Ultimate Bearing Capacity of Rock Mass Foundations Subjected to Seepage Forces Using Modified Hoek–Brown Criterion

AlKhafaji, Hazim; Imani, Meysam; Fahimifar, Ahmad

doi:10.1007/s00603-019-01905-6

Cited by 32 publications

(7 citation statements)

References 19 publications

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“…Zou et al [23] derived theoretical solutions for a circular opening in an elastic-brittle-plastic rock mass incorporating the out-of-plane stress and seepage force. AlKhafaji et al [24] studied the bearing capacity problem of shallow rigid foundations on rock matrix subjected to horizontal seepage force.…”

Section: Introductionmentioning

confidence: 99%

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

et al. 2021

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As a fluid flows through a porous media, a drag force, called seepage force in the paper, will be formed on the matrix of the media in the fluid flowing direction. However, the seepage force is normally ignored in the analysis of wellbore fracturing during hydraulic fracturing operation. In this paper, an analytical model for seepage force around a vertical wellbore is presented based on linear elasticity theory, and the effect of the seepage force on wellbore breakdown has been analyzed. Also studied are the effects of the two horizontal principal stresses and the reservoir permeability on the action of seepage force. The paper proves that seepage force lowers formation breakdown pressure of a vertical wellbores; the deeper a formation is, the greater action of the seepage force; seepage force contributes more to breakdown formation with small difference of the two horizontal stresses such as unconventional reservoirs; seepage force increases as rock permeability decreases, and it should not be ignored in hydraulic fracturing analysis, especially for low-permeability formation.

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Section: Introductionmentioning

confidence: 99%

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

et al. 2021

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“…Recent studies have focused on the Hoek and Brown criteria, and the associated flow law is usually presented [25,26]. The use of numerical methods and the progress of computational geomechanics have allowed access to the practical calculation of more sophisticated bearing capacity problems, involving anisotropic rock masses [27], and the shape of the foundation [28,29] or the bilayer rock under the footing [30].…”

Section: Introductionmentioning

confidence: 99%

Bearing Capacity of Footings on Rock Masses Using Flow Laws

2021

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The influence of the non-associative flow law on the bearing capacity of shallow foundations on rock masses is, in general, a subject that is not discussed in the field of rock mechanics. The calculation methods of bearing capacity usually do not define which flow law is adopted and, in some methods, the associative flow rule is assumed without knowing how that hypothesis influences the bearing capacity of the rock mass. In this paper, the study of the influence of the dilatancy angle on the bearing capacity of shallow foundations on rock masses is presented. The variation of the bearing capacity with the associative flow law and the non-associative flow law with zero dilatancy angle is studied using the finite difference method and by considering the influence of the self-weight of rock material. The calculations confirm the great influence of the flow law on the bearing capacity and a correction coefficient is proposed, which makes it possible to estimate the variation of the bearing capacity of the rock mass in terms of the function of the flow law for the hypothesis of weightless rock masses.

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“…The simulation found that the weak layer with a large transverse Biot coefficient has a stronger SF, which leads to hydraulic fracturing to open branch fractures. By expressing the variation of SFs as a gradient ratio function, AlKhafaji et al 14 studied the bearing capacity problem of shallow rigid foundations on rock masses under the action of horizontal SFs. The results indicated that the larger the value of the gradient ratio is, the smaller the magnitude of the bearing capacity coefficients is.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic study on the effect of seepage force on hydraulic fracture initiation

Wang,

Zhou

2024

Fatigue Fract Eng Mat Struct

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The flow of fracturing fluid through rock pores generates a seepage force (SF) that disrupts the existing stress equilibrium and significantly affects rock deformation and failure. Despite its impact, the effect of SF on hydraulic fracture (HF) initiation has yet to be fully understood. In this study, a mechanistic model of SF's impact on fracture initiation was established through analysis of the force balance on a microscopic element. Using the finite difference method, a transient hydro‐mechanical model was developed to simulate fluid seepage‐induced stress distribution and pore pressure variation around a wellbore. Model results were validated through comparison with an analytical solution of pore pressure. The influence of SF on fracture initiation was investigated by conducting simulations with various wellbore pressurization rates and fracturing fluid viscosities. The results showed that fluid viscosity and pressurization rate have a significant impact on fracture initiation pressure (FIP) and SF‐induced circumferential stress. A larger SF‐induced circumferential stress and a lower FIP were observed when the viscosity and pressurization rate were smaller. A higher Biot coefficient results in stronger SF and reduced FIP. The theoretical mechanical model of seepage force established in this paper can provide crucial theoretical support for understanding the mechanism of fracture initiation and propagation, as well as for optimizing the effectiveness of hydraulic fracturing construction.

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Ultimate Bearing Capacity of Rock Mass Foundations Subjected to Seepage Forces Using Modified Hoek–Brown Criterion

Cited by 32 publications

References 19 publications

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

Bearing Capacity of Footings on Rock Masses Using Flow Laws

Mechanistic study on the effect of seepage force on hydraulic fracture initiation

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