scholarly journals Influence of water saturation on strength of modified gypsum-alumina expanding cement at stage of delayed hardening

2018 ◽  
Vol 451 ◽  
pp. 012012
Author(s):  
S A Udodov ◽  
O A Bychkova
Keyword(s):  
Water Saturation ◽  
Influence Of Water

Time-dependent behaviour and water influence on the mechanical response of gypsum rock in underground quarry frameworks

2020 ◽  
Author(s):  
Chiara Caselle ◽  
Sabrina Bonetto ◽  
Patrick Baud
Keyword(s):  
Oil And Gas ◽  
Mechanical Response ◽  
Water Saturation ◽  
Triaxial Compression ◽  
Critical Time ◽  
Time Dependent ◽  
Wide Range ◽  
Influence Of Water ◽  
Gypsum Rock ◽  
Underground Quarry

<p>The mechanical response of natural gypsum rock is relevant in a wide range of engineering applications (e.g. tunnel excavation, stability assessment of underground quarries, oil and gas accumulation). In particular, in underground quarry environments, static loading conditions insisting on the gypsum pillars during and after the exploitation activities (i.e. several decades) require a specific attention to the sub-critical time-dependent deformation of the rock. The short-term stability (referred to the possibility of a failure in consequence to the sudden application of the axial load) does not preclude the possibility of deformation or even failure in the long-term.</p><p>In addition, the underground drifts of gypsum quarries are often located below the static level of the groundwater table, requiring a continuous water pumping to allow for the accessibility of the drifts themselves. The end of the quarry activity, coinciding with the interruption of the de-watering operations and the re-assessment of the original level of water table, brings to the new water saturation of the gypsum body. The water fills the connected porosity of the rock, influencing the general stability of the underground voids.</p><p>For these reasons, the present work aims to investigate the mechanical response of gypsum rock in time-dependent regime, also considering the influence of water saturation. The study proposes an experimental investigation of the influence of water on the rheology of a natural gypsum facies (i.e. branching selenite gypsum), distinguishing between the mechanical effects of a saturating fluid (in relation to the internal pore pressure), that should also be observed with a non-reactive fluid such as oil, and the water-gypsum chemical interactions. This influence of water is investigated in uniaxial compression, under uniaxial creep conditions and conventional triaxial compression. The new mechanical data are accompanied by microstructural observations of the effects induced in the rock by the mechanical compression, aiming to propose a description of the mechanisms involved in the gypsum deformation process.</p>

scholarly journals Influence of Water Saturation on the Mechanical Behaviour of Low-Permeability Reservoir Rocks

Energies ◽  
2017 ◽  
Vol 10 (2) ◽  
pp. 236 ◽  
Author(s):  
Decheng Zhang ◽  
Ranjith Pathegama Gamage ◽  
Mandadige Perera ◽  
Chengpeng Zhang ◽  
Wanniarachchillage Wanniarachchi
Keyword(s):  
Mechanical Behaviour ◽  
Water Saturation ◽  
Low Permeability ◽  
Reservoir Rocks ◽  
Low Permeability Reservoir ◽  
Influence Of Water

The Influence of Water Saturation on the Short- and Long-Term Mechanical Behavior of Red Sandstone

2018 ◽  
Vol 51 (9) ◽  
pp. 2669-2687 ◽  
Author(s):  
S. B. Tang ◽  
C. Y. Yu ◽  
M. J. Heap ◽  
P. Z. Chen ◽  
Y. G. Ren
Keyword(s):  
Mechanical Behavior ◽  
Water Saturation ◽  
Red Sandstone ◽  
Influence Of Water ◽  
Short And Long Term

scholarly journals Experimental Deformation of Opalinus Clay at Elevated Temperature and Pressure Conditions: Mechanical Properties and the Influence of Rock Fabric

2021 ◽  
Author(s):  
Valerian Schuster ◽  
Erik Rybacki ◽  
Audrey Bonnelye ◽  
Johannes Herrmann ◽  
Anja M. Schleicher ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Deformation Behavior ◽  
Water Saturation ◽  
Young's Modulus ◽  
Axial Strain ◽  
Shear Zones ◽  
Opalinus Clay ◽  
Triaxial Tests ◽  
Influence Of Water ◽  
Confining Pressures

AbstractThe mechanical behavior of the sandy facies of Opalinus Clay (OPA) was investigated in 42 triaxial tests performed on dry samples at unconsolidated, undrained conditions at confining pressures (pc) of 50–100 MPa, temperatures (T) between 25 and 200 °C and strain rates ($$\dot{\varepsilon }$$ ε ˙ ) of 1 × 10–3–5 × 10–6 s−1. Using a Paterson-type deformation apparatus, samples oriented at 0°, 45° and 90° to bedding were deformed up to about 15% axial strain. Additionally, the influence of water content, drainage condition and pre-consolidation was investigated at fixed pc–T conditions, using dry and re-saturated samples. Deformed samples display brittle to semi-brittle deformation behavior, characterized by cataclastic flow in quartz-rich sandy layers and granular flow in phyllosilicate-rich layers. Samples loaded parallel to bedding are less compliant compared to the other loading directions. With the exception of samples deformed 45° and 90° to bedding at pc = 100 MPa, strain is localized in discrete shear zones. Compressive strength (σmax) increases with increasing pc, resulting in an internal friction coefficient of ≈ 0.31 for samples deformed at 45° and 90° to bedding, and ≈ 0.44 for samples deformed parallel to bedding. In contrast, pre-consolidation, drainage condition, T and $$\dot{\varepsilon }$$ ε ˙ do not significantly affect deformation behavior of dried samples. However, σmax and Young’s modulus (E) decrease substantially with increasing water saturation. Compared to the clay-rich shaly facies of OPA, sandy facies specimens display higher strength σmax and Young’s modulus E at similar deformation conditions. Strength and Young’s modulus of samples deformed 90° and 45° to bedding are close to the iso-stress Reuss bound, suggesting a strong influence of weak clay-rich layers on the deformation behavior.

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