scholarly journals Features of formation of karst falls on the earth’s surface

2020 ◽  
Vol 192 ◽  
pp. 01012
Author(s):  
Vitaly Trofimov ◽  
Ivan Shipovskii

Karst manifestations are widespread in many regions and pose a significant danger to residence and economic activity. Failing funnels arise during the collapse of rocks over underground voids (caves, workings, etc.), formed during karst formation or in the process of anthropogenic doing in the rock massive. However, not every karst or technogenic cavity gives rise to a failure of the earth’s surface, and as a rule, its occurrence is unexpected. In this work, we consider the dynamics of the formation of dips of the earth’s surface in the form of a collapse pipe. To do this, the geomechanical problem is solved by the meshless code Smoothed Particle Hydrodynamics (SPH). The method allows to obtain a solution to the problem taking into account large deformations and possible discontinuities in the process of changing the stress-strain state. The Drucker-Prager fracture criterion is used, the parameters of which change over time in accordance with the accumulation of damage, which determines the temporary development of the fracture process, its beginning and speed. Various options for the formation of a vertical dip are considered depending on the geometrical parameters of the initial cavity, its depth and materials composing the rock mass, as well as the features of the destruction of various materials composing the mass during the formation of the dip. Relations are obtained that relate the depth of the cavity, the horizontal size of the hole, the strength properties of the rocks (adhesion, angle of internal friction), the coefficient of lateral pressure in the array. The features of wave processes generated by the formation of a dip are considered, for which a velocity field is obtained near the fracture zone at various time points in the fracture process.

Author(s):  
Виталий Алексанрович Трофимов ◽  
Иван Евгеньевич Шиповский

Карстовые проявления широко распространены во многих регионах и представляют значительную опасность для проживания и хозяйственной деятельности. Воронки возникают при обрушении горных пород над подземными пустотами (пещерами, выработками и т.д.), образовавшимися при карстовом процессе или в результате антропогенного воздействия в массиве горных пород. Однако не каждая карстовая или техногенная полость приводит к разрушению земной поверхности, и, как правило, ее возникновение является неожиданным. В данной работе рассматривается динамика формирования провалов земной поверхности в виде карстовой воронки. Для этого с помощью бессеточного метода сглаженных частиц (SPH) решается геомеханическая задача. Выбранный численный метод позволяет получить решение задачи с учетом больших деформаций и возможных разрушений в процессе изменения напряженно-деформированного состояния. Используется критерий разрушения Друккера-Прагера, параметры которого со временем меняются в соответствии с накоплением повреждений, которые определяют временное развитие процесса разрушения, его начало и скорость. Karst manifestations are widespread in many regions and pose a significant danger to residence and economic activity. Failing funnels arise during the collapse of rocks over underground voids (caves, workings, etc.), formed during karst formation or in the process of anthropogenic doing in the rock massive. However, not every karst or technogenic cavity gives rise to a failure of the earth’s surface, and as a rule, its occurrence is unexpected. In this work, we consider the dynamics of the formation of dips of the earth’s surface in the form of a collapse pipe. To do this, the geomechanical problem is solved by the meshless code Smoothed Particle Hydrodynamics (SPH). The method allows to obtain a solution to the problem taking into account large deformations and possible discontinuities in the process of changing the stress-strain state. The Drucker-Prager fracture criterion is used, the parameters of which change over time in accordance with the accumulation of damage, which determines the temporary development of the fracture process, its beginning and speed.


2009 ◽  
Vol 36 (7) ◽  
pp. 1133-1143 ◽  
Author(s):  
Simon Nolin ◽  
Varvara Roubtsova ◽  
Brian Morse ◽  
Tung Quach

This article presents a numerical public domain model, SPIKI, to simulate water and ice dynamics during ice-jam formation and river breakup events. The model has two independent coupled components. The first is a one-dimensional (1-D) finite volume Saint-Venant hydrodynamic model, whereas the second is a two-dimensional (2-D) model called smoothed particle hydrodynamics (SPH) ice-rubble model that simulates ice dynamics. Application to an idealized test case demonstrated the effect of a variable angle of internal friction and the effect of ice-bank friction during the formation of an ice jam. Application to an actual event on the Saint John River in New Brunswick, Canada reproduced, within the certainty of the observed data, an observed ice-jam profile and the rise in water level and discharge after the release of the jam.


2008 ◽  
Vol 96 (6) ◽  
pp. 263-268 ◽  
Author(s):  
E. Mounif ◽  
V. Bellenger ◽  
A. Ammar ◽  
R. Ata ◽  
P. Mazabraud ◽  
...  

2020 ◽  
Vol 59 (40) ◽  
pp. 18236-18246
Author(s):  
Tianwen Dong ◽  
Yadong He ◽  
Jianchun Wu ◽  
Shiyu Jiang ◽  
Xingyuan Huang ◽  
...  

Author(s):  
Steven J. Lind ◽  
Benedict D. Rogers ◽  
Peter K. Stansby

This paper presents a review of the progress of smoothed particle hydrodynamics (SPH) towards high-order converged simulations. As a mesh-free Lagrangian method suitable for complex flows with interfaces and multiple phases, SPH has developed considerably in the past decade. While original applications were in astrophysics, early engineering applications showed the versatility and robustness of the method without emphasis on accuracy and convergence. The early method was of weakly compressible form resulting in noisy pressures due to spurious pressure waves. This was effectively removed in the incompressible (divergence-free) form which followed; since then the weakly compressible form has been advanced, reducing pressure noise. Now numerical convergence studies are standard. While the method is computationally demanding on conventional processors, it is well suited to parallel processing on massively parallel computing and graphics processing units. Applications are diverse and encompass wave–structure interaction, geophysical flows due to landslides, nuclear sludge flows, welding, gearbox flows and many others. In the state of the art, convergence is typically between the first- and second-order theoretical limits. Recent advances are improving convergence to fourth order (and higher) and these will also be outlined. This can be necessary to resolve multi-scale aspects of turbulent flow.


2013 ◽  
Vol 61 (1) ◽  
pp. 111-121 ◽  
Author(s):  
T. Jankowiak ◽  
T. Łodygowski

Abstract The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper


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