Engineering Properties of Rocks

Bell, F. G.

doi:10.1016/b978-0-408-01457-1.50011-3

Cited by 61 publications

(101 citation statements)

References 26 publications

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“…Since dikes observed in Miyake-jima are located near the surface and dissect mostly soft pyroclastic layers, we assume the low Young's modulus (E) of 1 GPa as well as a Poisson's ratio (v) of 0.25 for the host rock [e.g., Bell, 2000;Geshi et al, 2010]. From the aspect ratios and these elastic parameters, we obtained the magma overpressure values in Figure 4 and Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…We can measure the elastic constants of the host rock or estimate their typical values from tables in textbooks and/or data handbooks [e.g., Bell, 2000;Lama and Vutukuri, 1978]. However, in general, it is difficult to determine the center and/or the total length of a dike since only parts of most dikes can be observed and measured in the field [e.g., Gudmundsson, 1984;Gudmundsson et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

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Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

Kusumoto

Geshi

Guðmundsson

2013

Geophysical Research Letters

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[1] We present a new method for estimating the length and maximum thickness (aperture) of a dike from the observed opening at one dike tip. We apply the method to 15 arrested non-feeder dikes (where the upper tip is known, the lower tip unknown) in the caldera walls of Miyake-jima, Japan, to estimate the length-thickness ratio, as well as the magma overpressure and fracture toughness. The calculated length-thickness ratio ranges from 61 to 246, with an average of 136. The ratios are low because the dikes are emplaced close to the surface in comparatively compliant (soft) rocks. Using these ratios and the appropriate elastic constants, the calculated magmatic overpressures of the dikes are between 2.3 and 8.9 MPa, and the stress intensity factors between 38 and 117 MPa m 1/2 . All these values are within the range of typical in situ estimates, supporting the validity of this new method. Citation: Kusumoto S., N.Geshi, and A. Gudmundsson (2013), Aspect ratios and magma overpressures of non-feeder dikes observed in the Miyake-jima volcano (Japan), and fracture toughness of its upper part,

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

Kusumoto

Geshi

Guðmundsson

2013

Geophysical Research Letters

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“…Shear strength of unweathered gault clay was equal to the undrained shear strength which was equal to 56 kPa under worst case conditions since the minimum Factor of Safety needs to be evaluated [11]. The same assumptions were made thus a homogeneous gault clay along the profile of the slope was examined.…”

Section: Case Study: Gault Clay-poplar Treementioning

confidence: 99%

“…Moreover, the undrained slope 16 to 23 degrees were entered in the software. Material properties of unweathered Gault Clay for worst case conditions were taken from Bell [11]. Moreover, a parametric study for b j parameter was conducted since a minimum, an average and a maximum value of it were taken.…”

Section: Case Study: Gault Clay-poplar Treementioning

confidence: 99%

Slope Stability and Vegetation

Charlafti¹

2014

J Archit Eng Tech

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This study explores issues related to vegetation effects in slope stability analysis. The main objective of this research was to assess the influences of suction in the stability of slopes. A slope inclination of 1:2 was tested in all cases using SLOPE/W which is sophisticated software with useful features, including suction parameter. Therefore, slope stability analysis was achieved with the usage of this sophisticated software so as to simplify the mathematical processes which are time-consuming. The analysis was based on the Mohr-Coulomb equation arranged appropriately so as to include suction effects. Field measurements recorded by Biddle for mature trees placed on clay subsoil were used to measure the suction effects for each case. Overall, a satisfactory association between field data and results was achieved. For the cases considered, it was indicated that moderately small suction changes from 18 to 39 kPa can influence the safety factor against failure of the slope. All of the analyses showed that the slope model was stable in each case, since safety factor ranged from 1.689 to 4.750. Under undrained conditions Gault clay was found to have a minimum safety factor of 2.553. Suction effects were found to increase the stability of slopes. In the unsaturated analysis, it was found that as b j increased the FOS also increased. Moreover, London clay was found to have a minimum FOS of 2.303 when tested with the effects of matric suction.cohesive and consequently τ f =c u where τ f is the shear strength of the soil. Vegetation effects were not taken into account in this type of analysis, since vegetation is correlated with suction and root strength.The fact that clay is purely cohesive under undrained conditions means that no drainage is allowed [2]. According to Craig, circular slips are associated with homogeneous and isotropic conditions of the soil. Failure of the slope could occur because of the weight of the soil above the slip surface. Finally, undrained shear strength ( u c ) was found for the three soil types (Boulder clay, Gault clay and London clay). Due to the fact that the aim of this dissertation is to estimate the minimum safety factor, worst case scenarios were taken into consideration, therefore the worst values of ( u c ) were chosen. Method of slices (Bishop's Simplified Method)Bishop's simplified method was used to analyse the stability of slopes for the next two stages where the cases of unsaturated clays were taken into account. The assumption made in this method is that the tangential interslice forces are equal and oppose each other thus

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“…Water plays a fundamental role in the phenomena of material decay and its presence favours different decay mechanisms, including salt weathering, freeze-thaw action, hydric swelling, material dissolution and biodeterioration. Moreover, the presence of a film of water may decrease the free surface energy of the material, weakening it (Bell 2000). This is particularly true in rocks, which contain clay minerals, where water may alter the structure of the material, causing swelling, stress and fractures (Jime´nez Gonza´lez and Scherer 2004;Steindlberger 2004;Weiss et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Experimental definition of microclimatic conditions based on water transfer and porous media properties for the conservation of prehistoric constructions: Cueva Pintada at Galdar, Gran Canaria, Spain

et al. 2008

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Microclimatic parameters and natural materials were studied in order to assess conservation of the cave complex at Galdar, Gran Canaria. Based on the microclimatic data, experimental simulations were carried out to quantify water retention capacity and water vapour transport kinetics under continuously changing extreme temperatures and relative humidity values. The behaviour of natural construction materials is greatly influenced by changes in thermo-hygrometric conditions and is linked to pore structure. The host rock has a complex porous media: high porosity and polymodal pore size distribution, where the smallest pores contribute to water condensation, whilst large pores lead to high water absorption rates. The axial compressive strength of the host-rock decreases between 30 and 70% at water saturation. Stuccos covering cave wall paintings are formed by clay minerals, mainly smectites. These clay minerals cover a large specific surface area, which leads to a high capacity for water condensation and retention. It is also shown that neither water condensation nor vapour transport are noticeably modified by the presence of stucco on the host-rock when rapid, highly variable changes occur in environmental conditions if large shrinkage cracks are present. Results show that safe threshold microclimatic conditions can be found below 75% RH in the natural temperature range and that slight variations in temperature and relative humidity do not modify durability properties.

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Engineering Properties of Rocks

Cited by 61 publications

References 26 publications

Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

Aspect ratios and magma overpressures of non‐feeder dikes observed in the Miyake‐jima volcano (Japan), and fracture toughness of its upper part

Slope Stability and Vegetation

Experimental definition of microclimatic conditions based on water transfer and porous media properties for the conservation of prehistoric constructions: Cueva Pintada at Galdar, Gran Canaria, Spain

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