Subcritical crack growth of edge and center cracks in. Implications for subcritical crack growth, international journal of solids and structures on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. For silicate rocks, subcritical crack growth has been investigated by various researchers. This slow fracturing process may lead to an accelerating crack velocity and to a sudden unstable failure event. Tkk dissertations 128 fracture mechanics and subcritical crack growth approach to model timedependent failure in brittle rock. Kenny due to high volumes of traffic at this time we are experiencing some slowness on the site. Olson, and zeno philip department of petroleum and geosystems engineering, university of texas at austin abstract. Numerical simulations of fracture patterns are sensitive to the subcritical crack growth index, the exponent used to describe the power law dependence of crack velocity on stress intensity. Subcritical crack growth in rocks under shear loading ko 2011. About cookies, including instructions on how to turn off cookies if you wish to do so. Subcritical crack growth plays an important role in evaluating the longterm stability of structures in rocks. Subcritical crack growth is one of the main causes of timedependent behavior in rocks. Subcritical crack growth is one of the main causes of timedependent fracturing in rock.
By continuing to browse this site you agree to us using cookies as described in. Specifically, influence of surrounding environment on subcritical crack growth in carbonate rock should be clarified to ensure the longterm stability of a rock mass. Fracture mechanics and subcritical crack growth approach to model timedependent failure in brittle rock mikael rinne. Evaluating longterm strength of rock under changing. Subcritical crack growth in oxide and nonoxide ceramics. The kv data are presented in terms of an equation in. Sub critical crack growth in anisotropic rock sub critical crack growth in anisotropic rock nara, y kaneko, k. The orthorhombic elastic properties of granite, caused by the preferred orientation of preexisting microcracks, were used to estimate the crack.
Critical crack length for fast fracture sub critical crack growth. Read determination of the subcritical crack growth parameters in rocks using the constant stressrate test, international journal of rock mechanics and mining sciences on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Pdf influence of relative humidity on fracture toughness of rock. International journal of distributed timedependent behavior. Experimental determination of subcritical crack growth parameters in sedimentary rock. Timedependent behavior of subcritical crack growth for. Pdf experimental determination of subcritical crack growth. Dissertation for the degree of doctor of science in technology to be presented with due permission of the faculty of engineering and architecture for public examination and debate in auditorium v1 at helsinki university of technology espoo, finland on the 7 th of august. Microcrack angle is a significant parameter in theoretical an however, it. Subcritical crack growth and other time and environment. The science of fracture mechanics provides a logical framework for understanding the effect of subcritical crack growth on structural ceramics and for predicting lifetime. Pdf subcritical crack growth in rocks in an aqueous. Sub critical crack growth in highly stressed formula 1 race car composite suspension components gary savage honda racing f1 team abstract one of the many advantages in the use of composite materials in engineering structures is their resistance to fatigue. In this study, subcritical crack growth in marble was investigated experimentally, focusing on the influence of the surrounding.
Testing study of subcritical crack growth mechanism during water rock interaction article in geotechnical and geological engineering 344 may 2016 with 42 reads how we measure reads. Fracture mechanics and subcritical crack growth approach to. In the present study, we investigated subcritical crack growth in rock in distilled water ph 57 and in an aqueous solution of sodium hydroxide naohaq, ph 12, comparing the results to those in air. Scg is thought to play an important role in longterm rock stability at all scales, ranging from laboratory samples to earthquakegenerating faults. In this study, we investigate subcritical crack growth in carbonate rock experimentally using a fracture mechanics testing method. International journal of distributed timedependent. Timedependent behavior of subcritical crack growth for rock. Influence of relative humidity on fracture toughness of. Abstract the contributions of moisture to the mechanical aspects of rock weathering and regolith production are poorly quantified. Effects of water on subcritical crack growth monash. In this section the subcritical crack extension below the high temperature regime is considered. T1 a model for nonlinear rock deformation under compression due to sub critical crack growth. Subcritical crack growth and longterm strength in rock and. Subcritical crack growth usually results from a stressenhanced chemical interaction between the solid and moisture in the environment and has been observed in glasses, porcelains, oxides, silicate minerals and titanates.
Subcritical crack growth in singlecrystal silicon using micromachined specimens volume 17 issue 3 a. Effect of water on critical and subcritical fracture. Subcritical crack growth is one of key factor to cause the timedependent behavior of rock. To anticipate failure dynamics in rock slopes, it is a key requirement to reveal the influence of water on subcritical crack growth mechanisms and material properties. It is based on brittle fracture mechanics principles and the theory of subcritical crack growth stress corrosion. This is a timedependent phenomenon, where a crack is growing at constant load below k 1 k 1inst. Apr 01, 2006 sub critical crack growth in anisotropic rock sub critical crack growth in anisotropic rock nara, y kaneko, k. These results are similar to those derived for rock mechanical experiments interpreted using the mean field theory for subcritical crack growth based on a modified griffith criterion for a fractal. Highstrength and ultra lowpermeability concrete hsulpc is a strong candidate for a radioactive waste package containing transuranic radionuclides tru waste for geological disposal. Hence the crack length c was calculated from the compliance as a function of time t. Therefore, the knowledge of subcritical crack growth is important for evaluation of longterm stability of structures in rock mass.
Pdf subcritical crack growth in rocks in an aqueous environment. Mounting evidence suggests that subcritical crack growth is an important mechanism for the development of natural fractures. We conclude that crack growth in rock is affected by humidity, and that clay content is an important. We conclude that crack growth in rock is affected by humidity, and that clay content is an important contributing factor to changes in fracture toughness and subcritical stress intensity factor.
Subcritical crack growth in geological materials nasaads. Subcritical crack growth in anisotropic rock sciencedirect. Subcritical crack growth in anisotropic rock, international. Marble obtained in skopje in macedonia is used as a carbonate rock sample. This was likely as a result of stress corrosion having little influence on the fracture toughness.
Test of subcritical crack growth and fracture toughness under waterrock interaction in three types of rocks. However, as with all geochemical reactions, the effect of ph is dependent on the exact constituents of the solution and the mineral involved. A model for nonlinear rock deformation under compression. Fracture mechanics and subcritical crack growth approach. Based on the results of subcritical crack growth parameters estimations, we. The immediate strain response is attributed to the reduction of surface energy and diffusion of the water into the rock. Schultz geomechanics rock fracture group, geological engineering program, department of geological sciences172, mackay school of mines, university of nevada, reno, nv 89557, usa. This paper herein studies subcritical crack growth scg behavior of a perovskite. Timedependent behavior of subcritical crack growth is one of the main characteristics in rocks. Specifically, the effects of temperature, relative humidity and water were investigated. Thus, it is important to research the dependence of subcritical crack growth in rocks on the environmental condition. Experimental and numerical study haiping yuan1,2, feng wang1, yan liu3, hanbing bian4, wen chen4 and yixian wang1,5,6 abstract timedependent behavior of subcritical crack growth is one of the main characteristics in rocks. For brittle rock material the model suggests that stable wingcrack propagation takes place under an increasing uniaxial load prior to crack coalescence and.
By using the results of subcritical crack growth measurements, the longterm strength of rock and. Canada rock mechanics symposium, asheville, nc june 28th july 1, 2009. Subcritical crack growth in rock also appears to be ph dependent. In the case of silicate materials, stress corrosion is a weakening process due to a chemical reaction between the strong siloxane bond structure near the crack tip. The double torsion method is used to measure the crack velocity and stress intensity factor. Subcritical crack growth scg is one of the main causes of. Due to the lack of experimental data, only subcritical crack growth is considered next. This subcritical crack propagation continues until a critical crack size is attained and the rock panel will fail under wind load.
A major problem with subcritical crack testing in weaker rocks such as sandstone is that nonelastic material behavior such as the breaking of intergranular cement can obscure crackrelated behavior. In the present study, we investigated subcritical crack growth in rock in distilled water ph57 and in an aqueous solution of sodium hydroxide naohaq, ph12, comparing the results to those in air. In this study, the subcritical crack growth parameters were estimated under various environmental conditions on igneous rocks andesite and granite using the doubletorsion method. Yantu lixue rock and soil mechanics, 299, 2527 2530. In the present study, we investigated subcritical crack growth in rock in distilled water ph57 and in. Subcritical crack growth in rocks in an aqueous environment. Especially, the influence of the temperature, relative humidity and water on subcritical crack growth in marble.
Knowledge of the timedependent fracturing of hsulpc and surrounding rock mass is essential to assess the longterm stability of such underground repositories. Aug 26, 2016 subcritical crack growth also leads to a time dependence of the strength, the slower the loading rate, the weaker the material. Effects of water on subcritical crack growth monash university. Seal integrity of cap rock is a critical constraint on the long term performance of co2 containment site. In this study, subcritical crack growth in rock and hsulpc was investigated. In particular, geomorphologists have largely overlooked the role of subcritical crack growth processes in physical weathering and the fact that moisture strongly influences the rates of those processes. Subcritical crack growth and longterm strength in rock. In this study, the subcritical crack growth parameters were estimated under various environmental conditions on igneous rocks. Experimental data are presented on stress corrosion in tensile deformation of quartz, quartz rocks, calcite rocks, basaltic rocks, granitic rocks and other geological. Testing study of subcritical crack growth mechanism during.
Subcritical crack growth and mechanical weathering. In spite of the monotonic increase of the externally applied stress intensity factor due to crack extension, the crack growth rates first decrease. The nonelastic transient load varia tions are often difficult to separate from those due to crack growth. Subcritical crack growth in zirconiatoughened alumina zta. Subcritical crack growth in a chemically reactive environment. Subcritical dyke propagation in a host rock with temperature. The aim is to predict scc attributes that existed in the past for use in geomechanical modeling of fracture growth. These results are similar to those derived for rock mechanical experiments interpreted using the mean field theory for subcritical crack growth based on a. Influence of temperature and water on subcritical crack growth parameters and longterm strength for igneous rocks. Test of subcritical crack growth and fracture toughness. The existing numerical simulation results did not involve time. In this study, the subcritical crack growth parameters for coconino sandstone under modes ii and iii loading were determined experimentally by. A schultz, growth of geologic fractures into largestrain populations. Influence of surrounding environment on subcritical crack.
Subcritical crack growth of edge and center cracks in facade. Subcritical crack growth and progressive failure in carrara. Experimental determination of subcritical crack growth. In this paper, we examine the effects of temperaturedependent viscoelastic properties of the host rock on the subcritical growth of a dyke from a mag. It is known that subcritical crack growth is affected by the environmental condition. Test of subcritical crack growth and fracture toughness under water. This slow fracturing process may lead to an accelerating crack velocity and to a. To study subcritical crack growth in rock, most researchers have used the power law. Subcritical crack growth scg takes place when a crack is stressed below its shortterm strength. To calculate structure lifetime, the rate of creep growth of a subcritical crack must be known. Research into the effects of micromechanical parameters on. Subcritical crack growth and the evolution of localized intergranular fractures are enhanced if water is present and readily approach tertiary creep when loaded above 80%. Subcritical crack growth plays an important role for longterm creep failure in brittle rock.
Frac is compiling subcritical crack index measurements and linking results to rock microstructure observations, and diagenesis predictions. Researchers led by professor yoshitaka nara at kyoto university in japan developed a new technique to evaluate the longterm strength of rock under changing environmental conditions, with a focus on the influence of water on subcritical crack growth in rocks. Analysis of crack path for subcritical crack growth in rocks. Subcritical crack growth also leads to a time dependence of the strength, the slower the loading rate, the weaker the material. Influence of water on subcritical crack growth and long. The main parameters describing subcritical crack growth are the critical stress intensity factor k c, the subcritical crack growth limit k o, and the stress intensity factor crack velocity kv relationship between k o and k c. Mechanisms controlling rupture shape during subcritical. The results show that waterrock interaction has a significant influence on subcritical crack growth. In the present study, we investigated subcritical crack growth in rock in.
Laboratory results using the double torsion test suggest that the subcritical index, a material property, is a function of grain size, cement volume, porosity and mineralogy. With waterrock interaction, the crack velocity increases, while the stress intensity factor declines, which illustrates that waterrock interaction can decrease the strength of rocks and accelerate the subcritical crack growth. Subcritical crack growth of edge and center cracks in facade rock. Subcritical crack growth in geological materials wiley. Dependence of subcritical crack growth on rock fabric and. Subcritical crack growth has been identified as an important mechanism for natural fracture growth in rock. We also investigated the effect of the ph in an aqueous environment. Mainly, the relations between crack velocity and stress intensity factor were investigated experimentally. Subcritical crack growth in singlecrystal silicon using. Slow, subcritical crack growth in rock is associated with distinctive changes in fracture population geometry, as shown by published numerical simulations of fracturenetwork evolution. Subcritical crack growth of macroscopic cracks in two al 2 o 3 ceramics is investigated with single. Subcritical crack growth in rocks under shear loading.
Studies of subcritical crack growth have been widely conducted for silicate rocks such as. Understanding subcritical crack growth in rock is essential for determining appropriate measures to ensure the longterm integrity of rock masses surrounding structures and for construction from rock material. Under low homologous temperatures and atmospheric pressure, stress corrosion is the main mechanism for subcritical crack growth in rocks. Fracture mechanics and subcritical crack growth approach to model. Subcritical crack growth in oxide and nonoxide ceramics using the constant stress rate test agnieszka wojteczko. Our concept of progressive rock slope failures is on the one hand embedded in aggregated subcritical crack growth mechanisms and on the other sensitive to environmental conditions, especially water.
In the present study, we investigated subcritical crack growth in rock in distilled water ph 5. Evidence for subcritical rupture of injectioninduced. It has been clarified that surrounding environmental conditions temperature, humidity, and existence of water have strong influence on subcritical crack growth in silicate rocks. Influence of temperature and water on subcritical crack. Growth of geologic fractures into largestrain populations. Influence of relative humidity on fracture toughness of rock. Timedependent behavior of subcritical crack growth for rock plate. In quartz this is especially the case at low stress intensity values, where crack velocities are significantly higher in basic water atkinson and meredith, 1981. Some statistical aspects of constant stressrate testing for subcritical crack growth, proceedings of the 43rd us rock mechanics symposium and 4th u. In this study, subcritical crack growth in marble was investigated. A timedependent crack growth model is developed to evaluate the delayed failure of a loaded rock. In the present study, we investigated subcritical crack.
The doubletorsion test is commonly used to study the slow crack growth behavior of brittle and quas. Sep 15, 2012 read influence of relative humidity on fracture toughness of rock. A third type of crack extension is called subcritical crack extension. Influence of water on subcritical crack growth and longterm. Studies of crack propagation in glass under vacuum have shown that subcritical cracking is possible even in the absence of chemical. Scg can be detected as rock loosening or as sudden rock movements around excavations. In this paper, the experimental results of the doubletorsion dt test and crack observation are presented, and the. Subcritical crack growth and longterm strength in rock and cementitious material yoshitaka nara1, 2, masafumi takada3, daisuke mori4, hitoshi owada5, tetsuro yoneda1, katsuhiko kaneko1 1 graduate school of engineering, hokkaido university, kita nishi 8, kitaku, sapporo 0608628, japan. N2 time dependency in rock deformation under compression is modelled by considering an elastic body containing cracks that grow under compressive stresses due to sub critical crack growth.
Subcritical crack growth rate under different chemical environment conditions is examined and compared with the experimental fracture mechanics testing. Subcritical crack growth and progressive failure in. Because subcritical crack growth in rocks was mainly studied in the context of geophysics and geology, fatigue cracking in rock has largely been neglected. Wiederhorn, 1972, a changing effective stiffness of the rock as joints propagate segall, 1984a, the increasing compressibility of individual cracks as they grow. It is known that subcritical crack growth is influenced by not only stress but also surrounding environment.
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