Empirical Correlations for Predicting Strength Properties of Rocks from P-Wave Velocity Under Different Degrees of Saturation

Karakul, Hasan; Ulusay, Reşat

doi:10.1007/s00603-012-0353-8

Cited by 145 publications

(67 citation statements)

References 37 publications

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“…The evolution of pore pressure with growth of micro-cracks and the effect of pore pressure on mechanical behavior of saturated MeuseHaute/Marne claystone were studied by Hu et al [30]. Karakul and Ulusay [35] proposed some empirical correlations between strength properties and P-wave velocity under different degrees of saturation. Fourteen different rock types mainly of sedimentary or volcanic origin were collected from Turkey.…”

Section: Other Sedimentary Rock Typesmentioning

confidence: 99%

Water effects on rock strength and stiffness degradation

2015

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Reduction in strength and stiffness in rocks attributed to an increase in water content has been extensively researched on a large variety of rock types over the past decades. Due to the considerable variations of texture and lithology, the extent of water-weakening effect is highly varied among different rock types, spanning from nearly negligible in quartzite to 90 % of uniaxial compressive strength reduction in shale. Readers, however, often face difficulties in comparing the data published in different sources due to the discrepancy of experimental procedures of obtaining the water saturation state and how the raw laboratory data is interpreted. In view of this, the present paper first reviews the terminologies commonly used to quantify the amount of water stored in rocks. The second part of the paper reviews the water-weakening effects on rock strengths, particularly focusing on uniaxial compressive strength and modulus, as well as tensile strength, under quasi-static loading and dynamic loading. The correlation relationships established among various parameters, including porosity, density and fabric of rocks, and external factors such as strain rate, surface tension and dielectric constant of the saturating liquid, absorption percentage and suction pressure, are reviewed and presented toward the end of the paper.

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Section: Other Sedimentary Rock Typesmentioning

confidence: 99%

Water effects on rock strength and stiffness degradation

2015

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“…Kahraman (2007) showed that for sedimentary rocks there is a strong linear correlation between P wave velocities of dry v d p and saturated rocks v w p . Most rocks show significant trends of UCS reduction with increasing degree of saturation (Shakoor and Barefield, 2009;Karakul and Ulusay, 2013). For Miocene limestones, there is a reduction of UCS and T 0 values with increasing saturation (Vásárhelyi, 2005).…”

Section: Applicability Of Empirical Relations To Predict In Situ Rockmentioning

confidence: 99%

Empirical relations of rock properties of outcrop and core samples from the Northwest German Basin for geothermal drilling

Reyer

Philipp

2014

Geoth. Energ. Sci.

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Abstract. Information about geomechanical and physical rock properties, particularly uniaxial compressive strength (UCS), are needed for geomechanical model development and updating with logging-while-drilling methods to minimise costs and risks of the drilling process. The following parameters with importance at different stages of geothermal exploitation and drilling are presented for typical sedimentary and volcanic rocks of the Northwest German Basin (NWGB): physical (P wave velocities, porosity, and bulk and grain density) and geomechanical parameters (UCS, static Young's modulus, destruction work and indirect tensile strength both perpendicular and parallel to bedding) for 35 rock samples from quarries and 14 core samples of sandstones and carbonate rocks.With regression analyses (linear-and non-linear) empirical relations are developed to predict UCS values from all other parameters. Analyses focus on sedimentary rocks and were repeated separately for clastic rock samples or carbonate rock samples as well as for outcrop samples or core samples. Empirical relations have high statistical significance for Young's modulus, tensile strength and destruction work; for physical properties, there is a wider scatter of data and prediction of UCS is less precise. For most relations, properties of core samples plot within the scatter of outcrop samples and lie within the 90 % prediction bands of developed regression functions. The results indicate the applicability of empirical relations that are based on outcrop data on questions related to drilling operations when the database contains a sufficient number of samples with varying rock properties. The presented equations may help to predict UCS values for sedimentary rocks at depth, and thus develop suitable geomechanical models for the adaptation of the drilling strategy on rock mechanical conditions in the NWGB.

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“…Therefore, the use of jaws with quite small contacts like those of the line loading condition are not suggested to prevent reaching excessive compressive stress concentrations that can make invalid failures. In the use of 15° jaw, compressive stresses were not found to be enough high for causing the invalid compressive failure as the ratio of the maximum compressive stress was 4 times of the maximum tensile stress [25][26][27].…”

Section: Resultsmentioning

confidence: 99%

Determination of Cohesion values of Rock Materials using Double Shear Jaws

Komurlu¹,

Demir²

2018

Period. Polytech. Civil Eng.

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IntroductionAlthough shear strength of rock materials is an important parameter for many different rock engineering applications, there is still a necessity for development of a standard method and details for determination of shear strength of rock materials. The conventional direct shear strength (DSS) test method suggested by International Society for Rock Mechanics and Rock Engineering (ISRM) and standards like ASTM D5607 are not a proper way to test high strength rock materials because of possible failure of cement mortar instead of rock core specimens [1][2][3]. The cement moulding method to hold specimens is more suitable for testing rock joints rather than intact rock materials. As another topic, the conventional DSS test has additional problems of impracticality in specimen preparation process including two steps cement mortar casting as seen in Fig 1. In this study, a practical test method for determination of cohesion values of rock materials is investigated to assess whether accurate strength values can be measured using double shear jaw (DSJ) which is a basic apparatus to test numerous specimens instead of only one specimen as in cement moulding method of holding. Within this purpose, new steel jaws for testing cohesion of rock materials were designed and manufactured in this study.Need for waiting the curing time of several days for holding specimens in the casted mortar method should be stated as another disadvantage of the conventional DSS test. As an important issue which prevents to measure the strength value under pure shearing, significant bending/tension effect is induced as the rock specimen loaded in the soft cement mortar. Having the bending effect in the specimen causes to measure smaller strength values than that determined under pure shearing condition [4][5][6][7]. In this study, a new method of using DSJ was investigated for the aim of having ideal loading condition. For the conventional DSS equipment in rock mechanics laboratories, manual load application by using the hydraulic jack is an additional lacking to cause a personal effect on the strength results. On the other hand, double shear jaws (DSJs) let specimens to be loaded vertically with a constant rate which can be supplied by the load controlled compressive equipment.

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Empirical Correlations for Predicting Strength Properties of Rocks from P-Wave Velocity Under Different Degrees of Saturation

Cited by 145 publications

References 37 publications

Water effects on rock strength and stiffness degradation

Water effects on rock strength and stiffness degradation

Empirical relations of rock properties of outcrop and core samples from the Northwest German Basin for geothermal drilling

Determination of Cohesion values of Rock Materials using Double Shear Jaws

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