The Skempton pore pressure coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> can characterize the process of volume change of hydrate-bearing sediments under undrained conditions during shearing. However, the interrelationship between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> value responses and deformation behaviors remain elusive. In this study, effects of hydrate saturation and effective confining pressure on the characteristics of pore pressure coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> are explored systematically based on published triaxial undrained compression test data of hydrate-bearing sand and clay-silt sediments. Results show that there is a higher value of the coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> with increasing hydrate saturation at small strain stage during shearing. This effect becomes more obvious when the effective confining pressure increases for hydrate-bearing sand sediments rather than hydrate-bearing clayey-silt sediments. An increasing hydrate saturation leads to a reduction in <i>A</i> values at failure. Although <i>A</i> values at failure of sand sediments increase with increasing effective confining pressure, there are no same monotonic effects on clayey-silt specimens. <i>A</i> values of hydrate-bearing sand sediments firstly go beyond 1/3 and then become lower than 1/3 at failure even lower than 0, while that of hydrate-bearing clayey-silt sediments is always larger than 1/3 when the effective confining pressure is high (e.g., >1 MPa). However, when the effective confining pressure is small (e.g., 100 kPa), that behaves similar to hydrate-bearing sand sediments but always bigger than 0. How the <i>A</i> value changes with hydrate saturation and effective confining pressure is inherently controlled by the alternation of effective mean stress. |
| first_indexed | 2024-03-09T04:31:45Z |
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| id | doaj.art-593896bfd82742f3904b5fae073188c5 |
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| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-09T04:31:45Z |
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| spelling | doaj.art-593896bfd82742f3904b5fae073188c52023-12-03T13:33:57ZengMDPI AGJournal of Marine Science and Engineering2077-13122022-04-0110450910.3390/jmse10040509Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial ShearRuchun Wei0Chao Jia1Lele Liu2Nengyou Wu3Institute of Marine Science and Technology, Shandong University, Qingdao 266232, ChinaInstitute of Marine Science and Technology, Shandong University, Qingdao 266232, ChinaLaboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, ChinaLaboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, ChinaIt is important to determine the volumetric change properties of hydrate reservoirs in the process of exploitation. The Skempton pore pressure coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> can characterize the process of volume change of hydrate-bearing sediments under undrained conditions during shearing. However, the interrelationship between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> value responses and deformation behaviors remain elusive. In this study, effects of hydrate saturation and effective confining pressure on the characteristics of pore pressure coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> are explored systematically based on published triaxial undrained compression test data of hydrate-bearing sand and clay-silt sediments. Results show that there is a higher value of the coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>A</mi></semantics></math></inline-formula> with increasing hydrate saturation at small strain stage during shearing. This effect becomes more obvious when the effective confining pressure increases for hydrate-bearing sand sediments rather than hydrate-bearing clayey-silt sediments. An increasing hydrate saturation leads to a reduction in <i>A</i> values at failure. Although <i>A</i> values at failure of sand sediments increase with increasing effective confining pressure, there are no same monotonic effects on clayey-silt specimens. <i>A</i> values of hydrate-bearing sand sediments firstly go beyond 1/3 and then become lower than 1/3 at failure even lower than 0, while that of hydrate-bearing clayey-silt sediments is always larger than 1/3 when the effective confining pressure is high (e.g., >1 MPa). However, when the effective confining pressure is small (e.g., 100 kPa), that behaves similar to hydrate-bearing sand sediments but always bigger than 0. How the <i>A</i> value changes with hydrate saturation and effective confining pressure is inherently controlled by the alternation of effective mean stress.https://www.mdpi.com/2077-1312/10/4/509hydrate-bearing sedimentsundrained conditionspore pressure coefficientvolume changestress path |
| spellingShingle | Ruchun Wei Chao Jia Lele Liu Nengyou Wu Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear Journal of Marine Science and Engineering hydrate-bearing sediments undrained conditions pore pressure coefficient volume change stress path |
| title | Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear |
| title_full | Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear |
| title_fullStr | Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear |
| title_full_unstemmed | Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear |
| title_short | Analysis of the Characteristics of Pore Pressure Coefficient for Two Different Hydrate-Bearing Sediments under Triaxial Shear |
| title_sort | analysis of the characteristics of pore pressure coefficient for two different hydrate bearing sediments under triaxial shear |
| topic | hydrate-bearing sediments undrained conditions pore pressure coefficient volume change stress path |
| url | https://www.mdpi.com/2077-1312/10/4/509 |
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