Road and railway tunnels in cold regions are often affected by problems related to water leakage and freezing temperatures. Water leakage in a tunnel leads to ice growth when the temperature goes below freezing and creates favourable environment for fallouts of shotcrete and rock. This paper presents results and observations from laboratory freezing – thawing experiments on rock blocks covered ...

It has been observed in field and laboratory conditions that failure of intact hard rocks at highly confined compression can be accompanied by abnormal violence. Under both of these conditions the failure process is associated with shear rupture development. David Ortlepp, who acquired more than 40 years of experience in the study of shear rupture rockbursts in deep and ultra-deep South African...

Underground rock masses have shown a general trend of natural balance over billions of years of ground movement. Nonetheless, man-made underground constructions disturb this balance and cause rock stability failure. Fractured rock masses are frequently encountered in underground constructions, and this study aims to restore the strength of rock masses that have experienced considerable fracturi...

a brief background to the development of the rock engineering design process is given, showing that since the development of the science of mathematics, deterministic methods have been used to perform various calculations. the variability of rock properties and support characteristics have always been known. however, they were not explicitly used in design but compensated for by the use of a sa...

This paper discusses Coulomb failure criteria for brittle deformation of intact rock and fault gouge. Data are presented from laboratory experiments designed to identify the critical gouge layer thickness required to effect a transition from the standard Coulomb criterion to a modified failure law (referred to as Coulomb plasticity) appropriate for simple shear of a gouge layer. Experiments wer...

Abstract To accurately predict coal burst hazards and estimate the failure of pillars in underground mining systems, it is great significance to understand mechanical behavior coal-rock bimaterial composite structures. This paper presents experimental numerical investigations on response rock-coal, coal-rock, rock-coal-rock structures under triaxial compression. The compression experiments are ...

This study aims to examine the performance of the rock materials in the protective layer of rubble-mound breakwaters in southern Iran, from Rostami Port in Bushehr Province to Beris Port in Sistan and Baluchestan Province. Field inspections were carried out on a great number of rubble-mound breakwaters built in the Persian Gulf and Oman Sea coastal regions to study the protective layer of these...

Some fundamental mechanisms associated with cooling/heating of the rock in the context of drilling and reservoir stimulation in enhanced geothermal systems are described. The role of temperature and pore pressure in wellbore failure and fracture width is considered using analytical and boundary element models. Results indicate that cooling induces a pore pressure drop inside the formation that ...

Joints and fissures in natural rocks have a significant influence on the stability of the rock mass, and it is often necessary to evaluate strength failure and crack evolution behavior. In this paper, based on experimental tests and numerical simulation (PFC2D), the macro-mechanical behavior and energy mechanism of jointed rock-like specimens with cross non-persistent joints under uniaxial load...

The small GTPase RhoA and its downstream target Rho kinase (Rho-associated coiled-coil protein kinase or ROCK) are involved in cell contraction and a variety of other cellular processes via modulation of actin cytoskeletal assembly. Several studies, including investigations in humans, have clearly shown an important pathophysiological role of this pathway in the cardiovascular system and in dis...