Preprint Article Version 1 This version is not peer-reviewed

Strength Design in Avoiding Engineering Disasters Based on the Mechanical Characteristics of Red Sandstone with Different Numbers of Pre-Existing Fissures

Version 1 : Received: 14 January 2018 / Approved: 16 January 2018 / Online: 16 January 2018 (10:48:13 CET)

How to cite: Wu, J.; Feng, M.; Zhang, W.; Chen, Z.; Han, G. Strength Design in Avoiding Engineering Disasters Based on the Mechanical Characteristics of Red Sandstone with Different Numbers of Pre-Existing Fissures. Preprints 2018, 2018010141 (doi: 10.20944/preprints201801.0141.v1). Wu, J.; Feng, M.; Zhang, W.; Chen, Z.; Han, G. Strength Design in Avoiding Engineering Disasters Based on the Mechanical Characteristics of Red Sandstone with Different Numbers of Pre-Existing Fissures. Preprints 2018, 2018010141 (doi: 10.20944/preprints201801.0141.v1).

Abstract

It is important to study the mechanical properties of cracked rock to understand the engineering behavior of cracked rock mass and avoid the engineering disasters. Consequently, the influence of the number of pre-existing fissures on the strength, deformation and acoustic emission (AE) characteristics of cracked rock specimen was analyzed, and the optimal selection of strength parameter in engineering design was discussed. The results show that the strength parameters (stress of dilatancy onset and uniaxial compressive strength) and axial deformation parameters (axial strain of dilatancy onset and axial peak strain) of cracked rock specimen decrease with the increase of the number of pre-existing fissures, and the relations which can use the negative exponential function to fit. Compared with the intact rock specimens, the different degrees of stress drop phenomena were produced in the cd-c stage of cracked rock specimens under loading. At this moment, the cracked rock specimens with the existence of stress drop are not instantaneous failure, but the circumferential strain, volumetric strain and AE signals increase burstingly. And the time and axial stress of this point occurred with stress drop decrease with the increase of number of pre-existing fissures, the relations which can use the negative exponential function to fit. It is noteworthy that the stress of dilatancy onset and its corresponding time are always ahead of the stress and the time of that point with the existence of stress drop. It indicates that the stress of dilatancy onset can be as the parameter of strength design in rock engineering, which can effectively prevent the large deformation of rock.

Subject Areas

rock mechanics; pre-existing fissures; strength; deformation; dilatancy behavior

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