FREE CONVECTION OF PORE WATER IN SATURATED PERMEABLE ROCK MASS DURING ARTIFICIAL FREEZING

2020 ◽  
Author(s):  
Mikhail Semin ◽  
Lev Levin
Keyword(s):  
Rock Mass ◽  
Free Convection ◽  
Pore Water ◽  
Permeable Rock ◽  
Artificial Freezing

Influence of Groundwater Seepage on Artificial Freezing of Rock Mass

2021 ◽  
Vol 94 (1) ◽  
pp. 45-55
Author(s):  
M. A. Semin ◽  
L. Yu. Levin ◽  
O. S. Parshakov
Keyword(s):  
Rock Mass ◽  
Groundwater Seepage ◽  
Artificial Freezing

scholarly journals Mechanism of Fracturing in Shaft Lining Caused by High-Pressure Pore Water in Stable Rock Strata

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jihuan Han ◽  
Jiuqun Zou ◽  
Weihao Yang ◽  
Chenchen Hu
Keyword(s):  
High Pressure ◽  
Rock Mass ◽  
Pore Water ◽  
Expansion Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Shaft Lining ◽  
Rock Strata ◽  
Expansion Effect

With the increase in shaft depth, the problem of cracks and leakage in single-layer concrete lining in porous water-rich stable rock strata has become increasingly clear, in which case the mechanism of fracturing in shaft lining remains unclear. Considering that the increase in pore water pressure can cause rock mass expansion, this paper presents the concept of hydraulic expansion coefficient. First, a cubic model containing spherical pores is established for studying hydraulic expansion, and the ANSYS numerical simulation, a finite element numerical method, was used for calculating the volume change of the model under the pore water pressure. By means of the multivariate nonlinear regression method, the regression equation of the hydraulic expansion coefficient is obtained. Second, based on the hydraulic expansion effect on the rock mass, an interaction model of pore water pressure–porous rock–shaft lining is established and further solved. Consequently, the mechanism of fracturing in shaft lining caused by high-pressure pore water is revealed. The results show that the hydraulic expansion effect on the surrounding rock increases with its porosity and decreases with its elastic modulus and Poisson’s ratio; the surrounding rock expansion caused by the change in pore water pressure can result in the outer edge of the lining peeling off from the surrounding rock and tensile fracturing at the inner edge. Therefore, the results have a considerable guiding significance for designing shaft lining through porous water-rich rock strata.

scholarly journals Effect of Wetting-Drying Cycle on the Deformation and Seepage Behaviors of Rock Masses around a Tunnel

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qingzhen Guo ◽  
Haijian Su ◽  
Hongwen Jing ◽  
Wenxin Zhu
Keyword(s):  
Rock Mass ◽  
Principal Stress ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Tunnel Excavation ◽  
Cycle Number ◽  
Simulation Results

Water inrush caused by the wetting-drying cycle is a difficult problem in tunnel excavation. To investigate the effect of the wetting-drying cycle on the stability of the tunnel surrounding rock, physical experiments and numerical simulations regarding the process of tunnel excavation with different wetting-drying cycle numbers were performed in this study. The evolutions of stress, displacement, and pore water pressure were analyzed. With the increase in cycle number, the pore water pressure, vertical stress, and top-bottom approach of the tunnel surrounding rock increase gradually. And the increasing process could be divided into three stages: slightly increasing stage, slowly increasing stage, and sharply increasing stage, respectively. The failure process of the surrounding rock under the wetting-drying cycle gradually occurs from the roof to side wall, while the baseplate changes slightly. The simulation results showed that the maximum principal stress in the surrounding rock mass of the tunnel increases, while the minimum principal stress decreases. Furthermore, the displacement of the rock mass decreases gradually with the increasing distance from the tunnel surface. By comparing the simulation results with the experimental results, well consistency is shown. The results in this study can provide helpful references for the safe excavation and scientific design of a tunnel under the wetting-drying cycle.

Natural Convection in Water-Saturated Rock Mass under Artificial Freezing

2020 ◽  
Vol 56 (2) ◽  
pp. 297-308
Author(s):  
M. A. Semin ◽  
L. Yu. Levin ◽  
M. S. Zhelnin ◽  
O. A. Plekhov
Keyword(s):  
Rock Mass ◽  
Natural Convection ◽  
Saturated Rock ◽  
Artificial Freezing ◽  
Water Saturated

scholarly journals Elastic-Plastic Numerical Analysis of Tunnel Stability Based on the Closest Point Projection Method Considering the Effect of Water Pressure

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Zhan-ping Song ◽  
Ten-tian Yang ◽  
An-nan Jiang
Keyword(s):  
Rock Mass ◽  
Numerical Analysis ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Tunnel Stability ◽  
Elastic Plastic ◽  
Closest Point Projection ◽  
Point Projection

To study the tunnel stability at various static water pressures and determine the mechanical properties and deformation behavior of surrounding rock, a modified effective stress formula was introduced into a numerical integration algorithm of elastic-plastic constitutive equation, that is, closest point projection method (CPPM). Taking the effects of water pressure and seepage into account, a CPPM-based formula was derived and a CPPM algorithm based on Drucker-Prager yield criterion considering the effect of pore water pressure was provided. On this basis, a CPPM-based elastic-plastic numerical analysis program considering pore water pressure was developed, which can be applied in the engineering of tunnels and other underground structures. The algorithm can accurately take the effects of groundwater on stability of surrounding rock mass into account and it can show the more pronounced effect of pore water pressure on stress, deformation, and the plastic zone in a tunnel. The stability of water flooding in Fusong tunnel was systematically analyzed using the developed program. The analysis results showed that the existence of groundwater seepage under tunnel construction will give rise to stress redistribution in the surrounding rock mass. Pore water pressure has a significant effect on the surrounding rock mass.

scholarly journals Study on the Variation Rule and Characteristics of Pore Water Pressure in the Failure Process of Saturated Rock

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yuezheng Zhang
Keyword(s):  
Rock Mass ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Failure Process ◽  
Engineering Practice ◽  
Surrounding Area ◽  
Saturated Rock ◽  
In Situ Conditions ◽  
Variation Rule

With the development of tunnels and other engineering constructions into the deep strata, rock masses are more prone to dynamic damage such as rock bursts under in situ conditions and excavation disturbances. The pore water in the rock mass will produce pressure changes during this process. According to the relationship between the change of pore water pressure and the development of rock mass damage, the variation rule and precursor characteristics of pore water pressure in the process of rock mass failure can be found. In this paper, through mechanical analysis, the evolution law of pore water pressure during the failure process of saturated rock is obtained. The study found that, in the process of rock failure, the pore water pressure presents three stages of linear growth, transition, and decrease. The rise and fall of pore water pressure are closely related to rock damage and influence each other. Through the observation of pore water pressure during coal mining, it is found that the coseismic effect of pore water pressure is significant. It is proved that there is a close correlation between the evolution of the stress field in the surrounding area of the stope and the change of pore water pressure in the surrounding area under the effect of mining disturbance. During the engineering practice, dynamic monitoring can be carried out on the change of pore water pressure inside the rock mass according to the law, and the precursor information of rock mass instability and failure can be explored.

scholarly journals Evaporation measurement to map the groundwater discharge on a tunnel wall of the low permeable rock mass. Part2. Field measurement.

1990 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Kunio WATANABE ◽  
Koichi YANAGISAWA ◽  
Roland PUSCH ◽  
Hideki SAKUMA ◽  
Toshiyuki AIZAWA ◽  
...  
Keyword(s):  
Rock Mass ◽  
Field Measurement ◽  
Groundwater Discharge ◽  
Tunnel Wall ◽  
Permeable Rock

scholarly journals Spatiotemporal Evolution Characteristics of Fluid Flow through Large-Scale 3D Rock Mass Containing Filling Joints: An Experimental and Numerical Study

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Qian Yin ◽  
Hongwen Jing ◽  
Tantan Zhu ◽  
Lizhou Wu ◽  
Haijian Su ◽  
...  
Keyword(s):  
Rock Mass ◽  
Flow Velocity ◽  
Pore Water ◽  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Spatiotemporal Evolution ◽  
Matrix Permeability ◽  
Evolution Characteristics ◽  
Joint Length

This study analyzes the spatiotemporal evolution characteristics of seepage through a large-scale rock mass containing a filling joint. Firstly, a conceptual model was established to characterize the geomechanical occurrence of a typical water-resistant slab adjacent to a water-bearing structure. Then, a special apparatus was developed to conduct a hydromechanical test of a 3D large-scale rock mass. For a certain boundary stress and inlet water pressure, the pore water pressure in the joint first experiences a dramatic increase before approaching a constant value, and the steady pore water pressure presents a linear decrease along the joint length. A water inrush phenomenon happens as a result of connected flowing channels induced by migration of fillings. Using the finite element of COMSOL multiphysics, the influences of filling joint permeability, matrix permeability, and joint thickness as well as the inlet water pressure on seepage evolution in the jointed rock mass were, respectively, investigated. The pore water pressure increases with all these factors, and the stable pressure values increase with the inlet water pressure but decrease along the joint length. The flow velocity undergoes an increase with both the joint permeability and inlet water pressure but presents constant values independent on the matrix permeability or joint thickness. The water pressure contour planes distributed along the flowing path generally transfer from a “long funnel” shape to a “short funnel” shape before reaching a series of parallel pressure planes perpendicular to the joint direction. By using the genetic algorithm, the coupling influences of these factors on the pore water pressure and flow velocity were investigated, and the decision parameters were optimized. The calculated values show a good agreement with the numerical results, indicating a good prediction of the seepage evolution through the filling joint.

scholarly journals Interpretation of Groundwater Inflow Testing from Imperfect Wells in Low-Permeable Rock Mass Considering a Flow in the Wellbore of a Perfect Observation Well Based on the Yeniseiskiy Site Case Study

2021 ◽  
Vol 16 (3) ◽  
pp. 61-71
Author(s):  
A. V. Rastorguev ◽  
◽  
G. D. Neuvazhaev ◽  
K. D. Smirnov ◽  
◽  
...  
Keyword(s):  
Rock Mass ◽  
Analytical Method ◽  
Three Dimensional ◽  
Observation Well ◽  
Groundwater Inflow ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Permeable Rock

The paper presents the processing of 2 cluster pumpings from imperfect wells inside a low-permeable rock mass. The processing was done using graphical-analytical method with three-dimensional modeling in GMS 10.4 software. The results obtained were analyzed and the interpretation methods of groundwater inflow testing (GIT) were compared. The paper identifies common patterns in the model GIT interpretation with some assumptions made on how to improve the processing of their results.

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