Measurement of Stiffness of Rock via Laboratory and Field Testing

Measurement of stiffness of rock by laboratory and field

checks

Naeem U. Abdulhadi & Amjad F. Barghouthi

Arab Center to get Engineering Studies (ACES)

SUBJECTIVE

This newspaper compares the deformation modulus of rock measured coming from laboratory and field assessments which were carried out as part of the site investigation functions for a major project in Irbid, Jordan. Laboratory resonant column and torsional shear tests had been performed by different limiting pressures whereas ultrasonic velocity tests were conducted upon unconfined ordinary specimens. Additionally , empirical human relationships were utilized for estimating the rock mass modulus making use of the outcomes of the uniaxial compression and point load strength checks. Field measurements comprised pressuremeter testing and also seismic geophysical methods including down-hole and crosshole tactics. The stationary and powerful in-situ tightness measurements were found to be reasonably in good agreement with the clinical values in the dynamic tests as well as empirical methods for price rock mass stiffness by uniaxial compressive strength benefits. INTRODUCTION

The modulus of deformation is undoubtedly the geomechanical parameter that best presents the mechanical behavior of rock mass. In particular, when it comes to underground excavations, this modulus becomes fundamental – long lasting type of design approach to be developed. Lab measurements have long been the research standard to get determining the mechanical homes of geomaterials. In addition , discipline tests to compliment the geotechnical analysis and lab testing is now an expedient and cost-effective way to look for the strength and stiffness parameters over a whole site.

The key purpose of this paper is usually to present and compare the stiffness from static and dynamic checks determined inside the laboratory and field from a comprehensive and integrated web page investigation that has been carried out by Arab Center pertaining to Engineering Research (ACES) for any major task in Irbid, Jordan. The field assessments comprised pressuremeter as well as seismic geophysical methods including down-hole and cross-hole techniques. However, the lab dynamic checks involved ultrasonic velocity, resonant column and torsional shear testing. In addition , uniaxial compression tests had been carried out in which the stiffness was estimated from your compressive strength results employing well-established scientific relationships.

RIGIDITY

The deformation constants of any material are the most important parameters in any style and their willpower involves the application of measuring techniques both to get load and deformation. The amount of deformation that a lot of of the rubble undergo is very small and the measurement requires special approaches. Deformation is identified as changes in form (expansion, contraction, or other designs of distortion). It happens usually in answer to an used load or perhaps stress, it also may result via a change in temperature (thermal expansion or perhaps contraction) or water content (swelling or perhaps shrinkage). Deformability describes the ease which rock can he deformed, and

its inverse, stiffness, the resistance to deformation. Deformability, like power, depends generally on the porosity and the amount of jointing of the rock under test. Follicles and important joints are the weakest and most deformable elements in the rock. Elements influencing ordinary deformability happen to be drying and vibration effects from blasting.

The rock mass deformations are determined by means of modulus of suppleness values while obtained from laboratory tests about rock primary specimens. In general, laboratory rock specimen test results will not represent the in-situ real estate of the general rock mass. This limitation has led to the introduction of several stationary and active field methods. To define the quality of the rock people based on mountain mechanics variables, both field and laboratory test effects should be utilized in the design. Based upon the...

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